Prizes for innovation of new medicines and vaccines.

PubMed

Love, James; Hubbard, Tim

2009-01-01

This article argues that prizes can help stimulate medical innovation, control costs and ensure greater access to new medicines and vaccines. The authors explore four increasingly ambitious prize options to reward medical innovation, each addressing flaws in the current patent system. The first option promotes innovation through a large prize fund linked to the impact on health outcomes; the second option rewards the sharing of knowledge, data, and technology with open source dividends; the third option awards prizes for interim benchmarks and discrete technical problems; and the final option removes the exclusive right to use patented inventions in upstream research in favor of prizes. The authors conclude that a system of prizes to reward drug development would break the link between R&D incentives and product prices, and that such a reform is needed to improve innovation and access to new medicines and vaccines.

Effects of emotion on prospection during decision-making.

PubMed

Worthy, Darrell A; Byrne, Kaileigh A; Fields, Sherecce

2014-01-01

In two experiments we examined the role of emotion, specifically worry, anxiety, and mood, on prospection during decision-making. Worry is a particularly relevant emotion to study in the context of prospection because high levels of worry may make individuals more aversive toward the uncertainty associated with the prospect of obtaining future improvements in rewards or states. Thus, high levels of worry might lead to reduced prospection during decision-making and enhance preference for immediate over delayed rewards. In Experiment 1 participants performed a two-choice dynamic decision-making task where they were required to choose between one option (the decreasing option) which provided larger immediate rewards but declines in future states, and another option (the increasing option) which provided smaller immediate rewards but improvements in future states, making it the optimal choice. High levels of worry were associated with poorer performance in the task. Additionally, fits of a sophisticated reinforcement-learning model that incorporated both reward-based and state-based information suggested that individuals reporting high levels of worry gave greater weight to the immediate rewards they would receive on each trial than to the degree to which each action would lead to improvements in their future state. In Experiment 2 we found that high levels of worry were associated with greater delay discounting using a standard delay discounting task. Combined, the results suggest that high levels of worry are associated with reduced prospection during decision-making. We attribute these results to high worriers' aversion toward the greater uncertainty associated with attempting to improve future rewards than to maximize immediate reward. These results have implications for researchers interested in the effects of emotion on cognition, and suggest that emotion strongly affects the focus on temporal outcomes during decision-making.

Modulation of Saccade Vigor during Value-Based Decision Making.

PubMed

Reppert, Thomas R; Lempert, Karolina M; Glimcher, Paul W; Shadmehr, Reza

2015-11-18

During value-based decision-making, individuals consider the various options and select the one that provides the maximum subjective value. Although the brain integrates abstract information to compute and compare these values, the only behavioral outcome is often the decision itself. However, if the options are visual stimuli, during deliberation the brain moves the eyes from one stimulus to the other. Previous work suggests that saccade vigor, i.e., peak velocity as a function of amplitude, is greater if reward is associated with the visual stimulus. This raises the possibility that vigor during the free viewing of options may be influenced by the valuation of each option. Here, humans chose between a small, immediate monetary reward and a larger but delayed reward. As the deliberation began, vigor was similar for the saccades made to the two options but diverged 0.5 s before decision time, becoming greater for the preferred option. This difference in vigor increased as a function of the difference in the subjective values that the participant assigned to the delayed and immediate options. After the decision was made, participants continued to gaze at the options, but with reduced vigor, making it possible to infer timing of the decision from the sudden drop in vigor. Therefore, the subjective value that the brain assigned to a stimulus during decision-making affected the motor system via the vigor with which the eyes moved toward that stimulus. We find that, as individuals deliberate between two rewarding options and arrive at a decision, the vigor with which they make saccades to each option reflects a real-time evaluation of that option. With deliberation, saccade vigor diverges between the two options, becoming greater for the option that the individual will eventually choose. The results suggest a shared element between the network that assigns value to a stimulus during the process of decision-making and the network that controls vigor of movements toward that stimulus. Copyright © 2015 the authors 0270-6474/15/3515369-10$15.00/0.

Modulation of Saccade Vigor during Value-Based Decision Making

PubMed Central

Lempert, Karolina M.; Glimcher, Paul W.; Shadmehr, Reza

2015-01-01

During value-based decision-making, individuals consider the various options and select the one that provides the maximum subjective value. Although the brain integrates abstract information to compute and compare these values, the only behavioral outcome is often the decision itself. However, if the options are visual stimuli, during deliberation the brain moves the eyes from one stimulus to the other. Previous work suggests that saccade vigor, i.e., peak velocity as a function of amplitude, is greater if reward is associated with the visual stimulus. This raises the possibility that vigor during the free viewing of options may be influenced by the valuation of each option. Here, humans chose between a small, immediate monetary reward and a larger but delayed reward. As the deliberation began, vigor was similar for the saccades made to the two options but diverged 0.5 s before decision time, becoming greater for the preferred option. This difference in vigor increased as a function of the difference in the subjective values that the participant assigned to the delayed and immediate options. After the decision was made, participants continued to gaze at the options, but with reduced vigor, making it possible to infer timing of the decision from the sudden drop in vigor. Therefore, the subjective value that the brain assigned to a stimulus during decision-making affected the motor system via the vigor with which the eyes moved toward that stimulus. SIGNIFICANCE STATEMENT We find that, as individuals deliberate between two rewarding options and arrive at a decision, the vigor with which they make saccades to each option reflects a real-time evaluation of that option. With deliberation, saccade vigor diverges between the two options, becoming greater for the option that the individual will eventually choose. The results suggest a shared element between the network that assigns value to a stimulus during the process of decision-making and the network that controls vigor of movements toward that stimulus. PMID:26586823

The influence of contextual reward statistics on risk preference

PubMed Central

Rigoli, Francesco; Rutledge, Robb B.; Dayan, Peter; Dolan, Raymond J.

2016-01-01

Decision theories mandate that organisms should adjust their behaviour in the light of the contextual reward statistics. We tested this notion using a gambling choice task involving distinct contexts with different reward distributions. The best fitting model of subjects' behaviour indicated that the subjective values of options depended on several factors, including a baseline gambling propensity, a gambling preference dependent on reward amount, and a contextual reward adaptation factor. Combining this behavioural model with simultaneous functional magnetic resonance imaging we probed neural responses in three key regions linked to reward and value, namely ventral tegmental area/substantia nigra (VTA/SN), ventromedial prefrontal cortex (vmPFC) and ventral striatum (VST). We show that activity in the VTA/SN reflected contextual reward statistics to the extent that context affected behaviour, activity in the vmPFC represented a value difference between chosen and unchosen options while VST responses reflected a non-linear mapping between the actual objective rewards and their subjective value. The findings highlight a multifaceted basis for choice behaviour with distinct mappings between components of this behaviour and value sensitive brain regions. PMID:26707890

Necessary Contributions of Human Frontal Lobe Subregions to Reward Learning in a Dynamic, Multidimensional Environment.

PubMed

Vaidya, Avinash R; Fellows, Lesley K

2016-09-21

Real-world decisions are typically made between options that vary along multiple dimensions, requiring prioritization of the important dimensions to support optimal choice. Learning in this setting depends on attributing decision outcomes to the dimensions with predictive relevance rather than to dimensions that are irrelevant and nonpredictive. This attribution problem is computationally challenging, and likely requires an interplay between selective attention and reward learning. Both these processes have been separately linked to the prefrontal cortex, but little is known about how they combine to support learning the reward value of multidimensional stimuli. Here, we examined the necessary contributions of frontal lobe subregions in attributing feedback to relevant and irrelevant dimensions on a trial-by-trial basis in humans. Patients with focal frontal lobe damage completed a demanding reward learning task where options varied on three dimensions, only one of which predicted reward. Participants with left lateral frontal lobe damage attributed rewards to irrelevant dimensions, rather than the relevant dimension. Damage to the ventromedial frontal lobe also impaired learning about the relevant dimension, but did not increase reward attribution to irrelevant dimensions. The results argue for distinct roles for these two regions in learning the value of multidimensional decision options under dynamic conditions, with the lateral frontal lobe required for selecting the relevant dimension to associate with reward, and the ventromedial frontal lobe required to learn the reward association itself. The real world is complex and multidimensional; how do we attribute rewards to predictive features when surrounded by competing cues? Here, we tested the critical involvement of human frontal lobe subregions in a probabilistic, multidimensional learning environment, asking whether focal lesions affected trial-by-trial attribution of feedback to relevant and irrelevant dimensions. The left lateral frontal lobe was required for filtering option dimensions to allow appropriate feedback attribution, while the ventromedial frontal lobe was necessary for learning the value of features in the relevant dimension. These findings argue that selective attention and associative learning processes mediated by anatomically distinct frontal lobe subregions are both critical for adaptive choice in more complex, ecologically valid settings. Copyright © 2016 the authors 0270-6474/16/369843-16$15.00/0.

Receptor-specific modulation of risk-based decision making by nucleus accumbens dopamine.

PubMed

Stopper, Colin M; Khayambashi, Shahin; Floresco, Stan B

2013-04-01

The nucleus accumbens (NAc) serves as an integral node within cortico-limbic circuitry that regulates various forms of cost-benefit decision making. The dopamine (DA) system has also been implicated in enabling organisms to overcome a variety of costs to obtain more valuable rewards. However, it remains unclear how DA activity within the NAc may regulate decision making involving reward uncertainty. This study investigated the contribution of different DA receptor subtypes in the NAc to risk-based decision making, assessed with a probabilistic discounting task. In well-trained rats, D1 receptor blockade with SCH 23,390 decreased preference for larger, uncertain rewards, which was associated with enhanced negative-feedback sensitivity (ie, an increased tendency to select a smaller/certain option after an unrewarded risky choice). Treatment with a D1 agonist (SKF 81,297) optimized decision making, increasing choice of the risky option when reward probability was high, and decreasing preference under low probability conditions. In stark contrast, neither blockade of NAc D2 receptors with eticlopride, nor stimulation of these receptors with quinpirole or bromocriptine influenced risky choice. In comparison, infusion of the D3-preferring agonist PD 128,907 decreased reward sensitivity and risky choice. Collectively, these results show that mesoaccumbens DA refines risk-reward decision biases via dissociable mechanisms recruiting D1 and D3, but not D2 receptors. D1 receptor activity mitigates the effect of reward omissions on subsequent choices to promote selection of reward options that may have greater long-term utility, whereas excessive D3 receptor activity blunts the impact that larger/uncertain rewards have in promoting riskier choices.

Cognitive influences on risk-seeking by rhesus macaques

PubMed Central

Hayden, Benjamin Y.; Heilbronner, Sarah R.; Nair, Amrita C.; Platt, Michael L.

2009-01-01

Humans and other animals are idiosyncratically sensitive to risk, either preferring or avoiding options having the same value but differing in uncertainty. Many explanations for risk sensitivity rely on the non-linear shape of a hypothesized utility curve. Because such models do not place any importance on uncertainty per se, utility curve-based accounts predict indifference between risky and riskless options that offer the same distribution of rewards. Here we show that monkeys strongly prefer uncertain gambles to alternating rewards with the same payoffs, demonstrating that uncertainty itself contributes to the appeal of risky options. Based on prior observations, we hypothesized that the appeal of the risky option is enhanced by the salience of the potential jackpot. To test this, we subtly manipulated payoffs in a second gambling task. We found that monkeys are more sensitive to small changes in the size of the large reward than to equivalent changes in the size of the small reward, indicating that they attend preferentially to the jackpots. Together, these results challenge utility curve-based accounts of risk sensitivity, and suggest that psychological factors, such as outcome salience and uncertainty itself, contribute to risky decision-making. PMID:19844596

Nucleus Accumbens Shell Dopamine Preferentially Tracks Information Related to Outcome Value of Reward.

PubMed

Sackett, Deirdre A; Saddoris, Michael P; Carelli, Regina M

2017-01-01

Effective decision-making requires organisms to predict reward values and bias behavior toward the best available option. The mesolimbic dopamine system, including the nucleus accumbens (NAc) shell and core, is involved in this process. Although studies support a role of the shell and core in specific aspects of decision-making (e.g., risk, effort, delay), no studies have directly compared dopamine release dynamics in these subregions to cues exclusively signaling the availability of different reward magnitudes. Here, fast-scan cyclic voltammetry was used to compare rapid dopamine release dynamics in the NAc subregions during a magnitude-based decision-making task. Rats learned that distinct cues signaled the availability of either a small or large reward (one or two sugar pellets), and then were given an opportunity to choose their preferred option. We found that peak dopamine release tracked the more preferred (higher-magnitude) option in both core and shell subregions. Critically, however, overall (i.e., global) dopamine release was significantly higher and longer lasting in the shell and tracked the preferred magnitude during the entire cue period. Further, in the shell (not core), dopamine signaling significantly declined immediately at the lever press for reward but increased during the period of reward consumption. Collectively, the results indicate that although dopamine release in both the core and shell are activated by cues signaling the opportunity to respond for rewards of different magnitudes, dopamine release in the shell plays a differential and unique role in tracking information related to the outcome value of reward.

[DNAStat, version 1.2 -- a software package for processing genetic profile databases and biostatistical calculations].

PubMed

Berent, Jarosław

2007-01-01

This paper presents the new DNAStat version 1.2 for processing genetic profile databases and biostatistical calculations. This new version contains, besides all the options of its predecessor 1.0, a calculation-results file export option in .xls format for Microsoft Office Excel, as well as the option of importing/exporting the population base of systems as .txt files for processing in Microsoft Notepad or EditPad

Propranolol reduces reference-dependence in intertemporal choice

PubMed Central

Lempert, Karolina M.; Lackovic, Sandra F.; Tobe, Russell H.; Glimcher, Paul W.

2017-01-01

Abstract In intertemporal choices between immediate and delayed rewards, people tend to prefer immediate rewards, often even when the delayed reward is larger. This is known as temporal discounting. It has been proposed that this tendency emerges because immediate rewards are more emotionally arousing than delayed rewards. However, in our previous research, we found no evidence for this but instead found that arousal responses (indexed with pupil dilation) in intertemporal choice are context-dependent. Specifically, arousal tracks the subjective value of the more variable reward option in the paradigm, whether it is immediate or delayed. Nevertheless, people tend to choose the less variable option in the choice task. In other words, their choices are reference-dependent and depend on variance in their recent history of offers. This suggests that there may be a causal relationship between reference-dependent choice and arousal, which we investigate here by reducing arousal pharmacologically using propranolol. Here, we show that propranolol reduces reference-dependence, leading to choices that are less influenced by recent history and more internally consistent. PMID:28992268

The effect of scopolamine on matching behavior and the estimation of relative reward magnitude.

PubMed

Leon, Matthew I; Rodriguez-Barrera, Vanessa; Amaya, Aldo

2017-10-01

We investigated the behavioral effects of scopolamine on rats that bar pressed for trains of electrically stimulating pulses under concurrent variable interval schedules of reward. For the first half of the session (30 min) a 1:4 ratio in the programmed number of stimulation trains delivered at each option was in effect. At the start of the second half of the session, an unsignaled reversal in the relative train number (4:1) occurred. We tracked the relative magnitude of reward estimated for each contiguous pair of reinforced visits to competing options. Scopolamine hydrobromide led to a reduction in the relative magnitude of reward. A similar result was obtained in a follow-up test in which relative magnitude was manipulated by varying the pulse frequency of stimulation, while equating the train number at each option. The effect of scopolamine hydrobromide could not be attributed to undermatching, side bias, nor to an effect of scopolamine on the reward integration process. When the same rats were treated with scopolamine methylbromide, no effects on matching behavior were observed. Our results suggest a cholinergic basis for the computation of choice variables related to matching behavior. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Technical options for processing additional light tight oil volumes within the United States

EIA Publications

2015-01-01

This report examines technical options for processing additional LTO volumes within the United States. Domestic processing of additional LTO would enable an increase in petroleum product exports from the United States, already the world’s largest net exporter of petroleum products. Unlike crude oil, products are not subject to export limitations or licensing requirements. While this is one possible approach to absorbing higher domestic LTO production in the absence of a relaxation of current limitations on crude exports, domestic LTO would have to be priced at a level required to encourage additional LTO runs at existing refinery units, debottlenecking, or possible additions of processing capacity.

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 2 2012-04-01 2012-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 2 2014-04-01 2014-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 2 2013-04-01 2013-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

State-based versus reward-based motivation in younger and older adults.

PubMed

Worthy, Darrell A; Cooper, Jessica A; Byrne, Kaileigh A; Gorlick, Marissa A; Maddox, W Todd

2014-12-01

Recent decision-making work has focused on a distinction between a habitual, model-free neural system that is motivated toward actions that lead directly to reward and a more computationally demanding goal-directed, model-based system that is motivated toward actions that improve one's future state. In this article, we examine how aging affects motivation toward reward-based versus state-based decision making. Participants performed tasks in which one type of option provided larger immediate rewards but the alternative type of option led to larger rewards on future trials, or improvements in state. We predicted that older adults would show a reduced preference for choices that led to improvements in state and a greater preference for choices that maximized immediate reward. We also predicted that fits from a hybrid reinforcement-learning model would indicate greater model-based strategy use in younger than in older adults. In line with these predictions, older adults selected the options that maximized reward more often than did younger adults in three of the four tasks, and modeling results suggested reduced model-based strategy use. In the task where older adults showed similar behavior to younger adults, our model-fitting results suggested that this was due to the utilization of a win-stay-lose-shift heuristic rather than a more complex model-based strategy. Additionally, within older adults, we found that model-based strategy use was positively correlated with memory measures from our neuropsychological test battery. We suggest that this shift from state-based to reward-based motivation may be due to age related declines in the neural structures needed for more computationally demanding model-based decision making.

Optimal decision making and matching are tied through diminishing returns

PubMed Central

2017-01-01

How individuals make decisions has been a matter of long-standing debate among economists and researchers in the life sciences. In economics, subjects are viewed as optimal decision makers who maximize their overall reward income. This framework has been widely influential, but requires a complete knowledge of the reward contingencies associated with a given choice situation. Psychologists and ecologists have observed that individuals tend to use a simpler “matching” strategy, distributing their behavior in proportion to relative rewards associated with their options. This article demonstrates that the two dominant frameworks of choice behavior are linked through the law of diminishing returns. The relatively simple matching can in fact provide maximal reward when the rewards associated with decision makers’ options saturate with the invested effort. Such saturating relationships between reward and effort are hallmarks of the law of diminishing returns. Given the prevalence of diminishing returns in nature and social settings, this finding can explain why humans and animals so commonly behave according to the matching law. The article underscores the importance of the law of diminishing returns in choice behavior. PMID:28739920

Optimal decision making and matching are tied through diminishing returns.

PubMed

Kubanek, Jan

2017-08-08

How individuals make decisions has been a matter of long-standing debate among economists and researchers in the life sciences. In economics, subjects are viewed as optimal decision makers who maximize their overall reward income. This framework has been widely influential, but requires a complete knowledge of the reward contingencies associated with a given choice situation. Psychologists and ecologists have observed that individuals tend to use a simpler "matching" strategy, distributing their behavior in proportion to relative rewards associated with their options. This article demonstrates that the two dominant frameworks of choice behavior are linked through the law of diminishing returns. The relatively simple matching can in fact provide maximal reward when the rewards associated with decision makers' options saturate with the invested effort. Such saturating relationships between reward and effort are hallmarks of the law of diminishing returns. Given the prevalence of diminishing returns in nature and social settings, this finding can explain why humans and animals so commonly behave according to the matching law. The article underscores the importance of the law of diminishing returns in choice behavior.

Stochastic satisficing account of confidence in uncertain value-based decisions

PubMed Central

Bahrami, Bahador; Keramati, Mehdi

2018-01-01

Every day we make choices under uncertainty; choosing what route to work or which queue in a supermarket to take, for example. It is unclear how outcome variance, e.g. uncertainty about waiting time in a queue, affects decisions and confidence when outcome is stochastic and continuous. How does one evaluate and choose between an option with unreliable but high expected reward, and an option with more certain but lower expected reward? Here we used an experimental design where two choices’ payoffs took continuous values, to examine the effect of outcome variance on decision and confidence. We found that our participants’ probability of choosing the good (high expected reward) option decreased when the good or the bad options’ payoffs were more variable. Their confidence ratings were affected by outcome variability, but only when choosing the good option. Unlike perceptual detection tasks, confidence ratings correlated only weakly with decisions’ time, but correlated with the consistency of trial-by-trial choices. Inspired by the satisficing heuristic, we propose a “stochastic satisficing” (SSAT) model for evaluating options with continuous uncertain outcomes. In this model, options are evaluated by their probability of exceeding an acceptability threshold, and confidence reports scale with the chosen option’s thus-defined satisficing probability. Participants’ decisions were best explained by an expected reward model, while the SSAT model provided the best prediction of decision confidence. We further tested and verified the predictions of this model in a second experiment. Our model and experimental results generalize the models of metacognition from perceptual detection tasks to continuous-value based decisions. Finally, we discuss how the stochastic satisficing account of decision confidence serves psychological and social purposes associated with the evaluation, communication and justification of decision-making. PMID:29621325

The Good, the Bad, and the Irrelevant: Neural Mechanisms of Learning Real and Hypothetical Rewards and Effort

PubMed Central

Kolling, Nils; Nelissen, Natalie; Wittmann, Marco K.; Harmer, Catherine J.; Rushworth, Matthew F. S.

2015-01-01

Natural environments are complex, and a single choice can lead to multiple outcomes. Agents should learn which outcomes are due to their choices and therefore relevant for future decisions and which are stochastic in ways common to all choices and therefore irrelevant for future decisions between options. We designed an experiment in which human participants learned the varying reward and effort magnitudes of two options and repeatedly chose between them. The reward associated with a choice was randomly real or hypothetical (i.e., participants only sometimes received the reward magnitude associated with the chosen option). The real/hypothetical nature of the reward on any one trial was, however, irrelevant for learning the longer-term values of the choices, and participants ought to have only focused on the informational content of the outcome and disregarded whether it was a real or hypothetical reward. However, we found that participants showed an irrational choice bias, preferring choices that had previously led, by chance, to a real reward in the last trial. Amygdala and ventromedial prefrontal activity was related to the way in which participants' choices were biased by real reward receipt. By contrast, activity in dorsal anterior cingulate cortex, frontal operculum/anterior insula, and especially lateral anterior prefrontal cortex was related to the degree to which participants resisted this bias and chose effectively in a manner guided by aspects of outcomes that had real and more sustained relationships with particular choices, suppressing irrelevant reward information for more optimal learning and decision making. SIGNIFICANCE STATEMENT In complex natural environments, a single choice can lead to multiple outcomes. Human agents should only learn from outcomes that are due to their choices, not from outcomes without such a relationship. We designed an experiment to measure learning about reward and effort magnitudes in an environment in which other features of the outcome were random and had no relationship with choice. We found that, although people could learn about reward magnitudes, they nevertheless were irrationally biased toward repeating certain choices as a function of the presence or absence of random reward features. Activity in different brain regions in the prefrontal cortex either reflected the bias or reflected resistance to the bias. PMID:26269633

Led into temptation? Rewarding brand logos bias the neural encoding of incidental economic decisions.

PubMed

Murawski, Carsten; Harris, Philip G; Bode, Stefan; Domínguez D, Juan F; Egan, Gary F

2012-01-01

Human decision-making is driven by subjective values assigned to alternative choice options. These valuations are based on reward cues. It is unknown, however, whether complex reward cues, such as brand logos, may bias the neural encoding of subjective value in unrelated decisions. In this functional magnetic resonance imaging (fMRI) study, we subliminally presented brand logos preceding intertemporal choices. We demonstrated that priming biased participants' preferences towards more immediate rewards in the subsequent temporal discounting task. This was associated with modulations of the neural encoding of subjective values of choice options in a network of brain regions, including but not restricted to medial prefrontal cortex. Our findings demonstrate the general susceptibility of the human decision making system to apparently incidental contextual information. We conclude that the brain incorporates seemingly unrelated value information that modifies decision making outside the decision-maker's awareness.

Led into Temptation? Rewarding Brand Logos Bias the Neural Encoding of Incidental Economic Decisions

PubMed Central

Murawski, Carsten; Harris, Philip G.; Bode, Stefan; Domínguez D., Juan F.; Egan, Gary F.

2012-01-01

Human decision-making is driven by subjective values assigned to alternative choice options. These valuations are based on reward cues. It is unknown, however, whether complex reward cues, such as brand logos, may bias the neural encoding of subjective value in unrelated decisions. In this functional magnetic resonance imaging (fMRI) study, we subliminally presented brand logos preceding intertemporal choices. We demonstrated that priming biased participants' preferences towards more immediate rewards in the subsequent temporal discounting task. This was associated with modulations of the neural encoding of subjective values of choice options in a network of brain regions, including but not restricted to medial prefrontal cortex. Our findings demonstrate the general susceptibility of the human decision making system to apparently incidental contextual information. We conclude that the brain incorporates seemingly unrelated value information that modifies decision making outside the decision-maker's awareness. PMID:22479547

Effects of acute administration of nicotine, amphetamine, diazepam, morphine, and ethanol on risky decision-making in rats

PubMed Central

Mitchell, Marci R.; Vokes, Colin M.; Blankenship, Amy L.; Simon, Nicholas W.

2011-01-01

Rationale Most individuals can accurately assess the risks and rewards associated with choice alternatives and decide accordingly; however, drug users often display maladaptive decision-making, such that choices are biased toward excessively risky options. Objective The purpose of this study was to investigate the effects of a range of drugs of abuse on risky decision-making. Methods Male Long–Evans rats were trained in the Risky Decision-Making Task, in which they chose between two levers, one which produced a small, “safe” food reward and the other which produced a large, “risky” food reward. The large reward was accompanied by the risk of a mild footshock, the probability of which increased over the course of each test session (0%, 25%, 50%, 75%, and 100%). Results Nicotine (0.6 mg/kg) and amphetamine (1.5 mg/kg) caused a significant decrease in choice of the large risky reward (decreased risk taking). Diazepam (1.0 mg/kg) caused a significant increase in choice of the large risky reward (increased risk taking), whereas morphine (3.0 mg/kg) caused only a trend toward increased choice of the large risky reward. Ethanol had no effect on choice behavior. Conclusions These results show that acute administration of drugs of abuse can modulate risk taking in a drug-specific manner, either increasing or decreasing preference for highly rewarding, but risky, options. PMID:21638222

Reward bias and lateralization in gambling behavior: behavioral activation system and alpha band analysis.

PubMed

Balconi, Michela; Finocchiaro, Roberta; Canavesio, Ylenia; Messina, Rossella

2014-11-30

The present research explored the main factors that can influence subjects' choices in the case of decisions. In order to elucidate the individual differences that influence the decisional processes, making their strategies more or less advantageous, we tested the effect of a reward sensitivity in the behavioral activation system (BAS-Reward) constructed on the ability to distinguish between high- and low-risk decisions. Secondly, the lateralization effect, related to increased activation of the left (BAS-related) hemisphere, was explored. Thirty-one subjects were tested using the Iowa Gambling Task, and the BAS-Reward measure was applied to distinguish between high-BAS and low-BAS groups. Behavioral responses (gain/loss options) and alpha-band modulation were considered. It was found that high-BAS group increased their tendency to opt in favor of the immediate reward (loss strategy) rather than the long-term option (win strategy). Secondly, high-BAS subjects showed an increased left-hemisphere activation in response to losing (with immediate reward) choices in comparison with low-BAS subjects. A "reward bias" effect was supposed to explain both the bad strategy and the unbalanced hemispheric activation for high-BAS and more risk-taking subjects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Attention as foraging for information and value

PubMed Central

Manohar, Sanjay G.; Husain, Masud

2013-01-01

What is the purpose of attention? One avenue of research has led to the proposal that attention might be crucial for gathering information about the environment, while other lines of study have demonstrated how attention may play a role in guiding behavior to rewarded options. Many experiments that study attention require participants to make a decision based on information acquired discretely at one point in time. In real-world situations, however, we are usually not presented with information about which option to select in such a manner. Rather we must initially search for information, weighing up reward values of options before we commit to a decision. Here, we propose that attention plays a role in both foraging for information and foraging for value. When foraging for information, attention is guided toward the unknown. When foraging for reward, attention is guided toward high reward values, allowing decision-making to proceed by accept-or-reject decisions on the currently attended option. According to this account, attention can be regarded as a low-cost alternative to moving around and physically interacting with the environment—“teleforaging”—before a decision is made to interact physically with the world. To track the timecourse of attention, we asked participants to seek out and acquire information about two gambles by directing their gaze, before choosing one of them. Participants often made multiple refixations on items before making a decision. Their eye movements revealed that early in the trial, attention was guided toward information, i.e., toward locations that reduced uncertainty about value. In contrast, late in the trial, attention was guided by expected value of the options. At the end of the decision period, participants were generally attending to the item they eventually chose. We suggest that attentional foraging shifts from an uncertainty-driven to a reward-driven mode during the evolution of a decision, permitting decisions to be made by an engage-or-search strategy. PMID:24204335

The effects of nectar addition on pollen removal and geitonogamy in the non-rewarding orchid Anacamptis morio.

PubMed Central

Johnson, Steven D.; Peter, Craig I.; Agren, Jon

2004-01-01

It has been suggested that the absence of floral rewards in many orchid species causes pollinators to probe fewer flowers on a plant, and thus reduces geitonogamy, i.e. self-pollination between flowers, which may result in inbreeding depression and reduced pollen export. We examined the effects of nectar addition on pollinator visitation and pollen transfer by tracking the fate of colour-labelled pollen in Anacamptis morio, a non-rewarding orchid species pollinated primarily by queen bumble-bees. Addition of nectar to spurs of A. morio significantly increased the number of flowers probed by bumble-bees, the time spent on an inflorescence, pollinarium removal and the proportion of removed pollen involved in self-pollination through geitonogamy, but did not affect pollen carryover (the fraction of a pollinarium carried over from one flower to the next). Only visits that exceeded 18 s resulted in geitonogamy, as this is the time taken for removed pollinaria to bend into a position to strike the stigma. A mutation for nectar production in A. morio would result in an initial 3.8-fold increase in pollinarium removal per visit, but also increase geitonogamous self-pollination from less than 10% of pollen depositions to ca. 40%. Greater efficiency of pollen export will favour deceptive plants when pollinators are relatively common and most pollinaria are removed from flowers or when inbreeding depression is severe. These findings provide empirical support both for Darwin's contention that pollinarium bending is an anti-selfing mechanism in orchids and for the idea that floral deception serves to maximize the efficiency of pollen export. PMID:15255098

Neural Signatures of Value Comparison in Human Cingulate Cortex during Decisions Requiring an Effort-Reward Trade-off

PubMed Central

Kennerley, Steven W.; Friston, Karl; Bestmann, Sven

2016-01-01

Integrating costs and benefits is crucial for optimal decision-making. Although much is known about decisions that involve outcome-related costs (e.g., delay, risk), many of our choices are attached to actions and require an evaluation of the associated motor costs. Yet how the brain incorporates motor costs into choices remains largely unclear. We used human fMRI during choices involving monetary reward and physical effort to identify brain regions that serve as a choice comparator for effort-reward trade-offs. By independently varying both options' effort and reward levels, we were able to identify the neural signature of a comparator mechanism. A network involving supplementary motor area and the caudal portion of dorsal anterior cingulate cortex encoded the difference in reward (positively) and effort levels (negatively) between chosen and unchosen choice options. We next modeled effort-discounted subjective values using a novel behavioral model. This revealed that the same network of regions involving dorsal anterior cingulate cortex and supplementary motor area encoded the difference between the chosen and unchosen options' subjective values, and that activity was best described using a concave model of effort-discounting. In addition, this signal reflected how precisely value determined participants' choices. By contrast, separate signals in supplementary motor area and ventromedial prefrontal cortex correlated with participants' tendency to avoid effort and seek reward, respectively. This suggests that the critical neural signature of decision-making for choices involving motor costs is found in human cingulate cortex and not ventromedial prefrontal cortex as typically reported for outcome-based choice. Furthermore, distinct frontal circuits seem to drive behavior toward reward maximization and effort minimization. SIGNIFICANCE STATEMENT The neural processes that govern the trade-off between expected benefits and motor costs remain largely unknown. This is striking because energetic requirements play an integral role in our day-to-day choices and instrumental behavior, and a diminished willingness to exert effort is a characteristic feature of a range of neurological disorders. We use a new behavioral characterization of how humans trade off reward maximization with effort minimization to examine the neural signatures that underpin such choices, using BOLD MRI neuroimaging data. We find the critical neural signature of decision-making, a signal that reflects the comparison of value between choice options, in human cingulate cortex, whereas two distinct brain circuits drive behavior toward reward maximization or effort minimization. PMID:27683898

Neural Signatures of Value Comparison in Human Cingulate Cortex during Decisions Requiring an Effort-Reward Trade-off.

PubMed

Klein-Flügge, Miriam C; Kennerley, Steven W; Friston, Karl; Bestmann, Sven

2016-09-28

Integrating costs and benefits is crucial for optimal decision-making. Although much is known about decisions that involve outcome-related costs (e.g., delay, risk), many of our choices are attached to actions and require an evaluation of the associated motor costs. Yet how the brain incorporates motor costs into choices remains largely unclear. We used human fMRI during choices involving monetary reward and physical effort to identify brain regions that serve as a choice comparator for effort-reward trade-offs. By independently varying both options' effort and reward levels, we were able to identify the neural signature of a comparator mechanism. A network involving supplementary motor area and the caudal portion of dorsal anterior cingulate cortex encoded the difference in reward (positively) and effort levels (negatively) between chosen and unchosen choice options. We next modeled effort-discounted subjective values using a novel behavioral model. This revealed that the same network of regions involving dorsal anterior cingulate cortex and supplementary motor area encoded the difference between the chosen and unchosen options' subjective values, and that activity was best described using a concave model of effort-discounting. In addition, this signal reflected how precisely value determined participants' choices. By contrast, separate signals in supplementary motor area and ventromedial prefrontal cortex correlated with participants' tendency to avoid effort and seek reward, respectively. This suggests that the critical neural signature of decision-making for choices involving motor costs is found in human cingulate cortex and not ventromedial prefrontal cortex as typically reported for outcome-based choice. Furthermore, distinct frontal circuits seem to drive behavior toward reward maximization and effort minimization. The neural processes that govern the trade-off between expected benefits and motor costs remain largely unknown. This is striking because energetic requirements play an integral role in our day-to-day choices and instrumental behavior, and a diminished willingness to exert effort is a characteristic feature of a range of neurological disorders. We use a new behavioral characterization of how humans trade off reward maximization with effort minimization to examine the neural signatures that underpin such choices, using BOLD MRI neuroimaging data. We find the critical neural signature of decision-making, a signal that reflects the comparison of value between choice options, in human cingulate cortex, whereas two distinct brain circuits drive behavior toward reward maximization or effort minimization. Copyright © 2016 Klein-Flügge et al.

Waiting for what comes later: capuchin monkeys show self-control even for nonvisible delayed rewards.

PubMed

Perdue, Bonnie M; Bramlett, Jessica L; Evans, Theodore A; Beran, Michael J

2015-09-01

Self-control tasks used with nonhuman animals typically involve the choice between an immediate option and a delayed, but more preferred option. However, in many self-control scenarios, not only does the more impulsive option come sooner in time, it is often more concrete than the delayed option. For example, studies have presented children with the option of eating a visible marshmallow immediately, or foregoing it for a better reward that can only be seen later. Thus, the immediately available option is visible and concrete, whereas the delayed option is not visible and more abstract. We tested eight capuchin monkeys to better understand this potential effect by manipulating the visibility of the response options and the visibility of the baiting itself. Monkeys observed two food items (20 or 5 g pieces of banana) each being placed either on top of or inside of one of the two opaque containers attached to a revolving tray apparatus, either in full view of monkeys or occluded by a barrier. Trials ended when monkeys removed a reward from the rotating tray. To demonstrate self-control, monkeys should have allowed the smaller piece of food to pass if the larger piece was forthcoming. Overall, monkeys were successful on the task, allowing a smaller, visible piece of banana to pass from reach in order to access the larger, nonvisible banana piece. This was true even when the entire baiting process took place out of sight of the monkeys. This finding suggests that capuchin monkeys succeed on self-control tasks even when the delayed option is also more abstract than the immediate one-a situation likely faced by primates in everyday life.

A neurocomputational account of reward and novelty processing and effects of psychostimulants in attention deficit hyperactivity disorder.

PubMed

Sethi, Arjun; Voon, Valerie; Critchley, Hugo D; Cercignani, Mara; Harrison, Neil A

2018-05-01

Computational models of reinforcement learning have helped dissect discrete components of reward-related function and characterize neurocognitive deficits in psychiatric illnesses. Stimulus novelty biases decision-making, even when unrelated to choice outcome, acting as if possessing intrinsic reward value to guide decisions toward uncertain options. Heightened novelty seeking is characteristic of attention deficit hyperactivity disorder, yet how this influences reward-related decision-making is computationally encoded, or is altered by stimulant medication, is currently uncertain. Here we used an established reinforcement-learning task to model effects of novelty on reward-related behaviour during functional MRI in 30 adults with attention deficit hyperactivity disorder and 30 age-, sex- and IQ-matched control subjects. Each participant was tested on two separate occasions, once ON and once OFF stimulant medication. OFF medication, patients with attention deficit hyperactivity disorder showed significantly impaired task performance (P = 0.027), and greater selection of novel options (P = 0.004). Moreover, persistence in selecting novel options predicted impaired task performance (P = 0.025). These behavioural deficits were accompanied by a significantly lower learning rate (P = 0.011) and heightened novelty signalling within the substantia nigra/ventral tegmental area (family-wise error corrected P < 0.05). Compared to effects in controls, stimulant medication improved attention deficit hyperactivity disorder participants' overall task performance (P = 0.011), increased reward-learning rates (P = 0.046) and enhanced their ability to differentiate optimal from non-optimal novel choices (P = 0.032). It also reduced substantia nigra/ventral tegmental area responses to novelty. Preliminary cross-sectional evidence additionally suggested an association between long-term stimulant treatment and a reduction in the rewarding value of novelty. These data suggest that aberrant substantia nigra/ventral tegmental area novelty processing plays an important role in the suboptimal reward-related decision-making characteristic of attention deficit hyperactivity disorder. Compared to effects in controls, abnormalities in novelty processing and reward-related learning were improved by stimulant medication, suggesting that they may be disorder-specific targets for the pharmacological management of attention deficit hyperactivity disorder symptoms.

Neurons in Anterior Cingulate Cortex Multiplex Information about Reward and Action

PubMed Central

Hayden, Benjamin Y.; Platt, Michael L.

2010-01-01

The dorsal anterior cingulate cortex (dACC) is thought to play a critical role in forming associations between rewards and actions. Currently available physiological data, however, remain inconclusive regarding the question of whether dACC neurons carry information linking particular actions to reward or, instead, encode abstract reward information independent of specific actions. Here we show that firing rates of a majority of dACC neurons in a population studied in an eight-option variably rewarded choice task were sensitive to both saccade direction and reward value. Furthermore, the influences of reward and saccade direction on neuronal activity were roughly equal in magnitude over the range of rewards tested and were statistically independent. Our results indicate that dACC neurons multiplex information about both reward and action, endorsing the idea that this area links motivational outcomes to behavior and undermining the notion that its neurons solely contribute to reward processing in the abstract. PMID:20203193

The Attraction Effect Modulates Reward Prediction Errors and Intertemporal Choices.

PubMed

Gluth, Sebastian; Hotaling, Jared M; Rieskamp, Jörg

2017-01-11

Classical economic theory contends that the utility of a choice option should be independent of other options. This view is challenged by the attraction effect, in which the relative preference between two options is altered by the addition of a third, asymmetrically dominated option. Here, we leveraged the attraction effect in the context of intertemporal choices to test whether both decisions and reward prediction errors (RPE) in the absence of choice violate the independence of irrelevant alternatives principle. We first demonstrate that intertemporal decision making is prone to the attraction effect in humans. In an independent group of participants, we then investigated how this affects the neural and behavioral valuation of outcomes using a novel intertemporal lottery task and fMRI. Participants' behavioral responses (i.e., satisfaction ratings) were modulated systematically by the attraction effect and this modulation was correlated across participants with the respective change of the RPE signal in the nucleus accumbens. Furthermore, we show that, because exponential and hyperbolic discounting models are unable to account for the attraction effect, recently proposed sequential sampling models might be more appropriate to describe intertemporal choices. Our findings demonstrate for the first time that the attraction effect modulates subjective valuation even in the absence of choice. The findings also challenge the prospect of using neuroscientific methods to measure utility in a context-free manner and have important implications for theories of reinforcement learning and delay discounting. Many theories of value-based decision making assume that people first assess the attractiveness of each option independently of each other and then pick the option with the highest subjective value. The attraction effect, however, shows that adding a new option to a choice set can change the relative value of the existing options, which is a violation of the independence principle. Using an intertemporal choice framework, we tested whether such violations also occur when the brain encodes the difference between expected and received rewards (i.e., the reward prediction error). Our results suggest that neither intertemporal choice nor valuation without choice adhere to the independence principle. Copyright © 2017 the authors 0270-6474/17/370371-12$15.00/0.

Episodic Memory Encoding Interferes with Reward Learning and Decreases Striatal Prediction Errors

PubMed Central

Braun, Erin Kendall; Daw, Nathaniel D.

2014-01-01

Learning is essential for adaptive decision making. The striatum and its dopaminergic inputs are known to support incremental reward-based learning, while the hippocampus is known to support encoding of single events (episodic memory). Although traditionally studied separately, in even simple experiences, these two types of learning are likely to co-occur and may interact. Here we sought to understand the nature of this interaction by examining how incremental reward learning is related to concurrent episodic memory encoding. During the experiment, human participants made choices between two options (colored squares), each associated with a drifting probability of reward, with the goal of earning as much money as possible. Incidental, trial-unique object pictures, unrelated to the choice, were overlaid on each option. The next day, participants were given a surprise memory test for these pictures. We found that better episodic memory was related to a decreased influence of recent reward experience on choice, both within and across participants. fMRI analyses further revealed that during learning the canonical striatal reward prediction error signal was significantly weaker when episodic memory was stronger. This decrease in reward prediction error signals in the striatum was associated with enhanced functional connectivity between the hippocampus and striatum at the time of choice. Our results suggest a mechanism by which memory encoding may compete for striatal processing and provide insight into how interactions between different forms of learning guide reward-based decision making. PMID:25378157

Competitive control of cognition in rhesus monkeys.

PubMed

Kowaguchi, Mayuka; Patel, Nirali P; Bunnell, Megan E; Kralik, Jerald D

2016-12-01

The brain has evolved different approaches to solve problems, but the mechanisms that determine which approach to take remain unclear. One possibility is that control progresses from simpler processes, such as associative learning, to more complex ones, such as relational reasoning, when the simpler ones prove inadequate. Alternatively, control could be based on competition between the processes. To test between these possibilities, we posed the support problem to rhesus monkeys using a tool-use paradigm, in which subjects could pull an object (the tool) toward themselves to obtain an otherwise out-of-reach goal item. We initially provided one problem exemplar as a choice: for the correct option, a food item placed on the support tool; for the incorrect option, the food item placed off the tool. Perceptual cues were also correlated with outcome: e.g., red, triangular tool correct, blue, rectangular tool incorrect. Although the monkeys simply needed to touch the tool to register a response, they immediately pulled it, reflecting a relational reasoning process between themselves and another object (R self-other ), rather than an associative one between the arbitrary touch response and reward (A resp-reward ). Probe testing then showed that all four monkeys used a conjunction of perceptual features to select the correct option, reflecting an associative process between stimuli and reward (A stim-reward ). We then added a second problem exemplar and subsequent testing revealed that the monkeys switched to using the on/off relationship, reflecting a relational reasoning process between two objects (R other-other ). Because behavior appeared to reflect R self-other rather than A resp-reward , and A stim-reward prior to R other-other , our results suggest that cognitive processes are selected via competitive control dynamics. Copyright © 2016 Elsevier B.V. All rights reserved.

78 FR 36508 - Notice of Sugar Purchase and Exchange for Re-Export Program Credits; and Notice of Re-Export...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-18

... DEPARTMENT OF AGRICULTURE Commodity Credit Corporation Office of the Secretary Notice of Sugar... to purchase sugar to be offered in exchange for Refined Sugar Re-export Program credits. CCC will purchase sugar from domestic sugarcane processors or beet processors under the Cost Reduction Options of...

75 FR 29680 - Importation of Mexican Hass Avocados; Additional Shipping Options

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-27

... Avocados; Additional Shipping Options AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION... originating in Michoacan, Mexico, into the United States by adding the option to ship avocados to the United... additional options for shipping Hass avocados from Mexico to the United States and allow Mexican exporters to...

Reward value comparison via mutual inhibition in ventromedial prefrontal cortex

PubMed Central

Strait, Caleb E.; Blanchard, Tommy C.; Hayden, Benjamin Y.

2014-01-01

Recent theories suggest that reward-based choice reflects competition between value signals in the ventromedial prefrontal cortex (vmPFC). We tested this idea by recording vmPFC neurons while macaques performed a gambling task with asynchronous offer presentation. We found that neuronal activity shows four patterns consistent with selection via mutual inhibition. (1) Correlated tuning for probability and reward size, suggesting that vmPFC carries an integrated value signal, (2) anti-correlated tuning curves for the two options, suggesting mutual inhibition, (3) neurons rapidly come to signal the value of the chosen offer, suggesting the circuit serves to produce a choice, (4) after regressing out the effects of option values, firing rates still could predict choice – a choice probability signal. In addition, neurons signaled gamble outcomes, suggesting that vmPFC contributes to both monitoring and choice processes. These data suggest a possible mechanism for reward-based choice and endorse the centrality of vmPFC in that process. PMID:24881835

Dynamic fluctuations in dopamine efflux in the prefrontal cortex and nucleus accumbens during risk-based decision making.

PubMed

St Onge, Jennifer R; Ahn, Soyon; Phillips, Anthony G; Floresco, Stan B

2012-11-21

Mesocorticolimbic dopamine (DA) has been implicated in cost/benefit decision making about risks and rewards. The prefrontal cortex (PFC) and nucleus accumbens (NAc) are two DA terminal regions that contribute to decision making in distinct manners. However, how fluctuations of tonic DA levels may relate to different aspects of decision making remains to be determined. The present study measured DA efflux in the PFC and NAc with microdialysis in well trained rats performing a probabilistic discounting task. Selection of a small/certain option always delivered one pellet, whereas another, large/risky option yielded four pellets, with probabilities that decreased (100-12.5%) or increased (12.5-100%) across four blocks of trials. Yoked-reward groups were also included to control for reward delivery. PFC DA efflux during decision making decreased or increased over a session, corresponding to changes in large/risky reward probabilities. Similar profiles were observed from yoked-rewarded rats, suggesting that fluctuations in PFC DA reflect changes in the relative rate of reward received. NAc DA efflux also showed decreasing/increasing trends over the session during both tasks. However, DA efflux was higher during decision making on free- versus forced-choice trials and during periods of greater reward uncertainty. Moreover, changes in NAc DA closely tracked shifts in choice biases. These data reveal dynamic and dissociable fluctuations in PFC and NAc DA transmission associated with different aspects of risk-based decision making. PFC DA may signal changes in reward availability that facilitates modification of choice biases, whereas NAc DA encodes integrated signals about reward rates, uncertainty, and choice, reflecting implementation of decision policies.

Dopamine neurons learn relative chosen value from probabilistic rewards

PubMed Central

Lak, Armin; Stauffer, William R; Schultz, Wolfram

2016-01-01

Economic theories posit reward probability as one of the factors defining reward value. Individuals learn the value of cues that predict probabilistic rewards from experienced reward frequencies. Building on the notion that responses of dopamine neurons increase with reward probability and expected value, we asked how dopamine neurons in monkeys acquire this value signal that may represent an economic decision variable. We found in a Pavlovian learning task that reward probability-dependent value signals arose from experienced reward frequencies. We then assessed neuronal response acquisition during choices among probabilistic rewards. Here, dopamine responses became sensitive to the value of both chosen and unchosen options. Both experiments showed also the novelty responses of dopamine neurones that decreased as learning advanced. These results show that dopamine neurons acquire predictive value signals from the frequency of experienced rewards. This flexible and fast signal reflects a specific decision variable and could update neuronal decision mechanisms. DOI: http://dx.doi.org/10.7554/eLife.18044.001 PMID:27787196

Neurons in Dorsal Anterior Cingulate Cortex Signal Postdecisional Variables in a Foraging Task

PubMed Central

Hayden, Benjamin Y.

2014-01-01

The dorsal anterior cingulate cortex (dACC) is a key hub of the brain's executive control system. Although a great deal is known about its role in outcome monitoring and behavioral adjustment, whether and how it contributes to the decision process remain unclear. Some theories suggest that dACC neurons track decision variables (e.g., option values) that feed into choice processes and is thus “predecisional.” Other theories suggest that dACC activity patterns differ qualitatively depending on the choice that is made and is thus “postdecisional.” To compare these hypotheses, we examined responses of 124 dACC neurons in a simple foraging task in which monkeys accepted or rejected offers of delayed rewards. In this task, options that vary in benefit (reward size) and cost (delay) appear for 1 s; accepting the option provides the cued reward after the cued delay. To get at dACC neurons' contributions to decisions, we focused on responses around the time of choice, several seconds before the reward and the end of the trial. We found that dACC neurons signal the foregone value of the rejected option, a postdecisional variable. Neurons also signal the profitability (that is, the relative value) of the offer, but even these signals are qualitatively different on accept and reject decisions, meaning that they are also postdecisional. These results suggest that dACC can be placed late in the decision process and also support models that give it a regulatory role in decision, rather than serving as a site of comparison. PMID:24403162

Separate valuation subsystems for delay and effort decision costs.

PubMed

Prévost, Charlotte; Pessiglione, Mathias; Météreau, Elise; Cléry-Melin, Marie-Laure; Dreher, Jean-Claude

2010-10-20

Decision making consists of choosing among available options on the basis of a valuation of their potential costs and benefits. Most theoretical models of decision making in behavioral economics, psychology, and computer science propose that the desirability of outcomes expected from alternative options can be quantified by utility functions. These utility functions allow a decision maker to assign subjective values to each option under consideration by weighting the likely benefits and costs resulting from an action and to select the one with the highest subjective value. Here, we used model-based neuroimaging to test whether the human brain uses separate valuation systems for rewards (erotic stimuli) associated with different types of costs, namely, delay and effort. We show that humans devalue rewards associated with physical effort in a strikingly similar fashion to those they devalue that are associated with delays, and that a single computational model derived from economics theory can account for the behavior observed in both delay discounting and effort discounting. However, our neuroimaging data reveal that the human brain uses distinct valuation subsystems for different types of costs, reflecting in opposite fashion delayed reward and future energetic expenses. The ventral striatum and the ventromedial prefrontal cortex represent the increasing subjective value of delayed rewards, whereas a distinct network, composed of the anterior cingulate cortex and the anterior insula, represent the decreasing value of the effortful option, coding the expected expense of energy. Together, these data demonstrate that the valuation processes underlying different types of costs can be fractionated at the cerebral level.

Exploiting risk-reward structures in decision making under uncertainty.

PubMed

Leuker, Christina; Pachur, Thorsten; Hertwig, Ralph; Pleskac, Timothy J

2018-06-01

People often have to make decisions under uncertainty-that is, in situations where the probabilities of obtaining a payoff are unknown or at least difficult to ascertain. One solution to this problem is to infer the probability from the magnitude of the potential payoff and thus exploit the inverse relationship between payoffs and probabilities that occurs in many domains in the environment. Here, we investigated how the mind may implement such a solution: (1) Do people learn about risk-reward relationships from the environment-and if so, how? (2) How do learned risk-reward relationships impact preferences in decision-making under uncertainty? Across three experiments (N = 352), we found that participants can learn risk-reward relationships from being exposed to choice environments with a negative, positive, or uncorrelated risk-reward relationship. They were able to learn the associations both from gambles with explicitly stated payoffs and probabilities (Experiments 1 & 2) and from gambles about epistemic events (Experiment 3). In subsequent decisions under uncertainty, participants often exploited the learned association by inferring probabilities from the magnitudes of the payoffs. This inference systematically influenced their preferences under uncertainty: Participants who had been exposed to a negative risk-reward relationship tended to prefer the uncertain option over a smaller sure option for low payoffs, but not for high payoffs. This pattern reversed in the positive condition and disappeared in the uncorrelated condition. This adaptive change in preferences is consistent with the use of the risk-reward heuristic. Copyright © 2018 Elsevier B.V. All rights reserved.

Risk-dependent reward value signal in human prefrontal cortex

PubMed Central

Tobler, Philippe N.; Christopoulos, George I.; O'Doherty, John P.; Dolan, Raymond J.; Schultz, Wolfram

2009-01-01

When making choices under uncertainty, people usually consider both the expected value and risk of each option, and choose the one with the higher utility. Expected value increases the expected utility of an option for all individuals. Risk increases the utility of an option for risk-seeking individuals, but decreases it for risk averse individuals. In 2 separate experiments, one involving imperative (no-choice), the other choice situations, we investigated how predicted risk and expected value aggregate into a common reward signal in the human brain. Blood oxygen level dependent responses in lateral regions of the prefrontal cortex increased monotonically with increasing reward value in the absence of risk in both experiments. Risk enhanced these responses in risk-seeking participants, but reduced them in risk-averse participants. The aggregate value and risk responses in lateral prefrontal cortex contrasted with pure value signals independent of risk in the striatum. These results demonstrate an aggregate risk and value signal in the prefrontal cortex that would be compatible with basic assumptions underlying the mean-variance approach to utility. PMID:19369207

Learning Reward Uncertainty in the Basal Ganglia

PubMed Central

Bogacz, Rafal

2016-01-01

Learning the reliability of different sources of rewards is critical for making optimal choices. However, despite the existence of detailed theory describing how the expected reward is learned in the basal ganglia, it is not known how reward uncertainty is estimated in these circuits. This paper presents a class of models that encode both the mean reward and the spread of the rewards, the former in the difference between the synaptic weights of D1 and D2 neurons, and the latter in their sum. In the models, the tendency to seek (or avoid) options with variable reward can be controlled by increasing (or decreasing) the tonic level of dopamine. The models are consistent with the physiology of and synaptic plasticity in the basal ganglia, they explain the effects of dopaminergic manipulations on choices involving risks, and they make multiple experimental predictions. PMID:27589489

The Computational Development of Reinforcement Learning during Adolescence

PubMed Central

Palminteri, Stefano; Coricelli, Giorgio; Blakemore, Sarah-Jayne

2016-01-01

Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adults carried out a novel reinforcement learning paradigm in which participants learned the association between cues and probabilistic outcomes, where the outcomes differed in valence (reward versus punishment) and feedback was either partial or complete (either the outcome of the chosen option only, or the outcomes of both the chosen and unchosen option, were displayed). Computational strategies changed during development: whereas adolescents’ behaviour was better explained by a basic reinforcement learning algorithm, adults’ behaviour integrated increasingly complex computational features, namely a counterfactual learning module (enabling enhanced performance in the presence of complete feedback) and a value contextualisation module (enabling symmetrical reward and punishment learning). Unlike adults, adolescent performance did not benefit from counterfactual (complete) feedback. In addition, while adults learned symmetrically from both reward and punishment, adolescents learned from reward but were less likely to learn from punishment. This tendency to rely on rewards and not to consider alternative consequences of actions might contribute to our understanding of decision-making in adolescence. PMID:27322574

Mechanisms and evolution of deceptive pollination in orchids.

PubMed

Jersáková, Jana; Johnson, Steven D; Kindlmann, Pavel

2006-05-01

The orchid family is renowned for its enormous diversity of pollination mechanisms and unusually high occurrence of non-rewarding flowers compared to other plant families. The mechanisms of deception in orchids include generalized food deception, food-deceptive floral mimicry, brood-site imitation, shelter imitation, pseudoantagonism, rendezvous attraction and sexual deception. Generalized food deception is the most common mechanism (reported in 38 genera) followed by sexual deception (18 genera). Floral deception in orchids has been intensively studied since Darwin, but the evolution of non-rewarding flowers still presents a major puzzle for evolutionary biology. The two principal hypotheses as to how deception could increase fitness in plants are (i) reallocation of resources associated with reward production to flowering and seed production, and (ii) higher levels of cross-pollination due to pollinators visiting fewer flowers on non-rewarding plants, resulting in more outcrossed progeny and more efficient pollen export. Biologists have also tried to explain why deception is overrepresented in the orchid family. These explanations include: (i) efficient removal and deposition of pollinaria from orchid flowers in a single pollinator visit, thus obviating the need for rewards to entice multiple visits from pollinators; (ii) efficient transport of orchid pollen, thus requiring less reward-induced pollinator constancy; (iii) low-density populations in many orchids, thus limiting the learning of associations of floral phenotypes and rewards by pollinators; (iv) packaging of pollen in pollinaria with limited carry-over from flower to flower, thus increasing the risks of geitonogamous self-pollination when pollinators visit many flowers on rewarding plants. All of these general and orchid-specific hypotheses are difficult to reconcile with the well-established pattern for rewardlessness to result in low pollinator visitation rates and consequently low levels of fruit production. Arguments that deception evolves because rewards are costly are particularly problematic in that small amounts of nectar are unlikely to have a significant effect on the energy budget of orchids, and because reproduction in orchids is often severely pollen-, rather than resource-limited. Several recent experimental studies have shown that deception promotes cross-pollination, but it remains unknown whether actual outcrossing rates are generally higher in deceptive orchids. Our review of the literature shows that there is currently no evidence that deceptive orchids carry higher levels of genetic load (an indirect measure of outcrossing rate) than their rewarding counterparts. Cross-pollination does, however, result in dramatic increases in seed quality in almost all orchids and has the potential to increase pollen export (by reducing pollen discounting). We suggest that floral deception is particularly beneficial, because of its promotion of outcrossing, when pollinators are abundant, but that when pollinators are consistently rare, selection may favour a nectar reward or a shift to autopollination. Given that nectar-rewardlessness is likely to have been the ancestral condition in orchids and yet is evolutionarily labile, more attention will need to be given to explanations as to why deception constitutes an 'evolutionarily stable strategy'.

Anhedonia and anxiety underlying depressive symptomatology have distinct effects on reward-based decision-making.

PubMed

Harlé, Katia M; Guo, Dalin; Zhang, Shunan; Paulus, Martin P; Yu, Angela J

2017-01-01

Depressive pathology, which includes both heightened negative affect (e.g., anxiety) and reduced positive affect (e.g., anhedonia), is known to be associated with sub-optimal decision-making, particularly in uncertain environments. Here, we use a computational approach to quantify and disambiguate how individual differences in these affective measures specifically relate to different aspects of learning and decision-making in reward-based choice behavior. Fifty-three individuals with a range of depressed mood completed a two-armed bandit task, in which they choose between two arms with fixed but unknown reward rates. The decision-making component, which chooses among options based on current expectations about reward rates, is modeled by two different decision policies: a learning-independent Win-stay/Lose-shift (WSLS) policy that ignores all previous experiences except the last trial, and Softmax, which prefers the arm with the higher expected reward. To model the learning component for the Softmax choice policy, we use a Bayesian inference model, which updates estimated reward rates based on the observed history of trial outcomes. Softmax with Bayesian learning better fits the behavior of 55% of the participants, while the others are better fit by a learning-independent WSLS strategy. Among Softmax "users", those with higher anhedonia are less likely to choose the option estimated to be most rewarding. Moreover, the Softmax parameter mediates the inverse relationship between anhedonia and overall monetary gains. On the other hand, among WSLS "users", higher state anxiety correlates with increasingly better ability of WSLS, relative to Softmax, to explain subjects' trial-by-trial choices. In summary, there is significant variability among individuals in their reward-based, exploratory decision-making, and this variability is at least partly mediated in a very specific manner by affective attributes, such as hedonic tone and state anxiety.

What Do I Want and When Do I Want It: Brain Correlates of Decisions Made for Self and Other

PubMed Central

Albrecht, Konstanze; Volz, Kirsten G.; Sutter, Matthias; von Cramon, D. Yves

2013-01-01

A number of recent functional Magnetic Resonance Imaging (fMRI) studies on intertemporal choice behavior have demonstrated that so-called emotion- and reward-related brain areas are preferentially activated by decisions involving immediately available (but smaller) rewards as compared to (larger) delayed rewards. This pattern of activation was not seen, however, when intertemporal choices were made for another (unknown) individual, which speaks to that activation having been triggered by self-relatedness. In the present fMRI study, we investigated the brain correlates of individuals who passively observed intertemporal choices being made either for themselves or for an unknown person. We found higher activation within the ventral striatum, medial prefrontal and orbitofrontal cortex, pregenual anterior cingulate cortex, and posterior cingulate cortex when an immediate reward was possible for the observer herself, which is in line with findings from studies in which individuals actively chose immediately available rewards. Additionally, activation in the dorsal anterior cingulate cortex, posterior cingulate cortex, and precuneus was higher for choices that included immediate options than for choices that offered only delayed options, irrespective of who was to be the beneficiary. These results indicate that (1) the activations found in active intertemporal decision making are also present when the same decisions are merely observed, thus supporting the assumption that a robust brain network is engaged in immediate gratification; and (2) with immediate rewards, certain brain areas are activated irrespective of whether the observer or another person is the beneficiary of a decision, suggesting that immediacy plays a more general role for neural activation. An explorative analysis of participants’ brain activation corresponding to chosen rewards, further indicates that activation in the aforementioned brain areas depends on the mere presence, availability, or actual reception of immediate rewards. PMID:23991196

Neural markers of social and monetary rewards in children with Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder.

PubMed

Gonzalez-Gadea, Maria Luz; Sigman, Mariano; Rattazzi, Alexia; Lavin, Claudio; Rivera-Rei, Alvaro; Marino, Julian; Manes, Facundo; Ibanez, Agustin

2016-07-28

Recent theories of decision making propose a shared value-related brain mechanism for encoding monetary and social rewards. We tested this model in children with Attention-Deficit/Hyperactivity Disorder (ADHD), children with Autism Spectrum Disorder (ASD) and control children. We monitored participants' brain dynamics using high density-electroencephalography while they played a monetary and social reward tasks. Control children exhibited a feedback Error-Related Negativity (fERN) modulation and Anterior Cingulate Cortex (ACC) source activation during both tasks. Remarkably, although cooperation resulted in greater losses for the participants, the betrayal options generated greater fERN responses. ADHD subjects exhibited an absence of fERN modulation and reduced ACC activation during both tasks. ASD subjects exhibited normal fERN modulation during monetary choices and inverted fERN/ACC responses in social options than did controls. These results suggest that in neurotypicals, monetary losses and observed disloyal social decisions induced similar activity in the brain value system. In ADHD children, difficulties in reward processing affected early brain signatures of monetary and social decisions. Conversely, ASD children showed intact neural markers of value-related monetary mechanisms, but no brain modulation by prosociality in the social task. These results offer insight into the typical and atypical developments of neural correlates of monetary and social reward processing.

Get it while it's hot: a peak-first bias in self-generated choice order in rhesus macaques.

PubMed

Jung, Kanghoon; Kralik, Jerald D

2013-01-01

Animals typically must make a number of successive choices to achieve a goal: e.g., eating multiple food items before becoming satiated. However, it is unclear whether choosing the best first or saving the best for last represents the best choice strategy to maximize overall reward. Specifically, since outcomes can be evaluated prospectively (with future rewards discounted and more immediate rewards preferred) or retrospectively (with prior rewards discounted and more recent rewards preferred), the conditions under which each are used remains unclear. On the one hand, humans and non-human animals clearly discount future reward, preferring immediate rewards to delayed ones, suggesting prospective evaluation; on the other hand, it has also been shown that a sequence that ends well, i.e., with the best event or item last, is often preferred, suggesting retrospective evaluation. Here we hypothesized that when individuals are allowed to build the sequence themselves they are more likely to evaluate each item individually and therefore build a sequence using prospective evaluation. We examined the relationship between self-generated choice order and preference in rhesus monkeys in two experiments in which the distinctiveness of options were relatively high and low, respectively. We observed a positive linear relationship between choice order and preference among highly distinct options, indicating that the rhesus monkeys chose their preferred food first: i.e., a peak-first order preference. Overall, choice order depended on the degree of relative preference among alternatives and a peak-first bias, providing evidence for prospective evaluation when choice order is self-generated.

Goal-Proximity Decision-Making

ERIC Educational Resources Information Center

Veksler, Vladislav D.; Gray, Wayne D.; Schoelles, Michael J.

2013-01-01

Reinforcement learning (RL) models of decision-making cannot account for human decisions in the absence of prior reward or punishment. We propose a mechanism for choosing among available options based on goal-option association strengths, where association strengths between objects represent previously experienced object proximity. The proposed…

Rare Earth Elements in National Defense: Background, Oversight Issues, and Options for Congress

DTIC Science & Technology

2011-03-31

12 U.S. Department of Energy Report on Critical Mineral Strategy...17 Institute a New Critical Minerals Program...exports of rare earth minerals by 72%. In September 2010, China temporarily cut rare earth exports to Japan apparently over a maritime dispute. This

Impacts of the Doha Round framework agreements on dairy policies.

PubMed

Suzuki, N; Kaiser, H M

2005-05-01

Dairy is highly regulated in many countries for several reasons. Perishability, seasonal imbalances, and inelastic supply and demand for milk can cause inherent market instability. Milk buyers typically have had more market power than dairy farmers. Comparative production advantages in some countries have led to regulations and policies to protect local dairy farmers by maintaining domestic prices higher than world prices. A worldwide consensus on reduction of border measures for protecting dairy products is unlikely, and dairy will probably be an exception in ongoing World Trade Organization (WTO) negotiations. Under the Doha Round framework agreements, countries may name some products such as dairy as "sensitive," thereby excluding them from further reforms. However, new Doha Round framework agreements depart from the current WTO rule and call for product-specific spending caps. Such caps will greatly affect the dairy sector because dairy accounts for much of the aggregate measure of support (AMS) in several countries, including the United States and Canada. Also, the amounts of dairy AMS in several countries may be recalculated relative to an international reference price. In addition, all export subsidies are targeted for elimination in the Doha Round, including export credit programs and state trading enterprises, which will limit options for disposing of surplus dairy products in foreign markets. Currently, with higher domestic prices, measures for cutting or disposing of surpluses have been used in many countries. Supply control, which is not regulated by WTO rules, remains as an option. Although explicit export subsidies are restricted by WTO rules, many countries use esoteric measures to promote dairy exports. If countries agree to eliminate "consumer financed" export subsidies using a theoretical definition and measurements proposed herein as Export Subsidy Equivalents (ESE), dairy exports in many countries may be affected. Although domestic supports and export subsidies will be reduced in the Doha Round, possible exclusion of "sensitive" products from tariff reduction will help some countries' dairy sectors survive after those final agreements. A key concern for those countries will be the simultaneous restriction of surplus-disposing measures. With fewer marketing options for surpluses, countries that continue border protection and high internal prices will likely be forced to use domestic supply control programs in the future.

Food Business Entrepreneurship

NASA Astrophysics Data System (ADS)

Weber, Peter

Though not a very traditional career path for food scientists, one option is to go into business for yourself by starting a food business. Food business entrepreneurship is a difficult career that entails long work hours, extensive decision making, and tasks that require knowledge beyond food science. However, there is high potential for rewards, including financial rewards, career progression, and personal flexibility.

Binding oneself to the mast: stimulating frontopolar cortex enhances precommitment

PubMed Central

Ugazio, Giuseppe; Crockett, Molly J.; Ruff, Christian C.; Kalenscher, Tobias; Tobler, Philippe N.

2017-01-01

Abstract Humans often give in to temptations that are in conflict with valuable long-term goals like health or saving for the future. Such willpower failures represent a prevalent problem in everyday life and in many psychiatric disorders. Strategies that increase resistance to temptations could therefore improve overall societal well-being. One important strategy is to voluntarily precommit, i.e. to restrict one’s future action space by removing the tempting short-term option from the choice set, thereby leaving only the long-term option for implementation. The neural mechanisms necessary to implement precommitment have remained unknown. Here, we test whether anodal transcranial direct current stimulation (tDCS) over the frontopolar cortex (FPC) can improve precommitment. Participants performed a self-control task in which they could precommit to obtain a delayed larger reward by removing an immediately available smaller reward from the future choice options. We found that anodal stimulation over FPC selectively increased the propensity to precommit. In contrast, tDCS had no effects on non-binding decisions, impulse control or reward preference. Our data establish a causal role for the FPC in the implementation of precommitment, revealing a novel route to improving resistance against temptations. PMID:28170049

The Effects of Heuristics and Apophenia on Probabilistic Choice.

PubMed

Ellerby, Zack W; Tunney, Richard J

2017-01-01

Given a repeated choice between two or more options with independent and identically distributed reward probabilities, overall pay-offs can be maximized by the exclusive selection of the option with the greatest likelihood of reward. The tendency to match response proportions to reward contingencies is suboptimal. Nevertheless, this behaviour is well documented. A number of explanatory accounts have been proposed for probability matching. These include failed pattern matching, driven by apophenia, and a heuristic-driven response that can be overruled with sufficient deliberation. We report two experiments that were designed to test the relative effects on choice behaviour of both an intuitive versus strategic approach to the task and belief that there was a predictable pattern in the reward sequence, through a combination of both direct experimental manipulation and post-experimental self-report. Mediation analysis was used to model the pathways of effects. Neither of two attempted experimental manipulations of apophenia, nor self-reported levels of apophenia, had a significant effect on proportions of maximizing choices. However, the use of strategy over intuition proved a consistent predictor of maximizing, across all experimental conditions. A parallel analysis was conducted to assess the effect of controlling for individual variance in perceptions of reward contingencies. Although this analysis suggested that apophenia did increase probability matching in the standard task preparation, this effect was found to result from an unforeseen relationship between self-reported apophenia and perceived reward probabilities. A Win-Stay Lose-Shift (WSLS ) analysis indicated no reliable relationship between WSLS and either intuition or strategy use.

15 CFR 758.5 - Conformity of documents and unloading of items.

Code of Federal Regulations, 2011 CFR

2011-01-01

... and Shipper's Export Declaration (SED) or AES electronic equivalent. (2) Optional ports of unloading... ultimate destination or are included on the BIS license and SED or AES electronic equivalent. (ii... ports of unloading on the SED or AES electronic equivalent and other export control documents, so long...

Exit, Punishment and Rewards in Commons Dilemmas: An Experimental Study

PubMed Central

Bravo, Giangiacomo; Squazzoni, Flaminio

2013-01-01

Commons dilemmas are interaction situations where a common good is provided or exploited by a group of individuals so that optimal collective outcomes clash with private interests. Although in these situations, social norms and institutions exist that might help individuals to cooperate, little is known about the interaction effects between positive and negative incentives and exit options by individuals. We performed a modified public good game experiment to examine the effect of exit, rewards and punishment, as well as the interplay between exit and rewards and punishment. We found that punishment had a stronger effect than rewards on cooperation if considered by itself, whereas rewards had a stronger effect when combined with voluntary participation. This can be explained in terms of the ‘framing effect’, i.e., as the combination of exit and rewards might induce people to attach higher expected payoffs to cooperative strategies and expect better behaviour from others. PMID:23936356

Exit, punishment and rewards in commons dilemmas: an experimental study.

PubMed

Bravo, Giangiacomo; Squazzoni, Flaminio

2013-01-01

Commons dilemmas are interaction situations where a common good is provided or exploited by a group of individuals so that optimal collective outcomes clash with private interests. Although in these situations, social norms and institutions exist that might help individuals to cooperate, little is known about the interaction effects between positive and negative incentives and exit options by individuals. We performed a modified public good game experiment to examine the effect of exit, rewards and punishment, as well as the interplay between exit and rewards and punishment. We found that punishment had a stronger effect than rewards on cooperation if considered by itself, whereas rewards had a stronger effect when combined with voluntary participation. This can be explained in terms of the 'framing effect', i.e., as the combination of exit and rewards might induce people to attach higher expected payoffs to cooperative strategies and expect better behaviour from others.

Orbitofrontal cortex and basolateral amygdala lesions result in suboptimal and dissociable reward choices on cue-guided effort in rats

PubMed Central

Ostrander, Serena; Cazares, Victor A.; Kim, Charissa; Cheung, Shauna; Gonzalez, Isabel; Izquierdo, Alicia

2011-01-01

The orbitofrontal cortex (OFC) and basolateral nucleus of the amygdala (BLA) are important neural regions in responding adaptively to changes in the incentive value of reward. Recent evidence suggests these structures may be differentially engaged in effort and cue-guided choice behavior. In two t-maze experiments, we examined the effects of bilateral lesions of either BLA or OFC on 1) effortful choices where rats could climb a barrier for a high reward or select a low reward with no effort and 2) effortful choices when a visual cue signaled changes in reward magnitude. In both experiments, BLA rats displayed transient work aversion, choosing the effortless low reward option. OFC rats were work averse only in the no cue conditions, displaying a pattern of attenuated recovery from the cue conditions signaling reward unavailability in the effortful arm. Control measures rule out an inability to discriminate the cue in either lesion group. PMID:21639604

Modulation of ventral striatal activity by cognitive effort

PubMed Central

Dobryakova, Ekaterina; Jessup, Ryan K; Tricomi, Elizabeth

2016-01-01

Effort discounting theory suggests that the value of a reward should be lower if it was effortful to obtain, whereas contrast theory suggests that the contrast between the costly effort and the reward makes the reward seem more valuable. To test these alternative hypotheses, we used functional magnetic resonance imaging (fMRI) as participants engaged in feedback-based learning that required low or high cognitive effort to obtain positive feedback, while the objective amount of information provided by feedback remained constant. In the low effort condition, a single image was presented with four response options. In the high effort condition, two images were presented, each with two response options, and correct feedback was presented only when participants responded correctly to both of the images. Accuracy was significantly lower for the high effort condition, and all participants reported that the high effort condition was more difficult. A region of the ventral striatum selected for sensitivity to feedback value also showed increased activation to feedback presentation associated with the high effort condition relative to the low effort condition, when controlling for activation from corresponding control conditions where feedback was random. These results suggest that increased cognitive effort produces corresponding increases in positive feedback-related ventral striatum activity, in line with the predictions made by contrast theory. The accomplishment of obtaining a hard-earned intrinsic reward, such as positive feedback, may be particularly likely to promote reward-related brain activity. PMID:27989778

Neural markers of social and monetary rewards in children with Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder

PubMed Central

Gonzalez-Gadea, Maria Luz; Sigman, Mariano; Rattazzi, Alexia; Lavin, Claudio; Rivera-Rei, Alvaro; Marino, Julian; Manes, Facundo; Ibanez, Agustin

2016-01-01

Recent theories of decision making propose a shared value-related brain mechanism for encoding monetary and social rewards. We tested this model in children with Attention-Deficit/Hyperactivity Disorder (ADHD), children with Autism Spectrum Disorder (ASD) and control children. We monitored participants’ brain dynamics using high density-electroencephalography while they played a monetary and social reward tasks. Control children exhibited a feedback Error-Related Negativity (fERN) modulation and Anterior Cingulate Cortex (ACC) source activation during both tasks. Remarkably, although cooperation resulted in greater losses for the participants, the betrayal options generated greater fERN responses. ADHD subjects exhibited an absence of fERN modulation and reduced ACC activation during both tasks. ASD subjects exhibited normal fERN modulation during monetary choices and inverted fERN/ACC responses in social options than did controls. These results suggest that in neurotypicals, monetary losses and observed disloyal social decisions induced similar activity in the brain value system. In ADHD children, difficulties in reward processing affected early brain signatures of monetary and social decisions. Conversely, ASD children showed intact neural markers of value-related monetary mechanisms, but no brain modulation by prosociality in the social task. These results offer insight into the typical and atypical developments of neural correlates of monetary and social reward processing. PMID:27464551

Contextual modulation of value signals in reward and punishment learning

PubMed Central

Palminteri, Stefano; Khamassi, Mehdi; Joffily, Mateus; Coricelli, Giorgio

2015-01-01

Compared with reward seeking, punishment avoidance learning is less clearly understood at both the computational and neurobiological levels. Here we demonstrate, using computational modelling and fMRI in humans, that learning option values in a relative—context-dependent—scale offers a simple computational solution for avoidance learning. The context (or state) value sets the reference point to which an outcome should be compared before updating the option value. Consequently, in contexts with an overall negative expected value, successful punishment avoidance acquires a positive value, thus reinforcing the response. As revealed by post-learning assessment of options values, contextual influences are enhanced when subjects are informed about the result of the forgone alternative (counterfactual information). This is mirrored at the neural level by a shift in negative outcome encoding from the anterior insula to the ventral striatum, suggesting that value contextualization also limits the need to mobilize an opponent punishment learning system. PMID:26302782

Evidence integration in model-based tree search

PubMed Central

Solway, Alec; Botvinick, Matthew M.

2015-01-01

Research on the dynamics of reward-based, goal-directed decision making has largely focused on simple choice, where participants decide among a set of unitary, mutually exclusive options. Recent work suggests that the deliberation process underlying simple choice can be understood in terms of evidence integration: Noisy evidence in favor of each option accrues over time, until the evidence in favor of one option is significantly greater than the rest. However, real-life decisions often involve not one, but several steps of action, requiring a consideration of cumulative rewards and a sensitivity to recursive decision structure. We present results from two experiments that leveraged techniques previously applied to simple choice to shed light on the deliberation process underlying multistep choice. We interpret the results from these experiments in terms of a new computational model, which extends the evidence accumulation perspective to multiple steps of action. PMID:26324932

Contextual modulation of value signals in reward and punishment learning.

PubMed

Palminteri, Stefano; Khamassi, Mehdi; Joffily, Mateus; Coricelli, Giorgio

2015-08-25

Compared with reward seeking, punishment avoidance learning is less clearly understood at both the computational and neurobiological levels. Here we demonstrate, using computational modelling and fMRI in humans, that learning option values in a relative--context-dependent--scale offers a simple computational solution for avoidance learning. The context (or state) value sets the reference point to which an outcome should be compared before updating the option value. Consequently, in contexts with an overall negative expected value, successful punishment avoidance acquires a positive value, thus reinforcing the response. As revealed by post-learning assessment of options values, contextual influences are enhanced when subjects are informed about the result of the forgone alternative (counterfactual information). This is mirrored at the neural level by a shift in negative outcome encoding from the anterior insula to the ventral striatum, suggesting that value contextualization also limits the need to mobilize an opponent punishment learning system.

Pro-Dopamine Regulator – (KB220) to Balance Brain Reward Circuitry in Reward Deficiency Syndrome (RDS)

PubMed Central

Blum, Kenneth; Febo, Marcelo; Fried, Lyle; Baron, David; Braverman, Eric R.; Dushaj, Kristina; Li, Mona; Demetrovics, Zsolt; Badgaiyan, Rajendra D.

2017-01-01

We are faced with a worldwide opiate/opioid epidemic that is devastating. According to the Centers for Disease Control and Prevention (CDC), at least 127 people, young and old, are dying every day in America due to narcotic overdose. The Food and Drug Administration (FDA) has approved Medication-Assisted Treatments (MATs) for opiate/opioids as well as alcohol and nicotine. The mechanism of action of most MATS favors either blocking of dopaminergic function or a form of Opiate Substitution Therapy (OST). These treatment options are adequate for short-term treatment of the symptoms of addiction and harm reduction but fail long-term to deal with the cause or lead to recovery. There is a need to continue to seek better treatment options. This mini-review is the history of the development of one such treatment; a glutaminergic-dopaminergic optimization complex called KB220. Growing evidence indicates that brain reward circuitry controls drug addiction, in conjunction with “anti-reward systems” as the “anti-reward systems” can be affected by both glutaminergic and dopaminergic transmission. KB220 may likely alter the function of these regions and provide for the possible eventual balancing the brain reward system and the induction of “dopamine homeostasis.” Many of these concepts have been reported elsewhere and have become an integral part of the addiction science literature. However, the concise review may encourage readership to reconsider these facts and stimulate further research focused on the impact that the induction of “dopamine homeostasis” may have on recovery and relapse prevention. PMID:28804788

Basolateral amygdala lesions abolish mutual reward preferences in rats.

PubMed

Hernandez-Lallement, Julen; van Wingerden, Marijn; Schäble, Sandra; Kalenscher, Tobias

2016-01-01

In a recent study, we demonstrated that rats prefer mutual rewards in a Prosocial Choice Task. Here, employing the same task, we show that the integrity of basolateral amygdala was necessary for the expression of mutual reward preferences. Actor rats received bilateral excitotoxic (n=12) or sham lesions (n=10) targeting the basolateral amygdala and were subsequently tested in a Prosocial Choice Task where they could decide between rewarding ("Both Reward") or not rewarding a partner rat ("Own Reward"), either choice yielding identical reward to the actors themselves. To manipulate the social context and control for secondary reinforcement sources, actor rats were paired with either a partner rat (partner condition) or with an inanimate rat toy (toy condition). Sham-operated animals revealed a significant preference for the Both-Reward-option in the partner condition, but not in the toy condition. Amygdala-lesioned animals exhibited significantly lower Both-Reward preferences than the sham group in the partner but not in the toy condition, suggesting that basolateral amygdala was required for the expression of mutual reward preferences. Critically, in a reward magnitude discrimination task in the same experimental setup, both sham-operated and amygdala-lesioned animals preferred large over small rewards, suggesting that amygdala lesion effects were restricted to decision making in social contexts, leaving self-oriented behavior unaffected. Copyright © 2015 Elsevier Inc. All rights reserved.

Starlings uphold principles of economic rationality for delay and probability of reward.

PubMed

Monteiro, Tiago; Vasconcelos, Marco; Kacelnik, Alex

2013-04-07

Rationality principles are the bedrock of normative theories of decision-making in biology and microeconomics, but whereas in microeconomics, consistent choice underlies the notion of utility; in biology, the assumption of consistent selective pressures justifies modelling decision mechanisms as if they were designed to maximize fitness. In either case, violations of consistency contradict expectations and attract theoretical interest. Reported violations of rationality in non-humans include intransitivity (i.e. circular preferences) and lack of independence of irrelevant alternatives (changes in relative preference between options when embedded in different choice sets), but the extent to which these observations truly represent breaches of rationality is debatable. We tested both principles with starlings (Sturnus vulgaris), training subjects either with five options differing in food delay (exp. 1) or with six options differing in reward probability (exp. 2), before letting them choose repeatedly one option out of several binary and trinary sets of options. The starlings conformed to economic rationality on both tests, showing strong stochastic transitivity and no violation of the independence principle. These results endorse the rational choice and optimality approaches used in behavioural ecology, and highlight the need for functional and mechanistic enquiring when apparent violations of such principles are observed.

Starlings uphold principles of economic rationality for delay and probability of reward

PubMed Central

Monteiro, Tiago; Vasconcelos, Marco; Kacelnik, Alex

2013-01-01

Rationality principles are the bedrock of normative theories of decision-making in biology and microeconomics, but whereas in microeconomics, consistent choice underlies the notion of utility; in biology, the assumption of consistent selective pressures justifies modelling decision mechanisms as if they were designed to maximize fitness. In either case, violations of consistency contradict expectations and attract theoretical interest. Reported violations of rationality in non-humans include intransitivity (i.e. circular preferences) and lack of independence of irrelevant alternatives (changes in relative preference between options when embedded in different choice sets), but the extent to which these observations truly represent breaches of rationality is debatable. We tested both principles with starlings (Sturnus vulgaris), training subjects either with five options differing in food delay (exp. 1) or with six options differing in reward probability (exp. 2), before letting them choose repeatedly one option out of several binary and trinary sets of options. The starlings conformed to economic rationality on both tests, showing strong stochastic transitivity and no violation of the independence principle. These results endorse the rational choice and optimality approaches used in behavioural ecology, and highlight the need for functional and mechanistic enquiring when apparent violations of such principles are observed. PMID:23390098

Dopamine D3 Receptors Modulate the Ability of Win-Paired Cues to Increase Risky Choice in a Rat Gambling Task.

PubMed

Barrus, Michael M; Winstanley, Catharine A

2016-01-20

Similar to other addiction disorders, the cues inherent in many gambling procedures are thought to play an important role in mediating their addictive nature. Animal models of gambling-related behavior, while capturing dimensions of economic decision making, have yet to address the impact that these salient cues may have in promoting maladaptive choice. Here, we determined whether adding win-associated audiovisual cues to a rat gambling task (rGT) would influence decision making. Thirty-two male Long-Evans rats were tested on either the cued or uncued rGT. In these tasks, animals chose between four options associated with different magnitudes and frequencies of reward and punishing time-out periods. As in the Iowa Gambling Task, favoring options associated with smaller per-trial rewards but smaller losses and avoiding the tempting "high-risk, high-reward" decks maximized profits. Although the reinforcement contingencies were identical in both task versions, rats' choice of the disadvantageous risky options was significantly greater on the cued task. Furthermore, a D3 receptor agonist increased choice of the disadvantageous options, whereas a D3 antagonist had the opposite effects, only on the cued task. These findings are consistent with the reported role of D3 receptors in mediating the facilitatory effects of cues in addiction. Collectively, these results indicate that the cued rGT is a valuable model with which to study the mechanism by which salient cues can invigorate maladaptive decision making, an important and understudied component of both gambling and substance use disorders. Significance statement: We used a rodent analog of the Iowa Gambling Task to determine whether the addition of audiovisual cues would affect choice preferences. Adding reward-concurrent cues significantly increased risky choice. This is the first clear demonstration that reward-paired cues can bias cost/benefit decision making against a subject's best interests in a manner concordant with elevated addiction susceptibility. Choice on the cued task was uniquely sensitive to modulation by D3 receptor ligands, yet these drugs did not alter decision making on the uncued task. The relatively unprecedented sensitivity of choice on the cued task to D3-receptor-mediated neurotransmission data suggest that similar neurobiological processes underlie the ability of cues to both bias animals toward risky options and facilitate drug addiction. Copyright © 2016 the authors 0270-6474/16/360785-10$15.00/0.

Putting Bandits into Context: How Function Learning Supports Decision Making

ERIC Educational Resources Information Center

Schulz, Eric; Konstantinidis, Emmanouil; Speekenbrink, Maarten

2018-01-01

The authors introduce the contextual multi-armed bandit task as a framework to investigate learning and decision making in uncertain environments. In this novel paradigm, participants repeatedly choose between multiple options in order to maximize their rewards. The options are described by a number of contextual features which are predictive of…

Of goals and habits: age-related and individual differences in goal-directed decision-making.

PubMed

Eppinger, Ben; Walter, Maik; Heekeren, Hauke R; Li, Shu-Chen

2013-01-01

In this study we investigated age-related and individual differences in habitual (model-free) and goal-directed (model-based) decision-making. Specifically, we were interested in three questions. First, does age affect the balance between model-based and model-free decision mechanisms? Second, are these age-related changes due to age differences in working memory (WM) capacity? Third, can model-based behavior be affected by manipulating the distinctiveness of the reward value of choice options? To answer these questions we used a two-stage Markov decision task in in combination with computational modeling to dissociate model-based and model-free decision mechanisms. To affect model-based behavior in this task we manipulated the distinctiveness of reward probabilities of choice options. The results show age-related deficits in model-based decision-making, which are particularly pronounced if unexpected reward indicates the need for a shift in decision strategy. In this situation younger adults explore the task structure, whereas older adults show perseverative behavior. Consistent with previous findings, these results indicate that older adults have deficits in the representation and updating of expected reward value. We also observed substantial individual differences in model-based behavior. In younger adults high WM capacity is associated with greater model-based behavior and this effect is further elevated when reward probabilities are more distinct. However, in older adults we found no effect of WM capacity. Moreover, age differences in model-based behavior remained statistically significant, even after controlling for WM capacity. Thus, factors other than decline in WM, such as deficits in the in the integration of expected reward value into strategic decisions may contribute to the observed impairments in model-based behavior in older adults.

Of goals and habits: age-related and individual differences in goal-directed decision-making

PubMed Central

Eppinger, Ben; Walter, Maik; Heekeren, Hauke R.; Li, Shu-Chen

2013-01-01

In this study we investigated age-related and individual differences in habitual (model-free) and goal-directed (model-based) decision-making. Specifically, we were interested in three questions. First, does age affect the balance between model-based and model-free decision mechanisms? Second, are these age-related changes due to age differences in working memory (WM) capacity? Third, can model-based behavior be affected by manipulating the distinctiveness of the reward value of choice options? To answer these questions we used a two-stage Markov decision task in in combination with computational modeling to dissociate model-based and model-free decision mechanisms. To affect model-based behavior in this task we manipulated the distinctiveness of reward probabilities of choice options. The results show age-related deficits in model-based decision-making, which are particularly pronounced if unexpected reward indicates the need for a shift in decision strategy. In this situation younger adults explore the task structure, whereas older adults show perseverative behavior. Consistent with previous findings, these results indicate that older adults have deficits in the representation and updating of expected reward value. We also observed substantial individual differences in model-based behavior. In younger adults high WM capacity is associated with greater model-based behavior and this effect is further elevated when reward probabilities are more distinct. However, in older adults we found no effect of WM capacity. Moreover, age differences in model-based behavior remained statistically significant, even after controlling for WM capacity. Thus, factors other than decline in WM, such as deficits in the in the integration of expected reward value into strategic decisions may contribute to the observed impairments in model-based behavior in older adults. PMID:24399925

Decision-making under risk and ambiguity in low-birth-weight pigs.

PubMed

Murphy, Eimear; Kraak, Lynn; van den Broek, Jan; Nordquist, Rebecca E; van der Staay, Franz Josef

2015-03-01

Low birth weight (LBW) in humans is a risk factor for later cognitive, behavioural and emotional problems. In pigs, LBW is associated with higher mortality, but little is known about consequences for surviving piglets. Alteration in hypothalamic-pituitary-adrenal axis function in LBW pigs suggests altered emotionality, but no behavioural indicators have been studied. Decision-making under uncertain conditions, e.g., risk or ambiguity, is susceptible to emotional influences and may provide a means of assessing long-term effects of LBW in piglets. We tested LBW (N = 8) and normal-birth-weight (NBW; N = 8) male pigs in two decision-making tasks. For decision-making under risk, we developed a simple two-choice probabilistic task, the Pig Gambling Task (PGT), where an 'advantageous' option offered small but frequent rewards and a 'disadvantageous' option offered large but infrequent rewards. The advantageous option offered greater overall gain. For decision-making under ambiguity, we used a Judgement Bias Task (JBT) where pigs were trained to make an active response to 'positive' and 'negative' tone cues (signalling large and small rewards, respectively). Responses to ambiguous tone cues were rated as more or less optimistic. LBW pigs chose the advantageous option more often in later blocks of the PGT, and were scored as less optimistic in the JBT, than NBW pigs. Our findings demonstrate that LBW pigs have developed different behavioural strategies with respect to decision-making. We propose that this is guided by changes in emotionality in LBW piglets, and we provide behavioural evidence of increased negative affect in LBW piglets.

The Nature of Belief-Directed Exploratory Choice in Human Decision-Making

PubMed Central

Knox, W. Bradley; Otto, A. Ross; Stone, Peter; Love, Bradley C.

2011-01-01

In non-stationary environments, there is a conflict between exploiting currently favored options and gaining information by exploring lesser-known options that in the past have proven less rewarding. Optimal decision-making in such tasks requires considering future states of the environment (i.e., planning) and properly updating beliefs about the state of the environment after observing outcomes associated with choices. Optimal belief-updating is reflective in that beliefs can change without directly observing environmental change. For example, after 10 s elapse, one might correctly believe that a traffic light last observed to be red is now more likely to be green. To understand human decision-making when rewards associated with choice options change over time, we develop a variant of the classic “bandit” task that is both rich enough to encompass relevant phenomena and sufficiently tractable to allow for ideal actor analysis of sequential choice behavior. We evaluate whether people update beliefs about the state of environment in a reflexive (i.e., only in response to observed changes in reward structure) or reflective manner. In contrast to purely “random” accounts of exploratory behavior, model-based analyses of the subjects’ choices and latencies indicate that people are reflective belief updaters. However, unlike the Ideal Actor model, our analyses indicate that people’s choice behavior does not reflect consideration of future environmental states. Thus, although people update beliefs in a reflective manner consistent with the Ideal Actor, they do not engage in optimal long-term planning, but instead myopically choose the option on every trial that is believed to have the highest immediate payoff. PMID:22319503

The Relationship Between Structural Game Characteristics and Gambling Behavior: A Population-Level Study.

PubMed

Leino, Tony; Torsheim, Torbjørn; Blaszczynski, Alex; Griffiths, Mark; Mentzoni, Rune; Pallesen, Ståle; Molde, Helge

2015-12-01

The aim of this study was to examine the relationship between the structural characteristics and gambling behavior among video lottery terminal (VLT) gamblers. The study was ecological valid, because the data consisted of actual gambling behavior registered in the participants natural gambling environment without intrusion by researchers. Online behavioral tracking data from Multix, an eight game video lottery terminal, were supplied by Norsk-Tipping (the state owned gambling company in Norway). The sample comprised the entire population of Multix gamblers (N = 31,109) who had gambled in January 2010. The individual number of bets made across games was defined as the dependent variable, reward characteristics of a game (i.e., payback percentage, hit frequency, size of winnings and size of jackpot) and bet characteristics of a game (i.e., range of betting options and availability of advanced betting options) served as the independent variables. Control variables were age and gender. Two separate cross-classified multilevel random intercepts models were used to analyze the relationship between bets made, reward characteristics and bet characteristics, where the number of bets was nested within both individuals and within games. The results show that the number of bets is positively associated with payback percentage, hit frequency, being female and age, and negatively associated with size of wins and range of available betting options. In summary, the results show that the reward characteristics and betting options explained 27% and 15% of the variance in the number of bets made, respectively. It is concluded that structural game characteristics affect gambling behavior. Implications of responsible gambling are discussed.

The Ecological Rationality of State-Dependent Valuation

ERIC Educational Resources Information Center

McNamara, J. M.; Trimmer, P. C.; Houston, A. I.

2012-01-01

Laboratory studies on a range of animals have identified a bias that seems to violate basic principles of rational behavior: A preference is shown for feeding options that previously provided food when reserves were low, even though another option had been found to give the same reward with less delay. The bias presents a challenge to normative…

Rewarding peer reviewers: maintaining the integrity of science communication.

PubMed

Gasparyan, Armen Yuri; Gerasimov, Alexey N; Voronov, Alexander A; Kitas, George D

2015-04-01

This article overviews currently available options for rewarding peer reviewers. Rewards and incentives may help maintain the quality and integrity of scholarly publications. Publishers around the world implemented a variety of financial and nonfinancial mechanisms for incentivizing their best reviewers. None of these is proved effective on its own. A strategy of combined rewards and credits for the reviewers1 creative contributions seems a workable solution. Opening access to reviews and assigning publication credits to the best reviews is one of the latest achievements of digitization. Reviews, posted on academic networking platforms, such as Publons, add to the transparency of the whole system of peer review. Reviewer credits, properly counted and displayed on individual digital profiles, help distinguish the best contributors, invite them to review and offer responsible editorial posts.

Rewarding Peer Reviewers: Maintaining the Integrity of Science Communication

PubMed Central

2015-01-01

This article overviews currently available options for rewarding peer reviewers. Rewards and incentives may help maintain the quality and integrity of scholarly publications. Publishers around the world implemented a variety of financial and nonfinancial mechanisms for incentivizing their best reviewers. None of these is proved effective on its own. A strategy of combined rewards and credits for the reviewers1 creative contributions seems a workable solution. Opening access to reviews and assigning publication credits to the best reviews is one of the latest achievements of digitization. Reviews, posted on academic networking platforms, such as Publons, add to the transparency of the whole system of peer review. Reviewer credits, properly counted and displayed on individual digital profiles, help distinguish the best contributors, invite them to review and offer responsible editorial posts. PMID:25829801

Evidence for the speed-value trade-off: human and monkey decision making is magnitude sensitive.

PubMed

Pirrone, Angelo; Azab, Habiba; Hayden, Benjamin Y; Stafford, Tom; Marshall, James A R

2018-04-01

Complex natural systems from brains to bee swarms have evolved to make adaptive multifactorial decisions. Recent theoretical and empirical work suggests that many evolved systems may take advantage of common motifs across multiple domains. We are particularly interested in value sensitivity (i.e., sensitivity to the magnitude or intensity of the stimuli or reward under consideration) as a mechanism to resolve deadlocks adaptively. This mechanism favours long-term reward maximization over accuracy in a simple manner, because it avoids costly delays associated with ambivalence between similar options; speed-value trade-offs have been proposed to be evolutionarily advantageous for many kinds of decision. A key prediction of the value-sensitivity hypothesis is that choices between equally-valued options will proceed faster when the options have a high value than when they have a low value. However, value-sensitivity is not part of idealised choice models such as diffusion to bound. Here we examine two different choice behaviours in two different species, perceptual decisions in humans and economic choices in rhesus monkeys, to test this hypothesis. We observe the same value sensitivity in both human perceptual decisions and monkey value-based decisions. These results endorse the idea that neural decision systems make use of the same basic principle of value-sensitivity in order to resolve costly deadlocks and thus improve long-term reward intake.

Evidence for the speed-value trade-off: human and monkey decision making is magnitude sensitive

PubMed Central

Pirrone, Angelo; Azab, Habiba; Hayden, Benjamin Y.; Stafford, Tom; Marshall, James A. R.

2017-01-01

Complex natural systems from brains to bee swarms have evolved to make adaptive multifactorial decisions. Recent theoretical and empirical work suggests that many evolved systems may take advantage of common motifs across multiple domains. We are particularly interested in value sensitivity (i.e., sensitivity to the magnitude or intensity of the stimuli or reward under consideration) as a mechanism to resolve deadlocks adaptively. This mechanism favours long-term reward maximization over accuracy in a simple manner, because it avoids costly delays associated with ambivalence between similar options; speed-value trade-offs have been proposed to be evolutionarily advantageous for many kinds of decision. A key prediction of the value-sensitivity hypothesis is that choices between equally-valued options will proceed faster when the options have a high value than when they have a low value. However, value-sensitivity is not part of idealised choice models such as diffusion to bound. Here we examine two different choice behaviours in two different species, perceptual decisions in humans and economic choices in rhesus monkeys, to test this hypothesis. We observe the same value sensitivity in both human perceptual decisions and monkey value-based decisions. These results endorse the idea that neural decision systems make use of the same basic principle of value-sensitivity in order to resolve costly deadlocks and thus improve long-term reward intake. PMID:29682592

The rewarding value of good motor performance in the context of monetary incentives.

PubMed

Lutz, Kai; Pedroni, Andreas; Nadig, Karin; Luechinger, Roger; Jäncke, Lutz

2012-07-01

Whether an agent receives positive task feedback or a monetary reward, neural activity in their striatum increases. In the latter case striatal activity reflects extrinsic reward processing, while in the former, striatal activity reflects the intrinsically rewarding effects of performing well. There can be a "hidden cost of reward", which is a detrimental effect of extrinsic on intrinsic reward value. This raises the question how these two types of reward interact. To address this, we applied a monetary incentive delay task: in all trials participants received feedback depending on their performance. In half of the trials they could additionally receive monetary reward if they performed well. This resulted in high performance trials, which were monetarily rewarded and high performance trials that were not. This made it possible to dissociate the neural correlates of performance feedback from the neural correlates of monetary reward that comes with high performance. Performance feedback alone elicits activation increases in the ventral striatum. This activation increases due to additional monetary reward. Neural response in the dorsal striatum on the other hand is only significantly increased by feedback when a monetary incentive is present. The quality of performance does not significantly influence dorsal striatum activity. In conclusion, our results indicate that the dorsal striatum is primarily sensitive to optional or actually received external rewards, whereas the ventral striatum may be coding intrinsic reward due to positive performance feedback. Thus the ventral striatum is suggested to be involved in the processing of intrinsically motivated behavior. Copyright © 2012 Elsevier Ltd. All rights reserved.

Noradrenergic modulation of risk/reward decision making.

PubMed

Montes, David R; Stopper, Colin M; Floresco, Stan B

2015-08-01

Catecholamine transmission modulates numerous cognitive and reward-related processes that can subserve more complex functions such as cost/benefit decision making. Dopamine has been shown to play an integral role in decisions involving reward uncertainty, yet there is a paucity of research investigating the contributions of noradrenaline (NA) transmission to these functions. The present study was designed to elucidate the contribution of NA to risk/reward decision making in rats, assessed with a probabilistic discounting task. We examined the effects of reducing noradrenergic transmission with the α2 agonist clonidine (10-100 μg/kg), and increasing activity at α2A receptor sites with the agonist guanfacine (0.1-1 mg/kg), the α2 antagonist yohimbine (1-3 mg/kg), and the noradrenaline transporter (NET) inhibitor atomoxetine (0.3-3 mg/kg) on probabilistic discounting. Rats chose between a small/certain reward and a larger/risky reward, wherein the probability of obtaining the larger reward either decreased (100-12.5 %) or increased (12.5-100 %) over a session. In well-trained rats, clonidine reduced risky choice by decreasing reward sensitivity, whereas guanfacine did not affect choice behavior. Yohimbine impaired adjustments in decision biases as reward probability changed within a session by altering negative feedback sensitivity. In a subset of rats that displayed prominent discounting of probabilistic rewards, the lowest dose of atomoxetine increased preference for the large/risky reward when this option had greater long-term utility. These data highlight an important and previously uncharacterized role for noradrenergic transmission in mediating different aspects of risk/reward decision making and mediating reward and negative feedback sensitivity.

The paradoxical effect of low reward probabilities in suboptimal choice.

PubMed

Fortes, Inês; Pinto, Carlos; Machado, Armando; Vasconcelos, Marco

2018-04-01

When offered a choice between 2 alternatives, animals sometimes prefer the option yielding less food. For instance, pigeons and starlings prefer an option that on 20% of the trials presents a stimulus always followed by food, and on the remaining 80% of the trials presents a stimulus never followed by food (the Informative Option), over an option that provides food on 50% of the trials regardless of the stimulus presented (the Noninformative Option). To explain this suboptimal behavior, it has been hypothesized that animals ignore (or do not engage with) the stimulus that is never followed by food in the Informative Option. To assess when pigeons attend to the stimulus usually not followed by food, we increased the probability of reinforcement, p, in the presence of that stimulus. Across 2 experiments, we found that the value of the Informative Option decreased with p. To account for the results, we added to the Reinforcement Rate Model (and also to the Hyperbolic Discounting Model) an engagement function, f(p), that specified the likelihood the animal attends to a stimulus followed by reward with probability p, and then derived the model predictions for 2 forms of f(p), a linear function, and an all-or-none threshold function. Both models predicted the observed findings with a linear engagement function: The higher the probability of reinforcement after a stimulus, the higher the probability of engaging the stimulus, and, surprisingly, the less the value of the option comprising the stimulus. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Curbing International Piracy of Intellectual Property. Policy Options for a Major Exporting Country.

ERIC Educational Resources Information Center

Hoffman, Gary M.; Marcou, George T.

This report of the International Piracy Project addresses three major topics: (1) The Costs and Complications of Piracy; (2) Rights Enforcement Today; and (3) Policy Options for Curbing Piracy. The first section discusses piracy of copyrights, patents, and other intellectual property, including economic losses and damage to the finances and…

75 FR 8352 - Agency Information Collection Activities: Final Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... utilization and management prospective insurance liability relative to risk premiums received. DATES: Comments...). SUMMARY: The Export-Import Bank of the United States (Ex-Im Bank), as a part of its continuing effort to... Institution'' as an option; b. Under ``Obligo Types'' we have deleted ``Eximbank Sole Risk'' as an option; c...

The role of the striatum in effort-based decision-making in the absence of reward.

PubMed

Schouppe, Nathalie; Demanet, Jelle; Boehler, Carsten N; Ridderinkhof, K Richard; Notebaert, Wim

2014-02-05

Decision-making involves weighing costs against benefits, for instance, in terms of the effort it takes to obtain a reward of a given magnitude. This evaluation process has been linked to the dorsal anterior cingulate cortex (dACC) and the striatum, with activation in these brain structures reflecting the discounting effect of effort on reward. Here, we investigate how cognitive effort influences neural choice processes in the absence of an extrinsic reward. Using functional magnetic resonance imaging in humans, we used an effort-based decision-making task in which participants were required to choose between two options for a subsequent flanker task that differed in the amount of cognitive effort. Cognitive effort was manipulated by varying the proportion of incongruent trials associated with each choice option. Choice-locked activation in the striatum was higher when participants chose voluntarily for the more effortful alternative but displayed the opposite trend on forced-choice trials. The dACC revealed a similar, yet only trend-level significant, activation pattern. Our results imply that activation levels in the striatum reflect a cost-benefit analysis, in which a balance is made between effort discounting and the intrinsic motivation to choose a cognitively challenging task. Moreover, our findings indicate that it matters whether this challenge is voluntarily chosen or externally imposed. As such, the present findings contrast with classical findings on effort discounting that found reductions in striatum activation for higher effort by finding enhancements of the same neural circuits when a cognitively challenging task is voluntarily selected and does not entail the danger of losing reward.

Evaluating the Impact of Naltrexone on the Rat Gambling Task to Test Its Predictive Validity for Gambling Disorder.

PubMed

Di Ciano, Patricia; Le Foll, Bernard

2016-01-01

Gambling Disorder has serious consequences and no medications are currently approved for the treatment of this disorder. One factor that may make medication development difficult is the lack of animal models of gambling that would allow for the pre-clinical screening of efficacy. Despite this, there is evidence from clinical trials that opiate antagonists, in particular naltrexone, may be useful in treating gambling disorder. To-date, the effects of naltrexone on pre-clinical models of gambling have not been evaluated. The purpose of the present study was to evaluate the effects of naltrexone in an animal model of gambling, the rat gambling task (rGT), to determine whether this model has some predictive validity. The rGT is a model in which rats are given a choice of making either a response that produces a large reward or a small reward. The larger the reward, the greater the punishment, and thus this task requires that the animal inhibit the 'tempting' choice, as the smaller reward option produces overall the most number of rewards per session. People with gambling disorder chose the tempting option more, thus the rGT may provide a model of problem gambling. It was found that naltrexone improved performance on this task in a subset of animals that chose the 'tempting', disadvantageous choice, more at baseline. Thus, the results of this study suggest that the rGT should be further investigated as a pre-clinical model of gambling disorder and that further investigation into whether opioid antagonists are effective in treating Gambling Disorder may be warranted.

Reduced Sensitivity to Sooner Reward During Intertemporal Decision-Making Following Insula Damage in Humans

PubMed Central

Sellitto, Manuela; Ciaramelli, Elisa; Mattioli, Flavia; di Pellegrino, Giuseppe

2016-01-01

During intertemporal choice, humans tend to prefer small-sooner rewards over larger-delayed rewards, reflecting temporal discounting (TD) of delayed outcomes. Functional neuroimaging (fMRI) evidence has implicated the insular cortex in time-sensitive decisions, yet it is not clear whether activity in this brain region is crucial for, or merely associated with, TD behavior. Here, patients with damage to the insula (Insular patients), control patients with lesions outside the insula, and healthy individuals chose between smaller-sooner and larger-later monetary rewards. Insular patients were less sensitive to sooner rewards than were the control groups, exhibiting reduced TD. A Voxel-based Lesion-Symptom Mapping (VLSM) analysis confirmed a statistically significant association between insular damage and reduced TD. These results indicate that the insular cortex is crucial for intertemporal choice. We suggest that he insula may be necessary to anticipate the bodily/emotional effects of receiving rewards at different delays, influencing the computation of their incentive value. Devoid of such input, insular patients’ choices would be governed by a heuristic of quantity, allowing patients to wait for larger options. PMID:26793084

Separate and overlapping brain areas encode subjective value during delay and effort discounting.

PubMed

Massar, Stijn A A; Libedinsky, Camilo; Weiyan, Chee; Huettel, Scott A; Chee, Michael W L

2015-10-15

Making decisions about rewards that involve delay or effort requires the integration of value and cost information. The brain areas recruited in this integration have been well characterized for delay discounting. However only a few studies have investigated how effort costs are integrated into value signals to eventually determine choice. In contrast to previous studies that have evaluated fMRI signals related to physical effort, we used a task that focused on cognitive effort. Participants discounted the value of delayed and effortful rewards. The value of cognitively effortful rewards was represented in the anterior portion of the inferior frontal gyrus and dorsolateral prefrontal cortex. Additionally, the value of the chosen option was encoded in the anterior cingulate cortex, caudate, and cerebellum. While most brain regions showed no significant dissociation between effort discounting and delay discounting, the ACC was significantly more activated in effort compared to delay discounting tasks. Finally, overlapping regions within the right orbitofrontal cortex and lateral temporal and parietal cortices encoded the value of the chosen option during both delay and effort discounting tasks. These results indicate that encoding of rewards discounted by cognitive effort and delay involves partially dissociable brain areas, but a common representation of chosen value is present in the orbitofrontal, temporal and parietal cortices. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Identifying nurses' rewards: a qualitative categorization study in Belgium

PubMed Central

De Gieter, Sara; De Cooman, Rein; Pepermans, Roland; Caers, Ralf; Du Bois, Cindy; Jegers, Marc

2006-01-01

Background Rewards are important in attracting, motivating and retaining the most qualified employees, and nurses are no exception to this rule. This makes the establishment of an efficient reward system for nurses a true challenge for every hospital manager. A reward does not necessarily have a financial connotation: non-financial rewards may matter too, or may even be more important. Therefore, the present study examines nurses' reward perceptions, in order to identify potential reward options. Methods To answer the research question "What do nurses consider a reward and how can these rewards be categorized?", 20 in-depth semi-structured interviews with nurses were conducted and analysed using discourse and content analyses. In addition, the respondents received a list of 34 rewards (derived from the literature) and were asked to indicate the extent to which they perceived each of them to be rewarding. Results Discourse analysis revealed three major reward categories: financial, non-financial and psychological, each containing different subcategories. In general, nurses more often mentioned financial rewards spontaneously in the interview, compared to non-financial and psychological rewards. The questionnaire results did not, however, indicate a significant difference in the rewarding potential of these three categories. Both the qualitative and quantitative data revealed that a number of psychological and non-financial rewards were important for nurses in addition to their monthly pay and other remunerations. In particular, appreciation for their work by others, compliments from others, presents from others and contact with patients were highly valued. Moreover, some demographical variables influenced the reward perceptions. Younger and less experienced nurses considered promotion possibilities as more rewarding than the older and more senior ones. The latter valued job security and working for a hospital with a good reputation higher than their younger and more junior colleagues. Conclusion When trying to establish an efficient reward system for nurses, hospital managers should not concentrate on the financial reward possibilities alone. They also ought to consider non-financial and psychological rewards (in combination with financial rewards), since nurses value these as well and they may lead to a more personalized reward system. PMID:16824227

Impaired Expected Value Computations Coupled With Overreliance on Stimulus-Response Learning in Schizophrenia.

PubMed

Hernaus, Dennis; Gold, James M; Waltz, James A; Frank, Michael J

2018-04-03

While many have emphasized impaired reward prediction error signaling in schizophrenia, multiple studies suggest that some decision-making deficits may arise from overreliance on stimulus-response systems together with a compromised ability to represent expected value. Guided by computational frameworks, we formulated and tested two scenarios in which maladaptive representations of expected value should be most evident, thereby delineating conditions that may evoke decision-making impairments in schizophrenia. In a modified reinforcement learning paradigm, 42 medicated people with schizophrenia and 36 healthy volunteers learned to select the most frequently rewarded option in a 75-25 pair: once when presented with a more deterministic (90-10) pair and once when presented with a more probabilistic (60-40) pair. Novel and old combinations of choice options were presented in a subsequent transfer phase. Computational modeling was employed to elucidate contributions from stimulus-response systems (actor-critic) and expected value (Q-learning). People with schizophrenia showed robust performance impairments with increasing value difference between two competing options, which strongly correlated with decreased contributions from expected value-based learning (Q-learning). Moreover, a subtle yet consistent contextual choice bias for the probabilistic 75 option was present in people with schizophrenia, which could be accounted for by a context-dependent reward prediction error in the actor-critic. We provide evidence that decision-making impairments in schizophrenia increase monotonically with demands placed on expected value computations. A contextual choice bias is consistent with overreliance on stimulus-response learning, which may signify a deficit secondary to the maladaptive representation of expected value. These results shed new light on conditions under which decision-making impairments may arise. Copyright © 2018 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Decisions in Motion: Decision Dynamics during Intertemporal Choice reflect Subjective Evaluation of Delayed Rewards

NASA Astrophysics Data System (ADS)

O'Hora, Denis; Carey, Rachel; Kervick, Aoife; Crowley, David; Dabrowski, Maciej

2016-02-01

People tend to discount rewards or losses that occur in the future. Such delay discounting has been linked to many behavioral and health problems, since people choose smaller short-term gains over greater long-term gains. We investigated whether the effect of delays on the subjective value of rewards is expressed in how people move when they make choices. Over 600 patrons of the RISK LAB exhibition hosted by the Science Gallery DublinTM played a short computer game in which they used a computer mouse to choose between amounts of money at various delays. Typical discounting effects were observed and decision dynamics indicated that choosing smaller short-term rewards became easier (i.e., shorter response times, tighter trajectories, less vacillation) as the delays until later rewards increased. Based on a sequence of choices, subjective values of delayed outcomes were estimated and decision dynamics during initial choices predicted these values. Decision dynamics are affected by subjective values of available options and thus provide a means to estimate such values.

America COMPETES Act: Programs, Funding, and Selected Issues

DTIC Science & Technology

2009-04-17

exhibited by the balance of trade in high -technology products, was declining as the U.S. share of world exports on research and development (R&D...fund high - risk research and development at small and medium-sized businesses. With respect to labor, the act takes actions that are intended to make...to fund high -risk, high -reward basic research projects. The act also expresses the sense of the Congress that appropriately funding NASA at the

Temporal discounting in major depressive disorder.

PubMed

Pulcu, E; Trotter, P D; Thomas, E J; McFarquhar, M; Juhasz, G; Sahakian, B J; Deakin, J F W; Zahn, R; Anderson, I M; Elliott, R

2014-07-01

Major depressive disorder (MDD) is associated with abnormalities in financial reward processing. Previous research suggests that patients with MDD show reduced sensitivity to frequency of financial rewards. However, there is a lack of conclusive evidence from studies investigating the evaluation of financial rewards over time, an important aspect of reward processing that influences the way people plan long-term investments. Beck's cognitive model posits that patients with MDD hold a negative view of the future that may influence the amount of resources patients are willing to invest into their future selves. We administered a delay discounting task to 82 participants: 29 healthy controls, 29 unmedicated participants with fully remitted MDD (rMDD) and 24 participants with current MDD (11 on medication). Patients with current MDD, relative to remitted patients and healthy subjects, discounted large-sized future rewards at a significantly higher rate and were insensitive to changes in reward size from medium to large. There was a main effect of clinical group on discounting rates for large-sized rewards, and discounting rates for large-sized rewards correlated with severity of depressive symptoms, particularly hopelessness. Higher discounting of delayed rewards in MDD seems to be state dependent and may be a reflection of depressive symptoms, specifically hopelessness. Discounting distant rewards at a higher rate means that patients are more likely to choose immediate financial options. Such impairments related to long-term investment planning may be important for understanding value-based decision making in MDD, and contribute to ongoing functional impairment.

Spontaneous prosocial choice by captive bottlenose dolphins, Tursiops truncatus.

PubMed

Nakahara, Fumio; Komaba, Masayuki; Sato, Ryoichi; Ikeda, Hisako; Komaba, Kumiko; Kawakubo, Akihiro

2017-02-01

Dolphins exhibit prosocial behavior across several different contexts. However, only a few experimental studies have investigated the psychological mechanisms underlying this behavior. In this study, we investigated the mechanisms underlying prosociality in bottlenose dolphins (Tursiops truncatus). In the experiments, water shower devices, developed as environmental enrichment items, were used. Two paradigms were used to measure prosociality. The first was the prosocial choice task, involving the subject typically being offered one choice between two options. The first option provided a reward (take a shower) to both the subject and partner (prosocial choice). The second option provided a reward only to the subject (selfish choice). The second paradigm was the giving assistance task, involving the subject being provided a choice between providing instrumental help to the partner (prosocial choice) or doing nothing. It was observed that the subjects chose the prosocial choices in both paradigms. In these experiments, prosocial choices were spontaneously taken without requests from the partners. These results indicated that the dolphins show preference for other-regarding behavior. Copyright © 2016 Elsevier B.V. All rights reserved.

A potential role of reward and punishment in the facilitation of the emotion-cognition dichotomy in the Iowa Gambling Task.

PubMed

Singh, Varsha

2013-01-01

The Iowa Gambling Task (IGT) is based on the assumption that a decision maker is equally motivated to seek reward and avoid punishment, and that decision making is governed solely by the intertemporal attribute (i.e., preference for an option that produces an immediate outcome instead of one that yields a delayed outcome is believed to reflect risky decision making and is considered a deficit). It was assumed in the present study that the emotion- and cognition-based processing dichotomy manifests in the IGT as reward and punishment frequency and the intertemporal attribute. It was further proposed that the delineation of emotion- and cognition-based processing is contingent upon reward and punishment as manifested in the frame of the task (variant type) and task motivation (instruction type). The effects of IGT variant type (reward vs. punishment) and instruction type (task motivation induced by instruction types: reward, punishment, reward and punishment, or no hint) on the intertemporal and frequency attributes of IGT decision-making were analyzed. Decision making in the reward variant was equally governed by both attributes, and significantly affected by instruction type, while decision making in the punishment variant was differentially affected by the two attributes and not significantly impacted by instruction type. These results suggest that reward and punishment manifested via task frame as well as the task motivation may facilitate the differentiation of emotion- and cognition-based processing in the IGT.

A potential role of reward and punishment in the facilitation of the emotion-cognition dichotomy in the Iowa Gambling Task

PubMed Central

Singh, Varsha

2013-01-01

The Iowa Gambling Task (IGT) is based on the assumption that a decision maker is equally motivated to seek reward and avoid punishment, and that decision making is governed solely by the intertemporal attribute (i.e., preference for an option that produces an immediate outcome instead of one that yields a delayed outcome is believed to reflect risky decision making and is considered a deficit). It was assumed in the present study that the emotion- and cognition-based processing dichotomy manifests in the IGT as reward and punishment frequency and the intertemporal attribute. It was further proposed that the delineation of emotion- and cognition-based processing is contingent upon reward and punishment as manifested in the frame of the task (variant type) and task motivation (instruction type). The effects of IGT variant type (reward vs. punishment) and instruction type (task motivation induced by instruction types: reward, punishment, reward and punishment, or no hint) on the intertemporal and frequency attributes of IGT decision-making were analyzed. Decision making in the reward variant was equally governed by both attributes, and significantly affected by instruction type, while decision making in the punishment variant was differentially affected by the two attributes and not significantly impacted by instruction type. These results suggest that reward and punishment manifested via task frame as well as the task motivation may facilitate the differentiation of emotion- and cognition-based processing in the IGT. PMID:24381567

Social and ecological challenges of market-oriented shrimp farming in Vietnam.

PubMed

Lan, Ngo Thi Phuong

2013-01-01

Vietnam is one of the largest shrimp exporters in the world. Since 2010, Vietnam has earned about two billion dollars annually through shrimp exports. As a fertile area of greatest potential for agricultural production in Vietnam, the Mekong Delta has been a major contributor to the country's achievements, especially in the agricultural sector. During recent decades, trade liberation along with various policies in support of aquaculture has accelerated the development of shrimp production in the Delta. Based on an ethnographic study of shrimp farming in the Mekong Delta of Vietnam, I assert that along with great rewards arising from the expansion of shrimp farming areas, productivity, and export value, the shrimp industry has brought various environmental, economic and social challenges. Consequently, shrimp farming is a risky business and local inhabitants have relied on various strategies to cope with these challenges. Risk mitigation in shrimp production and labor migration are the two important strategies of local inhabitants for securing their livelihoods. Water pollution and poor quality post-larvae shrimp are direct consequences of market-oriented production.

Voluntary rewards mediate the evolution of pool punishment for maintaining public goods in large populations

NASA Astrophysics Data System (ADS)

Sasaki, Tatsuya; Uchida, Satoshi; Chen, Xiaojie

2015-03-01

Punishment is a popular tool when governing commons in situations where free riders would otherwise take over. It is well known that sanctioning systems, such as the police and courts, are costly and thus can suffer from those who free ride on other's efforts to maintain the sanctioning systems (second-order free riders). Previous game-theory studies showed that if populations are very large, pool punishment rarely emerges in public good games, even when participation is optional, because of second-order free riders. Here we show that a matching fund for rewarding cooperation leads to the emergence of pool punishment, despite the presence of second-order free riders. We demonstrate that reward funds can pave the way for a transition from a population of free riders to a population of pool punishers. A key factor in promoting the transition is also to reward those who contribute to pool punishment, yet not abstaining from participation. Reward funds eventually vanish in raising pool punishment, which is sustainable by punishing the second-order free riders. This suggests that considering the interdependence of reward and punishment may help to better understand the origins and transitions of social norms and institutions.

Voluntary rewards mediate the evolution of pool punishment for maintaining public goods in large populations.

PubMed

Sasaki, Tatsuya; Uchida, Satoshi; Chen, Xiaojie

2015-03-10

Punishment is a popular tool when governing commons in situations where free riders would otherwise take over. It is well known that sanctioning systems, such as the police and courts, are costly and thus can suffer from those who free ride on other's efforts to maintain the sanctioning systems (second-order free riders). Previous game-theory studies showed that if populations are very large, pool punishment rarely emerges in public good games, even when participation is optional, because of second-order free riders. Here we show that a matching fund for rewarding cooperation leads to the emergence of pool punishment, despite the presence of second-order free riders. We demonstrate that reward funds can pave the way for a transition from a population of free riders to a population of pool punishers. A key factor in promoting the transition is also to reward those who contribute to pool punishment, yet not abstaining from participation. Reward funds eventually vanish in raising pool punishment, which is sustainable by punishing the second-order free riders. This suggests that considering the interdependence of reward and punishment may help to better understand the origins and transitions of social norms and institutions.

Distributed value representation in the medial prefrontal cortex during intertemporal choices.

PubMed

Wang, Qiang; Luo, Shan; Monterosso, John; Zhang, Jintao; Fang, Xiaoyi; Dong, Qi; Xue, Gui

2014-05-28

The ability to resist current temptations in favor of long-term benefits is a critical human capacity. Despite the extensive studies on the neural mechanisms of intertemporal choices, how the subjective value of immediate and delayed rewards is represented and compared in the brain remains to be elucidated. The present fMRI study addressed this question by simultaneously and independently manipulating the magnitude of immediate and delayed rewards in an intertemporal decision task, combined with univariate analysis and multiple voxel pattern analysis. We found that activities in the posterior portion of the dorsal medial prefrontal cortex (DmPFC) were modulated by the value of immediate options, whereas activities in the adjacent anterior DmPFC were modulated by the subjective value of delayed options. Brain signal change in the ventral mPFC was positively correlated with the "relative value" (the absolute difference of subjective value between two intertemporal alternatives). In contrast, the dorsal anterior cingulate cortex activity was negatively correlated with the relative value. These results suggest that immediate and delayed rewards are separately represented in the dorsal mPFC and compared in the ventral mPFC to guide decisions. The functional dissociation of posterior and anterior DmPFC in representing immediate and delayed reward is consistent with the general structural and functional architecture of the prefrontal cortex and may provide a neural basis for human's unique capacity to delayed gratification. Copyright © 2014 the authors 0270-6474/14/347522-09$15.00/0.

Posterior cingulate cortex mediates outcome-contingent allocation of behavior

PubMed Central

Hayden, Benjamin Y.; Nair, Amrita C.; McCoy, Allison N.; Platt, Michael L.

2008-01-01

SUMMARY Adaptive decision making requires selecting an action and then monitoring its consequences to improve future decisions. The neuronal mechanisms supporting action evaluation and subsequent behavioral modification, however, remain poorly understood. To investigate the contribution of posterior cingulate cortex (CGp) to these processes, we recorded activity of single neurons in monkeys performing a gambling task in which the reward outcome of each choice strongly influenced subsequent choices. We found that CGp neurons signaled reward outcomes in a nonlinear fashion, and that outcome-contingent modulations in firing rate persisted into subsequent trials. Moreover, firing rate on any one trial predicted switching to the alternative option on the next trial. Finally, microstimulation in CGp following risky choices promoted a preference reversal for the safe option on the following trial. Collectively, these results demonstrate that CGp directly contributes to the evaluative processes that support dynamic changes in decision making in volatile environments. PMID:18940585

Decisions in Motion: Decision Dynamics during Intertemporal Choice reflect Subjective Evaluation of Delayed Rewards

PubMed Central

O’Hora, Denis; Carey, Rachel; Kervick, Aoife; Crowley, David; Dabrowski, Maciej

2016-01-01

People tend to discount rewards or losses that occur in the future. Such delay discounting has been linked to many behavioral and health problems, since people choose smaller short-term gains over greater long-term gains. We investigated whether the effect of delays on the subjective value of rewards is expressed in how people move when they make choices. Over 600 patrons of the RISK LAB exhibition hosted by the Science Gallery DublinTM played a short computer game in which they used a computer mouse to choose between amounts of money at various delays. Typical discounting effects were observed and decision dynamics indicated that choosing smaller short-term rewards became easier (i.e., shorter response times, tighter trajectories, less vacillation) as the delays until later rewards increased. Based on a sequence of choices, subjective values of delayed outcomes were estimated and decision dynamics during initial choices predicted these values. Decision dynamics are affected by subjective values of available options and thus provide a means to estimate such values. PMID:26867497

A multi-criteria decision analysis assessment of waste paper management options.

PubMed

Hanan, Deirdre; Burnley, Stephen; Cooke, David

2013-03-01

The use of Multi-criteria Decision Analysis (MCDA) was investigated in an exercise using a panel of local residents and stakeholders to assess the options for managing waste paper on the Isle of Wight. Seven recycling, recovery and disposal options were considered by the panel who evaluated each option against seven environmental, financial and social criteria. The panel preferred options where the waste was managed on the island with gasification and recycling achieving the highest scores. Exporting the waste to the English mainland for incineration or landfill proved to be the least preferred options. This research has demonstrated that MCDA is an effective way of involving community groups in waste management decision making. Copyright © 2012 Elsevier Ltd. All rights reserved.

Learning the opportunity cost of time in a patch-foraging task

PubMed Central

Constantino, Sara; Daw, Nathaniel D.

2015-01-01

Although most decision research concerns choice between simultaneously presented options, in many situations options are encountered serially and the decision is whether to exploit an option or search for a better one. Such problems have a rich history in animal foraging but we know little about the psychological processes involved. In particular, it is unknown whether learning in these problems is supported by the well studied neurocomputational mechanisms involved in more conventional tasks. We investigated how humans learn in a foraging task, which requires deciding whether to harvest a depleting resource or switch to a replenished one. The optimal choice (given by the Marginal Value Theorem; MVT) requires comparing the immediate return from harvesting to the opportunity cost of time, which is given by the long-run average reward. In two experiments, we varied opportunity cost across blocks. Subjects adjusted their behavior to blockwise changes in environmental characteristics. We examined how subjects learned their choice strategies by comparing choice adjustments to a learning rule suggested by the MVT (where the opportunity cost threshold is estimated as an average over previous rewards) and to the predominant incremental learning theory in neuroscience, temporal-difference learning (TD). Trial-by-trial decisions were better explained by the MVT threshold learning rule. These findings expand on the foraging literature, which has focused on steady-state behavior, by elucidating a computational mechanism for learning in switching tasks that is distinct from those used in traditional tasks, and suggest connections to research on average reward rates in other domains of neuroscience. PMID:25917000

Differential Involvement of the Agranular vs Granular Insular Cortex in the Acquisition and Performance of Choice Behavior in a Rodent Gambling Task

PubMed Central

Pushparaj, Abhiram; Kim, Aaron S; Musiol, Martin; Zangen, Abraham; Daskalakis, Zafiris J; Zack, Martin; Winstanley, Catharine A; Le Foll, Bernard

2015-01-01

Substance-related and addictive disorders, in particular gambling disorder, are known to be associated with risky decision-making behavior. Several neuroimaging studies have identified the involvement of the insular cortex in decision-making under risk. However, the extent of this involvement remains unclear and the specific contributions of two distinct insular subregions, the rostral agranular (RAIC) and the caudal granular (CGIC), have yet to be examined. Animals were trained to perform a rat gambling task (rGT), in which subjects chose between four options that differed in the magnitude and probability of rewards and penalties. In order to address the roles of the RAIC and CGIC in established choice behavior, pharmacological inactivations of these two subregions via local infusions of GABA receptor agonists were performed following 30 rGT training sessions. The contribution made by the RAIC or CGIC to the acquisition of choice behavior was also determined by lesioning these areas before behavioral training. Inactivation of the RAIC, but not of the CGIC, shifted rats' preference toward options with greater reward frequency and lower punishment. Before rGT acquisition, lesions of the RAIC, but not the CGIC, likewise resulted in a higher preference for options with greater reward frequency and lower punishment, and this persisted throughout the 30 training sessions. Our results provide confirmation of the involvement of the RAIC in rGT choice behavior and suggest that the RAIC may mediate detrimental risky decision-making behavior, such as that associated with addiction and gambling disorder. PMID:25953358

Uncertainty exposure causes behavioural sensitization and increases risky decision-making in male rats: toward modelling gambling disorder.

PubMed

Zeeb, Fiona D; Li, Zhaoxia; Fisher, Daniel C; Zack, Martin H; Fletcher, Paul J

2017-11-01

An animal model of gambling disorder, previously known as pathological gambling, could advance our understanding of the disorder and help with treatment development. We hypothesized that repeated exposure to uncertainty during gambling induces behavioural and dopamine (DA) sensitization - similar to chronic exposure to drugs of abuse. Uncertainty exposure (UE) may also increase risky decision-making in an animal model of gambling disorder. Male Sprague Dawley rats received 56 UE sessions, during which animals responded for saccharin according to an unpredictable, variable ratio schedule of reinforcement (VR group). Control animals responded on a predictable, fixed ratio schedule (FR group). Rats yoked to receive unpredictable reward were also included (Y group). Animals were then tested on the Rat Gambling Task (rGT), an analogue of the Iowa Gambling Task, to measure decision-making. Compared with the FR group, the VR and Y groups experienced a greater locomotor response following administration of amphetamine. On the rGT, the FR and Y groups preferred the advantageous options over the risky, disadvantageous options throughout testing (40 sessions). However, rats in the VR group did not have a significant preference for the advantageous options during sessions 20-40. Amphetamine had a small, but significant, effect on decision-making only in the VR group. After rGT testing, only the VR group showed greater hyperactivity following administration of amphetamine compared with the FR group. Reward uncertainty was the only gambling feature modelled. Actively responding for uncertain reward likely sensitized the DA system and impaired the ability to make optimal decisions, modelling some aspects of gambling disorder.

Differential Involvement of the Agranular vs Granular Insular Cortex in the Acquisition and Performance of Choice Behavior in a Rodent Gambling Task.

PubMed

Pushparaj, Abhiram; Kim, Aaron S; Musiol, Martin; Zangen, Abraham; Daskalakis, Zafiris J; Zack, Martin; Winstanley, Catharine A; Le Foll, Bernard

2015-11-01

Substance-related and addictive disorders, in particular gambling disorder, are known to be associated with risky decision-making behavior. Several neuroimaging studies have identified the involvement of the insular cortex in decision-making under risk. However, the extent of this involvement remains unclear and the specific contributions of two distinct insular subregions, the rostral agranular (RAIC) and the caudal granular (CGIC), have yet to be examined. Animals were trained to perform a rat gambling task (rGT), in which subjects chose between four options that differed in the magnitude and probability of rewards and penalties. In order to address the roles of the RAIC and CGIC in established choice behavior, pharmacological inactivations of these two subregions via local infusions of GABA receptor agonists were performed following 30 rGT training sessions. The contribution made by the RAIC or CGIC to the acquisition of choice behavior was also determined by lesioning these areas before behavioral training. Inactivation of the RAIC, but not of the CGIC, shifted rats' preference toward options with greater reward frequency and lower punishment. Before rGT acquisition, lesions of the RAIC, but not the CGIC, likewise resulted in a higher preference for options with greater reward frequency and lower punishment, and this persisted throughout the 30 training sessions. Our results provide confirmation of the involvement of the RAIC in rGT choice behavior and suggest that the RAIC may mediate detrimental risky decision-making behavior, such as that associated with addiction and gambling disorder.

Chimpanzees, bonobos and children successfully coordinate in conflict situations.

PubMed

Sánchez-Amaro, Alejandro; Duguid, Shona; Call, Josep; Tomasello, Michael

2017-06-14

Social animals need to coordinate with others to reap the benefits of group-living even when individuals' interests are misaligned. We compare how chimpanzees, bonobos and children coordinate their actions with a conspecific in a Snowdrift game, which provides a model for understanding how organisms coordinate and make decisions under conflict. In study 1, we presented pairs of chimpanzees, bonobos and children with an unequal reward distribution. In the critical condition, the preferred reward could only be obtained by waiting for the partner to act, with the risk that if no one acted, both would lose the rewards. Apes and children successfully coordinated to obtain the rewards. Children used a 'both-partner-pull' strategy and communicated during the task, while some apes relied on an 'only-one-partner-pulls' strategy to solve the task, although there were also signs of strategic behaviour as they waited for their partner to pull when that strategy led to the preferred reward. In study 2, we presented pairs of chimpanzees and bonobos with the same set-up as in study 1 with the addition of a non-social option that provided them with a secure reward. In this situation, apes had to actively decide between the unequal distribution and the alternative. In this set-up, apes maximized their rewards by taking their partners' potential actions into account. In conclusion, children and apes showed clear instances of strategic decision-making to maximize their own rewards while maintaining successful coordination. © 2017 The Author(s).

Neural evidence for description dependent reward processing in the framing effect.

PubMed

Yu, Rongjun; Zhang, Ping

2014-01-01

Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the "worse than expected" negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to "better than expected" positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect.

Amygdala Contributions to Stimulus-Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning.

PubMed

Rudebeck, Peter H; Ripple, Joshua A; Mitz, Andrew R; Averbeck, Bruno B; Murray, Elisabeth A

2017-02-22

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus-reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus-reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus-reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus-reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus-reward associations. MFC also showed increased encoding of the instrumental responses that monkeys made on each trial. Behaviorally, changes in neural activity were accompanied by slower stimulus-reward learning. The findings suggest that interactions among amygdala, OFC, and MFC contribute to learning about stimuli that predict rewards. Copyright © 2017 the authors 0270-6474/17/372186-17$15.00/0.

Amygdala Contributions to Stimulus–Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning

PubMed Central

Averbeck, Bruno B.

2017-01-01

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus–reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus–reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus–reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus–reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus–reward associations. MFC also showed increased encoding of the instrumental responses that monkeys made on each trial. Behaviorally, changes in neural activity were accompanied by slower stimulus–reward learning. The findings suggest that interactions among amygdala, OFC, and MFC contribute to learning about stimuli that predict rewards. PMID:28123082

Role of nitric oxide pathway in the conditioned rewarding effects of MDMA in mice.

PubMed

García-Pardo, M P; Rodríguez-Arias, M; Miñarro, J; Aguilar, M A

2017-07-14

It is estimated that 2.1 million young adults used MDMA/Ecstasy in the last year in Europe. Vulnerable subjects can develop dependence after MDMA abuse but currently there does not exist an effective treatment for this disorder. The nitric oxide (NO) pathway seems to have an important role on the rewarding effects of different drugs and has been proposed as a new pharmacological treatment for psychostimulant addiction. In the present study, we intend to evaluate whether the blockade of the NO synthesis (NOS) interferes with the rewarding effects of MDMA in the conditioned preference place (CPP) paradigm in young adult male mice. Our results indicated that mice treated with 7-nitroindazole (a NOS inhibitor) did not show CPP after conditioning with MDMA (1.25mg/kg). These results demonstrated the role of the NO pathway in the rewarding effects of MDMA and suggested that the manipulation of this pathway could be a new therapeutic option for MDMA abuse. Copyright © 2017 Elsevier B.V. All rights reserved.

Lighting the darkness of addiction: can phototherapy enhance contingency-management-based treatment of substance-related and addictive disorders?

PubMed

Siporin, Sheldon

2014-01-01

Maladaptive patterns of substance use are serious social problems. Both pharmacological and nonpharmacological treatments are available, but nondrug options may be preferable because they avoid the expense and adverse side effects of psychotropic medication. Contingency management (CM) and nondrug social and recreational activities (NDSRAs) are based on operant conditioning principles and seek to decrease substance use by means of nondrug rewards. However, their efficacy may be hindered where brain reward circuitry is dysfunctional. Research shows that substance abuse biases neural reward systems in favor of drug-induced highs, while disrupting circadian-based rhythms. Circadian systems also have been found to influence human reward pathways. Possibly, a bidirectional relationship exists between circadian disturbance and substance abuse effects. If so, repair of abnormal circadian rhythms might help normalize reward response in substance abusers, with positive effects on CM or NDSRA treatment outcomes. Phototherapy has been effective in repairing circadian rhythms in persons with seasonal affective disorder and other chronobiological conditions. This article proposes that it similarly may repair circadian response in substance abusers, thereby normalizing brain reward systems. By doing so, it would enhance the efficacy of CM and NDSRA therapies and may also help prevent relapse. Given its low cost and ease of administration, phototherapy seems a promising avenue to pursue.

Gambling for Gatorade: risk-sensitive decision making for fluid rewards in humans

PubMed Central

Platt, Michael L.

2009-01-01

Determining how both humans and animals make decisions in risky situations is a central problem in economics, experimental psychology, behavioral economics, and neurobiology. Typically, humans are risk seeking for gains and risk averse for losses, while animals may display a variety of preferences under risk depending on, amongst other factors, internal state. Such differences in behavior may reflect major cognitive and cultural differences or they may reflect differences in the way risk sensitivity is probed in humans and animals. Notably, in most studies humans make one or a few choices amongst hypothetical or real monetary options, while animals make dozens of repeated choices amongst options offering primary rewards like food or drink. To address this issue, we probed risk-sensitive decision making in human participants using a paradigm modeled on animal studies, in which rewards were either small squirts of Gatorade or small amounts of real money. Possible outcomes and their probabilities were not made explicit in either case. We found that individual patterns of decision making were strikingly similar for both juice and for money, both in overall risk preferences and in trial-to-trial effects of reward outcome on choice. Comparison with decisions made by monkeys for juice in a similar task revealed highly similar gambling styles. These results unite known patterns of risk-sensitive decision making in human and nonhuman primates and suggest that factors such as the way a decision is framed or internal state may underlie observed variation in risk preferences between and within species. PMID:18719953

Undergraduate Student Advising: Options for Advertising Education.

ERIC Educational Resources Information Center

Marra, James L.; Schweitzer, John C.

1992-01-01

Investigates issues surrounding undergraduate student advising in advertising. Examines adviser work loads, advising practices, rewards or recognition for advising, and faculty attitudes toward advising. Finds that innovative solutions for solving advising problems are in scarce supply in business, advertising, and, presumably, journalism and mass…

Prior Haloperidol, but not Olanzapine, Exposure Augments the Pursuit of Reward Cues: Implications for Substance Abuse in Schizophrenia

PubMed Central

Samaha, Anne-Noël

2013-01-01

Drug abuse and addiction are excessively common in schizophrenia. Chronic antipsychotic treatment might contribute to this comorbidity by inducing supersensitivity within the brain’s dopamine system. Dopamine supersensitivity can enhance the incentive motivational properties of reward cues, and reward cues contribute to the maintenance and severity of drug addiction. We have shown previously that rats withdrawn from continuous haloperidol (HAL) treatment (via subcutaneous minipump) develop dopamine supersensitivity and pursue reward cues more vigorously than HAL-naive rats following an amphetamine (AMPH) challenge. Atypical antipsychotic drugs are thought to be less likely than typicals to produce dopamine supersensitivity. Thus, we compared the effects of HAL and the atypical antipsychotic olanzapine (OLZ) on the pursuit of reward cues. Rats were trained to associate a light-tone cue with water then treated with HAL or OLZ. Following antipsychotic withdrawal, we assessed AMPH-induced enhancement of lever pressing for the cue. Withdrawal from HAL, but not from OLZ, enhanced this effect. HAL, but not OLZ, also enhanced AMPH-induced psychomotor activation and c-fos mRNA expression in the caudate-putamen. Thus, prior HAL, but not OLZ, enhanced conditioned reward following an AMPH challenge, and this was potentially linked to enhanced behavioral sensitivity to AMPH and AMPH-induced engagement of the caudate-putamen. These findings suggest that HAL, but not an atypical like OLZ, modifies reward circuitry in ways that increase responsiveness to reward cues. Because enhanced responsiveness to reward cues can promote drug-seeking behavior, it should be investigated whether atypical antipsychotics might be a preferential option in schizophrenic patients at risk for drug abuse or addiction. PMID:22927669

Chronic atomoxetine treatment during adolescence does not influence decision-making on a rodent gambling task, but does modulate amphetamine's effect on impulsive action in adulthood.

PubMed

Silveira, Mason M; Murch, W Spencer; Clark, Luke; Winstanley, Catharine A

2016-06-01

In addition to the symptoms of inattention, hyperactivity, and impulsivity, individuals with attention deficit hyperactivity disorder exhibit impaired performance on tests of real-world cost/benefit decision-making. Atomoxetine, a nonstimulant drug approved for the treatment of attention deficit hyperactivity disorder, is a selective norepinephrine reuptake inhibitor administered chronically during adolescence, a time during which the frontal brain regions necessary for executive function undergo extensive maturation. This treatment protocol can affect behavior well into adulthood, but whether it produces long-term changes in complex decision-making has not been investigated. Twenty-four Long-Evans rats were administered saline or 1.0 mg/kg atomoxetine daily from postnatal day 40 to 54. Two weeks after treatment, the adult rats were trained and assessed on the rodent gambling task, in which the animals chose from four options varying in reward, punishment, and uncertainty. Impulsive action was also measured by recording the number of premature responses made. Regardless of the treatment administered during adolescence, rats learned to favor the advantageous options characterized by small, low-penalty rewards in lieu of the larger, higher-penalty reward options. Rodent gambling task performance was then assessed following acute treatment with atomoxetine (0.1-1.0 mg/kg) and amphetamine (0.3-1.5 mg/kg). Across groups, the highest dose of atomoxetine impaired decision-making and decreased premature responding at all doses tested. Amphetamine also impaired choice performance, but selectively increased impulsive action in rats that had previously received atomoxetine treatment during adolescence. These findings contribute to our understanding of the long-term effects associated with chronic adolescent atomoxetine exposure and suggest that this treatment does not alter decision-making under conditions of risk and uncertainty in adulthood.

Neurocomputational mechanisms underlying subjective valuation of effort costs

PubMed Central

Giehl, Kathrin; Sillence, Annie

2017-01-01

In everyday life, we have to decide whether it is worth exerting effort to obtain rewards. Effort can be experienced in different domains, with some tasks requiring significant cognitive demand and others being more physically effortful. The motivation to exert effort for reward is highly subjective and varies considerably across the different domains of behaviour. However, very little is known about the computational or neural basis of how different effort costs are subjectively weighed against rewards. Is there a common, domain-general system of brain areas that evaluates all costs and benefits? Here, we used computational modelling and functional magnetic resonance imaging (fMRI) to examine the mechanisms underlying value processing in both the cognitive and physical domains. Participants were trained on two novel tasks that parametrically varied either cognitive or physical effort. During fMRI, participants indicated their preferences between a fixed low-effort/low-reward option and a variable higher-effort/higher-reward offer for each effort domain. Critically, reward devaluation by both cognitive and physical effort was subserved by a common network of areas, including the dorsomedial and dorsolateral prefrontal cortex, the intraparietal sulcus, and the anterior insula. Activity within these domain-general areas also covaried negatively with reward and positively with effort, suggesting an integration of these parameters within these areas. Additionally, the amygdala appeared to play a unique, domain-specific role in processing the value of rewards associated with cognitive effort. These results are the first to reveal the neurocomputational mechanisms underlying subjective cost–benefit valuation across different domains of effort and provide insight into the multidimensional nature of motivation. PMID:28234892

Reward Contrast Effects on Impulsive Choice and Timing in Rats

PubMed Central

Smith, Aaron P.; Peterson, Jennifer R.; Kirkpatrick, Kimberly

2016-01-01

Despite considerable interest in impulsive choice as a predictor of a variety of maladaptive behaviors, the mechanisms that drive choice behavior are still poorly understood. The present study sought to examine the influence of one understudied variable, reward magnitude contrast, on choice and timing behavior as changes in magnitude commonly occur within choice procedures. In addition, assessments of indirect effects on choice behavior through magnitude-timing interactions were assessed by measuring timing within the choice task. Rats were exposed to choice procedures composed of different pairs of magnitudes of rewards for either the smaller-sooner (SS) or larger-later (LL) option. In Phase 2, the magnitude of reward either increased or decreased by 1 pellet in different groups (LL increase = 1v1→1v2; SS decrease = 2v2 → 1v2; SS increase = 1v2 → 2v2), followed by a return to baseline in Phase 3. Choice behavior was affected by the initial magnitudes experienced in the task, demonstrating a strong anchor effect. The nature of the change in magnitude affected choice behavior as well. Timing behavior was also affected by the reward contrast manipulation albeit to a lesser degree and the timing and choice effects were correlated. The results suggest that models of choice behavior should incorporate reinforcement history, reward contrast elements, and magnitude-timing interactions, but that direct effects of reward contrast on choice should be given more weight than the indirect reward-timing interactions. A better understanding of the factors that contribute to choice behavior could supply key insights into this important individual differences variable. PMID:27867839

Neural evidence for description dependent reward processing in the framing effect

PubMed Central

Yu, Rongjun; Zhang, Ping

2014-01-01

Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the “worse than expected” negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to “better than expected” positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect. PMID:24733998

Copyright Management for Scholarship

ERIC Educational Resources Information Center

Petersen, Rodney J.

2004-01-01

This article describes the author's experience working with copyright and teachers' level of awareness or unawareness of the basics about copyright. The article is divided into sections on the following topics: Rewards for Authors; Hypothetical Scenarios; Options for Managing Authors' Rights; and Emerging Principles for Scholarly Communications.…

Quantitative Risk Assessment for African Horse Sickness in Live Horses Exported from South Africa

PubMed Central

Sergeant, Evan S.

2016-01-01

African horse sickness (AHS) is a severe, often fatal, arbovirus infection of horses, transmitted by Culicoides spp. midges. AHS occurs in most of sub-Saharan Africa and is a significant impediment to export of live horses from infected countries, such as South Africa. A stochastic risk model was developed to estimate the probability of exporting an undetected AHS-infected horse through a vector protected pre-export quarantine facility, in accordance with OIE recommendations for trade from an infected country. The model also allows for additional risk management measures, including multiple PCR tests prior to and during pre-export quarantine and optionally during post-arrival quarantine, as well as for comparison of risk associated with exports from a demonstrated low-risk area for AHS and an area where AHS is endemic. If 1 million horses were exported from the low-risk area with no post-arrival quarantine we estimate the median number of infected horses to be 5.4 (95% prediction interval 0.5 to 41). This equates to an annual probability of 0.0016 (95% PI: 0.00015 to 0.012) assuming 300 horses exported per year. An additional PCR test while in vector-protected post-arrival quarantine reduced these probabilities by approximately 12-fold. Probabilities for horses exported from an area where AHS is endemic were approximately 15 to 17 times higher than for horses exported from the low-risk area under comparable scenarios. The probability of undetected AHS infection in horses exported from an infected country can be minimised by appropriate risk management measures. The final choice of risk management measures depends on the level of risk acceptable to the importing country. PMID:26986002

Quantitative Risk Assessment for African Horse Sickness in Live Horses Exported from South Africa.

PubMed

Sergeant, Evan S; Grewar, John D; Weyer, Camilla T; Guthrie, Alan J

2016-01-01

African horse sickness (AHS) is a severe, often fatal, arbovirus infection of horses, transmitted by Culicoides spp. midges. AHS occurs in most of sub-Saharan Africa and is a significant impediment to export of live horses from infected countries, such as South Africa. A stochastic risk model was developed to estimate the probability of exporting an undetected AHS-infected horse through a vector protected pre-export quarantine facility, in accordance with OIE recommendations for trade from an infected country. The model also allows for additional risk management measures, including multiple PCR tests prior to and during pre-export quarantine and optionally during post-arrival quarantine, as well as for comparison of risk associated with exports from a demonstrated low-risk area for AHS and an area where AHS is endemic. If 1 million horses were exported from the low-risk area with no post-arrival quarantine we estimate the median number of infected horses to be 5.4 (95% prediction interval 0.5 to 41). This equates to an annual probability of 0.0016 (95% PI: 0.00015 to 0.012) assuming 300 horses exported per year. An additional PCR test while in vector-protected post-arrival quarantine reduced these probabilities by approximately 12-fold. Probabilities for horses exported from an area where AHS is endemic were approximately 15 to 17 times higher than for horses exported from the low-risk area under comparable scenarios. The probability of undetected AHS infection in horses exported from an infected country can be minimised by appropriate risk management measures. The final choice of risk management measures depends on the level of risk acceptable to the importing country.

Evaluating export container pooling options in MN, WI, and MI's Upper Peninsula.

DOT National Transportation Integrated Search

2013-04-01

Research was undertaken to investigate the issues impacting the expansion of containerized cargo in : Wisconsin, Minnesota and the Upper Peninsula of Michigan. Best practices in container pooling, load matching, : inland ports and electronic tracking...

7 CFR 1488.10 - Evidence of entry into country of destination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Under CCC Export Credit Sales Program (GSM-5) Documents Required After Financing § 1488.10 Evidence of... option of CCC, become due and payable and liquidated damages shall be payable in accordance with § 1488...

7 CFR 1488.10 - Evidence of entry into country of destination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Under CCC Export Credit Sales Program (GSM-5) Documents Required After Financing § 1488.10 Evidence of... option of CCC, become due and payable and liquidated damages shall be payable in accordance with § 1488...

Decision-making impairments in the context of intact reward sensitivity in schizophrenia.

PubMed

Heerey, Erin A; Bell-Warren, Kimberly R; Gold, James M

2008-07-01

Deficits in motivated behavior and decision-making figure prominently in the behavioral syndrome that characterizes schizophrenia and are difficult both to treat and to understand. One explanation for these deficits is that schizophrenia decreases sensitivity to rewards in the environment. An alternate explanation is that sensitivity to rewards is intact but that poor integration of affective with cognitive information impairs the ability to use this information to guide behavior. We tested reward sensitivity with a modified version of an existing signal detection task with asymmetric reinforcement and decision-making with a probabilistic decision-making task in 40 participants with schizophrenia and 26 healthy participants. Results showed normal sensitivity to reward in participants with schizophrenia but differences in choice patterns on the decision-making task. A logistic regression model of the decision-making data showed that participants with schizophrenia differed from healthy participants in the ability to weigh potential outcomes, specifically potential losses, when choosing between competing response options. Deficits in working memory ability accounted for group differences in ability to use potential outcomes during decision-making. These results suggest that the implicit mechanisms that drive reward-based learning are surprisingly intact in schizophrenia but that poor ability to integrate cognitive and affective information when calculating the value of possible choices might hamper the ability to use such information during explicit decision-making.

The subjective value of probabilistic outcomes: Impact of reward magnitude on choice with uncertain rewards in rats.

PubMed

Zoratto, Francesca; Laviola, Giovanni; Adriani, Walter

2016-03-23

Interest is rising for animal modelling of Gambling disorder (GD), which is rapidly emerging as a mental health concern. In the present study, we assessed gambling proneness in male Wistar-Han rats using the "Probabilistic Delivery Task" (PDT). This operant protocol is based on choice between either certain, small amounts of food (SS) or larger amounts of food (LLL) delivered (or not) depending on a given (and progressively decreasing) probability. Here, we manipulated the ratio between large and small reward size to assess the impact of different magnitudes on rats' performance. Specifically, we drew a comparison between threefold (2 vs 6 pellets) and fivefold (1 vs 5 pellets) sizes. As a consequence, the "indifferent point" (IP, at which either choice is mathematically equivalent in terms of total foraging) was at 33% and 20% probability of delivery, respectively. Animals tested with the sharper contrast (i.e. fivefold ratio) exhibited sustained preference for LLL far beyond the IP, despite high uncertainty and low payoff, which rendered LLL a sub-optimal option. By contrast, animals facing a slighter contrast (i.e. threefold ratio) were increasingly disturbed by progressive rarefaction of rewards, as expressed by enhanced inadequate nose-poking: this was in accordance with their prompt shift in preference to SS, already shown around the IP. In conclusion, a five-folded LLL-to-SS ratio was not only more attractive, but also less frustrating than a three-folded one. Thus, a profile of gambling proneness in the PDT is more effectively induced by marked contrast between alternative options. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Aspiration, Performance, Reward: The Advanced Placement Program at 40.

ERIC Educational Resources Information Center

Rothschild, Eric

1995-01-01

The history of the College Entrance Examination Board's Advanced Placement Program is chronicled from its conception in 1951 through early developmental stages and 40 years of implementation. Issues discussed include test development, funding, administration at the institutional level, expansion of curriculum areas and testing options, teacher…

Estimating the economic impact of Trypanosoma evansi infection on production of camel herds in Somaliland.

PubMed

Salah, Abdirahman Abdikadir; Robertson, Ian; Mohamed, Abdullahi

2015-04-01

The traditional livestock sector in Somalia is based on nomadic pastoralism where sheep, goats and camels are herded in large numbers. Data from 1609 females (27 % lactating) and 550 males (26 % exported) belonging to 40 pastoralists were analysed in this study. The expected amount of revenue the herders could lose per year in the studied area was estimated at US$404,630 being made up of US$314,630 from decreased milk yield and US$90,000 from reduced market value of exported animals. However, all the camels in Somaliland are at risk of acquiring surra infection, and therefore extrapolating the current findings to the total population could potentially lose US$223,164,000. This highlights the loss in the magnitude of US$164,253,600 from decreased milk yield and US$58,910,400 from body condition loss. Overall, the benefit in controlling Trypanosoma evansi infection in the study area was US$398,880 (n = 2159). On average, US$720 was saved per head per year from improved milk production in treated animals and US$615 from the increased value of exported camels. It is concluded that all three-treatment options evaluated were economically beneficial strategies; however, the biannual treatment of seropositive camels in the herds was the best financial option.

GHGs and air pollutants embodied in China's international trade: Temporal and spatial index decomposition analysis.

PubMed

Liu, Zhengyan; Mao, Xianqiang; Song, Peng

2017-01-01

Temporal index decomposition analysis and spatial index decomposition analysis were applied to understand the driving forces of the emissions embodied in China's exports and net exports during 2002-2011, respectively. The accumulated emissions embodied in exports accounted for approximately 30% of the total emissions in China; although the contribution of the sectoral total emissions intensity (technique effect) declined, the scale effect was largely responsible for the mounting emissions associated with export, and the composition effect played a largely insignificant role. Calculations of the emissions embodied in net exports suggest that China is generally in an environmentally inferior position compared with its major trade partners. The differences in the economy-wide emission intensities between China and its major trade partners were the biggest contribution to this reality, and the trade balance effect played a less important role. However, a lower degree of specialization in pollution intensive products in exports than in imports helped to reduce slightly the emissions embodied in net exports. The temporal index decomposition analysis results suggest that China should take effective measures to optimize export and supply-side structure and reduce the total emissions intensity. According to spatial index decomposition analysis, it is suggested that a more aggressive import policy was useful for curbing domestic and global emissions, and the transfer of advanced production technologies and emission control technologies from developed to developing countries should be a compulsory global environmental policy option to mitigate the possible leakage of pollution emissions caused by international trade.

Role of AMPA glutamate receptors in the conditioned rewarding effects of MDMA in mice.

PubMed

García-Pardo, M P; Miñarro, J; Aguilar, M A

2018-07-16

Currently, there is not an effective treatment for 3,4-methylenedioxymethamphetamine (MDMA) dependence but pharmacotherapies targeting glutamate neurotransmission are a promising strategy. Previously, we showed that blockade of glutamate NMDA and AMPA receptors impairs the conditioned rewarding effects of MDMA and cocaine, respectively. In this study we evaluated the role of AMPA receptors in the rewarding effects of MDMA in mice using the conditioned place preference (CPP) paradigm. Mice were conditioned with MDMA (1.25 mg/kg) 60 min after the treatment with saline or different doses (0.25, 1 and 5 mg/kg) of the AMPA/kainate receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Mice conditioned with MDMA acquired CPP while those treated with any dose of CNQX + MDMA did not. These results supported the involvement of the glutamatergic system in the rewarding properties of MDMA, and suggest that AMPA receptor blockade could be a new therapeutic option for the treatment of those individuals that develop MDMA dependence. Copyright © 2018 Elsevier B.V. All rights reserved.

The role of pedunculopontine nucleus in choice behavior under risk

PubMed Central

Leblond, Mona; Sukharnikova, Tatyana; Yu, Chunxiu; Rossi, Mark A.; Yin, Henry H.

2014-01-01

The dopaminergic projections to the basal ganglia have long been implicated in reward guided behavior and decision making, yet little is known about the role of the posterior pedunculopontine nucleus (pPPN), a major source of excitatory input to the mesolimbic dopamine system. Here we studied the contributions of pPPN to decision making under risk, using excitoxic lesions and reversible inactivation in rats. Rats could choose between two options: a small but certain reward on one lever, or a large but uncertain reward on the other lever. The overall payoff associated with each choice is the same, but the reward variance (risk) associated with the risky choice is much higher. In Experiment 1, we showed that excitotoxic lesions of the pPPN before training did not affect acquisition of lever pressing. But whereas the controls strongly preferred the safe choice, the lesioned rats did not. In Experiment 2, we found that muscimol inactivation of the pPPN also reversibly altered choice behavior. These results show that permanent lesions or reversible inactivation of the pPPN both abolish risk aversion in decision making. PMID:24617747

A Selective Role for Dopamine in Learning to Maximize Reward But Not to Minimize Effort: Evidence from Patients with Parkinson's Disease.

PubMed

Skvortsova, Vasilisa; Degos, Bertrand; Welter, Marie-Laure; Vidailhet, Marie; Pessiglione, Mathias

2017-06-21

Instrumental learning is a fundamental process through which agents optimize their choices, taking into account various dimensions of available options such as the possible reward or punishment outcomes and the costs associated with potential actions. Although the implication of dopamine in learning from choice outcomes is well established, less is known about its role in learning the action costs such as effort. Here, we tested the ability of patients with Parkinson's disease (PD) to maximize monetary rewards and minimize physical efforts in a probabilistic instrumental learning task. The implication of dopamine was assessed by comparing performance ON and OFF prodopaminergic medication. In a first sample of PD patients ( n = 15), we observed that reward learning, but not effort learning, was selectively impaired in the absence of treatment, with a significant interaction between learning condition (reward vs effort) and medication status (OFF vs ON). These results were replicated in a second, independent sample of PD patients ( n = 20) using a simplified version of the task. According to Bayesian model selection, the best account for medication effects in both studies was a specific amplification of reward magnitude in a Q-learning algorithm. These results suggest that learning to avoid physical effort is independent from dopaminergic circuits and strengthen the general idea that dopaminergic signaling amplifies the effects of reward expectation or obtainment on instrumental behavior. SIGNIFICANCE STATEMENT Theoretically, maximizing reward and minimizing effort could involve the same computations and therefore rely on the same brain circuits. Here, we tested whether dopamine, a key component of reward-related circuitry, is also implicated in effort learning. We found that patients suffering from dopamine depletion due to Parkinson's disease were selectively impaired in reward learning, but not effort learning. Moreover, anti-parkinsonian medication restored the ability to maximize reward, but had no effect on effort minimization. This dissociation suggests that the brain has evolved separate, domain-specific systems for instrumental learning. These results help to disambiguate the motivational role of prodopaminergic medications: they amplify the impact of reward without affecting the integration of effort cost. Copyright © 2017 the authors 0270-6474/17/376087-11$15.00/0.

Functional disconnection of the orbitofrontal cortex and basolateral amygdala impairs acquisition of a rat gambling task and disrupts animals' ability to alter decision-making behavior after reinforcer devaluation.

PubMed

Zeeb, Fiona D; Winstanley, Catharine A

2013-04-10

An inability to adjust choice preferences in response to changes in reward value may underlie key symptoms of many psychiatric disorders, including chemical and behavioral addictions. We developed the rat gambling task (rGT) to investigate the neurobiology underlying complex decision-making processes. As in the Iowa Gambling task, the optimal strategy is to avoid choosing larger, riskier rewards and to instead favor options associated with smaller rewards but less loss and, ultimately, greater long-term gain. Given the demonstrated importance of the orbitofrontal cortex (OFC) and basolateral amygdala (BLA) in acquisition of the rGT and Iowa Gambling task, we used a contralateral disconnection lesion procedure to assess whether functional connectivity between these regions is necessary for optimal decision-making. Disrupting the OFC-BLA pathway retarded acquisition of the rGT. Devaluing the reinforcer by inducing sensory-specific satiety altered decision-making in control groups. In contrast, disconnected rats did not update their choice preference following reward devaluation, either when the devalued reward was still delivered or when animals needed to rely on stored representations of reward value (i.e., during extinction). However, all rats exhibited decreased premature responding and slower response latencies after satiety manipulations. Hence, disconnecting the OFC and BLA did not affect general behavioral changes caused by reduced motivation, but instead prevented alterations in the value of a specific reward from contributing appropriately to cost-benefit decision-making. These results highlight the role of the OFC-BLA pathway in the decision-making process and suggest that communication between these areas is vital for the appropriate assessment of reward value to influence choice.

Principles of Economic Rationality in Mice.

PubMed

Rivalan, Marion; Winter, York; Nachev, Vladislav

2017-12-12

Humans and non-human animals frequently violate principles of economic rationality, such as transitivity, independence of irrelevant alternatives, and regularity. The conditions that lead to these violations are not completely understood. Here we report a study on mice tested in automated home-cage setups using rewards of drinking water. Rewards differed in one of two dimensions, volume or probability. Our results suggest that mouse choice conforms to the principles of economic rationality for options that differ along a single reward dimension. A psychometric analysis of mouse choices further revealed that mice responded more strongly to differences in probability than to differences in volume, despite equivalence in return rates. This study also demonstrates the synergistic effect between the principles of economic rationality and psychophysics in making quantitative predictions about choices of healthy laboratory mice. This opens up new possibilities for the analyses of multi-dimensional choice and the use of mice with cognitive impairments that may violate economic rationality.

Pay-for-virtue: an option to improve pay-for-performance?

PubMed

Buetow, Stephen; Entwistle, Vikki

2011-10-01

Pay-for-performance schemes reward standardized professional behaviours associated with effective care. However, they neglect the significance of virtue and devalue and erode professional motivation based on virtue. Pay for training to cultivate virtue, and/or pay-for-virtue, may mitigate these dangers. Although virtue is typically considered its own reward, and the assessment of virtue is problematic, pay-for-virtue could involve (1) stringent checks on the appropriateness of the standardized care currently rewarded by pay-for-performance for individual patients or (2) pay for indicators of virtue. These indicators could be based on virtues identified from a framework of universal virtues and through logical inferences from features of practice. It is possible that pay-for-virtue could ultimately strengthen health professionals' intrinsic motivation for good practice, but this and the broader effects of pay-for-virtue would need careful investigation. © 2011 Blackwell Publishing Ltd.

Foraging for brain stimulation: toward a neurobiology of computation.

PubMed

Gallistel, C R

1994-01-01

The self-stimulating rat performs foraging tasks mediated by simple computations that use interreward intervals and subjective reward magnitudes to determine stay durations. This is a simplified preparation in which to study the neurobiology of the elementary computational operations that make cognition possible, because the neural signal specifying the value of a computationally relevant variable is produced by direct electrical stimulation of a neural pathway. Newly developed measurement methods yield functions relating the subjective reward magnitude to the parameters of the neural signal. These measurements also show that the decision process that governs foraging behavior divides the subjective reward magnitude by the most recent interreward interval to determine the preferability of an option (a foraging patch). The decision process sets the parameters that determine stay durations (durations of visits to foraging patches) so that the ratios of the stay durations match the ratios of the preferabilities.

Decision processes in choice overload: a product of delay and probability discounting?

PubMed

Kaplan, Brent A; Reed, Derek D

2013-07-01

Recent research in the behavioral decision making literature has demonstrated that humans hyperbolically discount the subjective value of options as the number of options increases (Reed et al., 2012). These findings provide a cognitive-behavioral synthesis of the "choice overload" phenomenon, also known as the "paradox of choice." Specifically, these findings suggest that temporal discounting may serve as the underlying process contributing to this effect. As an extension, this study examined the effects of reward magnitude sizes had on rates temporal and options discounting. This manipulation was conducted to determine what role temporal discounting plays in discounting of options. The present results suggest that temporal discounting may not be the only process contributing to the choice overload effect. Copyright © 2013 Elsevier B.V. All rights reserved.

Declining Resources, Targeted Strategies

ERIC Educational Resources Information Center

Levenson, Nathan

2011-01-01

As resources shrink, the need to do more with less becomes critical. As a business CEO turned superintendent, the author has seen firsthand that many options exist, but none are fun, easy, or politically rewarding. In 2005, he launched a 50-person listening tour with school committee members, central-office staff, curriculum leaders, and…

76 FR 28113 - Self-Regulatory Organizations; Notice of Filing and Immediate Effectiveness of Proposed Rule...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

... enter eligible contracts into the Exchange's Floor Broker Management System (``FBMS'').\\3\\ To qualify... brokers and/or their employees to enter, route, and report transactions stemming from options orders... the Exchange. The Exchange believes that rewarding members that contribute the most liquidity or...

Incentivizing with Bonus in a College Statistics Course

ERIC Educational Resources Information Center

Ingalls, Victoria

2018-01-01

Many studies have argued the negative effects of external rewards on internal motivation while others assert that external motivation does not necessarily undermine intrinsic motivation. At a private university, students were given the option to earn bonus points for achieving mastery in the online homework systems associated with Statistics and…

National Security and Information Technology: The New Regulatory Option?

ERIC Educational Resources Information Center

Irwin, Manley R.

1987-01-01

Summarizes recent developments in information technology research and development, telecommunication services, telephone manufacturing, telecommunication networks, information processing, and U.S. import/export policy. It is concluded that government regulation as a policy strategy depends on how one defines national security. (Author/CLB)

Chimpanzees (Pan troglodytes) Transfer Tokens Repeatedly with a Partner to Accumulate Rewards in a Self-Control Task

PubMed Central

Parrish, Audrey E.; Perdue, Bonnie M.; Evans, Theodore A.; Beran, Michael J.

2013-01-01

There has been extensive research investigating self-control in humans and nonhuman animals, yet we know surprisingly little about how one’s social environment influences self-control. The present study examined the self-control of chimpanzees in a task that required active engagement with conspecifics. The task consisted of transferring a token back and forth with a partner animal in order to accumulate food rewards, one item per token transfer. Self-control was required because at any point in the trial, either chimpanzee could obtain their accumulated rewards, but doing so discontinued the food accumulation and ended the trial for both individuals. Chimpanzees readily engaged the task and accumulated the majority of available rewards before ending each trial, and they did so across a number of conditions that varied the identity of the partner, the presence/absence of the experimenter, and the means by which they could obtain rewards. A second experiment examined chimpanzees’ self-control when given the choice between immediately available food items and a potentially larger amount of rewards that could be obtained by engaging the token transfer task with a partner. Chimpanzees were flexible in their decision-making in this test, typically choosing the option representing the largest amount of food, even if it involved delayed accumulation of the rewards via the token transfer task. These results demonstrate that chimpanzees can exhibit self-control in situations involving social interactions, and they encourage further research into this important aspect of the self-control scenario. PMID:23381691

Final Report for Clean, Reliable, Affordable Energy that Reflects the Values of the Pinoleville Pomo Nation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steele, Lenora; Sampsel, Zachary N

This report aims to present and analyze information on the potential of renewable energy power systems and electric vehicle charging near the Pinoleville Pomo Nation in Ukiah, California to provide an environmentally-friendly, cost-effective energy and transportation options for development. For each renewable energy option we examine, solar, wind, microhydro, and biogas in this case, we compiled technology and cost information for construction, estimates of energy capacity, and data on electricity exports rates.

Generalization of value in reinforcement learning by humans

PubMed Central

Wimmer, G. Elliott; Daw, Nathaniel D.; Shohamy, Daphna

2012-01-01

Research in decision making has focused on the role of dopamine and its striatal targets in guiding choices via learned stimulus-reward or stimulus-response associations, behavior that is well-described by reinforcement learning (RL) theories. However, basic RL is relatively limited in scope and does not explain how learning about stimulus regularities or relations may guide decision making. A candidate mechanism for this type of learning comes from the domain of memory, which has highlighted a role for the hippocampus in learning of stimulus-stimulus relations, typically dissociated from the role of the striatum in stimulus-response learning. Here, we used fMRI and computational model-based analyses to examine the joint contributions of these mechanisms to RL. Humans performed an RL task with added relational structure, modeled after tasks used to isolate hippocampal contributions to memory. On each trial participants chose one of four options, but the reward probabilities for pairs of options were correlated across trials. This (uninstructed) relationship between pairs of options potentially enabled an observer to learn about options’ values based on experience with the other options and to generalize across them. We observed BOLD activity related to learning in the striatum and also in the hippocampus. By comparing a basic RL model to one augmented to allow feedback to generalize between correlated options, we tested whether choice behavior and BOLD activity were influenced by the opportunity to generalize across correlated options. Although such generalization goes beyond standard computational accounts of RL and striatal BOLD, both choices and striatal BOLD were better explained by the augmented model. Consistent with the hypothesized role for the hippocampus in this generalization, functional connectivity between the ventral striatum and hippocampus was modulated, across participants, by the ability of the augmented model to capture participants’ choice. Our results thus point toward an interactive model in which striatal RL systems may employ relational representations typically associated with the hippocampus. PMID:22487039

GHGs and air pollutants embodied in China’s international trade: Temporal and spatial index decomposition analysis

PubMed Central

Liu, Zhengyan; Mao, Xianqiang; Song, Peng

2017-01-01

Temporal index decomposition analysis and spatial index decomposition analysis were applied to understand the driving forces of the emissions embodied in China’s exports and net exports during 2002–2011, respectively. The accumulated emissions embodied in exports accounted for approximately 30% of the total emissions in China; although the contribution of the sectoral total emissions intensity (technique effect) declined, the scale effect was largely responsible for the mounting emissions associated with export, and the composition effect played a largely insignificant role. Calculations of the emissions embodied in net exports suggest that China is generally in an environmentally inferior position compared with its major trade partners. The differences in the economy-wide emission intensities between China and its major trade partners were the biggest contribution to this reality, and the trade balance effect played a less important role. However, a lower degree of specialization in pollution intensive products in exports than in imports helped to reduce slightly the emissions embodied in net exports. The temporal index decomposition analysis results suggest that China should take effective measures to optimize export and supply-side structure and reduce the total emissions intensity. According to spatial index decomposition analysis, it is suggested that a more aggressive import policy was useful for curbing domestic and global emissions, and the transfer of advanced production technologies and emission control technologies from developed to developing countries should be a compulsory global environmental policy option to mitigate the possible leakage of pollution emissions caused by international trade. PMID:28441399

Tuning the Brake While Raising the Stake: Network Dynamics during Sequential Decision-Making.

PubMed

Meder, David; Haagensen, Brian Numelin; Hulme, Oliver; Morville, Tobias; Gelskov, Sofie; Herz, Damian Marc; Diomsina, Beata; Christensen, Mark Schram; Madsen, Kristoffer Hougaard; Siebner, Hartwig Roman

2016-05-11

When gathering valued goods, risk and reward are often coupled and escalate over time, for instance, during foraging, trading, or gambling. This escalating frame requires agents to continuously balance expectations of reward against those of risk. To address how the human brain dynamically computes these tradeoffs, we performed whole-brain fMRI while healthy young individuals engaged in a sequential gambling task. Participants were repeatedly confronted with the option to continue with throwing a die to accumulate monetary reward under escalating risk, or the alternative option to stop to bank the current balance. Within each gambling round, the accumulation of gains gradually increased reaction times for "continue" choices, indicating growing uncertainty in the decision to continue. Neural activity evoked by "continue" choices was associated with growing activity and connectivity of a cortico-subcortical "braking" network that positively scaled with the accumulated gains, including pre-supplementary motor area (pre-SMA), inferior frontal gyrus, caudate, and subthalamic nucleus (STN). The influence of the STN on continue-evoked activity in the pre-SMA was predicted by interindividual differences in risk-aversion attitudes expressed during the gambling task. Furthermore, activity in dorsal anterior cingulate cortex (ACC) reflected individual choice tendencies by showing increased activation when subjects made nondefault "continue" choices despite an increasing tendency to stop, but ACC activity did not change in proportion with subjective choice uncertainty. Together, the results implicate a key role of dorsal ACC, pre-SMA, inferior frontal gyrus, and STN in computing the trade-off between escalating reward and risk in sequential decision-making. Using a paradigm where subjects experienced increasing potential rewards coupled with increasing risk, this study addressed two unresolved questions in the field of decision-making: First, we investigated an "inhibitory" network of regions that has so far been investigated with externally cued action inhibition. In this study, we show that the dynamics in this network under increasingly risky decisions are predictive of subjects' risk attitudes. Second, we contribute to a currently ongoing debate about the anterior cingulate cortex's role in sequential foraging decisions by showing that its activity is related to making nondefault choices rather than to choice uncertainty. Copyright © 2016 Meder, Haagensen, et al.

Leadership through Fellowship: Distributed Leadership in a Professional Recognition Scheme for University Educators

ERIC Educational Resources Information Center

Beckmann, Elizabeth A.

2017-01-01

Researchers in the field of teaching and learning in higher education have identified concerns with top-down leadership models. Distributed (or shared) leadership approaches may provide more successful engagement with institutional change agendas, and provide more options to reward and recognise staff leading teaching and learning initiatives.…

Affordances and Alignments: Continuing Challenges in Advising Undergraduate Psychology Majors

ERIC Educational Resources Information Center

Landrum, R. Eric

2018-01-01

Challenges abound in providing accurate and useful information to prospective and declared psychology majors about their career options and how to make decisions that will lead to satisfying and rewarding postgraduate lives. One component of this challenge is that by majoring in psychology, career affordances (i.e., the opportunities and…

The Impact of Human Capital and Selected Job Rewards on Community College Faculty Job Satisfaction

ERIC Educational Resources Information Center

Lyons, Frankie W.; Akroyd, Duane

2014-01-01

Community colleges accommodate nearly half of all United States college students. Increased reliance upon community colleges is driven by the current economic downturn, rising costs of higher education, and changing expectations for today's workforce requiring advanced skill sets. Community colleges offer more affordable options for broader…

29 CFR 553.31 - Substitution-section 7(p)(3).

Code of Federal Regulations, 2010 CFR

2010-07-01

... employed in any occupation by the same public agency may agree, solely at their option and with the approval of the public agency, to substitute for one another during scheduled work hours in performance of... been made (i) without fear of reprisal or promise of reward by the employer, and (ii) exclusively for...

Declining Resources, Targeted Strategies

ERIC Educational Resources Information Center

Levenson, Nathan

2011-01-01

As resources shrink, the need to do more with less becomes critical. As a business CEO turned superintendent, this author has seen firsthand that many options exist, but none are fun, easy, or politically rewarding. He contends that the challenge of managing declining resources is not the choice between doing less for children or discovering new…

The influence of jumping risk and volatility risk on TAIEX option return

NASA Astrophysics Data System (ADS)

Lee, Wei-Long; Hsieh, Ching-Tang; Huang, Jui-Chan; Wu, Tzu-Jung

2017-06-01

Due to the low profits in recent years environmental, as well as the development of financial engineering that promote the derivatives trading Volume increased. Moreover, the fastest-growing of selected right and the lack of research about option risk. This study aim to explore the relationship between the risk and reward of selected right in Taiwan index. This study focus on the pricing the jump risk of selected right in Taiwan index. Using cross-sectional data as a 12-month study period, using the iteration method to research the effects of abnormal returns, the result shows that different risk factors of fluctuations affected the abnormal returns obviously will cause risk premium as well as the jump risk which consistent with the theory of behavioral finance. However, according to traditional finance theory, contrary to the results of this study consider that higher risks should generate higher-paying as well. According this study, the investors in behavioral finance in modern financial theory is not rational, and the trading behavior is non-random, moreover, the financial market is non-efficiency. Instead, the high risk low reward.

A Primer on Foraging and the Explore/Exploit Trade-Off for Psychiatry Research.

PubMed

Addicott, M A; Pearson, J M; Sweitzer, M M; Barack, D L; Platt, M L

2017-09-01

Foraging is a fundamental behavior, and many types of animals appear to have solved foraging problems using a shared set of mechanisms. Perhaps the most common foraging problem is the choice between exploiting a familiar option for a known reward and exploring unfamiliar options for unknown rewards-the so-called explore/exploit trade-off. This trade-off has been studied extensively in behavioral ecology and computational neuroscience, but is relatively new to the field of psychiatry. Explore/exploit paradigms can offer psychiatry research a new approach to studying motivation, outcome valuation, and effort-related processes, which are disrupted in many mental and emotional disorders. In addition, the explore/exploit trade-off encompasses elements of risk-taking and impulsivity-common behaviors in psychiatric disorders-and provides a novel framework for understanding these behaviors within an ecological context. Here we explain relevant concepts and some common paradigms used to measure explore/exploit decisions in the laboratory, review clinically relevant research on the neurobiology and neuroanatomy of explore/exploit decision making, and discuss how computational psychiatry can benefit from foraging theory.

The ecological rationality of state-dependent valuation.

PubMed

McNamara, J M; Trimmer, P C; Houston, A I

2012-01-01

Laboratory studies on a range of animals have identified a bias that seems to violate basic principles of rational behavior: a preference is shown for feeding options that previously provided food when reserves were low, even though another option had been found to give the same reward with less delay. The bias presents a challenge to normative models of decision making (which only take account of expected rewards and the state of the animal at the decision time). To understand the behavior, we take a broad ecological perspective and consider how valuation mechanisms evolve when the best action depends upon the environment being faced. We show that in a changing and uncertain environment, state-dependent valuation can be favored by natural selection: Individuals should allow their hunger to affect learning for future decisions. The valuation mechanism that typically evolves produces the kind of behavior seen in standard laboratory tests. By providing an insight into why learning should be affected by the state of an individual, we provide a basis for understanding psychological principles in terms of an animal's ecology.

SutraPlot, a graphical post-processor for SUTRA, a model for ground-water flow with solute or energy transport

USGS Publications Warehouse

Souza, W.R.

1999-01-01

This report documents a graphical display post-processor (SutraPlot) for the U.S. Geological Survey Saturated-Unsaturated flow and solute or energy TRAnsport simulation model SUTRA, Version 2D3D.1. This version of SutraPlot is an upgrade to SutraPlot for the 2D-only SUTRA model (Souza, 1987). It has been modified to add 3D functionality, a graphical user interface (GUI), and enhanced graphic output options. Graphical options for 2D SUTRA (2-dimension) simulations include: drawing the 2D finite-element mesh, mesh boundary, and velocity vectors; plots of contours for pressure, saturation, concentration, and temperature within the model region; 2D finite-element based gridding and interpolation; and 2D gridded data export files. Graphical options for 3D SUTRA (3-dimension) simulations include: drawing the 3D finite-element mesh; plots of contours for pressure, saturation, concentration, and temperature in 2D sections of the 3D model region; 3D finite-element based gridding and interpolation; drawing selected regions of velocity vectors (projected on principal coordinate planes); and 3D gridded data export files. Installation instructions and a description of all graphic options are presented. A sample SUTRA problem is described and three step-by-step SutraPlot applications are provided. In addition, the methodology and numerical algorithms for the 2D and 3D finite-element based gridding and interpolation, developed for SutraPlot, are described. 1

Value-based attentional capture influences context-dependent decision-making

PubMed Central

Cha, Kexin; Rangsipat, Napat; Serences, John T.

2015-01-01

Normative theories posit that value-based decision-making is context independent. However, decisions between two high-value options can be suboptimally biased by the introduction of a third low-value option. This context-dependent modulation is consistent with the divisive normalization of the value of each stimulus by the total value of all stimuli. In addition, an independent line of research demonstrates that pairing a stimulus with a high-value outcome can lead to attentional capture that can mediate the efficiency of visual information processing. Here we tested the hypothesis that value-based attentional capture interacts with value-based normalization to influence the optimality of decision-making. We used a binary-choice paradigm in which observers selected between two targets and the color of each target indicated the magnitude of their reward potential. Observers also had to simultaneously ignore a task-irrelevant distractor rendered in a color that was previously associated with a specific reward magnitude. When the color of the task-irrelevant distractor was previously associated with a high reward, observers responded more slowly and less optimally. Moreover, as the learned value of the distractor increased, electrophysiological data revealed an attenuation of the lateralized N1 and N2Pc responses evoked by the relevant choice stimuli and an attenuation of the late positive deflection (LPD). Collectively, these behavioral and electrophysiological data suggest that value-based attentional capture and value-based normalization jointly mediate the influence of context on free-choice decision-making. PMID:25995350

Value-based attentional capture influences context-dependent decision-making.

PubMed

Itthipuripat, Sirawaj; Cha, Kexin; Rangsipat, Napat; Serences, John T

2015-07-01

Normative theories posit that value-based decision-making is context independent. However, decisions between two high-value options can be suboptimally biased by the introduction of a third low-value option. This context-dependent modulation is consistent with the divisive normalization of the value of each stimulus by the total value of all stimuli. In addition, an independent line of research demonstrates that pairing a stimulus with a high-value outcome can lead to attentional capture that can mediate the efficiency of visual information processing. Here we tested the hypothesis that value-based attentional capture interacts with value-based normalization to influence the optimality of decision-making. We used a binary-choice paradigm in which observers selected between two targets and the color of each target indicated the magnitude of their reward potential. Observers also had to simultaneously ignore a task-irrelevant distractor rendered in a color that was previously associated with a specific reward magnitude. When the color of the task-irrelevant distractor was previously associated with a high reward, observers responded more slowly and less optimally. Moreover, as the learned value of the distractor increased, electrophysiological data revealed an attenuation of the lateralized N1 and N2Pc responses evoked by the relevant choice stimuli and an attenuation of the late positive deflection (LPD). Collectively, these behavioral and electrophysiological data suggest that value-based attentional capture and value-based normalization jointly mediate the influence of context on free-choice decision-making. Copyright © 2015 the American Physiological Society.

Social equality in the number of choice options is represented in the ventromedial prefrontal cortex.

PubMed

Aoki, Ryuta; Matsumoto, Madoka; Yomogida, Yukihito; Izuma, Keise; Murayama, Kou; Sugiura, Ayaka; Camerer, Colin F; Adolphs, Ralph; Matsumoto, Kenji

2014-04-30

A distinct aspect of the sense of fairness in humans is that we care not only about equality in material rewards but also about equality in nonmaterial values. One such value is the opportunity to choose freely among many options, often regarded as a fundamental right to economic freedom. In modern developed societies, equal opportunities in work, living, and lifestyle are enforced by antidiscrimination laws. Despite the widespread endorsement of equal opportunity, no studies have explored how people assign value to it. We used functional magnetic resonance imaging to identify the neural substrates for subjective valuation of equality in choice opportunity. Participants performed a two-person choice task in which the number of choices available was varied across trials independently of choice outcomes. By using this procedure, we manipulated the degree of equality in choice opportunity between players and dissociated it from the value of reward outcomes and their equality. We found that activation in the ventromedial prefrontal cortex (vmPFC) tracked the degree to which the number of options between the two players was equal. In contrast, activation in the ventral striatum tracked the number of options available to participants themselves but not the equality between players. Our results demonstrate that the vmPFC, a key brain region previously implicated in the processing of social values, is also involved in valuation of equality in choice opportunity between individuals. These findings may provide valuable insight into the human ability to value equal opportunity, a characteristic long emphasized in politics, economics, and philosophy.

Risk-prone individuals prefer the wrong options on a rat version of the Iowa Gambling Task.

PubMed

Rivalan, Marion; Ahmed, Serge H; Dellu-Hagedorn, Françoise

2009-10-15

Decision making in complex and conflicting situations, as measured in the widely used Iowa Gambling Task (IGT), can be profoundly impaired in psychiatric disorders, such as attention-deficit/hyperactivity disorder, drug addiction, and also in healthy individuals for whom immediate gratification prevails over long-term gain. The cognitive processes underlying these deficits are poorly understood, in part due to a lack of suitable animal models assessing complex decision making with good construct validity. We developed a rat gambling task analogous to the IGT that tracks, for the first time, the ongoing decision process within a single session in an operant cage. Rats could choose between various options. Disadvantageous options, as opposed to advantageous ones, offered bigger immediate food reward but were followed by longer, unpredictable penalties (time-out). The majority of rats can evaluate and deduce favorable options more or less rapidly according to task complexity, whereas others systematically choose disadvantageously. These interindividual differences are stable over time and do not depend on task difficulty or on the level of food restriction. We find that poor decision making does not result from a failure to acquire relevant information but from hypersensitivity to reward and higher risk taking in anxiogenic situations. These results suggest that rats, as well as human poor performers, share similar traits to those observed in decision-making related psychiatric disorders. These traits could constitute risk factors of developing such disorders. The rapid identification of poor decision makers using the rat gambling task should promote the discovery of the specific brain dysfunctions that cause maladapted decision making.

Transboundary Movements of Hazardous Wastes. A Comparative Analysis of Policy Options to Control the International Waste Trade.

ERIC Educational Resources Information Center

Hilz, Christoph; Ehrenfeld, John R.

1991-01-01

Several policy frameworks for managing hazardous waste import/export are examined with respect to economic issues, environmental sustainability, and administrative feasibility and effectiveness. Several recommendations for improving the present instrument and implementing process are offered. (Author/CW)

Novelty and Inductive Generalization in Human Reinforcement Learning.

PubMed

Gershman, Samuel J; Niv, Yael

2015-07-01

In reinforcement learning (RL), a decision maker searching for the most rewarding option is often faced with the question: What is the value of an option that has never been tried before? One way to frame this question is as an inductive problem: How can I generalize my previous experience with one set of options to a novel option? We show how hierarchical Bayesian inference can be used to solve this problem, and we describe an equivalence between the Bayesian model and temporal difference learning algorithms that have been proposed as models of RL in humans and animals. According to our view, the search for the best option is guided by abstract knowledge about the relationships between different options in an environment, resulting in greater search efficiency compared to traditional RL algorithms previously applied to human cognition. In two behavioral experiments, we test several predictions of our model, providing evidence that humans learn and exploit structured inductive knowledge to make predictions about novel options. In light of this model, we suggest a new interpretation of dopaminergic responses to novelty. Copyright © 2015 Cognitive Science Society, Inc.

Novelty and Inductive Generalization in Human Reinforcement Learning

PubMed Central

Gershman, Samuel J.; Niv, Yael

2015-01-01

In reinforcement learning, a decision maker searching for the most rewarding option is often faced with the question: what is the value of an option that has never been tried before? One way to frame this question is as an inductive problem: how can I generalize my previous experience with one set of options to a novel option? We show how hierarchical Bayesian inference can be used to solve this problem, and describe an equivalence between the Bayesian model and temporal difference learning algorithms that have been proposed as models of reinforcement learning in humans and animals. According to our view, the search for the best option is guided by abstract knowledge about the relationships between different options in an environment, resulting in greater search efficiency compared to traditional reinforcement learning algorithms previously applied to human cognition. In two behavioral experiments, we test several predictions of our model, providing evidence that humans learn and exploit structured inductive knowledge to make predictions about novel options. In light of this model, we suggest a new interpretation of dopaminergic responses to novelty. PMID:25808176

(Initiation of strategic assessment of fossil options, Phase 2). Summary. Progress report, November 1981-February 1982. [USA; coal transhipment capacity in 1990 for 37 ports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocur, G.; Adler, T.J.

1982-02-23

The export coal transportation study has proceeded through the first two subtasks. Figure 1 shows a comparison between past and projected US coal export demand and US port coal transshipment capacities. Projected export demand was taken from the MIT World Coal Study, and projected port capacities were determined primarily by personal communications with port managers. Table 1 details projected 1990 capacities at each major port, with a maximum-minimum range indicating undertain projects. The obvious observation from these data is the massive discrepancy between projected capacities and projected export movements. It is very likely that many ports have publicized ambitious expansionmore » plans in order to discourage competing ports from expanding. In addition, the excess port capacity could be used for exports of, for example, iron ore and grain. Nonetheless, Fig. 1 does indicate some need to determine which subset of ports will lie on the most cost-effective routing from mine to ultimate destination and which thus deserve the largest investments. The survey of rail export (steam) coal rates began with an identification of representative mines (13) to port (19) movement (total of 54 allowable). Per carload rail rates were then obtained for approximately 25 of these movements. Regression analyses were performed relating these rates to shipping distance, and other factors. 1 figure, 1 table.« less

The Impact of Selective Dopamine D2, D3 and D4 Ligands on the Rat Gambling Task.

PubMed

Di Ciano, Patricia; Pushparaj, Abhiram; Kim, Aaron; Hatch, Jessica; Masood, Talal; Ramzi, Abby; Khaled, Maram A T M; Boileau, Isabelle; Winstanley, Catherine A; Le Foll, Bernard

2015-01-01

Gambling is an addictive disorder with serious societal and personal costs. To-date, there are no approved pharmacological treatments for gambling disorder. Evidence suggests a role for dopamine in gambling disorder and thus may provide a therapeutic target. The present study therefore aimed to investigate the effects of selective antagonists and agonists of D2, D3 and D4 receptors in a rodent analogue of the Iowa gambling task used clinically. In this rat gambling task (rGT), animals are trained to associate different response holes with different magnitudes and probabilities of food pellet rewards and punishing time-out periods. As in the Iowa gambling task, the optimal strategy is to avoid the tempting high-risk high-reward options, and instead favor those linked to smaller per-trial rewards but also lower punishments, thereby maximizing the amount of reward earned over time. Administration of those selective ligands did not affect decision making under the rGT. Only the D4 drug had modest effects on latency measures suggesting that D4 may contribute in some ways to decision making under this task.

Fifty Years in the Development of a Glutaminergic-Dopaminergic Optimization Complex (KB220) to Balance Brain Reward Circuitry in Reward Deficiency Syndrome: A Pictorial

PubMed Central

Blum, K; Febo, M; Badgaiyan, RD

2016-01-01

Dopamine along with other chemical messengers like serotonin, cannabinoids, endorphins and glutamine, play significant roles in brain reward processing. There is a devastating opiate/opioid epidemicin the United States. According to the Centers for Disease Control and Prevention (CDC), at least 127 people, young and old, are dying every day due to narcotic overdose and alarmingly heroin overdose is on the rise. The Food and Drug Administration (FDA) has approved some Medication-Assisted Treatments (MATs) for alcoholism, opiate and nicotine dependence, but nothing for psychostimulant and cannabis abuse. While these pharmaceuticals are essential for the short-term induction of “psychological extinction,” in the long-term caution is necessary because their use favors blocking dopaminergic function indispensable for achieving normal satisfaction in life. The two institutions devoted to alcoholism and drug dependence (NIAAA & NIDA) realize that MATs are not optimal and continue to seek better treatment options. We review, herein, the history of the development of a glutaminergic-dopaminergic optimization complex called KB220 to provide for the possible eventual balancing of the brain reward system and the induction of “dopamine homeostasis.” This complex may provide substantial clinical benefit to the victims of Reward Deficiency Syndrome (RDS) and assist in recovery from iatrogenically induced addiction to unwanted opiates/opioids and other addictive behaviors. PMID:27840857

15 CFR 758.5 - Conformity of documents and unloading of items.

Code of Federal Regulations, 2013 CFR

2013-01-01

...., the SED or AES record, bill of lading or air waybill) must be consistent with the license. (c... and Shipper's Export Declaration (SED) or AES electronic equivalent. (2) Optional ports of unloading... ultimate destination or are included on the BIS license and SED or AES electronic equivalent. (ii...

15 CFR 758.5 - Conformity of documents and unloading of items.

Code of Federal Regulations, 2012 CFR

2012-01-01

...., the SED or AES record, bill of lading or air waybill) must be consistent with the license. (c... and Shipper's Export Declaration (SED) or AES electronic equivalent. (2) Optional ports of unloading... ultimate destination or are included on the BIS license and SED or AES electronic equivalent. (ii...

Generalization of value in reinforcement learning by humans.

PubMed

Wimmer, G Elliott; Daw, Nathaniel D; Shohamy, Daphna

2012-04-01

Research in decision-making has focused on the role of dopamine and its striatal targets in guiding choices via learned stimulus-reward or stimulus-response associations, behavior that is well described by reinforcement learning theories. However, basic reinforcement learning is relatively limited in scope and does not explain how learning about stimulus regularities or relations may guide decision-making. A candidate mechanism for this type of learning comes from the domain of memory, which has highlighted a role for the hippocampus in learning of stimulus-stimulus relations, typically dissociated from the role of the striatum in stimulus-response learning. Here, we used functional magnetic resonance imaging and computational model-based analyses to examine the joint contributions of these mechanisms to reinforcement learning. Humans performed a reinforcement learning task with added relational structure, modeled after tasks used to isolate hippocampal contributions to memory. On each trial participants chose one of four options, but the reward probabilities for pairs of options were correlated across trials. This (uninstructed) relationship between pairs of options potentially enabled an observer to learn about option values based on experience with the other options and to generalize across them. We observed blood oxygen level-dependent (BOLD) activity related to learning in the striatum and also in the hippocampus. By comparing a basic reinforcement learning model to one augmented to allow feedback to generalize between correlated options, we tested whether choice behavior and BOLD activity were influenced by the opportunity to generalize across correlated options. Although such generalization goes beyond standard computational accounts of reinforcement learning and striatal BOLD, both choices and striatal BOLD activity were better explained by the augmented model. Consistent with the hypothesized role for the hippocampus in this generalization, functional connectivity between the ventral striatum and hippocampus was modulated, across participants, by the ability of the augmented model to capture participants' choice. Our results thus point toward an interactive model in which striatal reinforcement learning systems may employ relational representations typically associated with the hippocampus. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Toward a new modeling of international economics: An attempt to reformulate an international trade model based on real option theory

NASA Astrophysics Data System (ADS)

Fujita, Yasunori

2007-09-01

Reformulation of economics by physics has been carried out intensively to reveal many features of the asset market, which were missed in the classical economic theories. The present paper attempts to shed new light on this field. That is, this paper aims at reformulating the international trade model by making use of the real option theory. Based on such a stochastic dynamic model, we examine how the fluctuation of the foreign exchange rate makes effect on the welfare of the exporting country.

A Representation of Effort in Decision-Making and Motor Control.

PubMed

Shadmehr, Reza; Huang, Helen J; Ahmed, Alaa A

2016-07-25

Given two rewarding stimuli, animals tend to choose the more rewarding (or less effortful) option. However, they also move faster toward that stimulus [1-5]. This suggests that reward and effort not only affect decision-making, they also influence motor control [6, 7]. How does the brain compute the effort requirements of a task? Here, we considered data acquired during walking, reaching, flying, or isometric force production. In analyzing the decision-making and motor-control behaviors of various animals, we considered the possibility that the brain may estimate effort objectively, via the metabolic energy consumed to produce the action. We measured the energetic cost of reaching and found that, like walking, it was convex in time, with a global minimum, implying that there existed a movement speed that minimized effort. However, reward made it worthwhile to be energetically inefficient. Using a framework in which utility of an action depended on reward and energetic cost, both discounted in time, we found that it was possible to account for a body of data in which animals were free to choose how to move (reach slow or fast), as well as what to do (walk or fly, produce force F1 or F2). We suggest that some forms of decision-making and motor control may share a common utility in which the brain represents the effort associated with performing an action objectively via its metabolic energy cost and then, like reward, temporally discounts it as a function of movement duration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Harnessing the Tax Code to Promote College Affordability: Options for Reform

ERIC Educational Resources Information Center

Valenti, Joe; Bergeron, David; Baylor, Elizabeth

2014-01-01

The United States tax code is full of provisions designed to encourage or reward specific behaviors, such as owning a home or saving for retirement. Tax benefits for higher education are no exception: Contributions to some college savings accounts grow tax-free, college tuition is often tax deductible, and some student-loan borrowers are able to…

Ambiguity Aversion in Rhesus Macaques

PubMed Central

Hayden, Benjamin Y.; Heilbronner, Sarah R.; Platt, Michael L.

2010-01-01

People generally prefer risky options, which have fully specified outcome probabilities, to ambiguous options, which have unspecified probabilities. This preference, formalized in economics, is strong enough that people will reliably prefer a risky option to an ambiguous option with a greater expected value. Explanations for ambiguity aversion often invoke uniquely human faculties like language, self-justification, or a desire to avoid public embarrassment. Challenging these ideas, here we demonstrate that a preference for unambiguous options is shared with rhesus macaques. We trained four monkeys to choose between pairs of options that both offered explicitly cued probabilities of large and small juice outcomes. We then introduced occasional trials where one of the options was obscured and examined their resulting preferences; we ran humans in a parallel experiment on a nearly identical task. We found that monkeys reliably preferred risky options to ambiguous ones, even when this bias was costly, closely matching the behavior of humans in the analogous task. Notably, ambiguity aversion varied parametrically with the extent of ambiguity. As expected, ambiguity aversion gradually declined as monkeys learned the underlying probability distribution of rewards. These data indicate that ambiguity aversion reflects fundamental cognitive biases shared with other animals rather than uniquely human factors guiding decisions. PMID:20922060

A query theory account of the effect of memory retrieval on the sunk cost bias.

PubMed

Ting, Hsuchi; Wallsten, Thomas S

2011-08-01

The sunk cost bias occurs when individuals continue to invest in the same option when better alternatives are available. Many researchers believe that this bias is due to overemphasizing the past investment over the (missed) opportunities offered by alternatives. As an alternative or complement to this view, we show that memory retrieval and attention play important roles in the sunk cost bias. In two experiments, individuals generated more reasons for pursuing the invested option than for an alternative; they generated those reasons earlier in a sequence of reasons; and these effects increased as the individuals made progress toward attaining the reward yielded by the invested option. Associated with these effects, individuals perceived an increasingly wide gap in value between the invested and alternative options as they progressed toward the goal, thereby creating the sunk cost bias. Forcing individuals to reverse the order in which they generated reasons for the invested and alternative options reduced the bias. [corrected

Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9.

PubMed

Lin, I Winnie; Sosso, Davide; Chen, Li-Qing; Gase, Klaus; Kim, Sang-Gyu; Kessler, Danny; Klinkenberg, Peter M; Gorder, Molly K; Hou, Bi-Huei; Qu, Xiao-Qing; Carter, Clay J; Baldwin, Ian T; Frommer, Wolf B

2014-04-24

Angiosperms developed floral nectaries that reward pollinating insects. Although nectar function and composition have been characterized, the mechanism of nectar secretion has remained unclear. Here we identify SWEET9 as a nectary-specific sugar transporter in three eudicot species: Arabidopsis thaliana, Brassica rapa (extrastaminal nectaries) and Nicotiana attenuata (gynoecial nectaries). We show that SWEET9 is essential for nectar production and can function as an efflux transporter. We also show that sucrose phosphate synthase genes, encoding key enzymes for sucrose biosynthesis, are highly expressed in nectaries and that their expression is also essential for nectar secretion. Together these data are consistent with a model in which sucrose is synthesized in the nectary parenchyma and subsequently secreted into the extracellular space via SWEET9, where sucrose is hydrolysed by an apoplasmic invertase to produce a mixture of sucrose, glucose and fructose. The recruitment of SWEET9 for sucrose export may have been a key innovation, and could have coincided with the evolution of core eudicots and contributed to the evolution of nectar secretion to reward pollinators.

Decision Making in the Balloon Analogue Risk Task (BART): Anterior Cingulate Cortex Signals Loss-Aversion but not the Infrequency of Risky Choices

PubMed Central

Fukunaga, Rena; Brown, Joshua W.; Bogg, Tim

2012-01-01

The inferior frontal gyrus/anterior insula (IFG/AI) and anterior cingulate cortex (ACC) are key regions involved in risk appraisal during decision making, but accounts of how these regions contribute to decision-making under risk remain contested. To help clarify the roles of these and other related regions, we used a modified version of the Balloon Analogue Risk Task (Lejuez et al., 2002) to distinguish between decision-making and feedback-related processes when participants decided to pursue a gain as the probability of loss increased parametrically. Specifically, we set out to test whether ACC and IFG/AI regions correspond to loss-aversion at the time of decision making in a way that is not confounded with either reward-seeking or infrequency effects. When participants chose to discontinue inflating the balloon (win option), we observed greater ACC and mainly bilateral IFG/AI activity at the time of decision as the probability of explosion increased, consistent with increased loss-aversion but inconsistent with an infrequency effect. In contrast, we found robust vmPFC activity when participants chose to continue inflating the balloon (risky option), consistent with reward-seeking. However, in the cingulate and mainly bilateral IFG regions, BOLD activation decreased when participants chose to inflate the balloon as the probability of explosion increased, findings consistent with a reduced loss-aversion signal. Our results highlight the existence of distinct reward-seeking and loss-averse signals during decision-making, as well as the importance of distinguishing decision and feedback signals. PMID:22707378

Obesity: Current and potential pharmacotherapeutics and targets.

PubMed

Narayanaswami, Vidya; Dwoskin, Linda P

2017-02-01

Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Obesity: Current and Potential Pharmacotherapeutics and Targets

PubMed Central

Narayanaswami, Vidya; Dwoskin, Linda P.

2016-01-01

Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed. PMID:27773782

Paralimbic and lateral prefrontal encoding of reward value during intertemporal choice in attempted suicide.

PubMed

Vanyukov, P M; Szanto, K; Hallquist, M N; Siegle, G J; Reynolds, C F; Forman, S D; Aizenstein, H J; Dombrovski, A Y

2016-01-01

Alongside impulsive suicide attempts, clinicians encounter highly premeditated suicidal acts, particularly in older adults. We have previously found that in contrast to the more impulsive suicide attempters' inability to delay gratification, serious and highly planned suicide attempts were associated with greater willingness to wait for larger rewards. This study examined neural underpinnings of intertemporal preference in suicide attempters. We expected that impulsivity and suicide attempts, particularly poorly planned ones, would predict altered paralimbic subjective value representations. We also examined lateral prefrontal and paralimbic correlates of premeditation in suicidal behavior. A total of 48 participants aged 46-90 years underwent extensive clinical and cognitive characterization and completed the delay discounting task in the scanner: 26 individuals with major depression (13 with and 13 without history of suicide attempts) and 22 healthy controls. More impulsive individuals displayed greater activation in the precuneus/posterior cingulate cortex (PCC) to value difference favoring the delayed option. Suicide attempts, particularly better-planned ones, were associated with deactivation of the lateral prefrontal cortex (lPFC) in response to value difference favoring the immediate option. Findings were robust to medication exposure, depression severity and possible brain damage from suicide attempts, among other confounders. Finally, in suicide attempters longer reward delays were associated with diminished parahippocampal responses. Impulsivity was associated with an altered paralimbic (precuneus/PCC) encoding of value difference during intertemporal choice. By contrast, better-planned suicidal acts were associated with altered lPFC representations of value difference. The study provides preliminary evidence of impaired decision processes in both impulsive and premeditated suicidal behavior.

Diversification: Midland/Odessa Health & Retirement Endeavor.

ERIC Educational Resources Information Center

Skipper, P. K.

In reaction to the economic risks associated with an over reliance on oil and gas exports, residents of the Midland/Odessa area of Texas began seeking diversification options for the local economy and, in 1986, formed the Midland/Odessa Health and Retirement Endeavor (MOHRE). This non-profit corporation was formed to examine the feasibility of…

Differential Contributions of Nucleus Accumbens Subregions to Cue-Guided Risk/Reward Decision Making and Implementation of Conditional Rules.

PubMed

Floresco, Stan B; Montes, David R; Tse, Maric M T; van Holstein, Mieke

2018-02-21

The nucleus accumbens (NAc) is a key node within corticolimbic circuitry for guiding action selection and cost/benefit decision making in situations involving reward uncertainty. Preclinical studies have typically assessed risk/reward decision making using assays where decisions are guided by internally generated representations of choice-outcome contingencies. Yet, real-life decisions are often influenced by external stimuli that inform about likelihoods of obtaining rewards. How different subregions of the NAc mediate decision making in such situations is unclear. Here, we used a novel assay colloquially termed the "Blackjack" task that models these types of situations. Male Long-Evans rats were trained to choose between one lever that always delivered a one-pellet reward and another that delivered four pellets with different probabilities [either 50% (good-odds) or 12.5% (poor-odds)], which were signaled by one of two auditory cues. Under control conditions, rats selected the large/risky option more often on good-odds versus poor-odds trials. Inactivation of the NAc core caused indiscriminate choice patterns. In contrast, NAc shell inactivation increased risky choice, more prominently on poor-odds trials. Additional experiments revealed that both subregions contribute to auditory conditional discrimination. NAc core or shell inactivation reduced Pavlovian approach elicited by an auditory CS+, yet shell inactivation also increased responding during presentation of a CS-. These data highlight distinct contributions for NAc subregions in decision making and reward seeking guided by discriminative stimuli. The core is crucial for implementation of conditional rules, whereas the shell refines reward seeking by mitigating the allure of larger, unlikely rewards and reducing expression of inappropriate or non-rewarded actions. SIGNIFICANCE STATEMENT Using external cues to guide decision making is crucial for adaptive behavior. Deficits in cue-guided behavior have been associated with neuropsychiatric disorders, such as attention deficit hyperactivity disorder and schizophrenia, which in turn has been linked to aberrant processing in the nucleus accumbens. However, many preclinical studies have often assessed risk/reward decision making in the absence of explicit cues. The current study fills that gap by using a novel task that allows for the assessment of cue-guided risk/reward decision making in rodents. Our findings identified distinct yet complementary roles for the medial versus lateral portions of this nucleus that provide a broader understanding of the differential contributions it makes to decision making and reward seeking guided by discriminative stimuli. Copyright © 2018 the authors 0270-6474/18/381901-14$15.00/0.

Rewards Not Working?

ERIC Educational Resources Information Center

Bryner, Jeanna

2005-01-01

Most teachers would say that they use incentives--such as gold stars and extra recess-time--to help kids stay on track in the classroom and they give warnings and time-outs when they are not. There is no question it is hard keeping a class of 25 energetic eight-year-olds engaged and learning. But is this approach the only option? There is always…

Options for Studying Teacher Pay Reform Using Natural Experiments

ERIC Educational Resources Information Center

Glazerman, Steven; Silva, Tom; Addy, Nii; Avellar, Sarah; Max, Jeffrey; McKie, Allison; Natzke, Brenda; Puma, Michael; Wolf, Patrick; Greszler, Rachel Ungerer

2006-01-01

How public school teachers are paid in the U.S. has been a controversial issue for many years. Critics of the traditional system, in which teachers are paid on the basis of years of experience and educational attainment, claim that it does not reward or promote good teaching as fairly as systems that tie pay to performance: having certain skills,…

Mirtazapine and ketanserin alter preference for gambling-like schedules of reinforcement in rats.

PubMed

Persons, Amanda L; Tedford, Stephanie E; Celeste Napier, T

2017-07-03

Drug and behavioral addictions have overlapping features, e.g., both manifest preference for larger, albeit costlier, reinforcement options in cost/benefit decision-making tasks. Our prior work revealed that the mixed-function serotonergic compound, mirtazapine, attenuates behaviors by rats motivated by abused drugs. To extend this work to behavioral addictions, here we determined if mirtazapine and/or ketanserin, another mixed-function serotonin-acting compound, can alter decision-making in rats that is independent of drug (or food)-motivated reward. Accordingly, we developed a novel variable-ratio task in rats wherein intracranial self-stimulation was used as the positive reinforcer. Using lever pressing for various levels of brain stimulation, the operant task provided choices between a small brain stimulation current delivered on a fixed-ratio schedule (i.e., a predictable reward) and a large brain stimulation delivered following an unpredictable number of responses (i.e., a variable-ratio schedule). This task allowed for demonstration of individualized preference and detection of shifts in motivational influences during a pharmacological treatment. Once baseline preference was established, we determined that pretreatment with mirtazapine or ketanserin significantly decreased preference for the large reinforcer presented after gambling-like schedules of reinforcement. When the rats were tested the next day without drug, preference for the unpredictable large reinforcer option was restored. These data demonstrate that mirtazapine and ketanserin can reduce preference for larger, costlier reinforcement options, and illustrate the potential for these drugs to alter behavior. Copyright © 2017 Elsevier Inc. All rights reserved.

Decision Making Under Objective Risk Conditions-a Review of Cognitive and Emotional Correlates, Strategies, Feedback Processing, and External Influences.

PubMed

Schiebener, Johannes; Brand, Matthias

2015-06-01

While making decisions under objective risk conditions, the probabilities of the consequences of the available options are either provided or calculable. Brand et al. (Neural Networks 19:1266-1276, 2006) introduced a model describing the neuro-cognitive processes involved in such decisions. In this model, executive functions associated with activity in the fronto-striatal loop are important for developing and applying decision-making strategies, and for verifying, adapting, or revising strategies according to feedback. Emotional rewards and punishments learned from such feedback accompany these processes. In this literature review, we found support for the role of executive functions, but also found evidence for the importance of further cognitive abilities in decision making. Moreover, in addition to reflective processing (driven by cognition), decisions can be guided by impulsive processing (driven by anticipation of emotional reward and punishment). Reflective and impulsive processing may interact during decision making, affecting the evaluation of available options, as both processes are affected by feedback. Decision-making processes are furthermore modulated by individual attributes (e.g., age), and external influences (e.g., stressors). Accordingly, we suggest a revised model of decision making under objective risk conditions.

Continuous, but not intermittent, antipsychotic drug delivery intensifies the pursuit of reward cues.

PubMed

Bédard, Anne-Marie; Maheux, Jérôme; Lévesque, Daniel; Samaha, Anne-Noël

2011-05-01

Chronic exposure to antipsychotic medications can persistently change brain dopamine systems. Most studies on the functional significance of these neural changes have focused on motor behavior and few have addressed how long-term antipsychotic treatment might influence dopamine-mediated reward function. We asked, therefore, whether a clinically relevant antipsychotic treatment regimen would alter the incentive motivational properties of a reward cue. We assessed the ability of a Pavlovian-conditioned stimulus to function as a conditioned reward, as well as to elicit approach behavior in rats treated with haloperidol, either continuously (achieved via subcutaneous osmotic minipump) or intermittently (achieved via daily subcutaneous injections). Continuous, but not intermittent, treatment enhanced the ability of amphetamine to potentiate the conditioned reinforcing effects of a cue associated with water. This effect was not related to differences in the ability to attribute predictive value to a conditioned stimulus (as measured by conditioned approach behavior), but was potentially linked to the development of behavioral supersensitivity to amphetamine and to augmented amphetamine-induced immediate early-gene expression (c-fos and Nur77) in dorsal striatopallidal and striatonigral cells. By enhancing the ability of reward cues to control behavior and by intensifying dopamine-mediated striatopallidal and striatonigral cell activity, standard (ie, continuous) antipsychotic treatment regimens might exacerbate drug-seeking and drug-taking behavior in schizophrenia. Achieving regular but transiently high antipsychotic levels in the brain (as modeled in the intermittent condition) might be a viable option to prevent these changes. This possibility should be explored in the clinic.

Opioid Modulation of Value-Based Decision-Making in Healthy Humans.

PubMed

Eikemo, Marie; Biele, Guido; Willoch, Frode; Thomsen, Lotte; Leknes, Siri

2017-08-01

Modifying behavior to maximize reward is integral to adaptive decision-making. In rodents, the μ-opioid receptor (MOR) system encodes motivation and preference for high-value rewards. Yet it remains unclear whether and how human MORs contribute to value-based decision-making. We reasoned that if the human MOR system modulates value-based choice, this would be reflected by opposite effects of agonist and antagonist drugs. In a double-blind pharmacological cross-over study, 30 healthy men received morphine (10 mg), placebo, and the opioid antagonist naltrexone (50 mg). They completed a two-alternative decision-making task known to induce a considerable bias towards the most frequently rewarded response option. To quantify MOR involvement in this bias, we fitted accuracy and reaction time data with the drift-diffusion model (DDM) of decision-making. The DDM analysis revealed the expected bidirectional drug effects for two decision subprocesses. MOR stimulation with morphine increased the preference for the stimulus with high-reward probability (shift in starting point). Compared to placebo, morphine also increased, and naltrexone reduced, the efficiency of evidence accumulation. Since neither drug affected motor-coordination, speed-accuracy trade-off, or subjective state (indeed participants were still blinded after the third session), we interpret the MOR effects on evidence accumulation efficiency as a consequence of changes in effort exerted in the task. Together, these findings support a role for the human MOR system in value-based choice by tuning decision-making towards high-value rewards across stimulus domains.

Incentivizing healthy eating in children: An investigation of the "ripple" and "temporal" effects of a reward-based intervention.

PubMed

Toossi, Saied

2017-10-01

Although previous studies have established the effectiveness of using small reward-based incentives in inducing the choice and consumption of healthier foods among children, little is known about their impact outside of experimental settings or their effectiveness over time when administered daily. This paper presents the results of a field experiment conducted to provide insight on these matters. The study employs a removed treatment within-subject design and was conducted at a summer program catering to low-income children between the ages of 5 and 12. The month long experiment-wherein participants were offered a small prize for choosing a fruit cup for dessert after lunch in lieu of cookies-involved 23 children between the ages of 5 and 8. Corroborating existing studies, the introduction of small reward-based incentives in this context was found to induce large increases in the number of children choosing the healthy dessert options after lunch, but disaggregating the results by week and day suggests that their impact diminished over time. Attempts to ascertain their effect outside of experimental settings did not indicate that the introduction of rewards had any adverse effects, but also did not provide definitive conclusions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The roles of the anterior cingulate cortex and its dopamine receptors in self-paced cost-benefit decision making in rats.

PubMed

Wang, Shuai; Hu, Shan-Hu; Shi, Yi; Li, Bao-Ming

2017-03-01

It has been shown that the anterior cingulate cortex (ACC) and its dopamine system are crucial for decision making that requires physical/emotional effort, but not for all forms of cost-benefit decision making. Previous studies had mostly employed behavioral tasks with two competing cost-reward options that were preset by the experimenters. However, few studies have been conducted using scenarios in which the subjects have full control over the energy/time expenditure required to obtain a proportional reward. Here, we assessed the roles of the ACC and its dopamine system in cost-benefit decision making by utilizing a "do more get more" (DMGM) task and a time-reward trade-off (TRTO) task, wherein the animals were able to self-determine how much effort or time to expend at a nosepoke operandum for a proportional reward. Our results showed that (1) ACC inactivation severely impaired DMGM task performance, with a reduction in the rate of correct responses and a decrease in the effort expended, but did not affect the TRTO task; and (2) blocking ACC D2 receptors had no impact on DMGM task performance in the baseline cost-benefit scenario, but it significantly reduced the attempts to invest increased effort for a large reward when the benefit-cost ratio was reduced by half. In contrast, blocking ACC D1 receptors had no effect on DMGM task performance. These findings suggest that the ACC is required for self-paced effort-based but not for time-reward trade-off decision making. Furthermore, ACC dopamine D2 but not D1 receptors are involved in DMGM decision making.

Methylmercury cycling, bioaccumulation, and export from agricultural and non-agricultural wetlands in the Yolo Bypass

USGS Publications Warehouse

Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark; Fleck, Jacob; Alpers, Charles N.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Stricker, Craig; Stephenson, Mark; Feliz, David; Gill, Gary; Bachand, Philip; Brice, Ann; Kulakow, Robin

2010-01-01

d) Identification and testing of potential management approaches for reducing MeHg contamination. In addition, the quantitative results reported here assess the effect of current land use practices in the Yolo Bypass MeHg production, bioaccumulation and export, and provide process-based advice towards achieving current goals of the RWQCB-CVR's Sacramento -- San Joaquin Delta Estuary TMDL for Methyl & Total Mercury (Wood et al., 2010b). Further work is necessary to evaluate biotic exposure in the Yolo Bypass Wildlife Area at higher trophic levels (e.g. birds), to quantify winter hydrologic flux of MeHg to the larger Delta ecosystem, and to evaluate rice straw management options to limit labile carbon supplies to surface sediment during winter months. In summary, agricultural management of rice fields -- specifically the periodic flooding and production of easily degraded organic matter -- promotes the production of MeHg beyond rates seen in naturally vegetated wetlands, whether seasonally or permanently flooded., The exported load from MeHg from these agricultural wetlands may be controlled by limiting hydrologic export from fields to enhance on-site MeHg removal processes, but the tradeoff is that this impoundement increases Me Hg exposure to resident organisms.

The Relationship between Saccadic Choice and Reaction Times with Manipulations of Target Value

PubMed Central

Milstein, David M.; Dorris, Michael C.

2011-01-01

Choosing the option with the highest expected value (EV; reward probability × reward magnitude) maximizes the intake of reward under conditions of uncertainty. However, human economic choices indicate that our value calculation has a subjective component whereby probability and reward magnitude are not linearly weighted. Using a similar economic framework, our goal was to characterize how subjective value influences the generation of simple motor actions. Specifically, we hypothesized that attributes of saccadic eye movements could provide insight into how rhesus monkeys, a well-studied animal model in cognitive neuroscience, subjectively value potential visual targets. In the first experiment, monkeys were free to choose by directing a saccade toward one of two simultaneously displayed targets, each of which had an uncertain outcome. In this task, choices were more likely to be allocated toward the higher valued target. In the second experiment, only one of the two possible targets appeared on each trial. In this task, saccadic reaction times (SRTs) decreased toward the higher valued target. Reward magnitude had a much stronger influence on both choices and SRTs than probability, whose effect was observed only when reward magnitude was similar for both targets. Across EV blocks, a strong relationship was observed between choice preferences and SRTs. However, choices tended to maximize at skewed values whereas SRTs varied more continuously. Lastly, SRTs were unchanged when all reward magnitudes were 1×, 1.5×, and 2× their normal amount, indicating that saccade preparation was influenced by the relative value of the targets rather than the absolute value of any single-target. We conclude that value is not only an important factor for deliberative decision making in primates, but also for the selection and preparation of simple motor actions, such as saccadic eye movements. More precisely, our results indicate that, under conditions of uncertainty, saccade choices and reaction times are influenced by the relative expected subjective value of potential movements. PMID:22028681

Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River.

PubMed

Donner, Simon D; Kucharik, Christopher J

2008-03-18

Corn cultivation in the United States is expected to increase to meet demand for ethanol. Nitrogen leaching from fertilized corn fields to the Mississippi-Atchafalaya River system is a primary cause of the bottom-water hypoxia that develops on the continental shelf of the northern Gulf of Mexico each summer. In this study, we combine agricultural land use scenarios with physically based models of terrestrial and aquatic nitrogen to examine the effect of present and future expansion of corn-based ethanol production on nitrogen export by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico. The results show that the increase in corn cultivation required to meet the goal of 15-36 billion gallons of renewable fuels by the year 2022 suggested by a recent U.S. Senate energy policy would increase the annual average flux of dissolved inorganic nitrogen (DIN) export by the Mississippi and Atchafalaya Rivers by 10-34%. Generating 15 billion gallons of corn-based ethanol by the year 2022 will increase the odds that annual DIN export exceeds the target set for reducing hypoxia in the Gulf of Mexico to >95%. Examination of extreme mitigation options shows that expanding corn-based ethanol production would make the already difficult challenges of reducing nitrogen export to the Gulf of Mexico and the extent of hypoxia practically impossible without large shifts in food production and agricultural management.

77 FR 40924 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-11

... execution, order or cancel information, which can be exported into a spreadsheet for review. TradeInfo.... This is the same fee assessed to NOM Participants and PHLX members for this service. Use of TradeInfo... allocate trades to the appropriate accounts and sub- accounts for clearing. The Options Clearing...

75 FR 71432 - Agency Information Collection Activities: Final Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-23

... company chooses to make use of some aspects of the additional flexibility. Customers who do not meet the...'' as an obligor type; added the option ``CAD or SDDP'' to the terms; deleted the ``Sight Payments (non.... Report of Premiums Payable for Exporters Only. OMB Number: 3048-0017. Type of Review: Regular. Need and...

75 FR 57020 - Agency Information Collection Activities: Final Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-17

... company chooses to make use of some aspects of the additional flexibility. Customers who do not meet the...'' as an obligor type; added the option ``CAD or SDDP'' to the terms; deleted the ``Sight Payments (non.... Report of Premiums Payable for Exporters Only. OMB Number: 3048-0017. Type of Review: Regular. Need and...

Pensions, investments, and taxation.

PubMed

Gerstein, Mitchell

2010-01-01

Having for retirement has become increasingly challenging with retirement plan rules changing along with taxes and investment choices. The only certainty is that everyone needs to save money in order to be able to stop working. The best plan for a small business can be complex and confusing but rewarding if designed properly. There are a number of options available and many factors to consider in choosing the most appropriate plan.

Using a discrete choice experiment to inform the design of programs to promote colon cancer screening for vulnerable populations in North Carolina.

PubMed

Pignone, Michael P; Crutchfield, Trisha M; Brown, Paul M; Hawley, Sarah T; Laping, Jane L; Lewis, Carmen L; Lich, Kristen Hassmiller; Richardson, Lisa C; Tangka, Florence Kl; Wheeler, Stephanie B

2014-11-30

Screening for colorectal cancer (CRC) is suboptimal, particularly for vulnerable populations. Effective intervention programs are needed to increase screening rates. We used a discrete choice experiment (DCE) to learn about how vulnerable individuals in North Carolina value different aspects of CRC screening programs. We enrolled English-speaking adults ages 50-75 at average risk of CRC from rural North Carolina communities with low rates of CRC screening, targeting those with public or no insurance and low incomes. Participants received basic information about CRC screening and potential program features, then completed a 16 task DCE and survey questions that examined preferences for four attributes of screening programs: testing options available; travel time required; money paid for screening or rewards for completing screening; and the portion of the cost of follow-up care paid out of pocket. We used Hierarchical Bayesian methods to calculate individual-level utilities for the 4 attributes' levels and individual-level attribute importance scores. For each individual, the attribute with the highest importance score was considered the most important attribute. Individual utilities were then aggregated to produce mean utilities for each attribute. We also compared DCE-based results with those from direct questions in a post-DCE survey. We enrolled 150 adults. Mean age was 57.8 (range 50-74); 55% were women; 76% White and 19% African-American; 87% annual household income under $30,000; and 51% were uninsured. Individuals preferred shorter travel; rewards or small copayments compared with large copayments; programs that included stool testing as an option; and greater coverage of follow-up costs. Follow-up cost coverage was most frequently found to be the most important attribute from the DCE (47%); followed by test reward/copayment (33%). From the survey, proportion of follow-up costs paid was most frequently cited as most important (42% of participants), followed by testing options (32%). There was moderate agreement (45%) in attribute importance between the DCE and the single question in the post-DCE survey. Screening test copayments and follow-up care coverage costs are important program characteristics in this vulnerable, rural population.

Decision making in the Balloon Analogue Risk Task (BART): anterior cingulate cortex signals loss aversion but not the infrequency of risky choices.

PubMed

Fukunaga, Rena; Brown, Joshua W; Bogg, Tim

2012-09-01

The inferior frontal gyrus/anterior insula (IFG/AI) and anterior cingulate cortex (ACC) are key regions involved in risk appraisal during decision making, but accounts of how these regions contribute to decision making under risk remain contested. To help clarify the roles of these and other related regions, we used a modified version of the Balloon Analogue Risk Task (Lejuez et al., Journal of Experimental Psychology: Applied, 8, 75-84, 2002) to distinguish between decision-making and feedback-related processes when participants decided to pursue a gain as the probability of loss increased parametrically. Specifically, we set out to test whether the ACC and IFG/AI regions correspond to loss aversion at the time of decision making in a way that is not confounded with either reward-seeking or infrequency effects. When participants chose to discontinue inflating the balloon (win option), we observed greater ACC and mainly bilateral IFG/AI activity at the time of decision as the probability of explosion increased, consistent with increased loss aversion but inconsistent with an infrequency effect. In contrast, we found robust vmPFC activity when participants chose to continue inflating the balloon (risky option), consistent with reward seeking. However, in the cingulate and in mainly bilateral IFG regions, blood-oxygenation-level-dependent activation decreased when participants chose to inflate the balloon as the probability of explosion increased, findings that are consistent with a reduced loss aversion signal. Our results highlight the existence of distinct reward-seeking and loss-averse signals during decision making, as well as the importance of distinguishing between decision and feedback signals.

Social Learning as a Way to Overcome Choice-Induced Preferences? Insights from Humans and Rhesus Macaques

PubMed Central

Monfardini, Elisabetta; Gaveau, Valérie; Boussaoud, Driss; Hadj-Bouziane, Fadila; Meunier, Martine

2012-01-01

Much theoretical attention is currently devoted to social learning. Yet, empirical studies formally comparing its effectiveness relative to individual learning are rare. Here, we focus on free choice, which is at the heart of individual reward-based learning, but absent in social learning. Choosing among two equally valued options is known to create a preference for the selected option in both humans and monkeys. We thus surmised that social learning should be more helpful when choice-induced preferences retard individual learning than when they optimize it. To test this prediction, the same task requiring to find which among two items concealed a reward was applied to rhesus macaques and humans. The initial trial was individual or social, rewarded or unrewarded. Learning was assessed on the second trial. Choice-induced preference strongly affected individual learning. Monkeys and humans performed much more poorly after an initial negative choice than after an initial positive choice. Comparison with social learning verified our prediction. For negative outcome, social learning surpassed or at least equaled individual learning in all subjects. For positive outcome, the predicted superiority of individual learning did occur in a majority of subjects (5/6 monkeys and 6/12 humans). A minority kept learning better socially though, perhaps due to a more dominant/aggressive attitude toward peers. Poor learning from errors due to over-valuation of personal choices is among the decision-making biases shared by humans and animals. The present study suggests that choice-immune social learning may help curbing this potentially harmful tendency. Learning from successes is an easier path. The present data suggest that whether one tends to walk it alone or with a peer’s help might depend on the social dynamics within the actor/observer dyad. PMID:22969703

Enhancing emotion-based learning in decision-making under uncertainty.

PubMed

Alarcón, David; Amián, Josué G; Sánchez-Medina, José A

2015-01-01

The Iowa Gambling Task (IGT) is widely used to study decision-making differences between several clinical and healthy populations. Unlike the healthy participants, clinical participants have difficulty choosing between advantageous options, which yield long-term benefits, and disadvantageous options, which give high immediate rewards but lead to negative profits. However, recent studies have found that healthy participants avoid the options with a higher frequency of losses regardless of whether or not they are profitable in the long run. The aim of this study was to control for the confounding effect of the frequency of losses between options to improve the performance of healthy participants on the IGT. Eighty healthy participants were randomly assigned to the original IGT or a modified version of the IGT that diminished the gap in the frequency of losses between options. The participants who used the modified IGT version learned to make better decisions based on long-term profit, as indicated by an earlier ability to discriminate good from bad options, and took less time to make their choices. This research represents an advance in the study of decision making under uncertainty by showing that emotion-based learning is improved by controlling for the loss-frequency bias effect.

Acute stress induces selective alterations in cost/benefit decision-making.

PubMed

Shafiei, Naghmeh; Gray, Megan; Viau, Victor; Floresco, Stan B

2012-09-01

Acute stress can exert beneficial or detrimental effects on different forms of cognition. In the present study, we assessed the effects of acute restraint stress on different forms of cost/benefit decision-making, and some of the hormonal and neurochemical mechanisms that may underlie these effects. Effort-based decision-making was assessed where rats chose between a low effort/reward (1 press=2 pellets) or high effort/reward option (4 pellets), with the effort requirement increasing over 4 blocks of trials (2, 5, 10, and 20 lever presses). Restraint stress for 1 h decreased preference for the more costly reward and induced longer choice latencies. Control experiments revealed that the effects on decision-making were not mediated by general reductions in motivation or preference for larger rewards. In contrast, acute stress did not affect delay-discounting, when rats chose between a small/immediate vs larger/delayed reward. The effects of stress on decision-making were not mimicked by treatment with physiological doses of corticosterone (1-3 mg/kg). Blockade of dopamine receptors with flupenthixol (0.25 mg/kg) before restraint did not attenuate stress-induced effects on effort-related choice, but abolished effects on choice latencies. These data suggest that acute stress interferes somewhat selectively with cost/benefit evaluations concerning effort costs. These effects do not appear to be mediated solely by enhanced glucocorticoid activity, whereas dopaminergic activation may contribute to increased deliberation times induced by stress. These findings may provide insight into impairments in decision-making and anergia associated with stress-related disorders, such as depression.

Acute Stress Induces Selective Alterations in Cost/Benefit Decision-Making

PubMed Central

Shafiei, Naghmeh; Gray, Megan; Viau, Victor; Floresco, Stan B

2012-01-01

Acute stress can exert beneficial or detrimental effects on different forms of cognition. In the present study, we assessed the effects of acute restraint stress on different forms of cost/benefit decision-making, and some of the hormonal and neurochemical mechanisms that may underlie these effects. Effort-based decision-making was assessed where rats chose between a low effort/reward (1 press=2 pellets) or high effort/reward option (4 pellets), with the effort requirement increasing over 4 blocks of trials (2, 5, 10, and 20 lever presses). Restraint stress for 1 h decreased preference for the more costly reward and induced longer choice latencies. Control experiments revealed that the effects on decision-making were not mediated by general reductions in motivation or preference for larger rewards. In contrast, acute stress did not affect delay-discounting, when rats chose between a small/immediate vs larger/delayed reward. The effects of stress on decision-making were not mimicked by treatment with physiological doses of corticosterone (1–3 mg/kg). Blockade of dopamine receptors with flupenthixol (0.25 mg/kg) before restraint did not attenuate stress-induced effects on effort-related choice, but abolished effects on choice latencies. These data suggest that acute stress interferes somewhat selectively with cost/benefit evaluations concerning effort costs. These effects do not appear to be mediated solely by enhanced glucocorticoid activity, whereas dopaminergic activation may contribute to increased deliberation times induced by stress. These findings may provide insight into impairments in decision-making and anergia associated with stress-related disorders, such as depression. PMID:22569506

Southeast Asia Report.

DTIC Science & Technology

1987-03-26

Members 102 ECONOMIC PLANNING, TRADE, AND FINANCE Increase in Consumer, Export Goods Urged (Pham Thanh; NHAN DAN, 2 Jan 87) 103 Reasons for...Economic Management 121 Kien Giang Increases Handicrafts 121 Population, Relocation Labor 121 AGRICULTURE Potential Economic Resources Available in Sea...imperative that ac- tion be taken to increase tax or reduce expenditure. Instead, they believe he won’t follow either option and may, in- deed

Contribution of plastic waste recovery to greenhouse gas (GHG) savings in Spain.

PubMed

Sevigné-Itoiz, Eva; Gasol, Carles M; Rieradevall, Joan; Gabarrell, Xavier

2015-12-01

This paper concentrates on the quantification of greenhouse gas (GHG) emissions of post-consumer plastic waste recovery (material or energy) by considering the influence of the plastic waste quality (high or low), the recycled plastic applications (virgin plastic substitution or non-plastic substitution) and the markets of recovered plastic (regional or global). The aim is to quantify the environmental consequences of different alternatives in order to evaluate opportunities and limitations to select the best and most feasible plastic waste recovery option to decrease the GHG emissions. The methodologies of material flow analysis (MFA) for a time period of thirteen years and consequential life cycle assessment (CLCA) have been integrated. The study focuses on Spain as a representative country for Europe. The results show that to improve resource efficiency and avoid more GHG emissions, the options for plastic waste management are dependent on the quality of the recovered plastic. The results also show that there is an increasing trend of exporting plastic waste for recycling, mainly to China, that reduces the GHG benefits from recycling, suggesting that a new focus should be introduced to take into account the split between local recycling and exporting. Copyright © 2015 Elsevier Ltd. All rights reserved.

MetNetMaker: a free and open-source tool for the creation of novel metabolic networks in SBML format.

PubMed

Forth, Thomas; McConkey, Glenn A; Westhead, David R

2010-09-15

An application has been developed to help with the creation and editing of Systems Biology Markup Language (SBML) format metabolic networks up to the organism scale. Networks are defined as a collection of Kyoto Encyclopedia of Genes and Genomes (KEGG) LIGAND reactions with an optional associated Enzyme Classification (EC) number for each reaction. Additional custom reactions can be defined by the user. Reactions within the network can be assigned flux constraints and compartmentalization is supported for each reaction in addition to the support for reactions that occur across compartment boundaries. Exported networks are fully SBML L2V4 compatible with an optional L2V1 export for compatibility with old versions of the COBRA toolbox. The software runs in the free Microsoft Access 2007 Runtime (Microsoft Inc.), which is included with the installer and works on Windows XP SP2 or better. Full source code is viewable in the full version of Access 2007 or 2010. Users must have a license to use the KEGG LIGAND database (free academic licensing is available). Please go to www.bioinformatics.leeds.ac.uk/~pytf/metnetmaker for software download, help and tutorials.

Some less conventional options for plutonium disposal

NASA Astrophysics Data System (ADS)

Stoll, Dr. Wolfgang, Prof.

2000-07-01

Disposition of weapons Pu (W-Pu) aims at the replacement of military access restrictions by inherent longlasting technical barriers to make the return into the weapons state difficult and not rewarding anymore. At the time of the NAS-study in 1994, two ways were perceived to be mature and selected: Fissioning of W-Pu as LWR-MOX and the disposal in a vitrified radionuclide-spiked form.1 Both options since have been questioned for equality, met different acceptance at both superpowers and showed slow progress. A criterion to measure disarmament would be the amount of W-Pu in the different proliferation resistant forms, multiplied by the effort needed for each form to return to weapons quality.

Reward Expectation Modulates Feedback-Related Negativity and EEG Spectra

PubMed Central

Cohen, Michael X; Elger, Christian E.; Ranganath, Charan

2007-01-01

The ability to evaluate outcomes of previous decisions is critical to adaptive decision-making. The feedback-related negativity (FRN) is an event-related potential (ERP) modulation that distinguishes losses from wins, but little is known about the effects of outcome probability on these ERP responses. Further, little is known about the frequency characteristics of feedback processing, for example, event-related oscillations and phase synchronizations. Here, we report an EEG experiment designed to address these issues. Subjects engaged in a probabilistic reinforcement learning task in which we manipulated, across blocks, the probability of winning and losing to each of two possible decision options. Behaviorally, all subjects quickly adapted their decision-making to maximize rewards. ERP analyses revealed that the probability of reward modulated neural responses to wins, but not to losses. This was seen both across blocks as well as within blocks, as learning progressed. Frequency decomposition via complex wavelets revealed that EEG responses to losses, compared to wins, were associated with enhanced power and phase coherence in the theta frequency band. As in the ERP analyses, power and phase coherence values following wins but not losses were modulated by reward probability. Some findings between ERP and frequency analyses diverged, suggesting that these analytic approaches provide complementary insights into neural processing. These findings suggest that the neural mechanisms of feedback processing may differ between wins and losses. PMID:17257860

How decisions emerge: action dynamics in intertemporal decision making.

PubMed

Dshemuchadse, Maja; Scherbaum, Stefan; Goschke, Thomas

2013-02-01

In intertemporal decision making, individuals prefer smaller rewards delivered sooner over larger rewards delivered later, often to an extent that seems irrational from an economical perspective. This behavior has been attributed to a lack of self-control and reflection, the nonlinearity of human time perception, and several other sources. Although an increasing number of models propose different mathematical descriptions of temporal discounting, the dynamics of the decision process behind temporal discounting are much less clear. In this study, we obtained further insights into the mechanisms of intertemporal decisions by observing choice action dynamics via a novel combination of continuously recorded mouse movements and a multiple regression approach. Participants had to choose between two hypothetical options (sooner/smaller vs. later/larger) by moving the mouse cursor from the bottom of the screen either to the top left or to the top right. We observed less direct mouse movements when participants chose later/larger rewards, indicating that participants had to overcome the attraction of the sooner/smaller reward first. Additionally, our results suggest that framing time information differently changes the weighting of value. We conclude that using a continuous process-oriented approach could further advance the understanding of intertemporal choice beyond the identification of the best fitted mathematical description of the discounting function by uncovering the way intertemporal decisions are performed. 2013 APA, all rights reserved

Working and waiting for better rewards: self-control in two monkey species (Cebus apella and Macaca mulatta).

PubMed

Evans, Theodore A; Perdue, Bonnie M; Parrish, Audrey E; Beran, Michael J

2014-03-01

Self-control is typically defined as choosing a greater, delayed reward over a lesser, more immediate reward. However, in nature, there are other costs besides delay associated with obtaining the greatest outcome including increased effort, potential punishment, and low probability of reward. Effort is an interesting case because it sometimes impairs self-control, by acting as an additional cost, and at other times facilitates self-control, by distracting one from impulsive options. Additionally, different species may perform differently in effortful self-control tasks, based on their natural ecology. To gain insight into these aspects of self-control behavior, we examined capuchin monkeys' and rhesus monkeys' self-control in separate working and waiting choice tasks. We hypothesized that capuchins would show greater self-control in the working task, given their naturally higher activity level, whereas rhesus would perform similarly in both tasks. Rhesus performed as predicted, whereas contrary to our hypothesis, capuchins exhibited lesser performance in the working task. Nonetheless, these results may still stem from inherent species differences interacting with details of the methodology. Capuchins, being highly energetic and social monkeys, may have divided their energy and attention between the working task and other elements of the test environment such as visible group mates or manipulanda. Copyright © 2014 Elsevier B.V. All rights reserved.

Reward type and behavioural patterns predict dogs’ success in a delay of gratification paradigm

PubMed Central

Brucks, Désirée; Soliani, Matteo; Range, Friederike; Marshall-Pescini, Sarah

2017-01-01

Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to ‘coping-strategies’ found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa. PMID:28272409

Sequential and simultaneous choices: testing the diet selection and sequential choice models.

PubMed

Freidin, Esteban; Aw, Justine; Kacelnik, Alex

2009-03-01

We investigate simultaneous and sequential choices in starlings, using Charnov's Diet Choice Model (DCM) and Shapiro, Siller and Kacelnik's Sequential Choice Model (SCM) to integrate function and mechanism. During a training phase, starlings encountered one food-related option per trial (A, B or R) in random sequence and with equal probability. A and B delivered food rewards after programmed delays (shorter for A), while R ('rejection') moved directly to the next trial without reward. In this phase we measured latencies to respond. In a later, choice, phase, birds encountered the pairs A-B, A-R and B-R, the first implementing a simultaneous choice and the second and third sequential choices. The DCM predicts when R should be chosen to maximize intake rate, and SCM uses latencies of the training phase to predict choices between any pair of options in the choice phase. The predictions of both models coincided, and both successfully predicted the birds' preferences. The DCM does not deal with partial preferences, while the SCM does, and experimental results were strongly correlated to this model's predictions. We believe that the SCM may expose a very general mechanism of animal choice, and that its wider domain of success reflects the greater ecological significance of sequential over simultaneous choices.

Language-Trained Chimpanzees (Pan troglodytes) Delay Gratification by Choosing Token Exchange Over Immediate Reward Consumption

PubMed Central

Beran, Michael J.; Evans, Theodore A.

2012-01-01

Token exchange inherently introduces an element of delay between behavior and reward and so token studies may help us better understand delay of gratification and self-control. To examine this possibility, we presented three language-trained chimpanzees with repeated choices involving different foods that could be eaten immediately or lexigram (graphic symbol) tokens that represented (and could be traded for) foods later. When both options were foods, chimpanzees always chose more preferred foods over less preferred foods. When both options were lexigram tokens representing those same foods, performance remained the same as chimpanzees selected the higher value token and then traded it for food. Then, when faced with choosing a token that could be traded later or choosing a food item that could be eaten immediately, most chimpanzees learned to make whatever response led to the more preferred food. They did this even when that meant selecting a high value lexigram token that could be traded only two to three minutes later instead of a medium value, but immediately available, food item. Thus, chimpanzees flexibly selected tokens even though such selections necessarily delayed gratification and required forgoing immediately available food. This finding illustrates the utility of symbolic token exchange for assessing self-control in nonhuman animals. PMID:22674686

Acute Δ-9-tetrahydrocannabinol administration in female rats attenuates immediate responses following losses but not multi-trial reinforcement learning from wins.

PubMed

Wong, Scott A; Randolph, Sienna H; Ivan, Victorita E; Gruber, Aaron J

2017-09-29

Δ-9-Tetrahydrocannabinol (THC) is the main psychoactive component of marijuana and has potent effects on decision-making, including a proposed reduction in cognitive flexibility. We demonstrate here that acute THC administration differentially affects some of the processes that contribute to cognitive flexibility. Specifically, THC reduces lose-shift responding in which female rats tend to immediately shift choice responses away from options that result in reward omission on the previous trial. THC, however, did not impair the ability of rats to flexibly bias responses toward feeders with higher probability of reward in a reversal task. This response adaptation developed over several trials, suggesting that THC did not impair slower forms of reinforcement learning needed to choose among options with unequal utility. This dissociation of THC's effects on innate/rapid and learned/gradual decision-making processes was unexpected, but is supported by emerging evidence that lose-shift responding is mediated by neural mechanisms distinct from those involved in other forms of reinforcement learning. The present data suggest that, at least in some tasks, the apparent reductions in cognitive flexibility by THC may be explained by the immediate effects on loss sensitivity, rather than impairments of all processes used for choice adaptation. Copyright © 2017 Elsevier B.V. All rights reserved.

Cognitive Factors Affecting Freeze-like Behavior in Humans.

PubMed

Alban, Michael W; Pocknell, Victoria

2017-01-01

Contemporary research on survival-related defensive behaviors has identified physiological markers of freeze/flight/fight. Our research focused on cognitive factors associated with freeze-like behavior in humans. Study 1 tested if an explicit decision to freeze is associated with the psychophysiological state of freezing. Heart rate deceleration occurred when participants chose to freeze. Study 2 varied the efficacy of freezing relative to other defense options and found "freeze" was responsive to variations in the perceived effectiveness of alternative actions. Study 3 tested if individual differences in motivational orientation affect preference for a "freeze" option when the efficacy of options is held constant. A trend in the predicted direction suggested that naturally occurring cognitions led loss-avoiders to select "freeze" more often than reward-seekers. In combination, our attention to the cognitive factors affecting freeze-like behavior in humans represents a preliminary step in addressing an important but neglected research area.

Self-interest without selfishness: the hedonic benefit of imposed self-interest.

PubMed

Berman, Jonathan Z; Small, Deborah A

2012-10-01

Despite commonsense appeal, the link between self-interest and happiness remains elusive. One reason why individuals may not feel satisfied with self-interest is that they feel uneasy about sacrificing the needs of others for their own gain. We propose that externally imposing self-interest allows individuals to enjoy self-benefiting outcomes that are untainted by self-reproach for failing to help others. Study 1 demonstrated that an imposed self-interested option (a reward) leads to greater happiness than does choosing between a self-interested option and a prosocial option (a charity donation). Study 2 demonstrated that this effect is not driven by choice in general; rather, it is the specific trade-off between benefiting the self and benefiting others that inhibits happiness gained from self-interest. We theorize that the agency inherent in choice reduces the hedonic value of self-interest. Results of Study 3 find support for this mechanism.

Preference for oddity: uniqueness heuristic or hierarchical choice process?

PubMed

Waite, Thomas A

2008-10-01

Traditional economic theories assume decision makers in multialternative choice tasks "assign" a value to each option and then express rational preferences. Here, I report an apparent violation of such rationality in gray jays (Perisoreus canadensis). I tested the jays' preference in a quaternary choice task where three options were the same color and the fourth option was a different color. All options offered an identical food reward and so the strictly rational expectation was that subjects would choose the odd-colored option in 25% of choices. In clear disagreement, every subject chose the odd option more frequently than expected. I speculate as to how this surprising preference for oddity might have been ecologically rational: by using a unique-choice heuristic, the jays might have been able to bypass a deliberative phase of the decision process and devote more attention to scanning for predators. Alternatively, it is conceivable that the jays did not prefer oddity per se. Instead, they might have used a hierarchical process, assigning options to color categories and then choosing between categories. If so, their behavior matches expectation after all (on average, subjects chose the odd option 50% of the time). It should be straightforward to test these competing hypotheses. The current results can be viewed as a new example of how simple mechanisms sometimes produce economically puzzling yet ecologically rational decision making.

Sex Differences in Risk Preference and c-Fos Expression in Paraventricular Thalamic Nucleus of Rats During Gambling Task

PubMed Central

Ishii, Hironori; Onodera, Mariko; Ohara, Shinya; Tsutsui, Ken-Ichiro; Iijima, Toshio

2018-01-01

Different biological requirements between males and females may cause sex differences in decision preference when choosing between taking a risk to get a higher gain or taking a lower but sure gain. Several studies have tested this assumption in rats, however the conclusion remains controversial because the previous real-world like gambling tasks contained a learning component to track a global payoff of probabilistic outcome in addition to risk preference. Therefore, we modified a simple gambling task allowing us to exclude such learning effect, and investigated the sex difference in risk preference of rats and its neural basis. The task required water deprived rats to choose between a risky option which provided four drops of water or no reward at a 50% random chance vs. a sure option which provided predictable amount x (x = 1, 2, 3, 4). The amount and the risk were explicitly instructed so that different choice conditions could be tested trial by trial without re-learning of reward contingency. Although both sexes correctly chose the sure option with the same level of accuracy when the sure option provided the best offer (x = 4), they exhibited different choice performances when two options had the same expected value (x = 2). Males and females both preferred to take risky choices than sure choices (risk seeking), but males were more risk seeking than females. Outcome-history analysis of their choice pattern revealed that females reduced their risk preference after losing risky choices, whereas males did not. Rather, as losses continued, reaction time for subsequent risky choices got shorter in males. Given that significant sex difference features mainly emerged after negative experiences, male and female rats may evaluate an unsuccessful outcome of their decision in different manners. Furthermore, c-Fos expression in the paraventricular nucleus of the thalamus (PV) was higher in the gambling task than for the control task in males while c-fos levels did not differ in females. The present study provides a clear evidence of sex differences in risk preference in rats and suggests that the PV is a candidate region contributing to sex differences in risky decision making. PMID:29692713

PLOT3D Export Tool for Tecplot

NASA Technical Reports Server (NTRS)

Alter, Stephen

2010-01-01

The PLOT3D export tool for Tecplot solves the problem of modified data being impossible to output for use by another computational science solver. The PLOT3D Exporter add-on enables the use of the most commonly available visualization tools to engineers for output of a standard format. The exportation of PLOT3D data from Tecplot has far reaching effects because it allows for grid and solution manipulation within a graphical user interface (GUI) that is easily customized with macro language-based and user-developed GUIs. The add-on also enables the use of Tecplot as an interpolation tool for solution conversion between different grids of different types. This one add-on enhances the functionality of Tecplot so significantly, it offers the ability to incorporate Tecplot into a general suite of tools for computational science applications as a 3D graphics engine for visualization of all data. Within the PLOT3D Export Add-on are several functions that enhance the operations and effectiveness of the add-on. Unlike Tecplot output functions, the PLOT3D Export Add-on enables the use of the zone selection dialog in Tecplot to choose which zones are to be written by offering three distinct options - output of active, inactive, or all zones (grid blocks). As the user modifies the zones to output with the zone selection dialog, the zones to be written are similarly updated. This enables the use of Tecplot to create multiple configurations of a geometry being analyzed. For example, if an aircraft is loaded with multiple deflections of flaps, by activating and deactivating different zones for a specific flap setting, new specific configurations of that aircraft can be easily generated by only writing out specific zones. Thus, if ten flap settings are loaded into Tecplot, the PLOT3D Export software can output ten different configurations, one for each flap setting.

Choice in experiential learning: True preferences or experimental artifacts?

PubMed

Ashby, Nathaniel J S; Konstantinidis, Emmanouil; Yechiam, Eldad

2017-03-01

The rate of selecting different options in the decisions-from-feedback paradigm is commonly used to measure preferences resulting from experiential learning. While convergence to a single option increases with experience, some variance in choice remains even when options are static and offer fixed rewards. Employing a decisions-from-feedback paradigm followed by a policy-setting task, we examined whether the observed variance in choice is driven by factors related to the paradigm itself: Continued exploration (e.g., believing options are non-stationary) or exploitation of perceived outcome patterns (i.e., a belief that sequential choices are not independent). Across two studies, participants showed variance in their choices, which was related (i.e., proportional) to the policies they set. In addition, in Study 2, participants' reported under-confidence was associated with the amount of choice variance in later choices and policies. These results suggest that variance in choice is better explained by participants lacking confidence in knowing which option is better, rather than methodological artifacts (i.e., exploration or failures to recognize outcome independence). As such, the current studies provide evidence for the decisions-from-feedback paradigm's validity as a behavioral research method for assessing learned preferences. Copyright © 2017 Elsevier B.V. All rights reserved.

Feedback-related potentials in a gambling task with randomised reward.

PubMed

Mushtaq, Faisal; Guillen, Pablo Puente; Wilkie, Richard M; Mon-Williams, Mark A; Schaefer, Alexandre

2016-03-01

Event-related potentials (ERPs) time-locked to decision outcomes are reported. Participants engaged in a gambling task (see [1] for details) in which they decided between a risky and a safe option (presented as different coloured shapes) on each trial (416 in total). Each decision was associated with (fully randomised) feedback about the reward outcome (Win/Loss) and its magnitude (varying as a function of decision response; 5-9 points for Risky decisions and 1-4 points for Safe decisions). Here, we show data demonstrating: (a) the influence of Win feedback in the preceding outcome (Outcome t-1) on activity related to the current outcome (Outcome t ); (b) difference wave analysis for outcome expectancy- separating Expected Outcomes (consecutive Loss trials subtracted from consecutive reward) from Unexpected Outcomes (subtracting Loss t-1Win t trials from Win t-1Loss t trials); (c) difference waves separating Switch and Stay responses for Outcome Expectancy; (d) the effect of magnitude induced by decisions (Risk t vs. Safe t ) on Outcome Expectancy; and finally, (e) expectations reflected by response switch direction (Risk to Safe responses vs. Safe to Risk t ) on the FRN at Outcome t .

Learning in Noise: Dynamic Decision-Making in a Variable Environment

PubMed Central

Gureckis, Todd M.; Love, Bradley C.

2009-01-01

In engineering systems, noise is a curse, obscuring important signals and increasing the uncertainty associated with measurement. However, the negative effects of noise and uncertainty are not universal. In this paper, we examine how people learn sequential control strategies given different sources and amounts of feedback variability. In particular, we consider people’s behavior in a task where short- and long-term rewards are placed in conflict (i.e., the best option in the short-term is worst in the long-term). Consistent with a model based on reinforcement learning principles (Gureckis & Love, in press), we find that learners differentially weight information predictive of the current task state. In particular, when cues that signal state are noisy and uncertain, we find that participants’ ability to identify an optimal strategy is strongly impaired relative to equivalent amounts of uncertainty that obscure the rewards/valuations of those states. In other situations, we find that noise and uncertainty in reward signals may paradoxically improve performance by encouraging exploration. Our results demonstrate how experimentally-manipulated task variability can be used to test predictions about the mechanisms that learners engage in dynamic decision making tasks. PMID:20161328

What should we call instruments commonly known as payments for environmental services? A review of the literature and a proposal.

PubMed

Shelley, Barry G

2011-02-01

Researchers, policy makers, and practitioners have used various terms to describe instruments that reward the stewardship of ecosystem services that benefit "external" actors. Payments for environmental services, or PES, has been the predominant name. However, critics have challenged both the payments and environmental components of this nomenclature, most commonly proposing markets, compensation, or rewards as alternatives for the former, and ecosystem for the latter. Additional questions arise regarding what to call the agents directly involved in the transaction: sellers and buyers, or stewards and beneficiaries? For some, concerns about this terminology have emerged from so-called "pro-poor PES" debates that ask if actors could and should incorporate poverty alleviation goals into PES instruments. This review of the modulating use of terms and the arguments about which best fit theory and experience points to the key policy and ethical issues at stake as PES programs face critical and timely questions about the direction they will head. The author contends that the choices of terms will influence that direction and proposes a new alternative-rewards for ecosystem service stewardship (RESS)-that better encompasses pro-poor options. © 2011 New York Academy of Sciences.

The Strategic Design of Reward Systems.

DTIC Science & Technology

1982-10-01

AuTO1 , 8 CO NTRACT Ok .NANT NUMO lll , Edward E. Lawler III N-00014-81-K-0048 9 PERFORMING ORGANIZATION NAME AND ADORErS 10. PROGRAM ELEMENT...SUPPLEMENTARY NOTES .iL L:~ 19 KEY WORDS (Continue on reveres side It necessary and Identify by block number) A Pay, performance appraisal, motivation...retention, culture development:, and skill development are considered. The relationship between these object iwv and such design options as performance pay

The Forbidden World of Off the Record Negotiating for Successful Air Force Media Engagements

DTIC Science & Technology

2012-02-15

reporters choose OTR as a first option. Since all parties perform a mental calculus of risks versus rewards before agreeing to OTR, the author...experience, calling OTR “the most often misunderstood” attribution category.15 One widely used journalism textbook says only that OTR is information... textbook , used at Columbia Journalism School, pays scant discussion to such a fundamental topic. In the 596-page textbook , discussion about attribution

Improving value assessment of high-risk, high-reward biotechnology research: the role of 'thick tails'.

PubMed

Casault, Sébastien; Groen, Aard J; Linton, Jonathan D

2014-03-25

This paper presents work toward improving the efficacy of financial models that describe the unique nature of biotechnology firms. We show that using a 'thick tailed' power law distribution to describe the behavior of the value of biotechnology R&D used in a Real Options Pricing model is significantly more accurate than the traditionally used Gaussian approach. A study of 287 North-American biotechnology firms gives insights into common problems faced by investors, managers and other stakeholders when using traditional techniques to calculate the commercial value of R&D. This is important because specific quantitative tools to assess the value of high-risk, high-reward R&D do not currently exist. This often leads to an undervaluation of biotechnology R&D and R&D intensive biotechnology firms. For example, the widely used Net Present Value (NPV) method assumes a fixed risk ignoring management flexibility and the changing environment. However, Real Options Pricing models assume that commercial returns from R&D investments are described by a normal random walk. A normal random walk model eliminates the possibility of drastic changes to the marketplace resulting from the introduction of revolutionary products and/or services. It is possible to better understand and manage biotechnology research projects and portfolios using a model that more accurately considers large non-Gaussian price fluctuations with thick tails, which recognize the unusually large risks and opportunities associated with Biotechnology R&D. Our empirical data show that opportunity overcompensates for the downside risk making biotechnology R&D statistically more valuable than other Gaussian options investments, which may otherwise appear to offer a similar combination of risk and return. Copyright © 2013 Elsevier B.V. All rights reserved.

Distinct effects of apathy and dopamine on effort-based decision-making in Parkinson's disease.

PubMed

Le Heron, Campbell; Plant, Olivia; Manohar, Sanjay; Ang, Yuen-Siang; Jackson, Matthew; Lennox, Graham; Hu, Michele T; Husain, Masud

2018-05-01

Effort-based decision-making is a cognitive process crucial to normal motivated behaviour. Apathy is a common and disabling complication of Parkinson's disease, but its aetiology remains unclear. Intriguingly, the neural substrates associated with apathy also subserve effort-based decision-making in animal models and humans. Furthermore, the dopaminergic system plays a core role in motivating effortful behaviour for reward, and its dysfunction has been proposed to play a crucial role in the aetiology of apathy in Parkinson's disease. We hypothesized that disrupted effort-based decision-making underlies the syndrome of apathy in Parkinson's disease, and that this disruption may be modulated by the dopaminergic system. An effort-based decision-making task was administered to 39 patients with Parkinson's disease, with and without clinical apathy, ON and OFF their normal dopaminergic medications across two separate sessions, as well as 32 healthy age- and gender-matched controls. On a trial-by-trial basis, participants decided whether to accept or reject offers of monetary reward in return for exerting different levels of physical effort via handheld, individually calibrated dynamometers. Effort and reward were manipulated independently, such that offers spanned the full range of effort/reward combinations. Apathy was assessed using the Lille apathy rating scale. Motor effects of the dopamine manipulation were assessed using the Unified Parkinson's Disease Rating Scale part three motor score. The primary outcome variable was choice (accept/decline offer) analysed using a hierarchical generalized linear mixed effects model, and the vigour of squeeze (Newtons exerted above required force). Both apathy and dopamine depletion were associated with reduced acceptance of offers. However, these effects were driven by dissociable patterns of responding. While apathy was characterized by increased rejection of predominantly low reward offers, dopamine increased responding to high effort, high reward offers, irrespective of underlying motivational state. Dopamine also exerted a main effect on motor vigour, increasing force production independently of reward offered, while apathy did not affect this measure. The findings demonstrate that disrupted effort-based decision-making underlies Parkinson's disease apathy, but in a manner distinct to that caused by dopamine depletion. Apathy is associated with reduced incentivization by the rewarding outcomes of actions. In contrast, dopamine has a general effect in motivating behaviour for high effort, high reward options without altering the response pattern that characterizes the apathetic state. Thus, the motivational deficit observed in Parkinson's disease appears not to be simply secondary to dopaminergic depletion of mesocorticolimbic pathways, suggesting non-dopaminergic therapeutic strategies for apathy may be important future targets.

Impaired Flexible Reward-Based Decision-Making in Binge Eating Disorder: Evidence from Computational Modeling and Functional Neuroimaging.

PubMed

Reiter, Andrea M F; Heinze, Hans-Jochen; Schlagenhauf, Florian; Deserno, Lorenz

2017-02-01

Despite its clinical relevance and the recent recognition as a diagnostic category in the DSM-5, binge eating disorder (BED) has rarely been investigated from a cognitive neuroscientific perspective targeting a more precise neurocognitive profiling of the disorder. BED patients suffer from a lack of behavioral control during recurrent binge eating episodes and thus fail to adapt their behavior in the face of negative consequences, eg, high risk for obesity. To examine impairments in flexible reward-based decision-making, we exposed BED patients (n=22) and matched healthy individuals (n=22) to a reward-guided decision-making task during functional resonance imaging (fMRI). Performing fMRI analysis informed via computational modeling of choice behavior, we were able to identify specific signatures of altered decision-making in BED. On the behavioral level, we observed impaired behavioral adaptation in BED, which was due to enhanced switching behavior, a putative deficit in striking a balance between exploration and exploitation appropriately. This was accompanied by diminished activation related to exploratory decisions in the anterior insula/ventro-lateral prefrontal cortex. Moreover, although so-called model-free reward prediction errors remained intact, representation of ventro-medial prefrontal learning signatures, incorporating inference on unchosen options, was reduced in BED, which was associated with successful decision-making in the task. On the basis of a computational psychiatry account, the presented findings contribute to defining a neurocognitive phenotype of BED.

Impaired Flexible Reward-Based Decision-Making in Binge Eating Disorder: Evidence from Computational Modeling and Functional Neuroimaging

PubMed Central

Reiter, Andrea M F; Heinze, Hans-Jochen; Schlagenhauf, Florian; Deserno, Lorenz

2017-01-01

Despite its clinical relevance and the recent recognition as a diagnostic category in the DSM-5, binge eating disorder (BED) has rarely been investigated from a cognitive neuroscientific perspective targeting a more precise neurocognitive profiling of the disorder. BED patients suffer from a lack of behavioral control during recurrent binge eating episodes and thus fail to adapt their behavior in the face of negative consequences, eg, high risk for obesity. To examine impairments in flexible reward-based decision-making, we exposed BED patients (n=22) and matched healthy individuals (n=22) to a reward-guided decision-making task during functional resonance imaging (fMRI). Performing fMRI analysis informed via computational modeling of choice behavior, we were able to identify specific signatures of altered decision-making in BED. On the behavioral level, we observed impaired behavioral adaptation in BED, which was due to enhanced switching behavior, a putative deficit in striking a balance between exploration and exploitation appropriately. This was accompanied by diminished activation related to exploratory decisions in the anterior insula/ventro-lateral prefrontal cortex. Moreover, although so-called model-free reward prediction errors remained intact, representation of ventro–medial prefrontal learning signatures, incorporating inference on unchosen options, was reduced in BED, which was associated with successful decision-making in the task. On the basis of a computational psychiatry account, the presented findings contribute to defining a neurocognitive phenotype of BED. PMID:27301429

Training Attention Improves Decision Making in Individuals with Elevated Self-Reported Depressive Symptoms

PubMed Central

Cooper, Jessica A.; Gorlick, Marissa A.; Denny, Taylor; Worthy, Darrell A.; Beevers, Christopher G.; Maddox, W. Todd

2013-01-01

Depression is often characterized by attentional biases toward negative items and away from positive items, which likely affects reward and punishment processing. Recent work reported that training attention away from negative stimuli reduced this bias and reduced depressive symptoms. However, the effect of attention training on subsequent learning has yet to be explored. In the current study, participants were required to learn to maximize reward during decision-making. Undergraduates with elevated self-reported depressive symptoms received attention training toward positive stimuli prior to performing the decision-making task (n=20; active training). The active training group was compared to two groups: undergraduates with elevated self-reported depressive symptoms who received placebo training (n=22; placebo training) and control subjects with low levels of depressive symptoms (n=33; non-depressive control). The placebo-training depressive group performed worse and switched between options more than non-depressive controls on the reward maximization task. However, depressives that received active training performed as well as non-depressive controls. Computational modeling indicated that the placebo-trained group learned more from negative than from positive prediction errors, leading to more frequent switching. The non-depressive control and active training depressive groups showed similar learning from positive and negative prediction errors, leading to less frequent switching and better performance. Our results indicate that individuals with elevated depressive symptoms are impaired at reward maximization, but that the deficit can be improved with attention training toward positive stimuli. PMID:24197612

Training attention improves decision making in individuals with elevated self-reported depressive symptoms.

PubMed

Cooper, Jessica A; Gorlick, Marissa A; Denny, Taylor; Worthy, Darrell A; Beevers, Christopher G; Maddox, W Todd

2014-06-01

Depression is often characterized by attentional biases toward negative items and away from positive items, which likely affects reward and punishment processing. Recent work has reported that training attention away from negative stimuli reduced this bias and reduced depressive symptoms. However, the effect of attention training on subsequent learning has yet to be explored. In the present study, participants were required to learn to maximize reward during decision making. Undergraduates with elevated self-reported depressive symptoms received attention training toward positive stimuli prior to performing the decision-making task (n = 20; active training). The active-training group was compared to two other groups: undergraduates with elevated self-reported depressive symptoms who received placebo training (n = 22; placebo training) and a control group with low levels of depressive symptoms (n = 33; nondepressive control). The placebo-training depressive group performed worse and switched between options more than did the nondepressive controls on the reward maximization task. However, depressives that received active training performed as well as the nondepressive controls. Computational modeling indicated that the placebo-trained group learned more from negative than from positive prediction errors, leading to more frequent switching. The nondepressive control and active-training depressive groups showed similar learning from positive and negative prediction errors, leading to less-frequent switching and better performance. Our results indicate that individuals with elevated depressive symptoms are impaired at reward maximization, but that the deficit can be improved with attention training toward positive stimuli.

The Feedback-related Negativity Codes Components of Abstract Inference during Reward-based Decision-making.

PubMed

Reiter, Andrea M F; Koch, Stefan P; Schröger, Erich; Hinrichs, Hermann; Heinze, Hans-Jochen; Deserno, Lorenz; Schlagenhauf, Florian

2016-08-01

Behavioral control is influenced not only by learning from the choices made and the rewards obtained but also by "what might have happened," that is, inference about unchosen options and their fictive outcomes. Substantial progress has been made in understanding the neural signatures of direct learning from choices that are actually made and their associated rewards via reward prediction errors (RPEs). However, electrophysiological correlates of abstract inference in decision-making are less clear. One seminal theory suggests that the so-called feedback-related negativity (FRN), an ERP peaking 200-300 msec after a feedback stimulus at frontocentral sites of the scalp, codes RPEs. Hitherto, the FRN has been predominantly related to a so-called "model-free" RPE: The difference between the observed outcome and what had been expected. Here, by means of computational modeling of choice behavior, we show that individuals employ abstract, "double-update" inference on the task structure by concurrently tracking values of chosen stimuli (associated with observed outcomes) and unchosen stimuli (linked to fictive outcomes). In a parametric analysis, model-free RPEs as well as their modification because of abstract inference were regressed against single-trial FRN amplitudes. We demonstrate that components related to abstract inference uniquely explain variance in the FRN beyond model-free RPEs. These findings advance our understanding of the FRN and its role in behavioral adaptation. This might further the investigation of disturbed abstract inference, as proposed, for example, for psychiatric disorders, and its underlying neural correlates.

Local dynamics in decision making: The evolution of preference within and across decisions

NASA Astrophysics Data System (ADS)

O'Hora, Denis; Dale, Rick; Piiroinen, Petri T.; Connolly, Fionnuala

2013-07-01

Within decisions, perceived alternatives compete until one is preferred. Across decisions, the playing field on which these alternatives compete evolves to favor certain alternatives. Mouse cursor trajectories provide rich continuous information related to such cognitive processes during decision making. In three experiments, participants learned to choose symbols to earn points in a discrimination learning paradigm and the cursor trajectories of their responses were recorded. Decisions between two choices that earned equally high-point rewards exhibited far less competition than decisions between choices that earned equally low-point rewards. Using positional coordinates in the trajectories, it was possible to infer a potential field in which the choice locations occupied areas of minimal potential. These decision spaces evolved through the experiments, as participants learned which options to choose. This visualisation approach provides a potential framework for the analysis of local dynamics in decision-making that could help mitigate both theoretical disputes and disparate empirical results.

Signatures of Value Comparison in Ventral Striatum Neurons

PubMed Central

Strait, Caleb E.; Sleezer, Brianna J.; Hayden, Benjamin Y.

2015-01-01

The ventral striatum (VS), like its cortical afferents, is closely associated with processing of rewards, but the relative contributions of striatal and cortical reward systems remains unclear. Most theories posit distinct roles for these structures, despite their similarities. We compared responses of VS neurons to those of ventromedial prefrontal cortex (vmPFC) Area 14 neurons, recorded in a risky choice task. Five major response patterns observed in vmPFC were also observed in VS: (1) offer value encoding, (2) value difference encoding, (3) preferential encoding of chosen relative to unchosen value, (4) a correlation between residual variance in responses and choices, and (5) prominent encoding of outcomes. We did observe some differences as well; in particular, preferential encoding of the chosen option was stronger and started earlier in VS than in vmPFC. Nonetheless, the close match between vmPFC and VS suggests that cortex and its striatal targets make overlapping contributions to economic choice. PMID:26086735

Reward and decision processes in the brains of humans and nonhuman primates.

PubMed

Sirigu, Angela; Duhamel, Jean-René

2016-03-01

Choice behavior requires weighing multiple decision variables, such as utility, uncertainty, delay, or effort, that combine to define a subjective value for each considered option or course of action. This capacity is based on prior learning about potential rewards (and punishments) that result from prior actions. When made in a social context, decisions can involve strategic thinking about the intentions of others and about the impact of others' behavior on one's own outcome. Valuation is also influenced by different emotions that serve to adaptively regulate our choices in order to, for example, stay away from excessively risky gambles, prevent future regrets, or avoid personal rejection or conflicts. Drawing on economic theory and on advances in the study of neuronal mechanisms, we review relevant recent experiments in nonhuman primates and clinical observations made in neurologically impaired patients suffering from impaired decision-making capacities.

Combining a clinical ladder and performance appraisal system as a reward strategy: the EXCEL clinical ladder program.

PubMed

Moe, J K; Lonowski, L R; Yancer, D A

1994-09-01

In response to the dramatic changes occurring in health care today and a desire to reward professional nurses for clinical behaviors that would be valued in the future, Bergan Mercy Medical Center (BMMC) has developed an innovative clinical ladder/performance appraisal system. The BMMC EXCEL Clinical Ladder program, which is based on the developmental model of Patricia Benner, is a competency-based system that uniquely combines a clinical ladder and performance appraisal system. The program is clinically focused and contains optional components in which registered nurses (RNs) can receive additional credit for participation in professional growth and leadership activities. Nurses document examples of their practice through nursing narratives that describe actual clinical situations. The development and implementation processes, challenges encountered, and recommendations for alternative approaches to the implementation of such a unique system are discussed.

Reward and decision processes in the brains of humans and nonhuman primates

PubMed Central

Sirigu, Angela; Duhamel, Jean-René

2016-01-01

Choice behavior requires weighing multiple decision variables, such as utility, uncertainty, delay, or effort, that combine to define a subjective value for each considered option or course of action. This capacity is based on prior learning about potential rewards (and punishments) that result from prior actions. When made in a social context, decisions can involve strategic thinking about the intentions of others and about the impact of others' behavior on one's own outcome. Valuation is also influenced by different emotions that serve to adaptively regulate our choices in order to, for example, stay away from excessively risky gambles, prevent future regrets, or avoid personal rejection or conflicts. Drawing on economic theory and on advances in the study of neuronal mechanisms, we review relevant recent experiments in nonhuman primates and clinical observations made in neurologically impaired patients suffering from impaired decision-making capacities. PMID:27069379

Land Combat Systems Industry Report, Industrial College of the Armed Forces Academic Year 2004-2005

DTIC Science & Technology

2005-01-01

international members of selected industries in both defense and non -defense environments, and prepare specific policy options to enhance industrial... policy implications. Consistent with the ICAF’s non -attribution policy , this report presents industry composite information only, disclosing neither...European firms regard these U.S. export control policies as protectionist and, indeed, many seek out partnership arrangements to circumvent U.S

TREPS, a tool for coordinate and time transformations in space physics

NASA Astrophysics Data System (ADS)

Génot, V.; Renard, B.; Dufourg, N.; Bouchemit, M.; Lormant, N.; Beigbeder, L.; Popescu, D.; Toniutti, J.-P.; André, N.; Pitout, F.; Jacquey, C.; Cecconi, B.; Gangloff, M.

2018-01-01

We present TREPS (Transformation de REpères en Physique Spatiale) an online tool to perform coordinate transformations commonly used in planetology and heliophysics. It is based on SPICE kernels developed by NASA/NAIF. Its usage is straightforward, with a 4-step process, including various import/export options. Interoperability with external services is available through Virtual Observatory technology which is illustrated in a use case.

United States Warship Transfers to Argentina, Brazil, and Chile: Options for U.S. Policy

DTIC Science & Technology

1991-12-19

127 C. ECONOMIC CONSIDERATIONS OF RECIPIENT COUNTRIES ...... ............. 130 D. APPEASES MILITARY IN POST -AUTHORITARIAN DEMOCRACIES...of transferring significant numbers of second-hand warships to the Southern Cone. In this post -Cold War environment a reassessment must be made as to... POST -AUTHORITARIAN DEMOCRACIES Exporting democracy and containing Communism has been a U.S. foreign policy goal throughout the Cold War. In the post Cold

Latin America and the International Lending Organizations: The Ties that Bind.

DTIC Science & Technology

1980-07-23

necessary end Identify by block number) Argentina , Authoritarian Regimes, Brazil, Bureaucratic-Authoritar- 4 J ianism, Debt-Public and Private, Direct...domestic poli- cies to satisfy the requirements and gain the approval of the international financial community. Third, during times of financial crisis ...bility of debt service obligations constrain the options available to a government facing a debt crisis created by an absolute drop in export earnings or

The Evolving Relations of Japan and India

DTIC Science & Technology

2014-12-01

Does it Affect Us?,” Malaysia Chronicle, December 22, 2013, http://www.malaysia- chronicle.com/index.php?option=com_k2&view=item&id=201131:chinese... food industries” while Japan’s primary exports have been machinery components like boilers, marine products, jewels, and iron and steel.147 These areas...that time, Japan has been seeking alternative sources of rare earth metals, including India, Australia, Kazakhstan, and Malaysia with the intention of

Immune-mediated hemolytic anemia: understanding the nemesis.

PubMed

McCullough, Sheila

2003-11-01

IMHA is one of the most common causes of anemia in small animals. Although treatment may be rewarding, many patients do not respond adequately to glucocorticoids alone and require additional immunosuppressive therapy. Some patients may succumb to acute severe anemia and die within the first few weeks of treatment; even if they survive, relapses may occur. IMHA is the nemesis; as our understanding of this disease increases and treatment options expand, it is hoped that survival rates will finally improve.

Fractionating choice: A study on reward discrimination, preference and relative valuation in the rat (Rattus norvegicus)

PubMed Central

Ricker, Joshua M.; Hatch, Justin D.; Powers, Daniel D.; Cromwell, Howard C.

2016-01-01

Choice behavior combines discrimination between distinctive outcomes, preference for specific outcomes and relative valuation of comparable outcomes. Previous work has focused on one component (i.e., preference) disregarding other influential processes that might provide a more complete understanding. Animal models of choice have been explored primarily utilizing extensive training, limited freedom for multiple decisions and sparse behavioral measures constrained to a single phase of motivated action. The present study used a paradigm that combines different elements of previous methods with the goal to distinguish among components of choice and explore how well components match predictions based on risk-sensitive foraging strategies. In order to analyze discrimination and relative valuation, it was necessary to have an option that shifted and an option that remained constant. Shifting outcomes among weeks included a change in single-option outcome (0 to 1 to 2 pellets) or a change in mixed-option outcome (0 or 5 to 0 or 3 to 0 or 1 pellets). Constant outcomes among weeks were also mixedoption (0 or 3 pellets) or single-option (1 pellet). Shifting single-option outcomes among weeks led to better discrimination, more robust preference and significant incentive contrast effects for the alternative outcome. Shifting multi-options altered choice components and led to dissociations among discrimination, preference, and reduced contrast effects. During extinction, all components were impacted with the greatest deficits during the shifting mixed-option outcome sessions. Results suggest choice behavior can be optimized for one component but suboptimal for others depending upon the complexity of alterations in outcome value between options. PMID:27078079

Adaptations for insect-trapping in brood-site pollinated Colocasia (Araceae)

PubMed Central

Bröderbauer, D.; Ulrich, S.; Weber, A.

2016-01-01

The Araceae include both taxa with rewarding and deceptive trap pollination systems. Here we report on a genus in which rewarding and imprisonment of the pollinators co-occur. We studied the pollination of four species of Colocasia in Southwest China and investigated the morpho-anatomical adaptations of the spathe related to the attraction and capture of pollinators. All four species were pollinated by drosophilid flies of the genus Colocasiomyia. The flies are temporally arrested within the inflorescence and departure is only possible after pollen release. Trapping of the flies is accomplished by the closure of the spathe during anthesis. Moreover, in two species the spathe is covered with papillate epidermal cells known to form slippery surfaces in deceptive traps of Araceae. However, in Colocasia the papillae proved not slippery for the flies. The morpho-anatomical properties of the spathe epidermis indicate that it is an elaborate osmophore and serves for the emission of odours only. Despite its similarity to deceptive traps of other aroids, Colocasia and Colocasiomyia have a close symbiotic relationship, as the attracted flies use the inflorescence as a site for mating and breeding. The trap mechanism has presumably evolved independently in Colocasia and is supposed to facilitate more efficient pollen export. PMID:24119060

Pollinator directionality as a response to nectar gradient: promoting outcrossing while avoiding geitonogamy.

PubMed

Fisogni, A; Cristofolini, G; Rossi, M; Galloni, M

2011-11-01

Plants with multiple flowers could be prone to autonomous self-pollination and insect-mediated geitonogamy, but physiological and ecological features have evolved preventing costs related to autogamy. We studied the rare perennial herb Dictamnus albus as a model plant, with the aim of describing the plant-pollinator system from both plant and pollinator perspectives and analysing features that promote outcrossing in an entomophilous species. The breeding system and reproductive success of D. albus were investigated in experimental and natural conditions, showing that it is potentially self-compatible, but only intra-inflorescence insect-mediated selfing is possible. Nectar analysis showed gender-biased production towards the female phase, which follows the male phase, and during flowering, full blooming is found in flowers at the bottom of the raceme. Among a wide spectrum of insect visitors, three genera (Bombus, Apis, Megachile) were found to be principal pollinators. A study of insect behaviour showed a tendency towards bottom-to-top flights for the most important pollinators Bombus spp. and Apis mellifera: upward movements on the racemes could be explained by foraging behaviour, from more to less rewarding flowers. In accordance with the 'declining reward hypothesis', bumblebees and honeybees leave the plant when gain of reward is low, after which few flowers are visited, reducing the chance of self-pollen transfer among flowers. Intra-flower self-pollination is prevented in D. albus by protandry and herkogamy, while the nectar-induced sequential pattern of pollinator visits avoids geitonogamy and tends to maximise pollen export, promoting outcrossing. All these features for preventing selfing benefit plant fitness and population genetic structure. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Rare Earth Elements in National Defense: Background, Oversight Issues, and Options for Congress

DTIC Science & Technology

2013-09-17

stockpile, and allow the Defense Logistics Agency to more proactively engage in the market . These changes would grant the President the authority to...workers and manufacturers in order to grow our economy, and ensure open markets for products made in America...advantages for China’s producers when competing against U.S. producers – both in China’s market and in other markets around the world. The improper export

Returning migrant characteristics and labor market demand in Greece.

PubMed

Petras, E M; Kousis, M

1988-01-01

Immigrants who repatriate bring with them modern work skills which many observers in labor exporting regions describe as a great contribution to the mother country. Using data from 2 samples of Greek repatriates as well as projections of industrial labor force demands in Greece for the 1980s, this article challenges this concept. The authors find that the uneven regional development and stunted industrial growth which pushed these workers abroad are also responsible for the narrowly limited employment options which they face once they repatriate. For the urban repatriate, the market is limited to unemployment, the urban informal sector and scattered jobs, while for the rural repatriate, small-scale agriculture, multiple job holdings and unemployment are the only viable options.

A probabilistic assessment of calcium carbonate export and dissolution in the modern ocean

NASA Astrophysics Data System (ADS)

Battaglia, Gianna; Steinacher, Marco; Joos, Fortunat

2016-05-01

The marine cycle of calcium carbonate (CaCO3) is an important element of the carbon cycle and co-governs the distribution of carbon and alkalinity within the ocean. However, CaCO3 export fluxes and mechanisms governing CaCO3 dissolution are highly uncertain. We present an observationally constrained, probabilistic assessment of the global and regional CaCO3 budgets. Parameters governing pelagic CaCO3 export fluxes and dissolution rates are sampled using a Monte Carlo scheme to construct a 1000-member ensemble with the Bern3D ocean model. Ensemble results are constrained by comparing simulated and observation-based fields of excess dissolved calcium carbonate (TA*). The minerals calcite and aragonite are modelled explicitly and ocean-sediment fluxes are considered. For local dissolution rates, either a strong or a weak dependency on CaCO3 saturation is assumed. In addition, there is the option to have saturation-independent dissolution above the saturation horizon. The median (and 68 % confidence interval) of the constrained model ensemble for global biogenic CaCO3 export is 0.90 (0.72-1.05) Gt C yr-1, that is within the lower half of previously published estimates (0.4-1.8 Gt C yr-1). The spatial pattern of CaCO3 export is broadly consistent with earlier assessments. Export is large in the Southern Ocean, the tropical Indo-Pacific, the northern Pacific and relatively small in the Atlantic. The constrained results are robust across a range of diapycnal mixing coefficients and, thus, ocean circulation strengths. Modelled ocean circulation and transport timescales for the different set-ups were further evaluated with CFC11 and radiocarbon observations. Parameters and mechanisms governing dissolution are hardly constrained by either the TA* data or the current compilation of CaCO3 flux measurements such that model realisations with and without saturation-dependent dissolution achieve skill. We suggest applying saturation-independent dissolution rates in Earth system models to minimise computational costs.

Nuclear exports: the perilous enterprise

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, G.

1977-03-01

A representative of the Sierra Club proposes that the United States can at least provide an opportunity for a break in the trend toward nuclear proliferation and may be able to offer the moral and economic persuasion for a worldwide moratorium. The combination of plutonium toxicity and its use in making nuclear explosives, together with the number of countries who have recently entered the nuclear community, indicate an increasing problem in limiting nuclear power to peaceful purposes. The ease with which plutonium can be diverted from power-generating plants into the hands of terrorists and unstable rulers limits the security options.more » The non-proliferation agreements are felt to have created additional problems by making it possible for non-signers of the treaty to have less-stringent safeguards than the signers. The International Atomic Energy Agency is considered to be effective only in a bookkeeping and monitoring capacity, while competition between nuclear suppliers may lead them to relax standards. The author feels that efforts to negotiate voluntary restraints on exporters could offer guarantees of fuel services and other nuclear assistance to those countries agreeing to forego nuclear explosives and reprocessing facilities and accepting safeguards restraints and export restrictions. (DCK)« less

Elucidating Poor Decision-Making in a Rat Gambling Task

PubMed Central

Seriès, Peggy; Marchand, Alain R.; Dellu-Hagedorn, Françoise

2013-01-01

Although poor decision-making is a hallmark of psychiatric conditions such as attention deficit/hyperactivity disorder, pathological gambling or substance abuse, a fraction of healthy individuals exhibit similar poor decision-making performances in everyday life and specific laboratory tasks such as the Iowa Gambling Task. These particular individuals may provide information on risk factors or common endophenotypes of these mental disorders. In a rodent version of the Iowa gambling task – the Rat Gambling Task (RGT), we identified a population of poor decision makers, and assessed how these rats scored for several behavioral traits relevant to executive disorders: risk taking, reward seeking, behavioral inflexibility, and several aspects of impulsivity. First, we found that poor decision-making could not be well predicted by single behavioral and cognitive characteristics when considered separately. By contrast, a combination of independent traits in the same individual, namely risk taking, reward seeking, behavioral inflexibility, as well as motor impulsivity, was highly predictive of poor decision-making. Second, using a reinforcement-learning model of the RGT, we confirmed that only the combination of extreme scores on these traits could induce maladaptive decision-making. Third, the model suggested that a combination of these behavioral traits results in an inaccurate representation of rewards and penalties and inefficient learning of the environment. Poor decision-making appears as a consequence of the over-valuation of high-reward-high-risk options in the task. Such a specific psychological profile could greatly impair clinically healthy individuals in decision-making tasks and may predispose to mental disorders with similar symptoms. PMID:24339988

Elucidating poor decision-making in a rat gambling task.

PubMed

Rivalan, Marion; Valton, Vincent; Seriès, Peggy; Marchand, Alain R; Dellu-Hagedorn, Françoise

2013-01-01

Although poor decision-making is a hallmark of psychiatric conditions such as attention deficit/hyperactivity disorder, pathological gambling or substance abuse, a fraction of healthy individuals exhibit similar poor decision-making performances in everyday life and specific laboratory tasks such as the Iowa Gambling Task. These particular individuals may provide information on risk factors or common endophenotypes of these mental disorders. In a rodent version of the Iowa gambling task--the Rat Gambling Task (RGT), we identified a population of poor decision makers, and assessed how these rats scored for several behavioral traits relevant to executive disorders: risk taking, reward seeking, behavioral inflexibility, and several aspects of impulsivity. First, we found that poor decision-making could not be well predicted by single behavioral and cognitive characteristics when considered separately. By contrast, a combination of independent traits in the same individual, namely risk taking, reward seeking, behavioral inflexibility, as well as motor impulsivity, was highly predictive of poor decision-making. Second, using a reinforcement-learning model of the RGT, we confirmed that only the combination of extreme scores on these traits could induce maladaptive decision-making. Third, the model suggested that a combination of these behavioral traits results in an inaccurate representation of rewards and penalties and inefficient learning of the environment. Poor decision-making appears as a consequence of the over-valuation of high-reward-high-risk options in the task. Such a specific psychological profile could greatly impair clinically healthy individuals in decision-making tasks and may predispose to mental disorders with similar symptoms.

Amphetamine primes enhanced motivation toward uncertain choices in rats with genetic alcohol preference.

PubMed

Oinio, Ville; Sundström, Mikko; Bäckström, Pia; Uhari-Väänänen, Johanna; Kiianmaa, Kalervo; Raasmaja, Atso; Piepponen, Petteri

2018-05-01

Comorbidity with gambling disorder (GD) and alcohol use disorder (AUD) is well documented. The purpose of our study was to examine the influence of genetic alcohol drinking tendency on reward-guided decision making behavior of rats and the impact of dopamine releaser D-amphetamine on this behavior. In this study, Alko alcohol (AA) and Wistar rats went through long periods of operant lever pressing training where the task was to choose the profitable of two options. The lever choices were guided by different-sized sucrose rewards (one or three pellets), and the probability of gaining the larger reward was slowly changed to a level where choosing the smaller reward would be the most profitable in the long run. After training, rats were injected (s.c.) with dopamine releaser D-amphetamine (0.3, 1.0 mg/kg) to study the impact of rapid dopamine release on this learned decision making behavior. Administration of D-amphetamine promoted unprofitable decision making of AA rats more robustly when compared to Wistar rats. At the same time, D-amphetamine reduced lever pressing responses. Interestingly, we found that this reduction in lever pressing was significantly greater in Wistar rats than in AA rats and it was not linked to motivation to consume sucrose. Our results indicate that conditioning to the lever pressing in uncertain environments is more pronounced in AA than in Wistar rats and indicate that the reinforcing effects of a gambling-like environment act as a stronger conditioning factor for rats that exhibit a genetic tendency for high alcohol drinking.

Perturbations in Effort-Related Decision-Making Driven by Acute Stress and Corticotropin-Releasing Factor.

PubMed

Bryce, Courtney A; Floresco, Stan B

2016-07-01

Acute stress activates numerous systems in a coordinated effort to promote homeostasis, and can exert differential effects on mnemonic and cognitive functions depending on a myriad of factors. Stress can alter different forms of cost/benefit decision-making, yet the mechanisms that drive these effects, remain unclear. In the present study, we probed how corticotropin-releasing factor (CRF) may contribute to stress-induced alterations in cost/benefit decision-making, using an task where well-trained rats chose between a low effort/low reward lever (LR; two pellets) and a high effort/high reward lever (HR; four pellets), with the effort requirement increasing over a session (2, 5, 10, and 20 presses). One-hour restraint stress markedly reduced preference for the HR option, but this effect was attenuated by infusions of the CRF antagonist, alpha-helical CRF. Conversely, central CRF infusion mimicked the effect of stress on decision-making, as well as increased decision latencies and reduced response vigor. CRF infusions did not alter preference for larger vs smaller rewards, but did reduce responding for food delivered on a progressive ratio, suggesting that these treatments may amplify perceived effort costs that may be required to obtain rewards. CRF infusions into the ventral tegmental area recapitulated the effect of central CRF treatment and restraint on choice behavior, suggesting that these effects may be mediated by perturbations in dopamine transmission. These findings highlight the involvement of CRF in regulating effort-related decisions and suggest that increased CRF activity may contribute to motivational impairments and abnormal decision-making associated with stress-related psychiatric disorders such as depression.

Perturbations in Effort-Related Decision-Making Driven by Acute Stress and Corticotropin-Releasing Factor

PubMed Central

Bryce, Courtney A; Floresco, Stan B

2016-01-01

Acute stress activates numerous systems in a coordinated effort to promote homeostasis, and can exert differential effects on mnemonic and cognitive functions depending on a myriad of factors. Stress can alter different forms of cost/benefit decision-making, yet the mechanisms that drive these effects, remain unclear. In the present study, we probed how corticotropin-releasing factor (CRF) may contribute to stress-induced alterations in cost/benefit decision-making, using an task where well-trained rats chose between a low effort/low reward lever (LR; two pellets) and a high effort/high reward lever (HR; four pellets), with the effort requirement increasing over a session (2, 5, 10, and 20 presses). One-hour restraint stress markedly reduced preference for the HR option, but this effect was attenuated by infusions of the CRF antagonist, alpha-helical CRF. Conversely, central CRF infusion mimicked the effect of stress on decision-making, as well as increased decision latencies and reduced response vigor. CRF infusions did not alter preference for larger vs smaller rewards, but did reduce responding for food delivered on a progressive ratio, suggesting that these treatments may amplify perceived effort costs that may be required to obtain rewards. CRF infusions into the ventral tegmental area recapitulated the effect of central CRF treatment and restraint on choice behavior, suggesting that these effects may be mediated by perturbations in dopamine transmission. These findings highlight the involvement of CRF in regulating effort-related decisions and suggest that increased CRF activity may contribute to motivational impairments and abnormal decision-making associated with stress-related psychiatric disorders such as depression. PMID:26830960

Phosphorus and dissolved organic carbon export during peak flow periods in three small homogenous catchments in eastern Germany

NASA Astrophysics Data System (ADS)

Benning, R.; Schwärzel, K.; Feger, K. H.

2012-04-01

Regional climate change scenarios for Central Europe predict both an overall increase in temperature and alterations in annual precipitation regimes. For large parts of Central Europe, climate change is expected to result in an increase in winter precipitation and a decrease in summer precipitation. In addition, an increase in extreme conditions, such as heat waves, prolonged drought periods, and heavy rainfall events are predicted. This research examines the potential impacts of increased heavy rainfall events on matter export from small catchment areas, and how different vegetation cover and land management options effects these exports. In order to evaluate the export of matter from different land-use types in the Eastern Ore Mountains (Saxony, NE Germany, 50° 48'18.06" North, 13° 36'24.54" East), study sites were established in three small catchments with homogeneous land-use. These study areas are each sub-catchments of the Ammelsdorf catchment, which provides inflow to the Lehnmühle reservoir (a major water supply for the city of Dresden). Each sub catchment represents one of the three main land-use types in the catchment area of the reservoir: crops (winter oilseed rape, winter wheat), grasslands, and forests (primarily spruce). Since November 2009 the discharge from these sub catchments has been continuously measured and water quality was analyzed on a weekly basis. During peak flow events, discharge was collected using automatic water samplers, which allowed for high temporal resolution analysis of matter export during these periods to be made. During the 2010 and 2011 hydrological years, several heavy rainfall events occurred which have been evaluated. During a 110-hour long precipitation event (P = 170 mm) between 37 and 81 water samples per sub catchment were collected and analyzed. The resulting export of dissolved phosphorus (ortho-PO4-) and dissolved organic carbon (DOC) from the sub catchments during this event is provided in the results. In addition, the matter export resulting from a 59-hour precipitation event (P = 39 mm, between 31 and 48 analyzed water samples per sub catchment) is presented. The contribution of these two events to the annual export of ortho-PO4- and DOC will be discussed.

Modeling the Violation of Reward Maximization and Invariance in Reinforcement Schedules

PubMed Central

La Camera, Giancarlo; Richmond, Barry J.

2008-01-01

It is often assumed that animals and people adjust their behavior to maximize reward acquisition. In visually cued reinforcement schedules, monkeys make errors in trials that are not immediately rewarded, despite having to repeat error trials. Here we show that error rates are typically smaller in trials equally distant from reward but belonging to longer schedules (referred to as “schedule length effect”). This violates the principles of reward maximization and invariance and cannot be predicted by the standard methods of Reinforcement Learning, such as the method of temporal differences. We develop a heuristic model that accounts for all of the properties of the behavior in the reinforcement schedule task but whose predictions are not different from those of the standard temporal difference model in choice tasks. In the modification of temporal difference learning introduced here, the effect of schedule length emerges spontaneously from the sensitivity to the immediately preceding trial. We also introduce a policy for general Markov Decision Processes, where the decision made at each node is conditioned on the motivation to perform an instrumental action, and show that the application of our model to the reinforcement schedule task and the choice task are special cases of this general theoretical framework. Within this framework, Reinforcement Learning can approach contextual learning with the mixture of empirical findings and principled assumptions that seem to coexist in the best descriptions of animal behavior. As examples, we discuss two phenomena observed in humans that often derive from the violation of the principle of invariance: “framing,” wherein equivalent options are treated differently depending on the context in which they are presented, and the “sunk cost” effect, the greater tendency to continue an endeavor once an investment in money, effort, or time has been made. The schedule length effect might be a manifestation of these phenomena in monkeys. PMID:18688266

Modeling the violation of reward maximization and invariance in reinforcement schedules.

PubMed

La Camera, Giancarlo; Richmond, Barry J

2008-08-08

It is often assumed that animals and people adjust their behavior to maximize reward acquisition. In visually cued reinforcement schedules, monkeys make errors in trials that are not immediately rewarded, despite having to repeat error trials. Here we show that error rates are typically smaller in trials equally distant from reward but belonging to longer schedules (referred to as "schedule length effect"). This violates the principles of reward maximization and invariance and cannot be predicted by the standard methods of Reinforcement Learning, such as the method of temporal differences. We develop a heuristic model that accounts for all of the properties of the behavior in the reinforcement schedule task but whose predictions are not different from those of the standard temporal difference model in choice tasks. In the modification of temporal difference learning introduced here, the effect of schedule length emerges spontaneously from the sensitivity to the immediately preceding trial. We also introduce a policy for general Markov Decision Processes, where the decision made at each node is conditioned on the motivation to perform an instrumental action, and show that the application of our model to the reinforcement schedule task and the choice task are special cases of this general theoretical framework. Within this framework, Reinforcement Learning can approach contextual learning with the mixture of empirical findings and principled assumptions that seem to coexist in the best descriptions of animal behavior. As examples, we discuss two phenomena observed in humans that often derive from the violation of the principle of invariance: "framing," wherein equivalent options are treated differently depending on the context in which they are presented, and the "sunk cost" effect, the greater tendency to continue an endeavor once an investment in money, effort, or time has been made. The schedule length effect might be a manifestation of these phenomena in monkeys.

I Plan Therefore I Choose: Free-Choice Bias Due to Prior Action-Probability but Not Action-Value

PubMed Central

Suriya-Arunroj, Lalitta; Gail, Alexander

2015-01-01

According to an emerging view, decision-making, and motor planning are tightly entangled at the level of neural processing. Choice is influenced not only by the values associated with different options, but also biased by other factors. Here we test the hypothesis that preliminary action planning can induce choice biases gradually and independently of objective value when planning overlaps with one of the potential action alternatives. Subjects performed center-out reaches obeying either a clockwise or counterclockwise cue-response rule in two tasks. In the probabilistic task, a pre-cue indicated the probability of each of the two potential rules to become valid. When the subsequent rule-cue unambiguously indicated which of the pre-cued rules was actually valid (instructed trials), subjects responded faster to rules pre-cued with higher probability. When subjects were allowed to choose freely between two equally rewarded rules (choice trials) they chose the originally more likely rule more often and faster, despite the lack of an objective advantage in selecting this target. In the amount task, the pre-cue indicated the amount of potential reward associated with each rule. Subjects responded faster to rules pre-cued with higher reward amount in instructed trials of the amount task, equivalent to the more likely rule in the probabilistic task. Yet, in contrast, subjects showed hardly any choice bias and no increase in response speed in favor of the original high-reward target in the choice trials of the amount task. We conclude that free-choice behavior is robustly biased when predictability encourages the planning of one of the potential responses, while prior reward expectations without action planning do not induce such strong bias. Our results provide behavioral evidence for distinct contributions of expected value and action planning in decision-making and a tight interdependence of motor planning and action selection, supporting the idea that the underlying neural mechanisms overlap. PMID:26635565

Priming memories of past wins induces risk seeking.

PubMed

Ludvig, Elliot A; Madan, Christopher R; Spetch, Marcia L

2015-02-01

People are often risk averse when making decisions under uncertainty. When those decisions are based on past experience, people necessarily rely on their memories. Thus, what is remembered at the time of the choice should influence risky choice. We tested this hypothesis by priming memory for past outcomes in a simple risky-choice task. In the task, people repeatedly chose between a safe option and a risky option that paid off with a larger or smaller reward with a 50/50 chance. Some trials were preceded by a priming cue that was previously paired with one of the outcomes. We found that priming cues associated with wins caused people to become risk seeking, whereas priming cues associated with relative losses had little effect. These results suggest that people can be induced to be more risk seeking through subtle reminders of previous winning experiences.

Food choice in the laboratory pigeon.

PubMed

Biedermann, Traci; Garlick, Dennis; Blaisdell, Aaron P

2012-09-01

Although food reward plays a large role in learning and behavioral experiments, there have been few studies examining the most motivating food reward for pigeons. Brown (1969) found that pigeons had a tendency to prefer peas, while Killeen et al. (1993) found pigeons to prefer peas and popcorn in Experiment 1A. We looked to further explore these options as well as expand upon the types of foods examined beyond mainly grains and seeds. Pigeons were presented with six novel foods (granulated peanuts, popping corn, freeze-dried mealworms, bread crumbs, split peas, and sunflower hearts) allocated into two sets of three food items. Once the most consumed food from each food set was determined, they were pooled together with sorghum seeds (a familiar food) to form a third set. Sunflower hearts were the most consumed of all the food items, followed by corn and granulated peanuts. We discuss the potential factors mediating consumption choice, including nutritional profile and food particle size. Copyright © 2012 Elsevier B.V. All rights reserved.

Food choice in the laboratory pigeon

PubMed Central

Biedermann, Traci; Garlick, Dennis; Blaisdell, Aaron P.

2012-01-01

Although food reward plays a large role in learning and behavioral experiments, there have been few studies examining the most motivating food reward for pigeons. Brown (1969) found that pigeons had a tendency to prefer peas, while Killeen, Cate, and Tran (1993) found pigeons to prefer peas and popcorn in Experiment 1A. We looked to further explore these options as well as expand upon the types of foods examined beyond mainly grains and seeds. Pigeons were presented with six novel foods (granulated peanuts, popping corn, freeze-dried mealworms, bread crumbs, split peas, and sunflower hearts) allocated into two sets of three food items. Once the most consumed food from each food set was determined, they were pooled together with sorghum seeds (a familiar food) to form a third set. Sunflower hearts were the most consumed of all the food items, followed by corn and granulated peanuts. We discuss the potential factors mediating consumption choice, including nutritional profile and food particle size. PMID:22750307

Short Term Gains, Long Term Pains: How Cues About State Aid Learning in Dynamic Environments

PubMed Central

Gureckis, Todd M.; Love, Bradley C.

2009-01-01

Successful investors seeking returns, animals foraging for food, and pilots controlling aircraft all must take into account how their current decisions will impact their future standing. One challenge facing decision makers is that options that appear attractive in the short-term may not turn out best in the long run. In this paper, we explore human learning in a dynamic decision-making task which places short- and long-term rewards in conflict. Our goal in these studies was to evaluate how people’s mental representation of a task affects their ability to discover an optimal decision strategy. We find that perceptual cues that readily align with the underlying state of the task environment help people overcome the impulsive appeal of short-term rewards. Our experimental manipulations, predictions, and analyses are motivated by current work in reinforcement learning which details how learners value delayed outcomes in sequential tasks and the importance that “state” identification plays in effective learning. PMID:19427635

Neural representation of expected value in the adolescent brain.

PubMed

Barkley-Levenson, Emily; Galván, Adriana

2014-01-28

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain.

Neural representation of expected value in the adolescent brain

PubMed Central

Barkley-Levenson, Emily; Galván, Adriana

2014-01-01

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain. PMID:24474790

Evidence for surprise minimization over value maximization in choice behavior

PubMed Central

Schwartenbeck, Philipp; FitzGerald, Thomas H. B.; Mathys, Christoph; Dolan, Ray; Kronbichler, Martin; Friston, Karl

2015-01-01

Classical economic models are predicated on the idea that the ultimate aim of choice is to maximize utility or reward. In contrast, an alternative perspective highlights the fact that adaptive behavior requires agents’ to model their environment and minimize surprise about the states they frequent. We propose that choice behavior can be more accurately accounted for by surprise minimization compared to reward or utility maximization alone. Minimizing surprise makes a prediction at variance with expected utility models; namely, that in addition to attaining valuable states, agents attempt to maximize the entropy over outcomes and thus ‘keep their options open’. We tested this prediction using a simple binary choice paradigm and show that human decision-making is better explained by surprise minimization compared to utility maximization. Furthermore, we replicated this entropy-seeking behavior in a control task with no explicit utilities. These findings highlight a limitation of purely economic motivations in explaining choice behavior and instead emphasize the importance of belief-based motivations. PMID:26564686

Introducing Upfront Money Can Decrease Discounting in Intertemporal Choices with Losses

PubMed Central

Jiang, Cheng-Ming; Sun, Hong-Yue; Zheng, Sheng-Hua; Wang, Liang-Jun; Qin, Yu

2016-01-01

People generally tend to advance gains and postpone losses in intertemporal choice. Jiang et al. (2014) recently showed that adding upfront losses or gains to both smaller and sooner (SS) and larger and later (LL) rewards can decrease people’s discounting. To account for this decrease, they proposed the salience hypothesis, which states that introducing upfront losses or gains makes the money dimension more salient than not, thus increasing people’s preference for LL rewards. Considering that decreasing the discounting of delayed losses is imperative and that most previous studies have focused on intertemporal choices with gains, in the current paper we conducted two experiments and used hypothetical money outcomes to examine whether the effect of upfront money could be extended to intertemporal choices with losses. The results showed that when both SS and LL intertemporal losses were combined with an upfront loss or gain, people’s discounting rate decreased and the preference for the SS option increased. This finding further supports the salience account. PMID:27597839

Introducing Upfront Money Can Decrease Discounting in Intertemporal Choices with Losses.

PubMed

Jiang, Cheng-Ming; Sun, Hong-Yue; Zheng, Sheng-Hua; Wang, Liang-Jun; Qin, Yu

2016-01-01

People generally tend to advance gains and postpone losses in intertemporal choice. Jiang et al. (2014) recently showed that adding upfront losses or gains to both smaller and sooner (SS) and larger and later (LL) rewards can decrease people's discounting. To account for this decrease, they proposed the salience hypothesis, which states that introducing upfront losses or gains makes the money dimension more salient than not, thus increasing people's preference for LL rewards. Considering that decreasing the discounting of delayed losses is imperative and that most previous studies have focused on intertemporal choices with gains, in the current paper we conducted two experiments and used hypothetical money outcomes to examine whether the effect of upfront money could be extended to intertemporal choices with losses. The results showed that when both SS and LL intertemporal losses were combined with an upfront loss or gain, people's discounting rate decreased and the preference for the SS option increased. This finding further supports the salience account.

Impulse Control Disorders and Related Complications of Parkinson’s Disease Therapy

PubMed Central

Lopez, Alexander M.; Weintraub, Daniel; Claassen, Daniel O.

2017-01-01

Impulsive and compulsive behaviors in Parkinson’s disease (PD) patients are most often attributed to dopamine agonist therapy; dysregulation of the mesocorticolimbic system accounts for this behavioral phenotype. The clinical presentation is commonly termed impulse control disorder (ICD): Behaviors include hypersexuality, compulsive eating, shopping, pathological gambling, and compulsive hobby participation. However, not all PD individuals taking dopamine agonists develop these behavioral changes. In this review, the authors focus on the similarities between the phenotypic presentation of ICDs with that of other reward-based behavioral disorders, including binge eating disorder, pathological gambling, and substance use disorders. With this comparison, we emphasize that the transition from an impulsive to compulsive behavior likely follows a ventral to dorsal striatal pattern, where an altered dopaminergic reward system underlies the emergence of these problematic behaviors. The authors discuss the neurobiological similarities between these latter disorders and ICDs, emphasizing similar pathophysiological processes and discussing treatment options that have potential for translation to PD patients. PMID:28511259

Reformulated Gasoline Foreign Refinery Rules (Short-Term Energy Outlook Supplement January 1998)

EIA Publications

1998-01-01

On August 27, 1997, the Environmental Protection Agency (EPA) promulgated revised the rules that allow foreign refiners to establish and use individual baselines, but it would not be mandatory (the optional use of an individual refinery baseline is not available to domestic refiners.) If a foreign refiner did not establish and use an individual baseline, the gasoline they export to the United States would be regulated through the importer, and subject to the importer's baseline (most likely the statutory baseline). Specific regulatory provisions are implemented to ensure that the option to use an individual baseline would not lead to adverse environmental impacts. This involves monitoring the average quality of imported gasoline, and if a specified benchmark is exceeded, remedial action would be taken by adjusting the requirements applicable to imported gasoline.

Paradoxical choice in rats: Subjective valuation and mechanism of choice.

PubMed

Ojeda, Andrés; Murphy, Robin A; Kacelnik, Alex

2018-07-01

Decision-makers benefit from information only when they can use it to guide behavior. However, recent experiments found that pigeons and starlings value information that they cannot use. Here we show that this paradox is also present in rats, and explore the underlying decision process. Subjects chose between two options that delivered food probabilistically after a fixed delay. In one option ("info"), outcomes (food/no-food) were signaled immediately after choice, whereas in the alternative ("non-info") the outcome was uncertain until the delay lapsed. Rats sacrificed up to 20% potential rewards by preferring the info option, but reversed preference when the cost was 60%. This reversal contrasts with the results found with pigeons and starlings and may reflect species' differences worth of further investigation. Results are consistent with predictions of the Sequential Choice Model (SCM), that proposes that choices are driven by the mechanisms that control action in sequential encounters. As expected from the SCM, latencies to respond in single-option trials predicted preferences in choice trials, and latencies in choice trials were the same or shorter than in single-option trials. We argue that the congruence of results in distant vertebrates probably reflects evolved adaptations to shared fundamental challenges in nature, and that the apparently paradoxical overvaluing of information is not sub-optimal as has been claimed, even though its functional significance is not yet understood. Copyright © 2018 Elsevier B.V. All rights reserved.

A unifying Bayesian account of contextual effects in value-based choice

PubMed Central

Friston, Karl J.; Dolan, Raymond J.

2017-01-01

Empirical evidence suggests the incentive value of an option is affected by other options available during choice and by options presented in the past. These contextual effects are hard to reconcile with classical theories and have inspired accounts where contextual influences play a crucial role. However, each account only addresses one or the other of the empirical findings and a unifying perspective has been elusive. Here, we offer a unifying theory of context effects on incentive value attribution and choice based on normative Bayesian principles. This formulation assumes that incentive value corresponds to a precision-weighted prediction error, where predictions are based upon expectations about reward. We show that this scheme explains a wide range of contextual effects, such as those elicited by other options available during choice (or within-choice context effects). These include both conditions in which choice requires an integration of multiple attributes and conditions where a multi-attribute integration is not necessary. Moreover, the same scheme explains context effects elicited by options presented in the past or between-choice context effects. Our formulation encompasses a wide range of contextual influences (comprising both within- and between-choice effects) by calling on Bayesian principles, without invoking ad-hoc assumptions. This helps clarify the contextual nature of incentive value and choice behaviour and may offer insights into psychopathologies characterized by dysfunctional decision-making, such as addiction and pathological gambling. PMID:28981514

Cortical and Hippocampal Correlates of Deliberation during Model-Based Decisions for Rewards in Humans

PubMed Central

Bornstein, Aaron M.; Daw, Nathaniel D.

2013-01-01

How do we use our memories of the past to guide decisions we've never had to make before? Although extensive work describes how the brain learns to repeat rewarded actions, decisions can also be influenced by associations between stimuli or events not directly involving reward — such as when planning routes using a cognitive map or chess moves using predicted countermoves — and these sorts of associations are critical when deciding among novel options. This process is known as model-based decision making. While the learning of environmental relations that might support model-based decisions is well studied, and separately this sort of information has been inferred to impact decisions, there is little evidence concerning the full cycle by which such associations are acquired and drive choices. Of particular interest is whether decisions are directly supported by the same mnemonic systems characterized for relational learning more generally, or instead rely on other, specialized representations. Here, building on our previous work, which isolated dual representations underlying sequential predictive learning, we directly demonstrate that one such representation, encoded by the hippocampal memory system and adjacent cortical structures, supports goal-directed decisions. Using interleaved learning and decision tasks, we monitor predictive learning directly and also trace its influence on decisions for reward. We quantitatively compare the learning processes underlying multiple behavioral and fMRI observables using computational model fits. Across both tasks, a quantitatively consistent learning process explains reaction times, choices, and both expectation- and surprise-related neural activity. The same hippocampal and ventral stream regions engaged in anticipating stimuli during learning are also engaged in proportion to the difficulty of decisions. These results support a role for predictive associations learned by the hippocampal memory system to be recalled during choice formation. PMID:24339770

Précis of Breakdown of Will.

PubMed

Ainslie, George

2005-10-01

Behavioral science has long been puzzled by the experience of temptation, the resulting impulsiveness, and the variably successful control of this impulsiveness. In conventional theories, a governing faculty like the ego evaluates future choices consistently over time, discounting their value for delay exponentially, that is, by a constant rate; impulses arise when this ego is confronted by a conditioned appetite. Breakdown of Will (Ainslie 2001) presents evidence that contradicts this model. Both people and nonhuman animals spontaneously discount the value of expected events in a curve where value is divided approximately by expected delay, a hyperbolic form that is more bowed than the rational, exponential curve. With hyperbolic discounting, options that pay off quickly will be temporarily preferred to richer but slower-paying alternatives, a phenomenon that, over periods from minutes to days, can account for impulsive behaviors, and over periods of fractional seconds can account for involuntary behaviors. Contradictory reward-getting processes can in effect bargain with each other, and stable preferences can be established by the perception of recurrent choices as test cases (precedents) in recurrent intertemporal prisoner's dilemmas. The resulting motivational pattern resembles traditional descriptions of the will, as well as of compulsive phenomena that can now be seen as side-effects of will: over-concern with precedent, intractable but circumscribed failures of self-control, a motivated ("dynamic") unconscious, and an inability to exploit emotional rewards. Hyperbolic curves also suggest a means of reducing classical conditioning to motivated choice, the last necessary step for modeling many involuntary processes like emotion and appetite as reward-seeking behaviors; such modeling, in turn, provides a rationale for empathic reward and the "construction" of reality.

The Decision Support Matrix (DSM) Approach to Reducing Risk of Flooding and Water Pollution in Farmed Landscapes

NASA Astrophysics Data System (ADS)

Hewett, Caspar J. M.; Quinn, Paul; Wilkinson, Mark

2014-05-01

Intense farming plays a key role in contributing to problems such as increased flood risk, soil erosion and poor water quality. This means that there is great potential for agricultural practitioners to play a major part in reducing multiple risks through better land-use management. Greater understanding by farmers, land managers, practitioners and policy-makers of the ways in which farmed landscapes contribute to risks and the ways in which those risks might be mitigated can be an essential component in improving practice. The Decision Support Matrix (DSM) approach involves the development of a range of visualization and communication tools to help compare the risks associated with different farming practices and explore options to manage runoff. DSMs are simple decision support systems intended for use by the non-expert which combine expert hydrological evidence with local knowledge of runoff patterns. They are developed through direct engagement with stakeholders, ensuring that the examples and language used makes sense to end-users. A key element of the tools is that they show the current conditions of the land and describe extremes of land-use management within a hydrological and agricultural land-management context. The tools include conceptual models of a series of pre-determined runoff scenarios, providing the end-user with a variety of potential land management practices and runoff management options. Visual examples of different farming practices are used to illustrate the impact of good and bad practice on specific problems such as nutrient export or risk of flooding. These show both how current conditions cause problems downstream and how systems are vulnerable to changes in climate and land-use intensification. The level of risk associated with a particular land management option is represented by a mapping on a two- or three-dimensional matrix. Interactive spreadsheet-based tools are developed in which multiple questions allow the user to explore different management options and see the impact of decisions plotted as a risk level on the DSM. They employ a ranking methodology combined with a simple mapping of information onto a visual matrix. A nominal scoring system is used to rank higher or lower runoff risk. The end-user can then assess numerous land use and runoff management options to lower risk. The objective is to encourage policy makers, catchment managers and farmers to produce resilient local landscapes at minimal cost. A number of DSMs have been developed successfully over a number of years working with a variety of stakeholders in the UK, including the Phosphorus Export Risk Matrix (PERM), The Nitrate Export Risk Matrix (NO3RM) and arable and livestock versions of the Floods and Agriculture Risk Matrix (FARM) (available from http://research.ncl.ac.uk/thefarm). Despite uncertainty, the tools do contribute to stakeholders having greater confidence in making decisions to make landscapes more resilient. DSMs have been taken up widely in the UK by bodies such as the Environment Agency and Defra, and have been successfully employed within wider decision support frameworks alongside modelling at multiple scales. Such tools could be used in similar farmed landscapes internationally.

The investment pyramid: give due consideration to risk-reward ratios and capital liquidity.

PubMed

Blau, Joel; Paprocki, Ronald J

2003-01-01

In spite of constraints in reimbursement and relatively flat incomes in many specialties for the last decade, most physicians can still look forward to significant incomes over their professional lives. Hopefully, they may accumulate sufficient funds for retirement. In the interim, the management of their resources has become evermore difficult with the vagaries of investment results over the past three years. This article details the authors' views to a balanced approach to structuring one's financial position with a focus on insurance and general investment options.

Easy rider: monkeys learn to drive a wheelchair to navigate through a complex maze.

PubMed

Etienne, Stephanie; Guthrie, Martin; Goillandeau, Michel; Nguyen, Tho Hai; Orignac, Hugues; Gross, Christian; Boraud, Thomas

2014-01-01

The neurological bases of spatial navigation are mainly investigated in rodents and seldom in primates. The few studies led on spatial navigation in both human and non-human primates are performed in virtual, not in real environments. This is mostly because of methodological difficulties inherent in conducting research on freely-moving monkeys in real world environments. There is some incertitude, however, regarding the extrapolation of rodent spatial navigation strategies to primates. Here we present an entirely new platform for investigating real spatial navigation in rhesus monkeys. We showed that monkeys can learn a pathway by using different strategies. In these experiments three monkeys learned to drive the wheelchair and to follow a specified route through a real maze. After learning the route, probe tests revealed that animals successively use three distinct navigation strategies based on i) the place of the reward, ii) the direction taken to obtain reward or iii) a cue indicating reward location. The strategy used depended of the options proposed and the duration of learning. This study reveals that monkeys, like rodents and humans, switch between different spatial navigation strategies with extended practice, implying well-conserved brain learning systems across different species. This new task with freely driving monkeys provides a good support for the electrophysiological and pharmacological investigation of spatial navigation in the real world by making possible electrophysiological and pharmacological investigations.

Altered risk-aversion and risk-taking behaviour in patients with Alzheimer's disease.

PubMed

Ha, Juwon; Kim, Eun-Jin; Lim, Sewon; Shin, Dong-Won; Kang, Yeo-Jin; Bae, Seung-Min; Yoon, Hyung-Kun; Oh, Kang-Seob

2012-09-01

Normal individuals are risk averse for decisions framed as gains but risk taking for decisions framed as losses. This framing effect is supposed to be attenuated in Alzheimer's disease (AD) patients. We investigated the effects of highlighting rewards versus highlighting punishments on the risky decision-making of AD patients. Fourteen mild to moderate AD patients (Mini-Mental Status Examination score, 11-23; Clinical Dementia Rating, 1-2) and 16 healthy volunteers were recruited for the study. Subjects completed a computerized task on risky decision-making in which mathematically equivalent dilemmas were presented in terms of opportunities to gain monetary rewards ('positive frame') or avoid suffering losses ('negative frame'). As expected, AD patients chose more risky options under the positive frame than the negative frame, contrary to the control group (Z =-2.671, P= 0.007). The normal difference in the distribution of risky choices between positively and negatively framed dilemmas was significantly reduced in the AD group after we adjusted for years of education, mean age and depression (F= 5.321, P= 0.030). Deliberation time did not differ significantly between the two groups. These results suggest that AD patients making high-risk choices is associated with attenuated sensitivity to the emotional frames that highlight rewards or punishments, possibly reflecting altered evaluations of prospective gains and losses. © 2012 The Authors. Psychogeriatrics © 2012 Japanese Psychogeriatric Society.

Is it patience or motivation? On motivational confounds in intertemporal choice tasks.

PubMed

Paglieri, Fabio; Addessi, Elsa; Sbaffi, Agnese; Tasselli, Maria Isabella; Delfino, Alexia

2015-01-01

Intertemporal choices create a tension between amount maximization, which would favor the larger and later option (LL), and delay minimization, which would promote the smaller and sooner reward (SS). Two common interpretations of intertemporal choice behavior are discussed: looking at LL responses as indicative of self-control, and using intertemporal choices to assess delay aversion. We argue that both interpretations need to take into account motivational confounds, in order to be warranted by data. In intertemporal choices with prepotent, salient stimuli (e.g., food amounts, typically used with nonhuman primates), LL responses could also be indicative of failed inhibition of a "go for more" impulsive response-the opposite of self-control. Similarly, intertemporal choices can be used to measure delay aversion only with respect to the subject's baseline motivation to maximize the reinforcer in question, and this baseline is not always assessed in current experimental protocols. This concern is especially crucial in comparing intertemporal choices across different groups or manipulation. We focus in particular on the effects of reward types on intertemporal choices, presenting two experimental studies where the difference in behavior with monetary versus food rewards is the product of different baseline motivation, rather than variations in delay aversion. We conclude discussing the implications of these and other similar recent findings, which are far-reaching. © Society for the Experimental Analysis of Behavior.

International trade of health services: global trends and local impact.

PubMed

Lautier, Marc

2014-10-01

Globalization is a key challenge facing health policy-makers. A significant dimension of this is trade in health services. Traditionally, the flow of health services exports went from North to South, with patients travelling in the opposite direction. This situation is changing and a number of papers have discussed the growth of health services exports from Southern countries in its different dimensions. Less attention has been paid to assess the real scope of this trade at the global level and its potential impact at the local level. Given the rapid development of this area, there are little empirical data. This paper therefore first built an estimate of the global size and of the growth trend of international trade in health services since 1997, which is compared with several country-based studies. The second purpose of the paper is to demonstrate the significant economic impact of this trade at the local level for the exporting country. We consider the case of health providers in the South-Mediterranean region for which the demand potential, the economic effects and the consequence for the health system are presented. These issues lead to the overall conclusion that different policy options would be appropriate, in relation to the nature of the demand. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Hanford Borehole Geologic Information System (HBGIS) Updated User’s Guide for Web-based Data Access and Export

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackley, Rob D.; Last, George V.; Allwardt, Craig H.

2008-09-24

The Hanford Borehole Geologic Information System (HBGIS) is a prototype web-based graphical user interface (GUI) for viewing and downloading borehole geologic data. The HBGIS is being developed as part of the Remediation Decision Support function of the Soil and Groundwater Remediation Project, managed by Fluor Hanford, Inc., Richland, Washington. Recent efforts have focused on improving the functionality of the HBGIS website in order to allow more efficient access and exportation of available data in HBGIS. Users will benefit from enhancements such as a dynamic browsing, user-driven forms, and multi-select options for selecting borehole geologic data for export. The need formore » translating borehole geologic data into electronic form within the HBGIS continues to increase, and efforts to populate the database continue at an increasing rate. These new web-based tools should help the end user quickly visualize what data are available in HBGIS, select from among these data, and download the borehole geologic data into a consistent and reproducible tabular form. This revised user’s guide supersedes the previous user’s guide (PNNL-15362) for viewing and downloading data from HBGIS. It contains an updated data dictionary for tables and fields containing borehole geologic data as well as instructions for viewing and downloading borehole geologic data.« less

Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting.

PubMed

Hopper, Lydia M; Kurtycz, Laura M; Ross, Stephen R; Bonnie, Kristin E

2015-01-01

In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they appeared to develop strategies to reduce the cost associated with obtaining the grapes, including scrounging rewards and tokens from group mates and carrying more than one token when travelling to the farther exchange location. By testing the chimpanzees in their social group we were able to tease apart the social and individual influences on their decision making and the interplay with the physical demands of the task, which revealed that the chimpanzees were willing to travel farther for better.

Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting

PubMed Central

Kurtycz, Laura M.; Ross, Stephen R.; Bonnie, Kristin E.

2015-01-01

In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they appeared to develop strategies to reduce the cost associated with obtaining the grapes, including scrounging rewards and tokens from group mates and carrying more than one token when travelling to the farther exchange location. By testing the chimpanzees in their social group we were able to tease apart the social and individual influences on their decision making and the interplay with the physical demands of the task, which revealed that the chimpanzees were willing to travel farther for better. PMID:25802805

Deep Brain Stimulation of the Subthalamic Nucleus Does Not Affect the Decrease of Decision Threshold during the Choice Process When There Is No Conflict, Time Pressure, or Reward.

PubMed

Leimbach, Friederike; Georgiev, Dejan; Litvak, Vladimir; Antoniades, Chrystalina; Limousin, Patricia; Jahanshahi, Marjan; Bogacz, Rafal

2018-06-01

During a decision process, the evidence supporting alternative options is integrated over time, and the choice is made when the accumulated evidence for one of the options reaches a decision threshold. Humans and animals have an ability to control the decision threshold, that is, the amount of evidence that needs to be gathered to commit to a choice, and it has been proposed that the subthalamic nucleus (STN) is important for this control. Recent behavioral and neurophysiological data suggest that, in some circumstances, the decision threshold decreases with time during choice trials, allowing overcoming of indecision during difficult choices. Here we asked whether this within-trial decrease of the decision threshold is mediated by the STN and if it is affected by disrupting information processing in the STN through deep brain stimulation (DBS). We assessed 13 patients with Parkinson disease receiving bilateral STN DBS six or more months after the surgery, 11 age-matched controls, and 12 young healthy controls. All participants completed a series of decision trials, in which the evidence was presented in discrete time points, which allowed more direct estimation of the decision threshold. The participants differed widely in the slope of their decision threshold, ranging from constant threshold within a trial to steeply decreasing. However, the slope of the decision threshold did not depend on whether STN DBS was switched on or off and did not differ between the patients and controls. Furthermore, there was no difference in accuracy and RT between the patients in the on and off stimulation conditions and healthy controls. Previous studies that have reported modulation of the decision threshold by STN DBS or unilateral subthalamotomy in Parkinson disease have involved either fast decision-making under conflict or time pressure or in anticipation of high reward. Our findings suggest that, in the absence of reward, decision conflict, or time pressure for decision-making, the STN does not play a critical role in modulating the within-trial decrease of decision thresholds during the choice process.

Neural encoding of competitive effort in the anterior cingulate cortex.

PubMed

Hillman, Kristin L; Bilkey, David K

2012-09-01

In social environments, animals often compete to obtain limited resources. Strategically electing to work against another animal represents a cost-benefit decision. Is the resource worth an investment of competitive effort? The anterior cingulate cortex (ACC) has been implicated in cost-benefit decision-making, but its role in competitive effort has not been examined. We recorded ACC neurons in freely moving rats as they performed a competitive foraging choice task. When at least one of the two choice options demanded competitive effort, the majority of ACC neurons exhibited heightened and differential firing between the goal trajectories. Inter- and intrasession manipulations revealed that differential firing was not attributable to effort or reward in isolation; instead ACC encoding patterns appeared to indicate net utility assessments of available choice options. Our findings suggest that the ACC is important for encoding competitive effort, a cost-benefit domain that has received little neural-level investigation despite its predominance in nature.

Dopamine antagonism decreases willingness to expend physical, but not cognitive, effort: a comparison of two rodent cost/benefit decision-making tasks.

PubMed

Hosking, Jay G; Floresco, Stan B; Winstanley, Catharine A

2015-03-01

Successful decision making often requires weighing a given option's costs against its associated benefits, an ability that appears perturbed in virtually every severe mental illness. Animal models of such cost/benefit decision making overwhelmingly implicate mesolimbic dopamine in our willingness to exert effort for a larger reward. Until recently, however, animal models have invariably manipulated the degree of physical effort, whereas human studies of effort have primarily relied on cognitive costs. Dopamine's relationship to cognitive effort has not been directly examined, nor has the relationship between individuals' willingness to expend mental versus physical effort. It is therefore unclear whether willingness to work hard in one domain corresponds to willingness in the other. Here we utilize a rat cognitive effort task (rCET), wherein animals can choose to allocate greater visuospatial attention for a greater reward, and a previously established physical effort-discounting task (EDT) to examine dopaminergic and noradrenergic contributions to effort. The dopamine antagonists eticlopride and SCH23390 each decreased willingness to exert physical effort on the EDT; these drugs had no effect on willingness to exert mental effort for the rCET. Preference for the high effort option correlated across the two tasks, although this effect was transient. These results suggest that dopamine is only minimally involved in cost/benefit decision making with cognitive effort costs. The constructs of mental and physical effort may therefore comprise overlapping, but distinct, circuitry, and therapeutic interventions that prove efficacious in one effort domain may not be beneficial in another.

Recipients Affect Prosocial and Altruistic Choices in Jackdaws, Corvus monedula

PubMed Central

Schwab, Christine; Swoboda, Ruth; Kotrschal, Kurt; Bugnyar, Thomas

2012-01-01

Other-regarding preferences are a critical feature of human cooperation but to what extent non-human animals exhibit these preferences is a matter of intense discussion. We tested whether jackdaws show prosocial behaviour (providing benefits to others at no cost to themselves) and altruism (providing benefits to others while incurring costs) with both sibling and non-sibling recipients. In the prosocial condition, a box was baited on both the actor's and the recipient's side (1/1 option), whereas another box provided food only for the actor (1/0 option). In the altruistic condition, the boxes contained food for either the actor (1/0 option) or the recipient (0/1 option). The proportion of selfish (1/0 option) and cooperative (1/1 and 0/1 option, respectively) actors' choices was significantly affected by the recipients' behaviour. If recipients approached the boxes first and positioned themselves next to the box baited on their side, trying to access the food reward (recipient-first trials), actors were significantly more cooperative than when the actors approached the boxes first and made their choice prior to the recipients' arrival (actor-first trials). Further, in recipient-first trials actors were more cooperative towards recipients of the opposite sex, an effect that was even more pronounced in the altruistic condition. Hence, at no cost to the actors, all recipients could significantly influence the actors' behaviour, whereas at high costs this could be achieved even more so by recipients of different sex. Local/stimulus enhancement is discussed as the most likely cognitive mechanism to account for these effects. PMID:22511972

Recipients affect prosocial and altruistic choices in jackdaws, Corvus monedula.

PubMed

Schwab, Christine; Swoboda, Ruth; Kotrschal, Kurt; Bugnyar, Thomas

2012-01-01

Other-regarding preferences are a critical feature of human cooperation but to what extent non-human animals exhibit these preferences is a matter of intense discussion. We tested whether jackdaws show prosocial behaviour (providing benefits to others at no cost to themselves) and altruism (providing benefits to others while incurring costs) with both sibling and non-sibling recipients. In the prosocial condition, a box was baited on both the actor's and the recipient's side (1/1 option), whereas another box provided food only for the actor (1/0 option). In the altruistic condition, the boxes contained food for either the actor (1/0 option) or the recipient (0/1 option). The proportion of selfish (1/0 option) and cooperative (1/1 and 0/1 option, respectively) actors' choices was significantly affected by the recipients' behaviour. If recipients approached the boxes first and positioned themselves next to the box baited on their side, trying to access the food reward (recipient-first trials), actors were significantly more cooperative than when the actors approached the boxes first and made their choice prior to the recipients' arrival (actor-first trials). Further, in recipient-first trials actors were more cooperative towards recipients of the opposite sex, an effect that was even more pronounced in the altruistic condition. Hence, at no cost to the actors, all recipients could significantly influence the actors' behaviour, whereas at high costs this could be achieved even more so by recipients of different sex. Local/stimulus enhancement is discussed as the most likely cognitive mechanism to account for these effects.

Feasibility study for the swaziland/mozambique interconector. Executive summary of the final report. Export trade information

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-11-01

This study, conducted by Black & Veatch, was funded by the U.S. Trade and Development Agency. The report, produced for the Ministry of National Resources, Energy and Environment (MNRE) of Swaziland, determines the least cost capacity expansion option to meet the future power demand and system reliability criteria of Swaziland, with particular emphasis on the propsoed Interconnector between Swaziland and Mozambique. Volume 1 contains the Executive Summary and is divided into the following sections: (1.0) Study Objectives; (2.0) Swaziland and its Economy; (3.0) The Power Sector Structure in Swaziland; (4.0) Electric Power Resources; (5.0) Past Demand Growth; (6.0) Load andmore » Energy Forecasts; (7.0) Need for Power; (8.0) Generation and Transmission Capacity Addition Option; (9.0) SEB Expansion Plan Scenario Development; (10.0) EDM Expansion Plan Development; (11.0) Cost Sharing of the Interconnector; (12.0) Interconnector Options and Environmental Evaluation; (13.0) Generation/Transmission Trade Offs; (14.0) EPC RFP and Draft Interconnection Agreement; (15.0) Transmission System Study; (16.0) Conclusions and Recommendations.« less

Exporting doctoral education: experience of a state-supported university.

PubMed

Stoskopf, Carleen H; Xirasagar, Sudha; Han, Whiejong M; Snowdon, Sonja

2007-01-01

There is a demand for non-traditional doctoral education in healthcare management and policy among many countries in support of their health system reform efforts. Healthcare professionals need retooling to provide stewardship to complex new health financing systems. Most health service leaders are mid career professionals and cannot transplant themselves to study on American university campuses. They demand high quality programs, designed to enable most coursework to be completed overseas. Aided by recent distance education technology, the University of South Carolina's Department of Health Services Policy and Management developed and provides doctoral programs for working professionals in Taiwan and South Korea with a minimal and convenient campus attendance requirement. This paper presents the experience of setting up the programs, management, quality control, and benefits for both students overseas and for our Department's mission and on-campus programs. Our experience is that there are many challenges, but it is also rewarding from academic, scholarly, and financial perspectives.

Converting ODM Metadata to FHIR Questionnaire Resources.

PubMed

Doods, Justin; Neuhaus, Philipp; Dugas, Martin

2016-01-01

Interoperability between systems and data sharing between domains is becoming more and more important. The portal medical-data-models.org offers more than 5.300 UMLS annotated forms in CDISC ODM format in order to support interoperability, but several additional export formats are available. CDISC's ODM and HL7's framework FHIR Questionnaire resource were analyzed, a mapping between elements created and a converter implemented. The developed converter was integrated into the portal with FHIR Questionnaire XML or JSON download options. New FHIR applications can now use this large library of forms.

Feasibility study for the Swaziland/Mozambique interconnector. EPC specifications. Export trade information

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-11-01

This study, conducted by Black & Veatch, was funded by the U.S. Trade and Development Agency. The report, produced for the Ministry of National Resources, Energy and Environment (MNRE) of Swaziland, determines the least cost capacity expansion option to meet the future power demand and system reliability criteria of Swaziland, with particular emphasis on the proposed Interconnector between Swaziland and Mozambique. Volume 3 contains EPC Specifications and is divided into the following divisions: (1) Commercial; (2) General Technical Requirements; (3) Transmission Line Technical Requirements; (4) Substation Technical Requirements; (5) Specifications.

[Decision Making and Electrodermal Activity].

PubMed

Kobayakawa, Mutsutaka

2016-08-01

Decision making is aided by emotions. Bodily responses, such as sweating, heartbeat, and visceral sensation, are used to monitor the emotional state during decision making. Because decision making in dairy life is complicated and cognitively demanding, these bodily signals are thought to facilitate the decision making process by assigning positive or negative values for each of the behavioral options. The sweat response in a decision making task is measured by skin conductance response (SCR). SCR in decision making is divided into two categories: anticipatory SCR is observed before making decisions, and reward/punishment SCR is observed after the outcome of the decision is perceived. Brain lesion studies in human revealed that the amygdala and ventromedial prefrontal cortex are important in decision making. Patients with lesinon in the amygdala exhibit neither the anticipatory nor reward/punishment SCRs, while patients with the ventromedial prefrontal lesions have deficits only in the anticipatory SCRs. Decision making tasks and SCR analysis have contributed to reveal the implicit aspects of decision making. Further research is necessary for clarifying the role of explicit process of decision making and its relationship with the implicit process.

Creative employee scheduling in the health information management department.

PubMed

Hyde, C S

1998-02-01

What effect do schedules have on employees and department activities? Negative effects such as backlogs, poor employee morale, and absenteeism may be due to scheduling practices currently in place. The value of effective employee scheduling practices may be seen in areas of improved productivity. The process of developing schedules should include assessing department areas, understanding operational needs, choosing an option, and implementation. Finding a schedule that meets the needs of managers as well as those of the employees is rewarding. It is a win-win situation, and the benefits can yield increased productivity, decreased turnover, and higher morale.

Removable Partial Denture in a Cleft Lip and Palate Patient: A Case Report

PubMed Central

Özdemir, Eylem

2008-01-01

This clinical report described the oral rehabilitation of a cleft lip and palate patient with removable partial denture. Although implant-supported fixed treatment was presented as part of the optimum treatment plan to achieve the best result, the patient declined this option due to the significant financial burden. Persons with a congenital or craniofacial defect are unique, and oral problems must be evaluated individually to the most ideal treatment. The changes in appearance, function, and psychological wellbeing have an enormous impact on patients' personal lives and are rewarding for the maxillofacial prosthodontist providing this care. PMID:18955808

Rewarding Healthy Food Choices in SNAP: Behavioral Economic Applications

PubMed Central

Richards, Michael R; Sindelar, Jody L

2013-01-01

Context American obesity rates continue to escalate, but an effective policy response remains elusive. Specific changes to the Supplemental Nutrition Assistance Program (SNAP) have been proposed as one way to improve nutrition and combat obesity among lower-income populations. While current SNAP proposals hold promise, some important challenges still remain. Methods We discuss the four most common recommendations for changes to SNAP and their benefits and limitations. We then propose three new delivery options for SNAP that take advantage of behavioral economic insights and encourage the selection of healthy foods. Findings Although the existing proposals could help SNAP recipients, they often do not address some important behavioral impediments to buying healthy foods. We believe that behavioral economics can be used to design alternative policies with several advantages, although we recognize and discuss some of their limitations. The first proposal rewards healthy purchases with more SNAP funds and provides an additional incentive to maintain healthier shopping patterns. The second proposal uses the opportunity to win prizes to reward healthy food choices, and the prizes further support healthier habits. The final proposal simplifies healthy food purchases by allowing individuals to commit their SNAP benefits to more nutritious selections in advance. Conclusions Reforming the delivery structure of SNAP's benefits could help improve nutrition, weight, and overall health of lower-income individuals. We advocate for more and diverse SNAP proposals, which should be tested and, possibly, combined. Their implementation, however, would require political will, administrative capacity, and funding. PMID:23758515

Ditch network maintenance in peat-dominated boreal forests: Review and analysis of water quality management options.

PubMed

Nieminen, Mika; Piirainen, Sirpa; Sikström, Ulf; Löfgren, Stefan; Marttila, Hannu; Sarkkola, Sakari; Laurén, Ari; Finér, Leena

2018-03-27

The objective of this study was to evaluate the potential of different water management options to mitigate sediment and nutrient exports from ditch network maintenance (DNM) areas in boreal peatland forests. Available literature was reviewed, past data reanalyzed, effects of drainage intensity modeled, and major research gaps identified. The results indicate that excess downstream loads may be difficult to prevent. Water protection structures constructed to capture eroded matter are either inefficient (sedimentation ponds) or difficult to apply (wetland buffers). It may be more efficient to decrease erosion, either by limiting peak water velocity (dam structures) or by adjusting ditch depth and spacing to enable satisfactory drainage without exposing the mineral soil below peat. Future research should be directed towards the effects of ditch breaks and adjusted ditch depth and spacing in managing water quality in DNM areas.

An enhanced export coefficient based optimization model for supporting agricultural nonpoint source pollution mitigation under uncertainty.

PubMed

Rong, Qiangqiang; Cai, Yanpeng; Chen, Bing; Yue, Wencong; Yin, Xin'an; Tan, Qian

2017-02-15

In this research, an export coefficient based dual inexact two-stage stochastic credibility constrained programming (ECDITSCCP) model was developed through integrating an improved export coefficient model (ECM), interval linear programming (ILP), fuzzy credibility constrained programming (FCCP) and a fuzzy expected value equation within a general two stage programming (TSP) framework. The proposed ECDITSCCP model can effectively address multiple uncertainties expressed as random variables, fuzzy numbers, pure and dual intervals. Also, the model can provide a direct linkage between pre-regulated management policies and the associated economic implications. Moreover, the solutions under multiple credibility levels can be obtained for providing potential decision alternatives for decision makers. The proposed model was then applied to identify optimal land use structures for agricultural NPS pollution mitigation in a representative upstream subcatchment of the Miyun Reservoir watershed in north China. Optimal solutions of the model were successfully obtained, indicating desired land use patterns and nutrient discharge schemes to get a maximum agricultural system benefits under a limited discharge permit. Also, numerous results under multiple credibility levels could provide policy makers with several options, which could help get an appropriate balance between system benefits and pollution mitigation. The developed ECDITSCCP model can be effectively applied to addressing the uncertain information in agricultural systems and shows great applicability to the land use adjustment for agricultural NPS pollution mitigation. Copyright © 2016 Elsevier B.V. All rights reserved.

Serotonin shapes risky decision making in monkeys.

PubMed

Long, Arwen B; Kuhn, Cynthia M; Platt, Michael L

2009-12-01

Some people love taking risks, while others avoid gambles at all costs. The neural mechanisms underlying individual variation in preference for risky or certain outcomes, however, remain poorly understood. Although behavioral pathologies associated with compulsive gambling, addiction and other psychiatric disorders implicate deficient serotonin signaling in pathological decision making, there is little experimental evidence demonstrating a link between serotonin and risky decision making, in part due to the lack of a good animal model. We used dietary rapid tryptophan depletion (RTD) to acutely lower brain serotonin in three macaques performing a simple gambling task for fluid rewards. To confirm the efficacy of RTD experiments, we measured total plasma tryptophan using high-performance liquid chromatography (HPLC) with electrochemical detection. Reducing brain serotonin synthesis decreased preference for the safe option in a gambling task. Moreover, lowering brain serotonin function significantly decreased the premium required for monkeys to switch their preference to the risky option, suggesting that diminished serotonin signaling enhances the relative subjective value of the risky option. These results implicate serotonin in risk-sensitive decision making and, further, suggest pharmacological therapies for treating pathological risk preferences in disorders such as problem gambling and addiction.

Molecule database framework: a framework for creating database applications with chemical structure search capability

PubMed Central

2013-01-01

Background Research in organic chemistry generates samples of novel chemicals together with their properties and other related data. The involved scientists must be able to store this data and search it by chemical structure. There are commercial solutions for common needs like chemical registration systems or electronic lab notebooks. However for specific requirements of in-house databases and processes no such solutions exist. Another issue is that commercial solutions have the risk of vendor lock-in and may require an expensive license of a proprietary relational database management system. To speed up and simplify the development for applications that require chemical structure search capabilities, I have developed Molecule Database Framework. The framework abstracts the storing and searching of chemical structures into method calls. Therefore software developers do not require extensive knowledge about chemistry and the underlying database cartridge. This decreases application development time. Results Molecule Database Framework is written in Java and I created it by integrating existing free and open-source tools and frameworks. The core functionality includes: • Support for multi-component compounds (mixtures) • Import and export of SD-files • Optional security (authorization) For chemical structure searching Molecule Database Framework leverages the capabilities of the Bingo Cartridge for PostgreSQL and provides type-safe searching, caching, transactions and optional method level security. Molecule Database Framework supports multi-component chemical compounds (mixtures). Furthermore the design of entity classes and the reasoning behind it are explained. By means of a simple web application I describe how the framework could be used. I then benchmarked this example application to create some basic performance expectations for chemical structure searches and import and export of SD-files. Conclusions By using a simple web application it was shown that Molecule Database Framework successfully abstracts chemical structure searches and SD-File import and export to simple method calls. The framework offers good search performance on a standard laptop without any database tuning. This is also due to the fact that chemical structure searches are paged and cached. Molecule Database Framework is available for download on the projects web page on bitbucket: https://bitbucket.org/kienerj/moleculedatabaseframework. PMID:24325762

Molecule database framework: a framework for creating database applications with chemical structure search capability.

PubMed

Kiener, Joos

2013-12-11

Research in organic chemistry generates samples of novel chemicals together with their properties and other related data. The involved scientists must be able to store this data and search it by chemical structure. There are commercial solutions for common needs like chemical registration systems or electronic lab notebooks. However for specific requirements of in-house databases and processes no such solutions exist. Another issue is that commercial solutions have the risk of vendor lock-in and may require an expensive license of a proprietary relational database management system. To speed up and simplify the development for applications that require chemical structure search capabilities, I have developed Molecule Database Framework. The framework abstracts the storing and searching of chemical structures into method calls. Therefore software developers do not require extensive knowledge about chemistry and the underlying database cartridge. This decreases application development time. Molecule Database Framework is written in Java and I created it by integrating existing free and open-source tools and frameworks. The core functionality includes:•Support for multi-component compounds (mixtures)•Import and export of SD-files•Optional security (authorization)For chemical structure searching Molecule Database Framework leverages the capabilities of the Bingo Cartridge for PostgreSQL and provides type-safe searching, caching, transactions and optional method level security. Molecule Database Framework supports multi-component chemical compounds (mixtures).Furthermore the design of entity classes and the reasoning behind it are explained. By means of a simple web application I describe how the framework could be used. I then benchmarked this example application to create some basic performance expectations for chemical structure searches and import and export of SD-files. By using a simple web application it was shown that Molecule Database Framework successfully abstracts chemical structure searches and SD-File import and export to simple method calls. The framework offers good search performance on a standard laptop without any database tuning. This is also due to the fact that chemical structure searches are paged and cached. Molecule Database Framework is available for download on the projects web page on bitbucket: https://bitbucket.org/kienerj/moleculedatabaseframework.

Decision-making under risk in children, adolescents, and young adults.

PubMed

Paulsen, David J; Platt, Michael L; Huettel, Scott A; Brannon, Elizabeth M

2011-01-01

Adolescents often make risky and impulsive decisions. Such behavior has led to the common assumption that a dysfunction in risk-related decision-making peaks during this age. Differences in how risk has been defined across studies, however, make it difficult to draw conclusions about developmental changes in risky decision-making. Here, we developed a non-symbolic economic decision-making task that can be used across a wide age span and that uses coefficient of variation (CV) in reward as an index of risk. We found that young children showed the strongest preference for risky compared to sure bet options of equal expected value, adolescents were intermediate in their risk preference, and young adults showed the strongest risk aversion. Furthermore, children's preference for the risky option increased for larger CVs, while adolescents and young adults showed the opposite pattern, favoring the sure bet more often as CV increased. Finally, when faced with two gambles in a risk-return tradeoff, all three age groups exhibited a greater preference for the option with the lower risk and return as the disparity in risk between the two options increased. These findings demonstrate clear age-related differences in economic risk preferences that vary with choice set and risk. Importantly, adolescence appears to represent an intermediate decision-making phenotype along the transition from childhood to adulthood, rather than an age of heightened preference for economic risk.

Decision-Making Under Risk in Children, Adolescents, and Young Adults

PubMed Central

Paulsen, David J.; Platt, Michael L.; Huettel, Scott A.; Brannon, Elizabeth M.

2011-01-01

Adolescents often make risky and impulsive decisions. Such behavior has led to the common assumption that a dysfunction in risk-related decision-making peaks during this age. Differences in how risk has been defined across studies, however, make it difficult to draw conclusions about developmental changes in risky decision-making. Here, we developed a non-symbolic economic decision-making task that can be used across a wide age span and that uses coefficient of variation (CV) in reward as an index of risk. We found that young children showed the strongest preference for risky compared to sure bet options of equal expected value, adolescents were intermediate in their risk preference, and young adults showed the strongest risk aversion. Furthermore, children's preference for the risky option increased for larger CVs, while adolescents and young adults showed the opposite pattern, favoring the sure bet more often as CV increased. Finally, when faced with two gambles in a risk–return tradeoff, all three age groups exhibited a greater preference for the option with the lower risk and return as the disparity in risk between the two options increased. These findings demonstrate clear age-related differences in economic risk preferences that vary with choice set and risk. Importantly, adolescence appears to represent an intermediate decision-making phenotype along the transition from childhood to adulthood, rather than an age of heightened preference for economic risk. PMID:21687443

eCOMPAGT integrates mtDNA: import, validation and export of mitochondrial DNA profiles for population genetics, tumour dynamics and genotype-phenotype association studies.

PubMed

Weissensteiner, Hansi; Schönherr, Sebastian; Specht, Günther; Kronenberg, Florian; Brandstätter, Anita

2010-03-09

Mitochondrial DNA (mtDNA) is widely being used for population genetics, forensic DNA fingerprinting and clinical disease association studies. The recent past has uncovered severe problems with mtDNA genotyping, not only due to the genotyping method itself, but mainly to the post-lab transcription, storage and report of mtDNA genotypes. eCOMPAGT, a system to store, administer and connect phenotype data to all kinds of genotype data is now enhanced by the possibility of storing mtDNA profiles and allowing their validation, linking to phenotypes and export as numerous formats. mtDNA profiles can be imported from different sequence evaluation programs, compared between evaluations and their haplogroup affiliations stored. Furthermore, eCOMPAGT has been improved in its sophisticated transparency (support of MySQL and Oracle), security aspects (by using database technology) and the option to import, manage and store genotypes derived from various genotyping methods (SNPlex, TaqMan, and STRs). It is a software solution designed for project management, laboratory work and the evaluation process all-in-one. The extended mtDNA version of eCOMPAGT was designed to enable error-free post-laboratory data handling of human mtDNA profiles. This software is suited for small to medium-sized human genetic, forensic and clinical genetic laboratories. The direct support of MySQL and the improved database security options render eCOMPAGT a powerful tool to build an automated workflow architecture for several genotyping methods. eCOMPAGT is freely available at http://dbis-informatik.uibk.ac.at/ecompagt.

eCOMPAGT integrates mtDNA: import, validation and export of mitochondrial DNA profiles for population genetics, tumour dynamics and genotype-phenotype association studies

PubMed Central

2010-01-01

Background Mitochondrial DNA (mtDNA) is widely being used for population genetics, forensic DNA fingerprinting and clinical disease association studies. The recent past has uncovered severe problems with mtDNA genotyping, not only due to the genotyping method itself, but mainly to the post-lab transcription, storage and report of mtDNA genotypes. Description eCOMPAGT, a system to store, administer and connect phenotype data to all kinds of genotype data is now enhanced by the possibility of storing mtDNA profiles and allowing their validation, linking to phenotypes and export as numerous formats. mtDNA profiles can be imported from different sequence evaluation programs, compared between evaluations and their haplogroup affiliations stored. Furthermore, eCOMPAGT has been improved in its sophisticated transparency (support of MySQL and Oracle), security aspects (by using database technology) and the option to import, manage and store genotypes derived from various genotyping methods (SNPlex, TaqMan, and STRs). It is a software solution designed for project management, laboratory work and the evaluation process all-in-one. Conclusions The extended mtDNA version of eCOMPAGT was designed to enable error-free post-laboratory data handling of human mtDNA profiles. This software is suited for small to medium-sized human genetic, forensic and clinical genetic laboratories. The direct support of MySQL and the improved database security options render eCOMPAGT a powerful tool to build an automated workflow architecture for several genotyping methods. eCOMPAGT is freely available at http://dbis-informatik.uibk.ac.at/ecompagt. PMID:20214782

On valuing information in adaptive-management models.

PubMed

Moore, Alana L; McCarthy, Michael A

2010-08-01

Active adaptive management looks at the benefit of using strategies that may be suboptimal in the near term but may provide additional information that will facilitate better management in the future. In many adaptive-management problems that have been studied, the optimal active and passive policies (accounting for learning when designing policies and designing policy on the basis of current best information, respectively) are very similar. This seems paradoxical; when faced with uncertainty about the best course of action, managers should spend very little effort on actively designing programs to learn about the system they are managing. We considered two possible reasons why active and passive adaptive solutions are often similar. First, the benefits of learning are often confined to the particular case study in the modeled scenario, whereas in reality information gained from local studies is often applied more broadly. Second, management objectives that incorporate the variance of an estimate may place greater emphasis on learning than more commonly used objectives that aim to maximize an expected value. We explored these issues in a case study of Merri Creek, Melbourne, Australia, in which the aim was to choose between two options for revegetation. We explicitly incorporated monitoring costs in the model. The value of the terminal rewards and the choice of objective both influenced the difference between active and passive adaptive solutions. Explicitly considering the cost of monitoring provided a different perspective on how the terminal reward and management objective affected learning. The states for which it was optimal to monitor did not always coincide with the states in which active and passive adaptive management differed. Our results emphasize that spending resources on monitoring is only optimal when the expected benefits of the options being considered are similar and when the pay-off for learning about their benefits is large.

Context influences decision-making in boys with attention-deficit/hyperactivity disorder: A comparison of traditional and novel choice-impulsivity paradigms.

PubMed

Patros, Connor H G; Alderson, R Matt; Lea, Sarah E; Tarle, Stephanie J

2017-02-01

Attention-deficit/hyperactivity disorder (ADHD) is characterized by an impaired ability to maintain attention and/or hyperactivity/impulsivity. Impulsivity is frequently defined as the preference for small, immediate rewards over larger, delayed rewards, and has been associated with a variety of negative outcomes such as risky behavior and academic difficulty. Extant studies have uniformly utilized the traditional paradigm of presenting two response choices, which limits the generalization of findings to scenarios in which children/adolescents are faced with dichotomous decisions. The current study is the first to examine the effect of manipulating the number of available response options on impulsive decision-making in boys with and without ADHD. A total of 39 boys (ADHD = 16, typically developing [TD] = 23) aged 8-12 years completed a traditional two-choice impulsivity task and a novel five-choice impulsivity task to examine the effect of manipulating the number of choice responses (two vs five) on impulsive decision-making. A five-choice task was utilized as it presents a more continuous array of choice options when compared to the typical two-choice task, and is comparable given its methodological similarity to the two-choice task. Results suggested that boys with ADHD were significantly more impulsive than TD boys during the two-choice task, but not during the five-choice task. Collectively, these findings suggest that ADHD-related impulsivity is not ubiquitous, but rather dependent on variation in demands and/or context. Further, these findings highlight the importance of examining ADHD-related decision-making within the context of alternative paradigms, as the exclusive utilization of two-choice tasks may promote inaccurate conceptualizations of the disorder.

Dissociable contributions of dorsal and ventral striatal regions on a rodent cost/benefit decision-making task requiring cognitive effort.

PubMed

Silveira, Mason M; Tremblay, Melanie; Winstanley, Catharine A

2018-04-24

Cognitive effort is a ubiquitous process, yet surprisingly little is known about the brain mechanisms responsible for evaluating it. Here, we utilize the rat Cognitive Effort Task (rCET) to probe the striatum's role in deciding between options that vary in the amount of cognitive effort required for success. In the rCET, animals choose to perform either an easy trial, in which the attentional demand is low but the potential reward is small, or a difficult trial which is more attentionally demanding but can yield twice the sugar pellets. Twenty-six male Long Evans rats were trained on the rCET and the effects of pharmacologically inactivating the dorsomedial striatum (DMS) and core region of the nucleus accumbens were determined. Temporary inactivation of the DMS decreased all animals' choice of the high-effort, high-reward option, impaired attentional accuracy, and robustly increased premature responding without impairing general indices of motor ability. The DMS therefore appears necessary for the integration of cognitive signals required for optimal performance. In stark contrast, following temporary inactivation of the ventral striatum, subjects were fundamentally unable to perform the task, as reflected by a drastic decrease in the number of trials initiated and an increase in omitted responses. Together, these data suggest the striatum is likely part of a larger cortico-limbic-striatal network whose function is to optimize decisions requiring cognitive effort costs, at least in the attentional domain, and that striatal subregions have dissociable roles in the adjudication and application of this form of cognitive effort. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling the development of drug addiction in male and female animals.

PubMed

Lynch, Wendy J

2018-01-01

An increasing emphasis has been placed on the development and use of animal models of addiction that capture defining features of human drug addiction, including escalation/binge drug use, enhanced motivation for the drug, preference for the drug over other reward options, use despite negative consequences, and enhanced drug-seeking/relapse vulnerability. The need to examine behavior in both males and females has also become apparent given evidence demonstrating that the addiction process occurs differently in males and females. This review discusses the procedures that are used to model features of addiction in animals, as well as factors that influence their development. Individual differences are also discussed, with a particular focus on sex differences. While no one procedure consistently produces all characteristics, different models have been developed to focus on certain characteristics. A history of escalating/binge patterns of use appears to be critical for producing other features characteristic of addiction, including an enhanced motivation for the drug, enhanced drug seeking, and use despite negative consequences. These characteristics tend to emerge over abstinence, and appear to increase rather than decrease in magnitude over time. In females, these characteristics develop sooner during abstinence and/or following less drug exposure as compared to males, and for psychostimulant addiction, may require estradiol. Although preference for the drug over other reward options has been demonstrated in non-human primates, it has been more difficult to establish in rats. Future research is needed to define the parameters that optimally induce each of these features of addiction in the majority of animals. Such models are essential for advancing our understanding of human drug addiction and its treatment in men and women. Copyright © 2017 Elsevier Inc. All rights reserved.

To drink or not to drink: Harmful drinking is associated with hyperactivation of reward areas rather than hypoactivation of control areas in men

PubMed Central

Stuke, Heiner; Gutwinski, Stefan; Wiers, Corinde E.; Schmidt, Timo T.; Gröpper, Sonja; Parnack, Jenny; Gawron, Christiane; Attar, Catherine Hindi; Spengler, Stephanie; Walter, Henrik; Heinz, Andreas; Bermpohl, Felix

2016-01-01

Background The maintenance of harmful alcohol use can be considered a reiterated decision in favour of alcohol in concrete drinking occasions. These decisions are often made despite an intention to quit or reduce alcohol consumption. We tested if a hyperactive reward system and/or an impaired cognitive control system contribute to such unfavourable decision-making. Methods In this fMRI study, men with modest to harmful drinking behaviour, which was measured using the Alcohol Use Disorders Identification Test (AUDIT), repeatedly made decisions between alcoholic and nonalcoholic drinks. Based on prior individual ratings, decision pairs were created with an alcoholic decision option considered more desirable but less beneficial by the participant. By correlating AUDIT scores with brain activation during decision-making, we determined areas explicitly related to pro-alcohol decisions in men with greater drinking severity. Results Thirty-eight men participated in our study. Behaviourally, we found a positive correlation between AUDIT scores and the number of decisions for desired alcoholic drinks compared with beneficial nonalcoholic drinks. The fMRI results show that AUDIT scores were positively associated with activation in areas associated with reward and motivation processing (i.e., ventral striatum, amygdala, medial prefrontal cortex) during decisions favouring a desired, nonbeneficial alcoholic drink. Conversely, we did not find hypoactivation in areas associated with self-control (dorsolateral prefrontal cortex). These effects were not present when participants chose a desired, nonbenefical, nonalcoholic drink. Limitations The men participating in our study had to be abstinent and would potentially consume an alcoholic drink at the end of the experiment. Hence, we did not define manifest alcohol dependence as an inclusion criterion and instead focused on less severely affected individuals. Conclusion Our results indicate that with growing drinking severity, decisions for alcoholic drinks are associated with increasing activity in reward-associated neural systems, rather than decreasing activity in self-control–associated systems. PMID:26900791

To drink or not to drink: Harmful drinking is associated with hyperactivation of reward areas rather than hypoactivation of control areas in men.

PubMed

Stuke, Heiner; Gutwinski, Stefan; Wiers, Corinde E; Schmidt, Timo T; Gröpper, Sonja; Parnack, Jenny; Gawron, Christiane; Hindi Attar, Catherine; Spengler, Stephanie; Walter, Henrik; Heinz, Andreas; Bermpohl, Felix

2016-04-01

The maintenance of harmful alcohol use can be considered a reiterated decision in favour of alcohol in concrete drinking occasions. These decisions are often made despite an intention to quit or reduce alcohol consumption. We tested if a hyperactive reward system and/or an impaired cognitive control system contribute to such unfavourable decision-making. In this fMRI study, men with modest to harmful drinking behaviour, which was measured using the Alcohol Use Disorders Identification Test (AUDIT), repeatedly made decisions between alcoholic and nonalcoholic drinks. Based on prior individual ratings, decision pairs were created with an alcoholic decision option considered more desirable but less beneficial by the participant. By correlating AUDIT scores with brain activation during decision-making, we determined areas explicitly related to pro-alcohol decisions in men with greater drinking severity. Thirty-eight men participated in our study. Behaviourally, we found a positive correlation between AUDIT scores and the number of decisions for desired alcoholic drinks compared with beneficial nonalcoholic drinks. The fMRI results show that AUDIT scores were positively associated with activation in areas associated with reward and motivation processing (i.e., ventral striatum, amygdala, medial prefrontal cortex) during decisions favouring a desired, nonbeneficial alcoholic drink. Conversely, we did not find hypoactivation in areas associated with self-control (dorsolateral prefrontal cortex). These effects were not present when participants chose a desired, nonbenefical, nonalcoholic drink. The men participating in our study had to be abstinent and would potentially consume an alcoholic drink at the end of the experiment. Hence, we did not define manifest alcohol dependence as an inclusion criterion and instead focused on less severely affected individuals. Our results indicate that with growing drinking severity, decisions for alcoholic drinks are associated with increasing activity in reward-associated neural systems, rather than decreasing activity in self-control-associated systems.

Covert shift of attention modulates the value encoding in the orbitofrontal cortex

PubMed Central

Xie, Yang; Nie, Chechang

2018-01-01

During value-based decision making, we often evaluate the value of each option sequentially by shifting our attention, even when the options are presented simultaneously. The orbitofrontal cortex (OFC) has been suggested to encode value during value-based decision making. Yet it is not known how its activity is modulated by attention shifts. We investigated this question by employing a passive viewing task that allowed us to disentangle effects of attention, value, choice and eye movement. We found that the attention modulated OFC activity through a winner-take-all mechanism. When we attracted the monkeys’ attention covertly, the OFC neuronal activity reflected the reward value of the newly attended cue. The shift of attention could be explained by a normalization model. Our results strongly argue for the hypothesis that the OFC neuronal activity represents the value of the attended item. They provide important insights toward understanding the OFC’s role in value-based decision making. PMID:29533184

Covert shift of attention modulates the value encoding in the orbitofrontal cortex.

PubMed

Xie, Yang; Nie, Chechang; Yang, Tianming

2018-03-13

During value-based decision making, we often evaluate the value of each option sequentially by shifting our attention, even when the options are presented simultaneously. The orbitofrontal cortex (OFC) has been suggested to encode value during value-based decision making. Yet it is not known how its activity is modulated by attention shifts. We investigated this question by employing a passive viewing task that allowed us to disentangle effects of attention, value, choice and eye movement. We found that the attention modulated OFC activity through a winner-take-all mechanism. When we attracted the monkeys' attention covertly, the OFC neuronal activity reflected the reward value of the newly attended cue. The shift of attention could be explained by a normalization model. Our results strongly argue for the hypothesis that the OFC neuronal activity represents the value of the attended item. They provide important insights toward understanding the OFC's role in value-based decision making. © 2018, Xie et al.

Rational choice, neuroeconomy and mixed emotions.

PubMed

Livet, Pierre

2010-01-27

Experimental psychology has shown differences between predictions of theory of decision and human choices. Emotions like regret can partly explain these differences. Neuroimagery used in combination with behavioural economics (neuroeconomics) has been used in order to try to disentangle the different emotional and rational factors (regret, rejoicing, reward, costs, uncertainty, trade-off between positive and negative aspects of different options). Emotions then appear as much more complex and mixed affective states than usually assumed. Not only might we feel a positive affect in punishing unfair partners, but mixed emotions can, for example, combine transmutation of previous anxiety into relief and elation by comparison with another less exciting option (elating relief). At the level of complexity of these mixed emotions--which we formally represent by comparisons between 'unexpected utilities' and expected ones--the main biases that Kahnemann and Tversky have shown can be explained. In spite of the complexity of these mixed emotions, some of these hypotheses might be partially tested by brain imagery.

Rational choice, neuroeconomy and mixed emotions

PubMed Central

Livet, Pierre

2010-01-01

Experimental psychology has shown differences between predictions of theory of decision and human choices. Emotions like regret can partly explain these differences. Neuroimagery used in combination with behavioural economics (neuroeconomics) has been used in order to try to disentangle the different emotional and rational factors (regret, rejoicing, reward, costs, uncertainty, trade-off between positive and negative aspects of different options). Emotions then appear as much more complex and mixed affective states than usually assumed. Not only might we feel a positive affect in punishing unfair partners, but mixed emotions can, for example, combine transmutation of previous anxiety into relief and elation by comparison with another less exciting option (elating relief). At the level of complexity of these mixed emotions—which we formally represent by comparisons between ‘unexpected utilities’ and expected ones—the main biases that Kahnemann and Tversky have shown can be explained. In spite of the complexity of these mixed emotions, some of these hypotheses might be partially tested by brain imagery. PMID:20026464

Choice from non-choice: Predicting consumer preferences from BOLD signals obtained during passive viewing

PubMed Central

Levy, Ifat; Lazzaro, Stephanie C.; Rutledge, Robb B.; Glimcher, Paul W.

2011-01-01

Decision-making is often viewed as a two-stage process, where subjective values are first assigned to each option and then the option of the highest value is selected. Converging evidence suggests that these subjective values are represented in the striatum and medial prefrontal cortex (MPFC). A separate line of evidence suggests that activation in the same areas represents the values of rewards even when choice is not required, as in classical conditioning tasks. However, it is unclear whether the same neural mechanism is engaged in both cases. To address this question we measured brain activation with fMRI while human subjects passively viewed individual consumer goods. We then sampled activation from predefined regions of interest and used it to predict subsequent choices between the same items made outside of the scanner. Our results show that activation in the striatum and MPFC in the absence of choice predicts subsequent choices, suggesting that these brain areas represent value in a similar manner whether or not choice is required. PMID:21209196

Nucleus accumbens shell moderates preference bias during voluntary choice behavior.

PubMed

Jang, Hyeran; Jung, Kanghoon; Jeong, Jaehoon; Park, Sang Ki; Kralik, Jerald D; Jeong, Jaeseung

2017-09-01

The nucleus accumbens (NAc) shell lies anatomically at a critical intersection within the brain's reward system circuitry, however, its role in voluntary choice behavior remains unclear. Rats with electrolytic lesions in the NAc shell were tested in a novel foraging paradigm. Over a continuous two-week period they freely chose among four nutritionally identical but differently flavored food pellets by pressing corresponding levers. We examined the lesion's effects on three behavioral dynamics components: motivation (when to eat), preference bias (what to choose) and persistence (how long to repeat the same choice). The lesion led to a marked increase in the preference bias: i.e., increased selection of the most-preferred choice option, and decreased selection of the others. We found no effects on any other behavioral measures, suggesting no effect on motivation or choice persistence. The results implicate the NAc shell in moderating the instrumental valuation process by inhibiting excessive bias toward preferred choice options. © The Author (2017). Published by Oxford University Press.

Nucleus accumbens shell moderates preference bias during voluntary choice behavior

PubMed Central

Jang, Hyeran; Jung, Kanghoon; Jeong, Jaehoon; Park, Sang Ki; Kralik, Jerald D.

2017-01-01

Abstract The nucleus accumbens (NAc) shell lies anatomically at a critical intersection within the brain’s reward system circuitry, however, its role in voluntary choice behavior remains unclear. Rats with electrolytic lesions in the NAc shell were tested in a novel foraging paradigm. Over a continuous two-week period they freely chose among four nutritionally identical but differently flavored food pellets by pressing corresponding levers. We examined the lesion’s effects on three behavioral dynamics components: motivation (when to eat), preference bias (what to choose) and persistence (how long to repeat the same choice). The lesion led to a marked increase in the preference bias: i.e., increased selection of the most-preferred choice option, and decreased selection of the others. We found no effects on any other behavioral measures, suggesting no effect on motivation or choice persistence. The results implicate the NAc shell in moderating the instrumental valuation process by inhibiting excessive bias toward preferred choice options. PMID:28992274

U.S. Crude Oil Production to 2025: Updated Projection of Crude Types

EIA Publications

2015-01-01

This report updates and extends a May 2014 EIA report, U.S. crude oil production forecast – analysis of crude types. It provides a projection of domestic crude oil production by crude type through 2025, supplementing the overall production projection provided in the AEO2015. Projections of production by crude type matter for several reasons. First, U.S. crude streams vary widely in quality. Second, the economics surrounding various options for the domestic use of additional domestic oil production are directly dependent on crude quality characteristics. Third, actual or potential export values also vary significantly with quality characteristics.

Trade, TRIPS, and pharmaceuticals.

PubMed

Smith, Richard D; Correa, Carlos; Oh, Cecilia

2009-02-21

The World Trade Organization's Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) set global minimum standards for the protection of intellectual property, substantially increasing and expanding intellectual-property rights, and generated clear gains for the pharmaceutical industry and the developed world. The question of whether TRIPS generates gains for developing countries, in the form of increased exports, is addressed in this paper through consideration of the importance of pharmaceuticals in health-care trade, outlining the essential requirements, implications, and issues related to TRIPS, and TRIPS-plus, in which increased restrictions are imposed as part of bilateral free-trade agreements. TRIPS has not generated substantial gains for developing countries, but has further increased pharmaceutical trade in developed countries. The unequal trade between developed and developing countries (ie, exporting and importing high-value patented drugs, respectively) raises the issue of access to medicines, which is exacerbated by TRIPS-plus provisions, although many countries have not even enacted provision for TRIPS flexibilities. Therefore this paper focuses on options that are available to the health community for negotiation to their advantage under TRIPS, and within the presence of TRIPS-plus.

[Computer games and Internet addiction as well as pathological gambling. Therapy approaches].

PubMed

Wölfling, K; Leménager, T; Peukert, P; Batra, A

2013-05-01

In accordance with the development of substance-related disorders, behavioral addictions, such as internet use disorder and pathological gambling are regarded as repetitive excessive behavior which increasingly turns into an automatic action which is difficult to control intentionally. This automatic behavior is reinforced by learning processes, associated with neuroadaption, especially in the dopaminergic reward system. Treatment aims at finding alternatives for gambling or online activities and reducing times online so that social contacts need to be re-established. The following article provides a short overview on studies assessing the effects of different psychotherapeutic and pharmacological interventions and details psychotherapeutic treatment options.

Victim advocates' perceptions of legal work.

PubMed

Kolb, Kenneth H

2011-12-01

Past scholarship has weighed the risks and rewards of legal remedies for victims of domestic violence and sexual assault. Missing from this debate, however, is an analysis of the social incentives for victim advocates to offer legal options to their clients. Preliminary findings show that victim advocates perceive that outsiders respect legal work more than their care work with clients (listening, caring, and empathizing). This study offers three explanations for this phenomenon: (1) the devaluation of women's care work in general, (2) the confidentiality constraints on communicating the value of their care work, and (3) popular assumptions that care work requires professional credentials in order to be legitimate.

Evaluation of the rewarding properties of nicotine and caffeine by implementation of a five-choice conditioned place preference task in zebrafish.

PubMed

Faillace, M P; Pisera-Fuster, A; Bernabeu, R

2018-06-08

The rewarding properties of drugs in zebrafish can be studied using the conditioned place preference (CPP) paradigm. Most devices that have been used for CPP consist of two-half tanks with or without a central chamber. Here we evaluated the rewarding effects of nicotine and caffeine using a tank with five arms distributed radially from a central chamber that we have denoted Fish Tank Radial Maze (FTRM). Zebrafish were trained to associate nicotine or caffeine with a coloured arm. In testing sessions to assess CPP induction, between two and five different arms were available to explore. We found that when offering the two arms, one of them associated to the drug mediating conditioning for 14 days, zebrafish showed nicotine-induced CPP but not caffeine-induced CPP. When zebrafish had the option to explore drug-paired arms together with new coloured arms as putative distractors, the nicotine-CPP strength was maintained for at least three days. The presence of novel environments induced caffeine-CPP, which was still positive after three days of testing sessions. Complementary behavioural data supported these findings. Nicotine-CPP was prevented by the histone deacetylase inhibitor phenylbutyrate administered during conditioning; however, there were no effects on caffeine-CPP. The specific acetylation of lysine 9 in histone 3 (H3-K9) was increased in nicotine-conditioned zebrafish brains. This study suggests that novel environmental cues facilitate drug-environment associations, and hence, the use of drugs of abuse. Copyright © 2018 Elsevier Inc. All rights reserved.

Insight Into the Relationship Between Impulsivity and Substance Abuse From Studies Using Animal Models

PubMed Central

Winstanley, Catharine A.; Olausson, Peter; Taylor, Jane R.; Jentsch, J. David

2010-01-01

Drug use disorders are often accompanied by deficits in the capacity to efficiently process reward-related information and to monitor, suppress, or override reward-controlled behavior when goals are in conflict with aversive or immediate outcomes. This emerging deficit in behavioral flexibility and impulse control may be a central component of the progression to addiction, as behavior becomes increasingly driven by drugs and drug-associated cues at the expense of more advantageous activities. Understanding how neural mechanisms implicated in impulse control are affected by addictive drugs may therefore prove a useful strategy in the search for new treatment options. Animal models of impulsivity and addiction could make a significant contribution to this endeavor. Here, some of the more common behavioral paradigms used to measure different aspects of impulsivity across species are outlined, and the importance of the response to reward-paired cues in such paradigms is discussed. Naturally occurring differences in forms of impulsivity have been found to be predictive of future drug self-administration, but drug exposure can also increase impulsive responding. Such data are in keeping with the suggestion that impulsivity may contribute to multiple stages within the spiral of addiction. From a neurobiological perspective, converging evidence from rat, monkey, and human studies suggest that compromised functioning within the orbitofrontal cortex may critically contribute to the cognitive sequelae of drug abuse. Changes in gene transcription and protein expression within this region may provide insight into the mechanism underlying drug-induced cortical hypofunction, reflecting new molecular targets for the treatment of uncontrolled drug-seeking and drug-taking behavior. PMID:20491734

Mice plan decision strategies based on previously learned time intervals, locations, and probabilities

PubMed Central

Tosun, Tuğçe; Gür, Ezgi; Balcı, Fuat

2016-01-01

Animals can shape their timed behaviors based on experienced probabilistic relations in a nearly optimal fashion. On the other hand, it is not clear if they adopt these timed decisions by making computations based on previously learnt task parameters (time intervals, locations, and probabilities) or if they gradually develop their decisions based on trial and error. To address this question, we tested mice in the timed-switching task, which required them to anticipate when (after a short or long delay) and at which of the two delay locations a reward would be presented. The probability of short trials differed between test groups in two experiments. Critically, we first trained mice on relevant task parameters by signaling the active trial with a discriminative stimulus and delivered the corresponding reward after the associated delay without any response requirement (without inducing switching behavior). During the test phase, both options were presented simultaneously to characterize the emergence and temporal characteristics of the switching behavior. Mice exhibited timed-switching behavior starting from the first few test trials, and their performance remained stable throughout testing in the majority of the conditions. Furthermore, as the probability of the short trial increased, mice waited longer before switching from the short to long location (experiment 1). These behavioral adjustments were in directions predicted by reward maximization. These results suggest that rather than gradually adjusting their time-dependent choice behavior, mice abruptly adopted temporal decision strategies by directly integrating their previous knowledge of task parameters into their timed behavior, supporting the model-based representational account of temporal risk assessment. PMID:26733674

Relationship between oscillatory neuronal activity during reward processing and trait impulsivity and sensation seeking.

PubMed

Leicht, Gregor; Troschütz, Stefan; Andreou, Christina; Karamatskos, Evangelos; Ertl, Matthias; Naber, Dieter; Mulert, Christoph

2013-01-01

The processing of reward and punishment stimuli in humans appears to involve brain oscillatory activity of several frequencies, probably each with a distinct function. The exact nature of associations of these electrophysiological measures with impulsive or risk-seeking personality traits is not completely clear. Thus, the aim of the present study was to investigate event-related oscillatory activity during reward processing across a wide spectrum of frequencies, and its associations with impulsivity and sensation seeking in healthy subjects. During recording of a 32-channel EEG 22 healthy volunteers were characterized with the Barratt Impulsiveness and the Sensation Seeking Scale and performed a computerized two-choice gambling task comprising different feedback options with positive vs. negative valence (gain or loss) and high or low magnitude (5 vs. 25 points). We observed greater increases of amplitudes of the feedback-related negativity and of activity in the theta, alpha and low-beta frequency range following loss feedback and, in contrast, greater increase of activity in the high-beta frequency range following gain feedback. Significant magnitude effects were observed for theta and delta oscillations, indicating greater amplitudes upon feedback concerning large stakes. The theta amplitude changes during loss were negatively correlated with motor impulsivity scores, whereas alpha and low-beta increase upon loss and high-beta increase upon gain were positively correlated with various dimensions of sensation seeking. The findings suggest that the processing of feedback information involves several distinct processes, which are subserved by oscillations of different frequencies and are associated with different personality traits.

Identifying Differences between Depressed Adolescent Suicide Ideators and Attempters

PubMed Central

Auerbach, Randy P.; Millner, Alexander J.; Stewart, Jeremy G.; Esposito, Erika

2015-01-01

Background Adolescent depression and suicide are pressing public health concerns, and identifying key differences among suicide ideators and attempters is critical. The goal of the current study is to test whether depressed adolescent suicide attempters report greater anhedonia severity and exhibit aberrant effort-cost computations in the face of uncertainty. Methods Depressed adolescents (n = 101) ages 13–19 years were administered structured clinical interviews to assess current mental health disorders and a history of suicidality (suicide ideators = 55, suicide attempters = 46). Then, participants completed self-report instruments assessing symptoms of suicidal ideation, depression, anhedonia, and anxiety as well as a computerized effort-cost computation task. Results Compared with depressed adolescent suicide ideators, attempters report greater anhedonia severity, even after concurrently controlling for symptoms of suicidal ideation, depression, and anxiety. Additionally, when completing the effort-cost computation task, suicide attempters are less likely to pursue the difficult, high value option when outcomes are uncertain. Follow-up, trial-level analyses of effort-cost computations suggest that receipt of reward does not influence future decision-making among suicide attempters, however, suicide ideators exhibit a win-stay approach when receiving rewards on previous trials. Limitations Findings should be considered in light of limitations including a modest sample size, which limits generalizability, and the cross-sectional design. Conclusions Depressed adolescent suicide attempters are characterized by greater anhedonia severity, which may impair the ability to integrate previous rewarding experiences to inform future decisions. Taken together, this may generate a feeling of powerlessness that contributes to increased suicidality and a needless loss of life. PMID:26233323

Emergence of β-Band Oscillations in the Aged Rat Amygdala during Discrimination Learning and Decision Making Tasks

PubMed Central

Samson, Rachel D.; Duarte, Leroy; Venkatesh, Anu

2017-01-01

Abstract Older adults tend to use strategies that differ from those used by young adults to solve decision-making tasks. MRI experiments suggest that altered strategy use during aging can be accompanied by a change in extent of activation of a given brain region, inter-hemispheric bilateralization or added brain structures. It has been suggested that these changes reflect compensation for less effective networks to enable optimal performance. One way that communication can be influenced within and between brain networks is through oscillatory events that help structure and synchronize incoming and outgoing information. It is unknown how aging impacts local oscillatory activity within the basolateral complex of the amygdala (BLA). The present study recorded local field potentials (LFPs) and single units in old and young rats during the performance of tasks that involve discrimination learning and probabilistic decision making. We found task- and age-specific increases in power selectively within the β range (15–30 Hz). The increased β power occurred after lever presses, as old animals reached the goal location. Periods of high-power β developed over training days in the aged rats, and was greatest in early trials of a session. β Power was also greater after pressing for the large reward option. These data suggest that aging of BLA networks results in strengthened synchrony of β oscillations when older animals are learning or deciding between rewards of different size. Whether this increased synchrony reflects the neural basis of a compensatory strategy change of old animals in reward-based decision-making tasks, remains to be verified. PMID:29034315

Children use salience to solve coordination problems.

PubMed

Grueneisen, Sebastian; Wyman, Emily; Tomasello, Michael

2015-05-01

Humans are routinely required to coordinate with others. When communication is not possible, adults often achieve this by using salient cues in the environment (e.g. going to the Eiffel Tower, as an obvious meeting point). To explore the development of this capacity, we presented dyads of 3-, 5-, and 8-year-olds (N = 144) with a coordination problem: Two balls had to be inserted into the same of four boxes to obtain a reward. Identical pictures were attached to three boxes whereas a unique--and thus salient--picture was attached to the fourth. Children either received one ball each, and so had to choose the same box (experimental condition), or they received both balls and could get the reward independently (control condition). In all cases, children could neither communicate nor see each other's choices. Children were significantly more likely to choose the salient option in the experimental condition than in the control condition. However, only the two older age groups chose the salient box above chance levels. This study is the first to show that children from at least age 5 can solve coordination problems by converging on a salient solution. © 2014 John Wiley & Sons Ltd.

Young Dutch people's experiences of trading sex: a qualitative study.

PubMed

van de Walle, Robert; Picavet, Charles; van Berlo, Willy; Verhoeff, Arnoud

2012-01-01

In recent years, the subject of transactional sex among young Dutch people has generated a heated social debate in the Netherlands. However, accurate data on this phenomenon are scarce. This article describes the findings of a qualitative study on young Dutch people's experiences of having sex in return for money or a material reward. Thirty in-depth interviews were conducted with young Dutch men and women aged 14 to 24. Participants came from diverse backgrounds in terms of gender, ethnicity, sexual orientation, and socioeconomic status. Experiences of trading sex differed in terms of the motivation to trade sex, the presence or absence of coercion, and the availability of other options for earning money. Participants' feelings about their experiences varied. For most participants, the sex itself was unpleasant and required considerable emotion management. Still, some felt adequately compensated by the reward or felt trading sex was preferable to other jobs. Gender played an important role, with feelings of disgust or shame reported especially by female participants, whereas male participants reported more positive experiences. Interactions involving coercion or financial dependence on trading sex generally had a negative emotional impact. Participants stressed the differences between their own experiences and professional prostitution.

Causal models of attention-deficit/hyperactivity disorder: from common simple deficits to multiple developmental pathways.

PubMed

Sonuga-Barke, Edmund J S

2005-06-01

Until recently, causal models of attention-deficit/hyperactivity disorder (ADHD) have tended to focus on the role of common, simple, core deficits. One such model highlights the role of executive dysfunction due to deficient inhibitory control resulting from disturbances in the frontodorsal striatal circuit and associated mesocortical dopaminergic branches. An alternative model presents ADHD as resulting from impaired signaling of delayed rewards arising from disturbances in motivational processes, involving frontoventral striatal reward circuits and mesolimbic branches terminating in the ventral striatum, particularly the nucleus accumbens. In the present article, these models are elaborated in two ways. First, they are each placed within their developmental context by consideration of the role of person x environment correlation and interaction and individual adaptation to developmental constraint. Second, their relationship to one another is reviewed in the light of recent data suggesting that delay aversion and executive functions might each make distinctive contributions to the development of the disorder. This provides an impetus for theoretical models built around the idea of multiple neurodevelopmental pathways. The possibility of neuropathologic heterogeneity in ADHD is likely to have important implications for the clinical management of the condition, potentially impacting on both diagnostic strategies and treatment options.

Functional specialization of the primate frontal cortex during decision making.

PubMed

Lee, Daeyeol; Rushworth, Matthew F S; Walton, Mark E; Watanabe, Masataka; Sakagami, Masamichi

2007-08-01

Economic theories of decision making are based on the principle of utility maximization, and reinforcement-learning theory provides computational algorithms that can be used to estimate the overall reward expected from alternative choices. These formal models not only account for a large range of behavioral observations in human and animal decision makers, but also provide useful tools for investigating the neural basis of decision making. Nevertheless, in reality, decision makers must combine different types of information about the costs and benefits associated with each available option, such as the quality and quantity of expected reward and required work. In this article, we put forward the hypothesis that different subdivisions of the primate frontal cortex may be specialized to focus on different aspects of dynamic decision-making processes. In this hypothesis, the lateral prefrontal cortex is primarily involved in maintaining the state representation necessary to identify optimal actions in a given environment. In contrast, the orbitofrontal cortex and the anterior cingulate cortex might be primarily involved in encoding and updating the utilities associated with different sensory stimuli and alternative actions, respectively. These cortical areas are also likely to contribute to decision making in a social context.

Color and shape discrimination in the stingless bee Scaptotrigona mexicana Guérin (Hymenoptera, Apidae).

PubMed

Sánchez, D; Vandame, R

2012-06-01

To increase our understanding in bee vision ecology, we investigated the color and shape discrimination performance of the stingless bee Scaptotrigona mexicana Guérin. Our main goal was to describe the choice behavior of experienced foragers over time, trying to understand to what extent color and shape stimuli (separately tested) aid them to choose the rewarding option, in the presence of distracting, unrewarding stimuli. Single foragers were trained to collect sucrose solution from a target plate. Afterwards, one distracting, unrewarding plate was placed besides the target plate and eight choices were recorded. Our results showed that both color and shape stimuli assisted efficiently the trained foragers in locating the target plate. However, foragers chose significantly more often the target plate in the color experiments than in the shape experiments. In conclusion, in our experimental setup, color was of better assistance to the foragers of S. mexicana than shape to choose their rewards. This is the first study in which it is demonstrated that the choice performance over time in a stingless bee depends upon the characteristics of the resource, such as shape and color.

Motivated To Win: Relationship between Anticipatory and Outcome Reward-Related Neural Activity

PubMed Central

Nusslock, Robin

2015-01-01

Reward-processing involves two temporal stages characterized by two distinct neural processes: reward-anticipation and reward-outcome. Intriguingly, very little research has examined the relationship between neural processes involved in reward-anticipation and reward-outcome. To investigate this, one needs to consider the heterogeneity of reward-processing within each stage. To identify different stages of reward processing, we adapted a reward time-estimation task. While EEG data were recorded, participants were instructed to button-press 3.5 s after the onset of an Anticipation-Cue and received monetary reward for good time-estimation on the Reward trials, but not on No-Reward trials. We first separated reward-anticipation into event related potentials (ERPs) occurring at three sub-stages: reward/no-reward cue-evaluation, motor-preparation and feedback-anticipation. During reward/no-reward cue-evaluation, the Reward-Anticipation Cue led to a smaller N2 and larger P3. During motor-preparation, we report, for the first time, that the Reward-Anticipation Cue enhanced the Readiness Potential (RP), starting approximately 1 s before movement. At the subsequent feedback-anticipation stage, the Reward-Anticipation Cue elevated the Stimulus-Preceding Negativity (SPN). We also separated reward-outcome ERPs into different components occurring at different time-windows: the Feedback-Related Negativity (FRN), Feedback-P3 (FB-P3) and Late-Positive Potentials (LPP). Lastly, we examined the relationship between reward-anticipation and reward-outcome ERPs. We report that individual-differences in specific reward-anticipation ERPs uniquely predicted specific reward-outcome ERPs. In particular, the reward-anticipation Early-RP (1 to .8 s before movement) predicted early reward-outcome ERPs (FRN and FB-P3), whereas, the reward-anticipation SPN most strongly predicted a later reward-outcome ERP (LPP). Results have important implications for understanding the nature of the relationship between reward-anticipation and reward-outcome neural-processes. PMID:26433773

New thinking on how to link executive pay with performance.

PubMed

Rappaport, A

1999-01-01

As the stock market began its ascent in the mid-1990s, executive pay--always the subject of heated debate--mounted along with it. That's because among the largest U.S. companies, stock options now account for more than half of total CEO compensation and about 30% of senior operating managers' pay. One problem became particularly clear during the bull market's astonishing run: even below-average performers reap huge gains from stock options when the market is rising rapidly. The author proposes steps to close the gap between existing compensation practices and those needed to promote higher levels of achievement at all levels of the corporation. For top managers, he recommends replacing conventional stock options with options that are tied to a market or peer index. Below-average performers would not be rewarded under such plans; superior performers could, depending on the way plans were structured, receive even more. He notes that managers at the business unit level should not be judged on the company's stock price--over which they have little control--and advocates an approach that accurately measures the value added by each unit. Finally, he suggests how certain indicators of value can be used to measure the contribution of frontline managers and employees. The concept of pay for performance has gained wide acceptance, but the link between incentive pay and superior performance is still too weak. Reforms must be adopted at all levels of the organization. Shareholders will applaud changes in pay schemes that motivate companies to deliver more value.

Willing to Wait: Elevated Reward-Processing EEG Activity Associated with a Greater Preference for Larger-But-Delayed Rewards

PubMed Central

Pornpattananangkul, Narun; Nusslock, Robin

2016-01-01

While almost everyone discounts the value of future rewards over immediate rewards, people differ in their so-called delay-discounting. One of the several factors that may explain individual differences in delay-discounting is reward-processing. To study individual-differences in reward-processing, however, one needs to consider the heterogeneity of neural-activity at each reward-processing stage. Here using EEG, we separated reward-related neural activity into distinct reward-anticipation and reward-outcome stages using time-frequency characteristics. Thirty-seven individuals completed a behavioral delay-discounting task. Reward-processing EEG activity was assessed using a separate reward-learning task, called a reward time-estimation task. During this task, participants were instructed to estimate time duration and were provided performance feedback on a trial-by-trial basis. Participants received monetary-reward for accurate-performance on Reward trials, but not on No-Reward trials. Reward trials, relative to No-Reward trials, enhanced EEG activity during both reward-anticipation stage (including, cued-locked delta power during cue-evaluation and pre-feedback alpha suppression during feedback-anticipation) and at the reward-outcome stage (including, feedback-locked delta, theta and beta power). Moreover, all of these EEG indices correlated with behavioral performance in the time-estimation task, suggesting their essential roles in learning and adjusting performance to maximize winnings in a reward-learning situation. Importantly, enhanced EEG power during Reward trials for 1) pre-feedback alpha suppression, 2) feedback-locked theta and 3) feedback-locked beta was associated with a greater preference for larger-but-delayed rewards. Results highlight the association between a stronger preference toward larger-but-delayed rewards and enhanced reward-processing. Moreover, our reward-processing EEG indices detail the specific stages of reward-processing where these associations occur. PMID:27477630

Willing to wait: Elevated reward-processing EEG activity associated with a greater preference for larger-but-delayed rewards.

PubMed

Pornpattananangkul, Narun; Nusslock, Robin

2016-10-01

While almost everyone discounts the value of future rewards over immediate rewards, people differ in their so-called delay-discounting. One of the several factors that may explain individual differences in delay-discounting is reward-processing. To study individual-differences in reward-processing, however, one needs to consider the heterogeneity of neural-activity at each reward-processing stage. Here using EEG, we separated reward-related neural activity into distinct reward-anticipation and reward-outcome stages using time-frequency characteristics. Thirty-seven individuals first completed a behavioral delay-discounting task. Then reward-processing EEG activity was assessed using a separate reward-learning task, called a reward time-estimation task. During this EEG task, participants were instructed to estimate time duration and were provided performance feedback on a trial-by-trial basis. Participants received monetary-reward for accurate-performance on Reward trials, but not on No-Reward trials. Reward trials, relative to No-Reward trials, enhanced EEG activity during both reward-anticipation (including, cued-locked delta power during cue-evaluation and pre-feedback alpha suppression during feedback-anticipation) and reward-outcome (including, feedback-locked delta, theta and beta power) stages. Moreover, all of these EEG indices correlated with behavioral performance in the time-estimation task, suggesting their essential roles in learning and adjusting performance to maximize winnings in a reward-learning situation. Importantly, enhanced EEG power during Reward trials, as reflected by stronger 1) pre-feedback alpha suppression, 2) feedback-locked theta and 3) feedback-locked beta, was associated with a greater preference for larger-but-delayed rewards in a separate, behavioral delay-discounting task. Results highlight the association between a stronger preference toward larger-but-delayed rewards and enhanced reward-processing. Moreover, our reward-processing EEG indices detail the specific stages of reward-processing where these associations occur. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rewards and Performance Incentives.

ERIC Educational Resources Information Center

Zigon, Jack

1994-01-01

Discusses rewards and performance incentives for employees, including types of rewards; how rewards help in managing; dysfunctional awards; selecting the right reward; how to find rewards that fit; and delivering rewards effectively. Examples are included. (three references) (LRW)

Neurotoxicants: emerging issues and policy options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulebak, K.L.

1987-03-01

Neurotoxicants are increasingly seen as significant public health hazards, the resolution of which is influenced by science as well as economics, politics, and emotions. Three topical issues are presented to illustrate the application or abuse of scientific data in the political arena and to suggest appropriate responsibilities of scientists beyond the generation of data. The examples include regulation of occupation-related neurotoxic exposure, transfer of neurotoxic pollutants among environmental media, and export of neurotoxic hazards to Third World countries. These examples illustrate the variety of ways in which neurotoxicants impinge on policy questions--from international trade, through ecosystem effects, to personal occupationalmore » health and safety.« less

Cognitive dissonance experienced by nurse practitioner faculty.

PubMed

Fontenot, Holly B; Hawkins, Joellen W; Weiss, Josie A

2012-08-01

The purpose of this study was to explicate the concept of cognitive dissonance as experienced and reported by nurse practitioner (NP) faculty members. Responses from NP faculty members to an online survey about their experiences with cognitive dissonance. The respondents detailed their experiences with cognitive dissonance, citing differences between expectations for which they are rewarded and those for which they are paid. Expecting all faculty members to excel in practice, research, teaching, and service may create unrealistic workloads for NP faculty members. Examining expectations and considering creation of a clinical track for faculty who practice may be options administrators of NP programs might explore. ©2012 The Author(s) Journal compilation ©2012 American Academy of Nurse Practitioners.

Comforts of Home: Home Care of the Terminally Ill

PubMed Central

Fraser, Jacqueline

1990-01-01

When a terminal illness is diagnosed, it is appropriate for the family physician to take a primary role in future management. Care goals change from being disease-focused and cure-directed to being person-focused and comfort-targeted. The patient and family comprise the unit of care. Care of the terminally ill in the home requires good planning, teamwork, excellent symptom management, and a commitment by the family physician to be available or provide alternate coverage. Death in the home should be an option for the patient and family whenever feasible. Caring for patients until death and supporting their families and friends are rewarding and positive parts of family practice. PMID:21233972

The Function of Verbal Rewards in the Science Classroom.

ERIC Educational Resources Information Center

Lawlor, Francis Xavier

Contained is a review of the research done on the use of verbal rewards in the classroom. Some verbal rewards are tasks rewards, other rewards are more personal; and still other verbal rewards are impersonal. Verbal rewards, therefore, have both intellectual and emotional implications. Research literature indicates that "verbal reward"…

Systemic administration of 8-OH-DPAT and eticlopride, but not SCH23390, alters loss-chasing behavior in the rat.

PubMed

Rogers, Robert D; Wong, Adeline; McKinnon, Chris; Winstanley, Catharine A

2013-05-01

Gambling to recover losses is a common gaming behavior. In a clinical context, however, this phenomenon mediates the relationship between diminished control over gambling and the adverse socioeconomic consequences of gambling problems. Modeling loss-chasing through analogous behaviors in rats could facilitate its pharmacological investigation as a potential therapeutic target. Here, rats were trained to make operant responses that produced both food rewards, and unpredictably, imminent time-out periods in which rewards would be unavailable. At these decision points, rats were offered choices between waiting for these time-out periods to elapse before resuming responding for rewards ('quit' responses), or selecting risky options with a 0.5 probability of avoiding the time-outs altogether and a 0.5 probability of time-out periods twice as long as signaled originally ('chase' responses). Chasing behavior, and the latencies to chase or quit, during sequences of unfavorable outcomes were tested following systemic administration of the 5-HT1A receptor agonist, 8-OH-DPAT, the D2 receptor antagonist, eticlopride, and the D1 receptor antagonist, SCH23390. 8-OH-DPAT and eticlopride significantly reduced the proportion of chase responses, and the mean number of consecutive chase responses, in a dose-dependent manner. 8-OH-DPAT also increased latencies to chase. Increasing doses of eticlopride first speeded, then slowed, latencies to quit while SCH23390 had no significant effects on any measure. Research is needed to identify the precise cognitive mechanisms mediating these kinds of risky choices in rats. However, our data provide the first experimental demonstration that 5-HT1A and D2, but not D1, receptor activity influence a behavioral analog of loss-chasing in rats.

Systemic Administration of 8-OH-DPAT and Eticlopride, but not SCH23390, Alters Loss-Chasing Behavior in the Rat

PubMed Central

Rogers, Robert D; Wong, Adeline; McKinnon, Chris; Winstanley, Catharine A

2013-01-01

Gambling to recover losses is a common gaming behavior. In a clinical context, however, this phenomenon mediates the relationship between diminished control over gambling and the adverse socioeconomic consequences of gambling problems. Modeling loss-chasing through analogous behaviors in rats could facilitate its pharmacological investigation as a potential therapeutic target. Here, rats were trained to make operant responses that produced both food rewards, and unpredictably, imminent time-out periods in which rewards would be unavailable. At these decision points, rats were offered choices between waiting for these time-out periods to elapse before resuming responding for rewards (‘quit' responses), or selecting risky options with a 0.5 probability of avoiding the time-outs altogether and a 0.5 probability of time-out periods twice as long as signaled originally (‘chase' responses). Chasing behavior, and the latencies to chase or quit, during sequences of unfavorable outcomes were tested following systemic administration of the 5-HT1A receptor agonist, 8-OH-DPAT, the D2 receptor antagonist, eticlopride, and the D1 receptor antagonist, SCH23390. 8-OH-DPAT and eticlopride significantly reduced the proportion of chase responses, and the mean number of consecutive chase responses, in a dose-dependent manner. 8-OH-DPAT also increased latencies to chase. Increasing doses of eticlopride first speeded, then slowed, latencies to quit while SCH23390 had no significant effects on any measure. Research is needed to identify the precise cognitive mechanisms mediating these kinds of risky choices in rats. However, our data provide the first experimental demonstration that 5-HT1A and D2, but not D1, receptor activity influence a behavioral analog of loss-chasing in rats. PMID:23303072

An Assessment of Incentive Versus Survey Length Trade-offs in a Web Survey of Radiologists

PubMed Central

Niederhauser, Blake D; Kallmes, David; Beebe, Timothy J

2013-01-01

Background It is generally understood that shorter Web surveys and use of incentives result in higher response rates in Web surveys directed to health care providers. Less is known about potential respondent preference for reduced burden as compared to increased reward. Objective To help elicit preference for minimized burden compared to reward for completion of a survey, we observed physician preferences for shorter Web surveys compared to incentives as well as incentive preference (small guaranteed incentive compared to larger lottery incentive) accompanying an electronic request to complete a survey. Methods This was an observational study that accompanied a large Web survey study of radiology staff, fellows, and residents at select academic medical centers in the United States. With the request to complete the survey, potential respondents were offered three options: (1) a 10-minute Web survey with the chance to win an iPad, (2) a 10-minute Web survey with a guaranteed nominal incentive ($5 amazon.com gift card), or (3) a shorter (5-7 minute) Web survey with no incentive. A total of 254 individuals responded to the Web survey request. Results Overwhelmingly, individuals chose a longer survey accompanied by an incentive compared to a shorter survey with no incentive (85% compared to 15%, P<.001). Of those opting for an incentive, a small, but not significant majority chose the chance to win an iPad over a guaranteed $5 gift card (56% compared to 44%). Conclusions When given the choice, radiologists preferred a reward (either guaranteed or based on a lottery) to a less burdensome survey, indicating that researchers should focus more attention at increasing perceived benefits of completing a Web survey compared to decreasing perceived burden. PMID:23514869

An assessment of incentive versus survey length trade-offs in a Web survey of radiologists.

PubMed

Ziegenfuss, Jeanette Y; Niederhauser, Blake D; Kallmes, David; Beebe, Timothy J

2013-03-20

It is generally understood that shorter Web surveys and use of incentives result in higher response rates in Web surveys directed to health care providers. Less is known about potential respondent preference for reduced burden as compared to increased reward. To help elicit preference for minimized burden compared to reward for completion of a survey, we observed physician preferences for shorter Web surveys compared to incentives as well as incentive preference (small guaranteed incentive compared to larger lottery incentive) accompanying an electronic request to complete a survey. This was an observational study that accompanied a large Web survey study of radiology staff, fellows, and residents at select academic medical centers in the United States. With the request to complete the survey, potential respondents were offered three options: (1) a 10-minute Web survey with the chance to win an iPad, (2) a 10-minute Web survey with a guaranteed nominal incentive ($5 amazon.com gift card), or (3) a shorter (5-7 minute) Web survey with no incentive. A total of 254 individuals responded to the Web survey request. Overwhelmingly, individuals chose a longer survey accompanied by an incentive compared to a shorter survey with no incentive (85% compared to 15%, P<.001). Of those opting for an incentive, a small, but not significant majority chose the chance to win an iPad over a guaranteed $5 gift card (56% compared to 44%). When given the choice, radiologists preferred a reward (either guaranteed or based on a lottery) to a less burdensome survey, indicating that researchers should focus more attention at increasing perceived benefits of completing a Web survey compared to decreasing perceived burden.

Working Memory Load Strengthens Reward Prediction Errors.

PubMed

Collins, Anne G E; Ciullo, Brittany; Frank, Michael J; Badre, David

2017-04-19

Reinforcement learning (RL) in simple instrumental tasks is usually modeled as a monolithic process in which reward prediction errors (RPEs) are used to update expected values of choice options. This modeling ignores the different contributions of different memory and decision-making systems thought to contribute even to simple learning. In an fMRI experiment, we investigated how working memory (WM) and incremental RL processes interact to guide human learning. WM load was manipulated by varying the number of stimuli to be learned across blocks. Behavioral results and computational modeling confirmed that learning was best explained as a mixture of two mechanisms: a fast, capacity-limited, and delay-sensitive WM process together with slower RL. Model-based analysis of fMRI data showed that striatum and lateral prefrontal cortex were sensitive to RPE, as shown previously, but, critically, these signals were reduced when the learning problem was within capacity of WM. The degree of this neural interaction related to individual differences in the use of WM to guide behavioral learning. These results indicate that the two systems do not process information independently, but rather interact during learning. SIGNIFICANCE STATEMENT Reinforcement learning (RL) theory has been remarkably productive at improving our understanding of instrumental learning as well as dopaminergic and striatal network function across many mammalian species. However, this neural network is only one contributor to human learning and other mechanisms such as prefrontal cortex working memory also play a key role. Our results also show that these other players interact with the dopaminergic RL system, interfering with its key computation of reward prediction errors. Copyright © 2017 the authors 0270-6474/17/374332-11$15.00/0.

Importance of punishment frequency in the Iowa gambling task: an fMRI study.

PubMed

Ma, Shuangye; Zang, Yufeng; Cheung, Vinci; Chan, Chetwyn C H

2015-12-01

It has been widely found that in the Iowa Gambling Task (IGT; Bechara et al. Cognition, 50(1), 7-15 1994) normal subjects would gradually learn to prefer obtaining rewards for long-term benefits than seeking immediate rewards to maximize the overall profit. The current study aimed to gain an understanding of how punishment frequency in the IGT would be processed and its association with subjects' reward preferences. In this study, we employed the clinical version of the IGT, in which response options are not only different in the long-term outcome, but also associated with different punishment frequencies. Event-related functional Magnetic Resonance Imaging (fMRI) was used to capture the subjects' brain activity when performing the IGT. A total of 24 male subjects (mean age = 21.7 years, SD = 1.8 years), who were university students, participated in the experiment. It is found that subjects learned to select more from the decks that were advantageous in the long-term, but they were more sensitive to the effect of long-term outcome under the condition of high punishment frequency. The corresponding brain activation showed that the Anterior Cingulate Cortex (ACC) had significantly higher activation during the disadvantageous choices than the advantageous choices. Such activity difference between the two conditions of long-term outcome was more prominent with high punishment frequency than low punishment frequency; and this brain activity difference was significantly correlated with the behavioral performance under the condition of high punishment frequency. The results suggested that only in the context with high punishment frequency, there would be increased neural activity in ACC when subjects intended to select from the disadvantageous choices so that these choices would be inhibited and advantageous choices would be selected.

fMRI of alterations in reward selection, anticipation, and feedback in major depressive disorder.

PubMed

Smoski, Moria J; Felder, Jennifer; Bizzell, Joshua; Green, Steven R; Ernst, Monique; Lynch, Thomas R; Dichter, Gabriel S

2009-11-01

The purpose of the present investigation was to evaluate reward processing in unipolar major depressive disorder (MDD). Specifically, we investigated whether adults with MDD demonstrated hyporesponsivity in striatal brain regions and/or hyperresponsivity in cortical brain regions involved in conflict monitoring using a Wheel of Fortune task designed to probe responses during reward selection, reward anticipation, and reward feedback. Functional magnetic resonance imaging (fMRI) data indicated that the MDD group was characterized by reduced activation of striatal reward regions during reward selection, reward anticipation, and reward feedback, supporting previous data indicating hyporesponsivity of reward systems in MDD. Support was not found for hyperresponsivity of cognitive control regions during reward selection or reward anticipation. Instead, MDD participants showed hyperresponsivity in orbitofrontal cortex, a region associated with assessment of risk and reward, during reward selection, as well as decreased activation of the middle frontal gyrus and the rostral cingulate gyrus during reward selection and anticipation. Finally, depression severity was predicted by activation in bilateral midfrontal gyrus during reward selection. Results indicate that MDD is characterized by striatal hyporesponsivity, and that future studies of MDD treatments that seek to improve responses to rewarding stimuli should assess striatal functioning.

BOLD responses in reward regions to hypothetical and imaginary monetary rewards

PubMed Central

Miyapuram, Krishna P.; Tobler, Philippe N.; Gregorios-Pippas, Lucy; Schultz, Wolfram

2015-01-01

Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary rewards per trial (e.g. 5p) if all trials are to be treated equally. However, small payoffs can have detrimental effects on performance due to their limited buying power. Hypothetical monetary rewards can overcome the limitations of smaller monetary rewards but it is less well known whether predictors of hypothetical rewards activate reward regions. In two experiments, visual stimuli were associated with hypothetical monetary rewards. In Experiment 1, we used stimuli predicting either visually presented or imagined hypothetical monetary rewards, together with non-rewarding control pictures. Activations to reward predictive stimuli occurred in reward regions, namely the medial orbitofrontal cortex and midbrain. In Experiment 2, we parametrically varied the amount of visually presented hypothetical monetary reward keeping constant the amount of actually received reward. Graded activation in midbrain was observed to stimuli predicting increasing hypothetical rewards. The results demonstrate the efficacy of using hypothetical monetary rewards in fMRI studies. PMID:21985912

BOLD responses in reward regions to hypothetical and imaginary monetary rewards.

PubMed

Miyapuram, Krishna P; Tobler, Philippe N; Gregorios-Pippas, Lucy; Schultz, Wolfram

2012-01-16

Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary rewards per trial (e.g. 5p) if all trials are to be treated equally. However, small payoffs can have detrimental effects on performance due to their limited buying power. Hypothetical monetary rewards can overcome the limitations of smaller monetary rewards but it is less well known whether predictors of hypothetical rewards activate reward regions. In two experiments, visual stimuli were associated with hypothetical monetary rewards. In Experiment 1, we used stimuli predicting either visually presented or imagined hypothetical monetary rewards, together with non-rewarding control pictures. Activations to reward predictive stimuli occurred in reward regions, namely the medial orbitofrontal cortex and midbrain. In Experiment 2, we parametrically varied the amount of visually presented hypothetical monetary reward keeping constant the amount of actually received reward. Graded activation in midbrain was observed to stimuli predicting increasing hypothetical rewards. The results demonstrate the efficacy of using hypothetical monetary rewards in fMRI studies. Copyright © 2011 Elsevier Inc. All rights reserved.

Motor Cortex-Evoked Activity in Reciprocal Muscles Is Modulated by Reward Probability

PubMed Central

Suzuki, Makoto; Kirimoto, Hikari; Sugawara, Kazuhiro; Oyama, Mineo; Yamada, Sumio; Yamamoto, Jun-ichi; Matsunaga, Atsuhiko; Fukuda, Michinari; Onishi, Hideaki

2014-01-01

Horizontal intracortical projections for agonist and antagonist muscles exist in the primary motor cortex (M1), and reward may induce a reinforcement of transmission efficiency of intracortical circuits. We investigated reward-induced change in M1 excitability for agonist and antagonist muscles. Participants were 8 healthy volunteers. Probabilistic reward tasks comprised 3 conditions of 30 trials each: 30 trials contained 10% reward, 30 trials contained 50% reward, and 30 trials contained 90% reward. Each trial began with a cue (red fixation cross), followed by blue circle for 1 s. The subjects were instructed to perform wrist flexion and press a button with the dorsal aspect of middle finger phalanx as quickly as possible in response to disappearance of the blue circle without looking at their hand or the button. Two seconds after the button press, reward/non-reward stimulus was randomly presented for 2-s duration. The reward stimulus was a picture of Japanese 10-yen coin, and each subject received monetary reward at the end of experiment. Subjects were not informed of the reward probabilities. We delivered transcranial magnetic stimulation of the left M1 at the midpoint between center of gravities of agonist flexor carpi radialis (FCR) and antagonist extensor carpi radialis (ECR) muscles at 2 s after the red fixation cross and 1 s after the reward/non-reward stimuli. Relative motor evoked potential (MEP) amplitudes at 2 s after the red fixation cross were significantly higher for 10% reward probability than for 90% reward probability, whereas relative MEP amplitudes at 1 s after reward/non-reward stimuli were significantly higher for 90% reward probability than for 10% and 50% reward probabilities. These results implied that reward could affect the horizontal intracortical projections in M1 for agonist and antagonist muscles, and M1 excitability including the reward-related circuit before and after reward stimulus could be differently altered by reward probability. PMID:24603644

Dopamine reward prediction error coding.

PubMed

Schultz, Wolfram

2016-03-01

Reward prediction errors consist of the differences between received and predicted rewards. They are crucial for basic forms of learning about rewards and make us strive for more rewards-an evolutionary beneficial trait. Most dopamine neurons in the midbrain of humans, monkeys, and rodents signal a reward prediction error; they are activated by more reward than predicted (positive prediction error), remain at baseline activity for fully predicted rewards, and show depressed activity with less reward than predicted (negative prediction error). The dopamine signal increases nonlinearly with reward value and codes formal economic utility. Drugs of addiction generate, hijack, and amplify the dopamine reward signal and induce exaggerated, uncontrolled dopamine effects on neuronal plasticity. The striatum, amygdala, and frontal cortex also show reward prediction error coding, but only in subpopulations of neurons. Thus, the important concept of reward prediction errors is implemented in neuronal hardware.

An Exploration of Dual Systems via Time Pressure Manipulation in Decision-making Problems

NASA Astrophysics Data System (ADS)

Guo, Lisa

Every day, decisions need to be made where time is a limiting factor. Regardless of situation, time constraints often place a premium on rapid decision-making. Researchers have been interested in studying this human behavior and understanding its underlying cognitive processes. In previous studies, scientists have believed that the cognitive processes underlying decision-making behavior were consistent with dual-process modes of thinking. Critics of dual-process theory question the vagueness of its definition, and claim that single-process accounts can explain the data just as well. My aim is to elucidate the cognitive processes that underlie decisions which involve some level of risk through the experimental manipulation of time pressure. Using this method, I hope to distinguish between competing hypotheses related to the origin of the effect. I will explore three types of decisions that illustrate these concepts: risky decision-making involving gambles, intertemporal choice, and one-shot public goods games involving social cooperation. In our experiments, participants made decisions about gambles framed as either gains or losses; decided upon intertemporal choices for smaller but sooner rewards or larger but later rewards; and played a one-shot public goods game involving social cooperation and contributing an amount of money to a group. In each case, we experimentally manipulated time pressure, either within subjects or among individuals. Results showed under time pressure, increased framing effects under in both hypothetical and incentivized choices; and greater contributions and cooperation among individuals, lending support to the dual process hypothesis that these effects arise from a fast, intuitive system. However, our intertemporal choice experiment showed that time constraints led to increased selection of the larger but later options, which suggests that the magnitude of the reward may play larger role in choice selection under cognitive load than previously studied. This diverges from the current dual-process interpretation that myopic choices under time pressure favor smaller but sooner rewards, and suggests that more studies are needed in this realm to disentangle the intuitive from the deliberative system through the manipulation of cognitive load.

China's water shortage could shake world food security.

PubMed

Brown, L R; Halweil, B

1998-01-01

This report indicates the global concern about China's water shortages and describes basin supplies, global availability of grain, and reasons for water losses. There is little precise data on how land productivity will be affected by declines in irrigation. Reports from the "China Daily" indicate that the 1995 grain harvest in Shandong province declined by 2.7 million tons (food for 9 million people) due to water failures of the Yellow River. A delegate at the 1998 National People's Congress pointed out that rural villages nationwide had shortages of 30 billion cu. m and losses of 20 million tons of grain production. About 70% of grain harvests rely on irrigation. Water demand for residential use and industrial use is likely to increase and compete with farm use. One unlikely option is to divert irrigation water to cities as needed and import grain. The entire agricultural, energy, and industrial economies need to be made more water efficient. Agriculture will need to produce more water efficient crops and livestock products and less water intensive energy supplies. Another alternative is to divert water from one location to another. Water pricing could reinforce efficiency of use. Use of composting toilets could reduce human residential water demand. Urban capacity building should rely on separate industrial and residential wastewater systems. Investing in technologies for industry can reduce water demand among paper and steel producers. The fastest growing grain market is in North Africa and the Middle East. Trends in principal grain exporting countries with 85% of global exports indicate no growth in grain production for export since 1980.

Egalitarian reward contingency in competitive games and primate prefrontal neuronal activity.

PubMed

Hosokawa, Takayuki; Watanabe, Masataka

2015-01-01

How people work to obtain a reward depends on the context of the reward delivery, such as the presence/absence of competition and the contingency of reward delivery. Since resources are limited, winning a competition is critically important for organisms' obtaining a reward. People usually expect ordinary performance-reward contingency, with better performers obtaining better rewards. Unordinary reward contingency, such as egalitarianism (equal rewards/no-rewards to both good and poor performers), dampens people's motivation. We previously reported that monkeys were more motivated, and neurons in the lateral prefrontal cortex (LPFC) showed higher outcome-related activity in a competitive than in a noncompetitive game (Hosokawa and Watanabe, 2012). However, monkey's behavior and LPFC neuronal activity have not been examined in a competitive situation with an unordinary performance-reward contingency. Also, the fixed performance-reward contingency in the previous study did not allow us to examine effects of win/loss separately from those of reward/no-reward on prefrontal neuronal activity. Here, we employed the egalitarian competitive situation in which both the winner and loser, or neither of them, got a reward as well as the normal competitive situation in which only the winner got a reward. Monkey's behavioral performance greatly deteriorated in trials with the egalitarian outcome conditions. LPFC neurons showed activities that reflected the normal or egalitarian outcome condition while very few neurons coded win/loss independent of reward/no-reward. Importantly, we found neurons that showed reward-related activity in the normal, but not in the egalitarian outcome conditions, even though the same reward was given to the animal. These results indicate that LPFC may play an important role in monitoring the current reward contingency and integrating it with the performance outcome (win-loss) for better performing the competitive game, and thus for better survival.

Listening to music in a risk-reward context: The roles of the temporoparietal junction and the orbitofrontal/insular cortices in reward-anticipation, reward-gain, and reward-loss.

PubMed

Li, Chia-Wei; Chen, Jyh-Horng; Tsai, Chen-Gia

2015-12-10

Artificial rewards, such as visual arts and music, produce pleasurable feelings. Popular songs in the verse-chorus form provide a useful model for understanding the neural mechanisms underlying the processing of artificial rewards, because the chorus is usually the most rewarding element of a song. In this functional magnetic resonance imaging (fMRI) study, the stimuli were excerpts of 10 popular songs with a tensioned verse-to-chorus transition. We examined the neural correlates of three phases of reward processing: (1) reward-anticipation during the verse-to-chorus transition, (2) reward-gain during the first phrase of the chorus, and (3) reward-loss during the unexpected noise followed by the verse-to-chorus transition. Participants listened to these excerpts in a risk-reward context because the verse was followed by either the chorus or noise with equal probability. The results showed that reward-gain and reward-loss were associated with left- and right-biased temporoparietal junction activation, respectively. The bilateral temporoparietal junctions were active during reward-anticipation. Moreover, we observed left-biased lateral orbitofrontal activation during reward-anticipation, whereas the medial orbitofrontal cortex was activated during reward-gain. The findings are discussed in relation to the cognitive and emotional aspects of reward processing. Copyright © 2015 Elsevier B.V. All rights reserved.

Dopamine Receptor-Specific Contributions to the Computation of Value.

PubMed

Burke, Christopher J; Soutschek, Alexander; Weber, Susanna; Raja Beharelle, Anjali; Fehr, Ernst; Haker, Helene; Tobler, Philippe N

2018-05-01

Dopamine is thought to play a crucial role in value-based decision making. However, the specific contributions of different dopamine receptor subtypes to the computation of subjective value remain unknown. Here we demonstrate how the balance between D1 and D2 dopamine receptor subtypes shapes subjective value computation during risky decision making. We administered the D2 receptor antagonist amisulpride or placebo before participants made choices between risky options. Compared with placebo, D2 receptor blockade resulted in more frequent choice of higher risk and higher expected value options. Using a novel model fitting procedure, we concurrently estimated the three parameters that define individual risk attitude according to an influential theoretical account of risky decision making (prospect theory). This analysis revealed that the observed reduction in risk aversion under amisulpride was driven by increased sensitivity to reward magnitude and decreased distortion of outcome probability, resulting in more linear value coding. Our data suggest that different components that govern individual risk attitude are under dopaminergic control, such that D2 receptor blockade facilitates risk taking and expected value processing.

Managing health care costs: strategies available to small businesses.

PubMed

Higgins, C W; Finley, L; Kinard, J

1990-07-01

Although health care costs continue to rise at an alarming rate, small businesses can take steps to help moderate these costs. First, business firms must restructure benefits so that needless surgery is eliminated and inpatient hospital care is minimized. Next, small firms should investigate the feasibility of partial self-insurance options such as risk pooling and purchasing preferred premium plans. Finally, small firms should investigate the cost savings that can be realized through the use of alternative health care delivery systems such as HMOs and PPOs. Today, competition is reshaping the health care industry by creating more options and rewarding efficiency. The prospect of steadily rising prices and more choices makes it essential that small employers become prudent purchasers of employee health benefits. For American businesses, the issue is crucial. Unless firms can control health care costs, they will have to keep boosting the prices of their goods and services and thus become less competitive in the global marketplace. In that event, many workers will face a prospect even more grim than rising medical premiums: losing their jobs.

Strategic interactions, affective reactions, and fast adaptations.

PubMed

Kareev, Yaakov; Avrahami, Judith; Fiedler, Klaus

2014-06-01

We studied repeated choices under uncertainty in situations in which the source of uncertainty is the choice of an interaction partner. In 1 experiment the participants engaged in repeated decisions in a mixed motive game; in another experiment the options and outcomes were identical to those in the 1st, but periods of the mixed-motive game alternated with periods of a coordination game, with the change in period not announced. We analyzed choice dynamics-the relationship between an outcome and the choice that followed-and aggregate choice probabilities to gauge the relative merit of reward-based or affect-based accounts (the affects considered being disappointment and regret). In both experiments choice dynamics were essentially identical and were compatible with only the regret-based account. This was true irrespective of the game played or the stage (early or late) of the game. Moreover, the same dynamics explained the very different aggregate probabilities with which the 2 options were chosen in the 2 games and the remarkably fast adaptations to unannounced changes in the game played. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Two systems drive attention to rewards.

PubMed

Kovach, Christopher K; Sutterer, Matthew J; Rushia, Sara N; Teriakidis, Adrianna; Jenison, Rick L

2014-01-01

How options are framed can dramatically influence choice preference. While salience of information plays a central role in this effect, precisely how it is mediated by attentional processes remains unknown. Current models assume a simple relationship between attention and choice, according to which preference should be uniformly biased towards the attended item over the whole time-course of a decision between similarly valued items. To test this prediction we considered how framing alters the orienting of gaze during a simple choice between two options, using eye movements as a sensitive online measure of attention. In one condition participants selected the less preferred item to discard and in the other, the more preferred item to keep. We found that gaze gravitates towards the item ultimately selected, but did not observe the effect to be uniform over time. Instead, we found evidence for distinct early and late processes that guide attention according to preference in the first case and task demands in the second. We conclude that multiple time-dependent processes govern attention during choice, and that these may contribute to framing effects in different ways.

Normalized value coding explains dynamic adaptation in the human valuation process.

PubMed

Khaw, Mel W; Glimcher, Paul W; Louie, Kenway

2017-11-28

The notion of subjective value is central to choice theories in ecology, economics, and psychology, serving as an integrated decision variable by which options are compared. Subjective value is often assumed to be an absolute quantity, determined in a static manner by the properties of an individual option. Recent neurobiological studies, however, have shown that neural value coding dynamically adapts to the statistics of the recent reward environment, introducing an intrinsic temporal context dependence into the neural representation of value. Whether valuation exhibits this kind of dynamic adaptation at the behavioral level is unknown. Here, we show that the valuation process in human subjects adapts to the history of previous values, with current valuations varying inversely with the average value of recently observed items. The dynamics of this adaptive valuation are captured by divisive normalization, linking these temporal context effects to spatial context effects in decision making as well as spatial and temporal context effects in perception. These findings suggest that adaptation is a universal feature of neural information processing and offer a unifying explanation for contextual phenomena in fields ranging from visual psychophysics to economic choice.

Impaired risk evaluation in people with Internet gaming disorder: fMRI evidence from a probability discounting task.

PubMed

Lin, Xiao; Zhou, Hongli; Dong, Guangheng; Du, Xiaoxia

2015-01-02

This study examined how Internet gaming disorder (IGD) subjects modulating reward and risk at a neural level under a probability-discounting task with functional magnetic resonance imaging (fMRI). Behavioral and imaging data were collected from 19 IGD subjects (22.2 ± 3.08 years) and 21 healthy controls (HC, 22.8 ± 3.5 years). Behavior results showed that IGD subjects prefer the probabilistic options to fixed ones and were associated with shorter reaction time, when comparing to HC. The fMRI results revealed that IGD subjects show decreased activation in the inferior frontal gyrus and the precentral gyrus when choosing the probabilistic options than HC. Correlations were also calculated between behavioral performances and brain activities in relevant brain regions. Both of the behavioral performance and fMRI results indicate that people with IGD show impaired risk evaluation, which might be the reason why IGD subjects continue playing online games despite the risks of widely known negative consequence. Copyright © 2014 Elsevier Inc. All rights reserved.

Two systems drive attention to rewards

PubMed Central

Kovach, Christopher K.; Sutterer, Matthew J.; Rushia, Sara N.; Teriakidis, Adrianna; Jenison, Rick L.

2014-01-01

How options are framed can dramatically influence choice preference. While salience of information plays a central role in this effect, precisely how it is mediated by attentional processes remains unknown. Current models assume a simple relationship between attention and choice, according to which preference should be uniformly biased towards the attended item over the whole time-course of a decision between similarly valued items. To test this prediction we considered how framing alters the orienting of gaze during a simple choice between two options, using eye movements as a sensitive online measure of attention. In one condition participants selected the less preferred item to discard and in the other, the more preferred item to keep. We found that gaze gravitates towards the item ultimately selected, but did not observe the effect to be uniform over time. Instead, we found evidence for distinct early and late processes that guide attention according to preference in the first case and task demands in the second. We conclude that multiple time-dependent processes govern attention during choice, and that these may contribute to framing effects in different ways. PMID:24550868

Choice from non-choice: predicting consumer preferences from blood oxygenation level-dependent signals obtained during passive viewing.

PubMed

Levy, Ifat; Lazzaro, Stephanie C; Rutledge, Robb B; Glimcher, Paul W

2011-01-05

Decision-making is often viewed as a two-stage process, where subjective values are first assigned to each option and then the option of the highest value is selected. Converging evidence suggests that these subjective values are represented in the striatum and medial prefrontal cortex (MPFC). A separate line of evidence suggests that activation in the same areas represents the values of rewards even when choice is not required, as in classical conditioning tasks. However, it is unclear whether the same neural mechanism is engaged in both cases. To address this question we measured brain activation with functional magnetic resonance imaging while human subjects passively viewed individual consumer goods. We then sampled activation from predefined regions of interest and used it to predict subsequent choices between the same items made outside of the scanner. Our results show that activation in the striatum and MPFC in the absence of choice predicts subsequent choices, suggesting that these brain areas represent value in a similar manner whether or not choice is required.

Distinct Reward Properties are Encoded via Corticostriatal Interactions

PubMed Central

Smith, David V.; Rigney, Anastasia E.; Delgado, Mauricio R.

2016-01-01

The striatum serves as a critical brain region for reward processing. Yet, understanding the link between striatum and reward presents a challenge because rewards are composed of multiple properties. Notably, affective properties modulate emotion while informative properties help obtain future rewards. We approached this problem by emphasizing affective and informative reward properties within two independent guessing games. We found that both reward properties evoked activation within the nucleus accumbens, a subregion of the striatum. Striatal responses to informative, but not affective, reward properties predicted subsequent utilization of information for obtaining monetary reward. We hypothesized that activation of the striatum may be necessary but not sufficient to encode distinct reward properties. To investigate this possibility, we examined whether affective and informative reward properties were differentially encoded in corticostriatal interactions. Strikingly, we found that the striatum exhibited dissociable connectivity patterns with the ventrolateral prefrontal cortex, with increasing connectivity for affective reward properties and decreasing connectivity for informative reward properties. Our results demonstrate that affective and informative reward properties are encoded via corticostriatal interactions. These findings highlight how corticostriatal systems contribute to reward processing, potentially advancing models linking striatal activation to behavior. PMID:26831208

Distinct Reward Properties are Encoded via Corticostriatal Interactions.

PubMed

Smith, David V; Rigney, Anastasia E; Delgado, Mauricio R

2016-02-02

The striatum serves as a critical brain region for reward processing. Yet, understanding the link between striatum and reward presents a challenge because rewards are composed of multiple properties. Notably, affective properties modulate emotion while informative properties help obtain future rewards. We approached this problem by emphasizing affective and informative reward properties within two independent guessing games. We found that both reward properties evoked activation within the nucleus accumbens, a subregion of the striatum. Striatal responses to informative, but not affective, reward properties predicted subsequent utilization of information for obtaining monetary reward. We hypothesized that activation of the striatum may be necessary but not sufficient to encode distinct reward properties. To investigate this possibility, we examined whether affective and informative reward properties were differentially encoded in corticostriatal interactions. Strikingly, we found that the striatum exhibited dissociable connectivity patterns with the ventrolateral prefrontal cortex, with increasing connectivity for affective reward properties and decreasing connectivity for informative reward properties. Our results demonstrate that affective and informative reward properties are encoded via corticostriatal interactions. These findings highlight how corticostriatal systems contribute to reward processing, potentially advancing models linking striatal activation to behavior.

High temporal discounters overvalue immediate rewards rather than undervalue future rewards: an event-related brain potential study.

PubMed

Cherniawsky, Avital S; Holroyd, Clay B

2013-03-01

Impulsivity is characterized in part by heightened sensitivity to immediate relative to future rewards. Although previous research has suggested that "high discounters" in intertemporal choice tasks tend to prefer immediate over future rewards because they devalue the latter, it remains possible that they instead overvalue immediate rewards. To investigate this question, we recorded the reward positivity, a component of the event-related brain potential (ERP) associated with reward processing, with participants engaged in a task in which they received both immediate and future rewards and nonrewards. The participants also completed a temporal discounting task without ERP recording. We found that immediate but not future rewards elicited the reward positivity. High discounters also produced larger reward positivities to immediate rewards than did low discounters, indicating that high discounters relatively overvalued immediate rewards. These findings suggest that high discounters may be more motivated than low discounters to work for monetary rewards, irrespective of the time of arrival of the incentives.

How to buy a medical home? Policy options and practical questions.

PubMed

Berenson, Robert A; Rich, Eugene C

2010-06-01

In this paper, we describe a range of payment options to support the PCMH, identifying their conceptual strengths and weaknesses. These include enhanced FFS payment for office visits to the PCMH; paying additional FFS for "new" PCMH services; variations of traditional FFS combined with new PCMH-oriented per patient per month capitation; and combined capitation payments for traditional primary care medical services as well as new medical home services. In discussing options for PCMH payment reform we consider issues in patient severity adjustment, performance payment, and the role of payments to community service organizations to collaborate with the PCMH. We also highlight some of the practical challenges that can complicate reimbursement reform for primary care and the PCMH. Through this discussion we identify key dimensions to provider payment reform relevant to promoting enhanced primary care through the patient centered medical home. These consist of paying for the basic medical home services, rewarding excellent performance of medical homes, incentivizing medical home connections to other community health care resources, and overcoming implementation challenges to medical home payments. Each of these overarching policy issues invokes a substantial subset of policy relevant research questions that collectively comprise a robust research agenda. We conclude that the conceptual strengths and weaknesses of available payment models for medical home functions invoke a complex array of options with varying levels of real-world feasibility. The different needs of patients and communities, and varying characteristics of practices must also be factors guiding PCMH payment reform. Indeed, it may be that different circumstances will require different payment approaches in various combinations.

Anterior cingulate cortex supports effort allocation towards a qualitatively preferred option.

PubMed

Hart, Evan E; Gerson, Julian O; Zoken, Yael; Garcia, Marisella; Izquierdo, Alicia

2017-07-01

The anterior cingulate cortex (ACC) is known to be involved in effortful choice, yet its role in cost-benefit evaluation of qualitatively different rewards (more/less preferred), beyond magnitude differences (larger/smaller), is poorly understood. Selecting between qualitatively different options is a decision type commonly faced by humans. Here, we assessed the role of ACC on a task that has primarily been used to probe striatal function in motivation. Rats were trained to stable performance on a progressive ratio schedule for sucrose pellets and were then given sham surgeries (control) or excitotoxic NMDA lesions of ACC. Subsequently, a choice was introduced: chow was concurrently available while animals could work for the preferred sucrose pellets. ACC lesions produced a significant decrease in lever presses for sucrose pellets compared to control, whereas chow consumption was unaffected. Lesions had no effect on sucrose pellet preference when both options were freely available. When laboratory chow was not concurrently available, ACC-lesioned rats exhibited similar lever pressing as controls. During a test under specific satiety for sucrose pellets, ACC-lesioned rats also showed intact devaluation effects. The effects of ACC lesions in our task are not mediated by decreased appetite, a change in food preference, a failure to update value or a learning deficit. Taken together, we found that ACC lesions decreased effort for a qualitatively preferred option. These results are discussed with reference to effects of striatal manipulations and our recent report of a role for basolateral amygdala in effortful choice. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

How to Buy a Medical Home? Policy Options and Practical Questions

PubMed Central

Berenson, Robert A.

2010-01-01

In this paper, we describe a range of payment options to support the PCMH, identifying their conceptual strengths and weaknesses. These include enhanced FFS payment for office visits to the PCMH; paying additional FFS for “new” PCMH services; variations of traditional FFS combined with new PCMH-oriented per patient per month capitation; and combined capitation payments for traditional primary care medical services as well as new medical home services. In discussing options for PCMH payment reform we consider issues in patient severity adjustment, performance payment, and the role of payments to community service organizations to collaborate with the PCMH. We also highlight some of the practical challenges that can complicate reimbursement reform for primary care and the PCMH. Through this discussion we identify key dimensions to provider payment reform relevant to promoting enhanced primary care through the patient centered medical home. These consist of paying for the basic medical home services, rewarding excellent performance of medical homes, incentivizing medical home connections to other community health care resources, and overcoming implementation challenges to medical home payments. Each of these overarching policy issues invokes a substantial subset of policy relevant research questions that collectively comprise a robust research agenda. We conclude that the conceptual strengths and weaknesses of available payment models for medical home functions invoke a complex array of options with varying levels of real-world feasibility. The different needs of patients and communities, and varying characteristics of practices must also be factors guiding PCMH payment reform. Indeed, it may be that different circumstances will require different payment approaches in various combinations. PMID:20467911

NLSdb-major update for database of nuclear localization signals and nuclear export signals.

PubMed

Bernhofer, Michael; Goldberg, Tatyana; Wolf, Silvana; Ahmed, Mohamed; Zaugg, Julian; Boden, Mikael; Rost, Burkhard

2018-01-04

NLSdb is a database collecting nuclear export signals (NES) and nuclear localization signals (NLS) along with experimentally annotated nuclear and non-nuclear proteins. NES and NLS are short sequence motifs related to protein transport out of and into the nucleus. The updated NLSdb now contains 2253 NLS and introduces 398 NES. The potential sets of novel NES and NLS have been generated by a simple 'in silico mutagenesis' protocol. We started with motifs annotated by experiments. In step 1, we increased specificity such that no known non-nuclear protein matched the refined motif. In step 2, we increased the sensitivity trying to match several different families with a motif. We then iterated over steps 1 and 2. The final set of 2253 NLS motifs matched 35% of 8421 experimentally verified nuclear proteins (up from 21% for the previous version) and none of 18 278 non-nuclear proteins. We updated the web interface providing multiple options to search protein sequences for NES and NLS motifs, and to evaluate your own signal sequences. NLSdb can be accessed via Rostlab services at: https://rostlab.org/services/nlsdb/. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Neural Sensitivity to Absolute and Relative Anticipated Reward in Adolescents

PubMed Central

Vaidya, Jatin G.; Knutson, Brian; O'Leary, Daniel S.; Block, Robert I.; Magnotta, Vincent

2013-01-01

Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

Real and hypothetical rewards

PubMed Central

Locey, Matthew L.; Jones, Bryan A.; Rachlin, Howard

2012-01-01

Laboratory studies of choice and decision making among real monetary rewards typically use smaller real rewards than those common in real life. When laboratory rewards are large, they are almost always hypothetical. In applying laboratory results meaningfully to real-life situations, it is important to know the extent to which choices among hypothetical rewards correspond to choices among real rewards and whether variation of the magnitude of hypothetical rewards affects behavior in meaningful ways. The present study compared real and hypothetical monetary rewards in two experiments. In Experiment 1, participants played a temporal discounting game that incorporates the logic of a repeated prisoner’s-dilemma (PD) type game versus tit-for-tat; choice of one alternative (“defection” in PD terminology) resulted in a small-immediate reward; choice of the other alternative (“cooperation” in PD terminology) resulted in a larger reward delayed until the following trial. The larger-delayed reward was greater for half of the groups than for the other half. Rewards also differed in type across groups: multiples of real nickels, hypothetical nickels or hypothetical hundred-dollar bills. All groups significantly increased choice of the larger delayed reward over the 40 trials of the experiment. Over the last 10 trials, cooperation was significantly higher when the difference between larger and smaller hypothetical rewards was greater. Reward type (real or hypothetical) made no significant difference in cooperation. In Experiment 2, real and hypothetical rewards were compared in social discounting – the decrease in value to the giver of a reward as social distance increases to the receiver of the reward. Social discount rates were well described by a hyperbolic function. Discounting rates for real and hypothetical rewards did not significantly differ. These results add to the evidence that results of experiments with hypothetical rewards validly apply in everyday life. PMID:22582110

Dopamine reward prediction error coding

PubMed Central

Schultz, Wolfram

2016-01-01

Reward prediction errors consist of the differences between received and predicted rewards. They are crucial for basic forms of learning about rewards and make us strive for more rewards—an evolutionary beneficial trait. Most dopamine neurons in the midbrain of humans, monkeys, and rodents signal a reward prediction error; they are activated by more reward than predicted (positive prediction error), remain at baseline activity for fully predicted rewards, and show depressed activity with less reward than predicted (negative prediction error). The dopamine signal increases nonlinearly with reward value and codes formal economic utility. Drugs of addiction generate, hijack, and amplify the dopamine reward signal and induce exaggerated, uncontrolled dopamine effects on neuronal plasticity. The striatum, amygdala, and frontal cortex also show reward prediction error coding, but only in subpopulations of neurons. Thus, the important concept of reward prediction errors is implemented in neuronal hardware. PMID:27069377

Reward processing in neurodegenerative disease

PubMed Central

Perry, David C.; Kramer, Joel H.

2015-01-01

Representation of reward value involves a distributed network including cortical and subcortical structures. Because neurodegenerative illnesses target specific anatomic networks that partially overlap with the reward circuit they would be predicted to have distinct impairments in reward processing. This review presents the existing evidence of reward processing changes in neurodegenerative diseases including mild cognitive impairment, Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease, as well as in healthy aging. Carefully distinguishing the different aspects of reward processing (primary rewards, secondary rewards, reward-based learning, and reward-based decision-making) and using tasks that differentiate the stages of processing reward will lead to improved understanding of this fundamental process and clarify a contributing cause of behavioral change in these illnesses. PMID:24417286

Mechanisms of impulsive choice: III. The role of reward processes

PubMed Central

Marshall, Andrew T.

2015-01-01

Two experiments examined the relationship between reward processing and impulsive choice. In Experiment 1, rats chose between a smaller-sooner (SS) reward (1 pellet, 10 s) and a larger-later (LL) reward (1, 2, and 4 pellets, 30 s). The rats then experienced concurrent variable-interval 30-s schedules with variations in reward magnitude to evaluate reward magnitude discrimination. LL choice behavior positively correlated with reward magnitude discrimination. In Experiment 2, rats chose between an SS reward (1 pellet, 10 s) and an LL reward (2 and 4 pellets, 30 s). The rats then received either a reward intervention which consisted of concurrent fixed-ratio schedules associated with different magnitudes to improve their reward magnitude discrimination, or a control task. All rats then experienced a post-intervention impulsive choice task followed by a reward magnitude discrimination task to assess intervention efficacy. The rats that received the intervention exhibited increases in post-intervention LL choice behavior, and made more responses for larger-reward magnitudes in the reward magnitude discrimination task, suggesting that the intervention heightened sensitivities to reward magnitude. The results suggest that reward magnitude discrimination plays a key role in individual differences in impulsive choice, and could be a potential target for further intervention developments. PMID:26506254

Social and monetary reward processing in autism spectrum disorders

PubMed Central

2012-01-01

Background Social motivation theory suggests that deficits in social reward processing underlie social impairments in autism spectrum disorders (ASD). However, the extent to which abnormalities in reward processing generalize to other classes of stimuli remains unresolved. The aim of the current study was to examine if reward processing abnormalities in ASD are specific to social stimuli or can be generalized to other classes of reward. Additionally, we sought to examine the results in the light of behavioral impairments in ASD. Methods Participants performed adapted versions of the social and monetary incentive delay tasks. Data from 21 unmedicated right-handed male participants with ASD and 21 age- and IQ-matched controls were analyzed using a factorial design to examine the blood-oxygen-level-dependent (BOLD) response during the anticipation and receipt of both reward types. Results Behaviorally, the ASD group showed less of a reduction in reaction time (RT) for rewarded compared to unrewarded trials than the control group. In terms of the fMRI results, there were no significant group differences in reward circuitry during reward anticipation. During the receipt of rewards, there was a significant interaction between group and reward type in the left dorsal striatum (DS). The ASD group showed reduced activity in the DS compared to controls for social rewards but not monetary rewards and decreased activation for social rewards compared to monetary rewards. Controls showed no significant difference between the two reward types. Increased activation in the DS during social reward processing was associated with faster response times for rewarded trials, compared to unrewarded trials, in both groups. This is in line with behavioral results indicating that the ASD group showed less of a reduction in RT for rewarded compared to unrewarded trials. Additionally, de-activation to social rewards was associated with increased repetitive behavior in ASD. Conclusions In line with social motivation theory, the ASD group showed reduced activation, compared to controls, during the receipt of social rewards in the DS. Groups did not differ significantly during the processing of monetary rewards. BOLD activation in the DS, during social reward processing, was associated with behavioral impairments in ASD. PMID:23014171

Social and monetary reward processing in autism spectrum disorders.

PubMed

Delmonte, Sonja; Balsters, Joshua H; McGrath, Jane; Fitzgerald, Jacqueline; Brennan, Sean; Fagan, Andrew J; Gallagher, Louise

2012-09-26

Social motivation theory suggests that deficits in social reward processing underlie social impairments in autism spectrum disorders (ASD). However, the extent to which abnormalities in reward processing generalize to other classes of stimuli remains unresolved. The aim of the current study was to examine if reward processing abnormalities in ASD are specific to social stimuli or can be generalized to other classes of reward. Additionally, we sought to examine the results in the light of behavioral impairments in ASD. Participants performed adapted versions of the social and monetary incentive delay tasks. Data from 21 unmedicated right-handed male participants with ASD and 21 age- and IQ-matched controls were analyzed using a factorial design to examine the blood-oxygen-level-dependent (BOLD) response during the anticipation and receipt of both reward types. Behaviorally, the ASD group showed less of a reduction in reaction time (RT) for rewarded compared to unrewarded trials than the control group. In terms of the fMRI results, there were no significant group differences in reward circuitry during reward anticipation. During the receipt of rewards, there was a significant interaction between group and reward type in the left dorsal striatum (DS). The ASD group showed reduced activity in the DS compared to controls for social rewards but not monetary rewards and decreased activation for social rewards compared to monetary rewards. Controls showed no significant difference between the two reward types. Increased activation in the DS during social reward processing was associated with faster response times for rewarded trials, compared to unrewarded trials, in both groups. This is in line with behavioral results indicating that the ASD group showed less of a reduction in RT for rewarded compared to unrewarded trials. Additionally, de-activation to social rewards was associated with increased repetitive behavior in ASD. In line with social motivation theory, the ASD group showed reduced activation, compared to controls, during the receipt of social rewards in the DS. Groups did not differ significantly during the processing of monetary rewards. BOLD activation in the DS, during social reward processing, was associated with behavioral impairments in ASD.

Nicotine increases impulsivity and decreases willingness to exert cognitive effort despite improving attention in "slacker" rats: insights into cholinergic regulation of cost/benefit decision making.

PubMed

Hosking, Jay G; Lam, Fred C W; Winstanley, Catharine A

2014-01-01

Successful decision making in our daily lives requires weighing an option's costs against its associated benefits. The neuromodulator acetylcholine underlies both the etiology and treatment of a number of illnesses in which decision making is perturbed, including Alzheimer's disease, attention-deficit/hyperactivity disorder, and schizophrenia. Nicotine acts on the cholinergic system and has been touted as a cognitive enhancer by both smokers and some researchers for its attention-boosting effects; however, it is unclear whether treatments that have a beneficial effect on attention would also have a beneficial effect on decision making. Here we utilize the rodent Cognitive Effort Task (rCET), wherein animals can choose to allocate greater visuospatial attention for a greater reward, to examine cholinergic contributions to both attentional performance and choice based on attentional demand. Following the establishment of baseline behavior, four drug challenges were administered: nicotine, mecamylamine, scopolamine, and oxotremorine (saline plus three doses for each). As per previous rCET studies, animals were divided by their baseline preferences, with "worker" rats choosing high-effort/high-reward options more than their "slacker" counterparts. Nicotine caused slackers to choose even fewer high-effort trials than at baseline, but had no effect on workers' choice. Despite slackers' decreased willingness to expend effort, nicotine improved their attentional performance on the task. Nicotine also increased measures of motor impulsivity in all animals. In contrast, scopolamine decreased animals' choice of high-effort trials, especially for workers, while oxotremorine decreased motor impulsivity for all animals. In sum, the cholinergic system appears to contribute to decision making, and in part these contributions can be understood as a function of individual differences. While nicotine has been considered as a cognitive enhancer, these data suggest that its modest benefits to attention may be coupled with impulsiveness and decreased willingness to work hard, especially in individuals who are particularly sensitive to effort costs (i.e. slackers).

Addictive drugs and brain stimulation reward.

PubMed

Wise, R A

1996-01-01

Direct electrical or chemical stimulation of specific brain regions can establish response habits similar to those established by natural rewards such as food or sexual contact. Cocaine, mu and delta opiates, nicotine, phencyclidine, and cannabis each have actions that summate with rewarding electrical stimulation of the medial forebrain bundle (MFB). The reward-potentiating effects of amphetamine and opiates are associated with central sites of action where these drugs also have their direct rewarding effects, suggesting common mechanisms for drug reward per se and for drug potentiation of brain stimulation reward. The central sites at which these and perhaps other drugs of abuse potentiate brain stimulation reward and are rewarding in their own right are consistent with the hypothesis that the laboratory reward of brain stimulation and the pharmacological rewards of addictive drugs are habit forming because they act in the brain circuits that subserve more natural and biologically significant rewards.

Job Satisfaction Analysis in Rural China: A Qualitative Study of Doctors in a Township Hospital

PubMed Central

Chen, Qiwei; Yang, Lan; Tighe, Scott S.

2017-01-01

Background. Township hospitals in China provide rural communities with basic but much needed critical health care services. The doctors working in these hospitals often feel unsatisfied when considering their work schedules and financial rewards. Method. To explore job satisfaction of health workers in a township hospital, a qualitative study was conducted of 39 doctors from five township hospitals in Guangxi Zhuang Autonomous Region. The goal was to understand the level of job satisfaction of doctors and to make recommendations for improvements. Results. About 75% (28/39) of the doctors expressed negative attitudes related to their work conditions. Slightly more than half (22/39) mentioned they should receive greater compensation for their work and more than one were seriously considering other options. Many participants (35/39) showed their satisfaction about the achievement of serving as a doctor. Conclusion. Their main concerns related to job satisfaction included working conditions, financial rewards, and the doctor's relationships with patients. Increasing the incomes and fringe benefits of healthcare workers, improving their work conditions, and providing training and continuing education opportunities would help rural clinics retain doctors and eliminate the current unsatisfactory conditions. The findings also highlight the need for the government to increase financial support of township hospitals. PMID:28409052

Decision-making without a brain: how an amoeboid organism solves the two-armed bandit.

PubMed

Reid, Chris R; MacDonald, Hannelore; Mann, Richard P; Marshall, James A R; Latty, Tanya; Garnier, Simon

2016-06-01

Several recent studies hint at shared patterns in decision-making between taxonomically distant organisms, yet few studies demonstrate and dissect mechanisms of decision-making in simpler organisms. We examine decision-making in the unicellular slime mould Physarum polycephalum using a classical decision problem adapted from human and animal decision-making studies: the two-armed bandit problem. This problem has previously only been used to study organisms with brains, yet here we demonstrate that a brainless unicellular organism compares the relative qualities of multiple options, integrates over repeated samplings to perform well in random environments, and combines information on reward frequency and magnitude in order to make correct and adaptive decisions. We extend our inquiry by using Bayesian model selection to determine the most likely algorithm used by the cell when making decisions. We deduce that this algorithm centres around a tendency to exploit environments in proportion to their reward experienced through past sampling. The algorithm is intermediate in computational complexity between simple, reactionary heuristics and calculation-intensive optimal performance algorithms, yet it has very good relative performance. Our study provides insight into ancestral mechanisms of decision-making and suggests that fundamental principles of decision-making, information processing and even cognition are shared among diverse biological systems. © 2016 The Authors.

PPARγ activation attenuates opioid consumption and modulates mesolimbic dopamine transmission.

PubMed

de Guglielmo, Giordano; Melis, Miriam; De Luca, Maria Antonietta; Kallupi, Marsida; Li, Hong Wu; Niswender, Kevin; Giordano, Antonio; Senzacqua, Martina; Somaini, Lorenzo; Cippitelli, Andrea; Gaitanaris, George; Demopulos, Gregory; Damadzic, Ruslan; Tapocik, Jenica; Heilig, Markus; Ciccocioppo, Roberto

2015-03-01

PPARγ is one of the three isoforms identified for the peroxisome proliferator-activated receptors (PPARs) and is the receptor for the thiazolidinedione class of anti-diabetic medications including pioglitazone. PPARγ has been long studied for its role in adipogenesis and glucose metabolism, but the discovery of the localization in ventral tegmental area (VTA) neurons opens new vistas for a potential role in the regulation of reward processing and motivated behavior in drug addiction. Here, we demonstrate that activation of PPARγ by pioglitazone reduces the motivation for heroin and attenuates its rewarding properties. These effects are associated with a marked reduction of heroin-induced increase in phosphorylation of DARPP-32 protein in the nucleus accumbens (NAc) and with a marked and selective reduction of acute heroin-induced elevation of extracellular dopamine (DA) levels in the NAc shell, as measured by in vivo microdialysis. Through ex vivo electrophysiology in acute midbrain slices, we also show that stimulation of PPARγ attenuates opioid-induced excitation of VTA DA neurons via reduction of presynaptic GABA release from the rostromedial tegmental nucleus (RMTg). Consistent with this finding, site-specific microinjection of pioglitazone into the RMTg but not into the VTA reduced heroin taking. Our data illustrate that activation of PPARγ may represent a new pharmacotherapeutic option for the treatment of opioid addiction.

Intertemporal choice in lemurs.

PubMed

Stevens, Jeffrey R; Mühlhoff, Nelly

2012-02-01

Different species vary in their ability to wait for delayed rewards in intertemporal choice tasks. Models of rate maximization account for part of this variation, but other factors such as social structure and feeding ecology seem to underly some species differences. Though studies have evaluated intertemporal choice in several primate species, including Old World monkeys, New World monkeys, and apes, prosimians have not been tested. This study investigated intertemporal choices in three species of lemur (black-and-white ruffed lemurs, Varecia variegata, red ruffed lemurs, Varecia rubra, and black lemurs, Eulemur macaco) to assess how they compare to other primate species and whether their choices are consistent with rate maximization. We offered lemurs a choice between two food items available immediately and six food items available after a delay. We found that by adjusting the delay to the larger reward, the lemurs were indifferent between the two options at a mean delay of 17 s, ranging from 9 to 25 s. These data are comparable to data collected from common marmosets (Callithrix jacchus). The lemur data were not consistent with models of rate maximization. The addition of lemurs to the list of species tested in these tasks will help uncover the role of life history and socio-ecological factors influencing intertemporal choices. Copyright © 2011 Elsevier B.V. All rights reserved.

A marker of biological ageing predicts adult risk preference in European starlings, Sturnus vulgaris

PubMed Central

Nettle, Daniel; Reichert, Sophie; Bedford, Tom; Monaghan, Pat; Bateson, Melissa

2018-01-01

Abstract Why are some individuals more prone to gamble than others? Animals often show preferences between 2 foraging options with the same mean reward but different degrees of variability in the reward, and such risk preferences vary between individuals. Previous attempts to explain variation in risk preference have focused on energy budgets, but with limited empirical support. Here, we consider whether biological ageing, which affects mortality and residual reproductive value, predicts risk preference. We studied a cohort of European starlings (Sturnus vulgaris) in which we had previously measured developmental erythrocyte telomere attrition, an established integrative biomarker of biological ageing. We measured the adult birds’ preferences when choosing between a fixed amount of food and a variable amount with an equal mean. After controlling for change in body weight during the experiment (a proxy for energy budget), we found that birds that had undergone greater developmental telomere attrition were more risk averse as adults than were those whose telomeres had shortened less as nestlings. Developmental telomere attrition was a better predictor of adult risk preference than either juvenile telomere length or early-life food supply and begging effort. Our longitudinal study thus demonstrates that biological ageing, as measured via developmental telomere attrition, is an important source of lasting differences in adult risk preferences. PMID:29769793

A marker of biological ageing predicts adult risk preference in European starlings, Sturnus vulgaris.

PubMed

Andrews, Clare; Nettle, Daniel; Reichert, Sophie; Bedford, Tom; Monaghan, Pat; Bateson, Melissa

2018-01-01

Why are some individuals more prone to gamble than others? Animals often show preferences between 2 foraging options with the same mean reward but different degrees of variability in the reward, and such risk preferences vary between individuals. Previous attempts to explain variation in risk preference have focused on energy budgets, but with limited empirical support. Here, we consider whether biological ageing, which affects mortality and residual reproductive value, predicts risk preference. We studied a cohort of European starlings ( Sturnus vulgaris ) in which we had previously measured developmental erythrocyte telomere attrition, an established integrative biomarker of biological ageing. We measured the adult birds' preferences when choosing between a fixed amount of food and a variable amount with an equal mean. After controlling for change in body weight during the experiment (a proxy for energy budget), we found that birds that had undergone greater developmental telomere attrition were more risk averse as adults than were those whose telomeres had shortened less as nestlings. Developmental telomere attrition was a better predictor of adult risk preference than either juvenile telomere length or early-life food supply and begging effort. Our longitudinal study thus demonstrates that biological ageing, as measured via developmental telomere attrition, is an important source of lasting differences in adult risk preferences.

Regulating task-monitoring systems in response to variable reward contingencies and outcomes in cocaine addicts.

PubMed

Morie, Kristen P; De Sanctis, Pierfilippo; Garavan, Hugh; Foxe, John J

2016-03-01

We investigated anticipatory and consummatory reward processing in cocaine addiction. In addition, we set out to assess whether task-monitoring systems were appropriately recalibrated in light of variable reward schedules. We also examined neural measures of task-monitoring and reward processing as a function of hedonic tone, since anhedonia is a vulnerability marker for addiction that is obviously germane in the context of reward processing. High-density event-related potentials were recorded while participants performed a speeded response task that systematically varied anticipated probabilities of reward receipt. The paradigm dissociated feedback regarding task success (or failure) from feedback regarding the value of reward (or loss), so that task-monitoring and reward processing could be examined in partial isolation. Twenty-three active cocaine abusers and 23 age-matched healthy controls participated. Cocaine abusers showed amplified anticipatory responses to reward predictive cues, but crucially, these responses were not as strongly modulated by reward probability as in controls. Cocaine users also showed blunted responses to feedback about task success or failure and did not use this information to update predictions about reward. In turn, they showed clearly blunted responses to reward feedback. In controls and users, measures of anhedonia were associated with reward motivation. In cocaine users, anhedonia was also associated with diminished monitoring and reward feedback responses. Findings imply that reward anticipation and monitoring deficiencies in addiction are associated with increased responsiveness to reward cues but impaired ability to predict reward in light of task contingencies, compounded by deficits in responding to actual reward outcomes.

Fuel not fun: Reinterpreting attenuated brain responses to reward in obesity.

PubMed

Kroemer, Nils B; Small, Dana M

2016-08-01

There is a well-established literature linking obesity to altered dopamine signaling and brain response to food-related stimuli. Neuroimaging studies frequently report enhanced responses in dopaminergic regions during food anticipation and decreased responses during reward receipt. This has been interpreted as reflecting anticipatory "reward surfeit", and consummatory "reward deficiency". In particular, attenuated response in the dorsal striatum to primary food rewards is proposed to reflect anhedonia, which leads to overeating in an attempt to compensate for the reward deficit. In this paper, we propose an alternative view. We consider brain response to food-related stimuli in a reinforcement-learning framework, which can be employed to separate the contributions of reward sensitivity and reward-related learning that are typically entangled in the brain response to reward. Consequently, we posit that decreased striatal responses to milkshake receipt reflect reduced reward-related learning rather than reward deficiency or anhedonia because reduced reward sensitivity would translate uniformly into reduced anticipatory and consummatory responses to reward. By re-conceptualizing reward deficiency as a shift in learning about subjective value of rewards, we attempt to reconcile neuroimaging findings with the putative role of dopamine in effort, energy expenditure and exploration and suggest that attenuated brain responses to energy dense foods reflect the "fuel", not the fun entailed by the reward. Copyright © 2016 Elsevier Inc. All rights reserved.

Promising high monetary rewards for future task performance increases intermediate task performance.

PubMed

Zedelius, Claire M; Veling, Harm; Bijleveld, Erik; Aarts, Henk

2012-01-01

In everyday life contexts and work settings, monetary rewards are often contingent on future performance. Based on research showing that the anticipation of rewards causes improved task performance through enhanced task preparation, the present study tested the hypothesis that the promise of monetary rewards for future performance would not only increase future performance, but also performance on an unrewarded intermediate task. Participants performed an auditory Simon task in which they responded to two consecutive tones. While participants could earn high vs. low monetary rewards for fast responses to every second tone, their responses to the first tone were not rewarded. Moreover, we compared performance under conditions in which reward information could prompt strategic performance adjustments (i.e., when reward information was presented for a relatively long duration) to conditions preventing strategic performance adjustments (i.e., when reward information was presented very briefly). Results showed that high (vs. low) rewards sped up both rewarded and intermediate, unrewarded responses, and the effect was independent of the duration of reward presentation. Moreover, long presentation led to a speed-accuracy trade-off for both rewarded and unrewarded tones, whereas short presentation sped up responses to rewarded and unrewarded tones without this trade-off. These results suggest that high rewards for future performance boost intermediate performance due to enhanced task preparation, and they do so regardless whether people respond to rewards in a strategic or non-strategic manner.

Promising High Monetary Rewards for Future Task Performance Increases Intermediate Task Performance

PubMed Central

Zedelius, Claire M.; Veling, Harm; Bijleveld, Erik; Aarts, Henk

2012-01-01

In everyday life contexts and work settings, monetary rewards are often contingent on future performance. Based on research showing that the anticipation of rewards causes improved task performance through enhanced task preparation, the present study tested the hypothesis that the promise of monetary rewards for future performance would not only increase future performance, but also performance on an unrewarded intermediate task. Participants performed an auditory Simon task in which they responded to two consecutive tones. While participants could earn high vs. low monetary rewards for fast responses to every second tone, their responses to the first tone were not rewarded. Moreover, we compared performance under conditions in which reward information could prompt strategic performance adjustments (i.e., when reward information was presented for a relatively long duration) to conditions preventing strategic performance adjustments (i.e., when reward information was presented very briefly). Results showed that high (vs. low) rewards sped up both rewarded and intermediate, unrewarded responses, and the effect was independent of the duration of reward presentation. Moreover, long presentation led to a speed-accuracy trade-off for both rewarded and unrewarded tones, whereas short presentation sped up responses to rewarded and unrewarded tones without this trade-off. These results suggest that high rewards for future performance boost intermediate performance due to enhanced task preparation, and they do so regardless whether people respond to rewards in a strategic or non-strategic manner. PMID:22905145

Registered nurses' perceptions of rewarding and its significance.

PubMed

Seitovirta, Jaana; Lehtimäki, Aku-Ville; Vehviläinen-Julkunen, Katri; Mitronen, Lasse; Kvist, Tarja

2017-11-07

To examine reward type preferences and their relationships with the significance of rewarding perceived by registered nurses in Finland. Previous studies have found relationships between nurses' rewarding and their motivation at work, job satisfaction and organisational commitment. Data were collected in a cross-sectional, descriptive, questionnaire survey from 402 registered nurses using the Registered Nurses' Perceptions of Rewarding Scale in 2015, and analysed with descriptive and multivariate statistical methods. Registered nurses assigned slightly higher values to several non-financial than to financial rewards. The non-financial reward types appreciation and feedback from work community, worktime arrangements, work content, and opportunity to develop, influence and participate were highly related to the significance of rewarding. We identified various rewards that registered nurses value, and indications that providing an appropriate array of rewards, particularly non-financial rewards, is a highly beneficial element of nursing management. It is important to understand the value of rewards for nursing management. Nurse managers should offer diverse rewards to their registered nurses to promote excellent performance and to help efforts to secure and maintain high-quality, safe patient care. The use of appropriate rewards is especially crucial to improving registered nurses' reward satisfaction and job satisfaction globally in the nursing profession. © 2017 John Wiley & Sons Ltd.

Reward abundance interferes with error-based learning in a visuomotor adaptation task

PubMed Central

Oostwoud Wijdenes, Leonie; Rigterink, Tessa; Overvliet, Krista E.; Smeets, Joeren B. J.

2018-01-01

The brain rapidly adapts reaching movements to changing circumstances by using visual feedback about errors. Providing reward in addition to error feedback facilitates the adaptation but the underlying mechanism is unknown. Here, we investigate whether the proportion of trials rewarded (the ‘reward abundance’) influences how much participants adapt to their errors. We used a 3D multi-target pointing task in which reward alone is insufficient for motor adaptation. Participants (N = 423) performed the pointing task with feedback based on a shifted hand-position. On a proportion of trials we gave them rewarding feedback that their hand hit the target. Half of the participants only received this reward feedback. The other half also received feedback about endpoint errors. In different groups, we varied the proportion of trials that was rewarded. As expected, participants who received feedback about their errors did adapt, but participants who only received reward-feedback did not. Critically, participants who received abundant rewards adapted less to their errors than participants who received less reward. Thus, reward abundance negatively influences how much participants learn from their errors. Probably participants used a mechanism that relied more on the reward feedback when the reward was abundant. Because participants could not adapt to the reward, this interfered with adaptation to errors. PMID:29513681

Differential encoding of factors influencing predicted reward value in monkey rostral anterior cingulate cortex.

PubMed

Toda, Koji; Sugase-Miyamoto, Yasuko; Mizuhiki, Takashi; Inaba, Kiyonori; Richmond, Barry J; Shidara, Munetaka

2012-01-01

The value of a predicted reward can be estimated based on the conjunction of both the intrinsic reward value and the length of time to obtain it. The question we addressed is how the two aspects, reward size and proximity to reward, influence the responses of neurons in rostral anterior cingulate cortex (rACC), a brain region thought to play an important role in reward processing. We recorded from single neurons while two monkeys performed a multi-trial reward schedule task. The monkeys performed 1-4 sequential color discrimination trials to obtain a reward of 1-3 liquid drops. There were two task conditions, a valid cue condition, where the number of trials and reward amount were associated with visual cues, and a random cue condition, where the cue was picked from the cue set at random. In the valid cue condition, the neuronal firing is strongly modulated by the predicted reward proximity during the trials. Information about the predicted reward amount is almost absent at those times. In substantial subpopulations, the neuronal responses decreased or increased gradually through schedule progress to the predicted outcome. These two gradually modulating signals could be used to calculate the effect of time on the perception of reward value. In the random cue condition, little information about the reward proximity or reward amount is encoded during the course of the trial before reward delivery, but when the reward is actually delivered the responses reflect both the reward proximity and reward amount. Our results suggest that the rACC neurons encode information about reward proximity and amount in a manner that is dependent on utility of reward information. The manner in which the information is represented could be used in the moment-to-moment calculation of the effect of time and amount on predicted outcome value.

Major depressive disorder is characterized by greater reward network activation to monetary than pleasant image rewards

PubMed Central

Smoski, Moria J.; Rittenberg, Alison; Dichter, Gabriel S.

2011-01-01

Anhedonia, the loss of interest or pleasure in normally rewarding activities, is a hallmark feature of unipolar Major Depressive Disorder (MDD). A growing body of literature has identified frontostriatal dysfunction during reward anticipation and outcomes in MDD. However, no study to date has directly compared responses to different types of rewards such as pleasant images and monetary rewards in MDD. To investigate the neural responses to monetary and pleasant image rewards in MDD, a modified Monetary Incentive Delay task was used during fMRI scanning to assess neural responses during anticipation and receipt of monetary and pleasant image rewards. Participants included nine adults with MDD and thirteen affectively healthy controls. The MDD group showed lower activation than controls when anticipating monetary rewards in right orbitofrontal cortex and subcallosal cortex, and when anticipating pleasant image rewards in paracingulate and supplementary motor cortex. The MDD group had relatively greater activation in right putamen when anticipating monetary versus pleasant image rewards, relative to the control group. Results suggest reduced reward network activation in MDD when anticipating rewards, as well as relatively greater hypoactivation to pleasant image than monetary rewards. PMID:22079658

Major depressive disorder is characterized by greater reward network activation to monetary than pleasant image rewards.

PubMed

Smoski, Moria J; Rittenberg, Alison; Dichter, Gabriel S

2011-12-30

Anhedonia, the loss of interest or pleasure in normally rewarding activities, is a hallmark feature of unipolar Major Depressive Disorder (MDD). A growing body of literature has identified frontostriatal dysfunction during reward anticipation and outcomes in MDD. However, no study to date has directly compared responses to different types of rewards such as pleasant images and monetary rewards in MDD. To investigate the neural responses to monetary and pleasant image rewards in MDD, a modified Monetary Incentive Delay task was used during functional magnetic resonance imaging to assess neural responses during anticipation and receipt of monetary and pleasant image rewards. Participants included nine adults with MDD and 13 affectively healthy controls. The MDD group showed lower activation than controls when anticipating monetary rewards in right orbitofrontal cortex and subcallosal cortex, and when anticipating pleasant image rewards in paracingulate and supplementary motor cortex. The MDD group had relatively greater activation in right putamen when anticipating monetary versus pleasant image rewards, relative to the control group. Results suggest reduced reward network activation in MDD when anticipating rewards, as well as relatively greater hypoactivation to pleasant image than monetary rewards. 2011 Elsevier Ireland Ltd. All rights reserved.

Caloric primary rewards systematically alter time perception.

PubMed

Fung, Bowen J; Murawski, Carsten; Bode, Stefan

2017-11-01

Human time perception can be influenced by contextual factors, such as the presence of reward. Yet, the exact nature of the relationship between time perception and reward has not been conclusively characterized. We implemented a novel experimental paradigm to measure estimations of time across a range of suprasecond intervals, during the anticipation and after the consumption of fruit juice, a physiologically relevant primary reward. We show that average time estimations were systematically affected by the consumption of reward, but not by the anticipation of reward. Compared with baseline estimations of time, reward consumption was associated with subsequent overproductions of time, and this effect increased for larger magnitudes of reward. Additional experiments demonstrated that the effect of consumption did not extend to a secondary reward (money), a tasteless, noncaloric primary reward (water), or a sweet, noncaloric reward (aspartame). However, a tasteless caloric reward (maltodexrin) did induce overproductions of time, although this effect did not scale with reward magnitude. These results suggest that the consumption of caloric primary rewards can alter time perception, which may be a psychophysiological mechanism by which organisms regulate homeostatic balance. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Reward Improves Cancellation and Restraint Inhibition Across Childhood and Adolescence

PubMed Central

Sinopoli, Katia J.; Schachar, Russell; Dennis, Maureen

2011-01-01

Inhibitory control allows for the regulation of thought and action, and interacts with motivational variables, such as reward, to modify behavior adaptively as environments change. We examined the effects of reward on two distinct forms of inhibitory control, cancellation and restraint. Typically developing children and adolescents completed two versions of the stop signal task (cancellation and restraint) under three reward conditions (neutral, low reward, and high reward), where rewards were earned for successful inhibitory control. Rewards improved both cancellation and restraint inhibition, with similar effects of reward on each form of inhibitory control. Rewards did not alter the speed of response execution in either task, suggesting that rewards specifically altered inhibition processes without influencing processes related to response execution. Adolescents were faster and less variable than children when executing and inhibiting their responses. There were similar developmental effects of reward on the speed of inhibitory control, but group differences were found in terms of accuracy of inhibition in the restraint task. These results clarify how reward modulates two different forms of regulatory behavior in children and adolescents. PMID:21744952

Differential effects of social and non-social reward on response inhibition in children and adolescents.

PubMed

Kohls, Gregor; Peltzer, Judith; Herpertz-Dahlmann, Beate; Konrad, Kerstin

2009-07-01

An important issue in the field of clinical and developmental psychopathology is whether cognitive control processes, such as response inhibition, can be specifically enhanced by motivation. To determine whether non-social (i.e. monetary) and social (i.e. positive facial expressions) rewards are able to differentially improve response inhibition accuracy in typically developing children and adolescents, an 'incentive' go/no-go task was applied with reward contingencies for successful inhibition. In addition, the impact of children's personality traits (such as reward seeking and empathy) on monetary and social reward responsiveness was assessed in 65 boys, ages 8 to 12 years. All subjects were tested twice: At baseline, inhibitory control was assessed without reward, and then subjects were pseudorandomly assigned to one of four experimental conditions, including (1) social reward only, (2) monetary reward only, (3) mixed social and monetary reward, or (4) a retest condition without reward. Both social and non-social reward significantly improved task performance, although larger effects were observed for monetary reward. The higher the children scored on reward seeking scales, the larger was their improvement in response inhibition, but only if monetary reward was used. In addition, there was a tendency for an association between empathic skills and benefits from social reward. These data suggest that social incentives do not have an equally strong reinforcing value as compared to financial incentives. However, different personality traits seem to determine to what extent a child profits from different types of reward. Clinical implications regarding probable hyposensitivity to social reward in subjects with autism and dysregulated reward-seeking behaviour in children with attention-deficit/hyperactivity disorder (ADHD) are discussed.

Pavlovian reward learning underlies value driven attentional capture.

PubMed

Bucker, Berno; Theeuwes, Jan

2017-02-01

Recent evidence shows that distractors that signal high compared to low reward availability elicit stronger attentional capture, even when this is detrimental for task-performance. This suggests that simply correlating stimuli with reward administration, rather than their instrumental relationship with obtaining reward, produces value-driven attentional capture. However, in previous studies, reward delivery was never response independent, as only correct responses were rewarded, nor was it completely task-irrelevant, as the distractor signaled the magnitude of reward that could be earned on that trial. In two experiments, we ensured that associative reward learning was completely response independent by letting participants perform a task at fixation, while high and low rewards were automatically administered following the presentation of task-irrelevant colored stimuli in the periphery (Experiment 1) or at fixation (Experiment 2). In a following non-reward test phase, using the additional singleton paradigm, the previously reward signaling stimuli were presented as distractors to assess truly task-irrelevant value driven attentional capture. The results showed that high compared to low reward-value associated distractors impaired performance, and thus captured attention more strongly. This suggests that genuine Pavlovian conditioning of stimulus-reward contingencies is sufficient to obtain value-driven attentional capture. Furthermore, value-driven attentional capture can occur following associative reward learning of temporally and spatially task-irrelevant distractors that signal the magnitude of available reward (Experiment 1), and is independent of training spatial shifts of attention towards the reward signaling stimuli (Experiment 2). This confirms and strengthens the idea that Pavlovian reward learning underlies value driven attentional capture.

Modulation of neural activity by reward in medial intraparietal cortex is sensitive to temporal sequence of reward

PubMed Central

Rajalingham, Rishi; Stacey, Richard Greg; Tsoulfas, Georgios

2014-01-01

To restore movements to paralyzed patients, neural prosthetic systems must accurately decode patients' intentions from neural signals. Despite significant advancements, current systems are unable to restore complex movements. Decoding reward-related signals from the medial intraparietal area (MIP) could enhance prosthetic performance. However, the dynamics of reward sensitivity in MIP is not known. Furthermore, reward-related modulation in premotor areas has been attributed to behavioral confounds. Here we investigated the stability of reward encoding in MIP by assessing the effect of reward history on reward sensitivity. We recorded from neurons in MIP while monkeys performed a delayed-reach task under two reward schedules. In the variable schedule, an equal number of small- and large-rewards trials were randomly interleaved. In the constant schedule, one reward size was delivered for a block of trials. The memory period firing rate of most neurons in response to identical rewards varied according to schedule. Using systems identification tools, we attributed the schedule sensitivity to the dependence of neural activity on the history of reward. We did not find schedule-dependent behavioral changes, suggesting that reward modulates neural activity in MIP. Neural discrimination between rewards was less in the variable than in the constant schedule, degrading our ability to decode reach target and reward simultaneously. The effect of schedule was mitigated by adding Haar wavelet coefficients to the decoding model. This raises the possibility of multiple encoding schemes at different timescales and reinforces the potential utility of reward information for prosthetic performance. PMID:25008408

Modulation of neural activity by reward in medial intraparietal cortex is sensitive to temporal sequence of reward.

PubMed

Rajalingham, Rishi; Stacey, Richard Greg; Tsoulfas, Georgios; Musallam, Sam

2014-10-01

To restore movements to paralyzed patients, neural prosthetic systems must accurately decode patients' intentions from neural signals. Despite significant advancements, current systems are unable to restore complex movements. Decoding reward-related signals from the medial intraparietal area (MIP) could enhance prosthetic performance. However, the dynamics of reward sensitivity in MIP is not known. Furthermore, reward-related modulation in premotor areas has been attributed to behavioral confounds. Here we investigated the stability of reward encoding in MIP by assessing the effect of reward history on reward sensitivity. We recorded from neurons in MIP while monkeys performed a delayed-reach task under two reward schedules. In the variable schedule, an equal number of small- and large-rewards trials were randomly interleaved. In the constant schedule, one reward size was delivered for a block of trials. The memory period firing rate of most neurons in response to identical rewards varied according to schedule. Using systems identification tools, we attributed the schedule sensitivity to the dependence of neural activity on the history of reward. We did not find schedule-dependent behavioral changes, suggesting that reward modulates neural activity in MIP. Neural discrimination between rewards was less in the variable than in the constant schedule, degrading our ability to decode reach target and reward simultaneously. The effect of schedule was mitigated by adding Haar wavelet coefficients to the decoding model. This raises the possibility of multiple encoding schemes at different timescales and reinforces the potential utility of reward information for prosthetic performance. Copyright © 2014 the American Physiological Society.

Spontaneous Eye-Blink Rate as an Index of Reward Responsivity: Validation and Links to Bipolar Disorder

PubMed Central

Peckham, Andrew D.; Johnson, Sheri L.

2015-01-01

Extensive research supports the role of striatal dopamine in pursuing and responding to reward, and that eye-blink rate is a valid indicator of striatal dopamine. This study tested whether phasic changes in blink rate could provide an index of reward pursuit. This hypothesis was tested in people with bipolar I disorder (BD; a population with aberrations in reward responsivity), and in those without BD. Thirty-one adults with BD and 28 control participants completed a laboratory task involving effort towards monetary reward. Blink rate was recorded using eye-tracking at baseline, reward anticipation, and post-reward. Those in the BD group completed self-report measures relating to reward and ambition. Results showed that across all participants, blink rates increased from reward anticipation to post-reward. In the BD group, reward-relevant measures were strongly correlated with variation in blink rate. These findings provide validation for phasic changes in blink rate as an index of reward response. PMID:27274949

Adaptive scaling of reward in episodic memory: a replication study.

PubMed

Mason, Alice; Ludwig, Casimir; Farrell, Simon

2017-11-01

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). A common mechanism for adaptive scaling of reward and novelty. Human Brain Mapping, 31, 1380-1394] provided functional magnetic resonance imaging (fMRI) and behavioural evidence that reward and episodic memory systems are sensitive to the contextual value of a reward-whether it is relatively higher or lower-as opposed to absolute value or prediction error. We carried out a direct replication of their behavioural study and did not replicate their finding that memory performance associated with reward follows this pattern of adaptive scaling. An effect of reward outcome was in the opposite direction to that in the original study, with lower reward outcomes leading to better memory than higher outcomes. There was a marginal effect of reward context, suggesting that expected value affected memory performance. We discuss the robustness of the reward memory relationship to variations in reward context, and whether other reward-related factors have a more reliable influence on episodic memory.

A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation.

PubMed

Deci, E L; Koestner, R; Ryan, R M

1999-11-01

A meta-analysis of 128 studies examined the effects of extrinsic rewards on intrinsic motivation. As predicted, engagement-contingent, completion-contingent, and performance-contingent rewards significantly undermined free-choice intrinsic motivation (d = -0.40, -0.36, and -0.28, respectively), as did all rewards, all tangible rewards, and all expected rewards. Engagement-contingent and completion-contingent rewards also significantly undermined self-reported interest (d = -0.15, and -0.17), as did all tangible rewards and all expected rewards. Positive feedback enhanced both free-choice behavior (d = 0.33) and self-reported interest (d = 0.31). Tangible rewards tended to be more detrimental for children than college students, and verbal rewards tended to be less enhancing for children than college students. The authors review 4 previous meta-analyses of this literature and detail how this study's methods, analyses, and results differed from the previous ones.

Reward Processing, Neuroeconomics, and Psychopathology.

PubMed

Zald, David H; Treadway, Michael T

2017-05-08

Abnormal reward processing is a prominent transdiagnostic feature of psychopathology. The present review provides a framework for considering the different aspects of reward processing and their assessment, and highlights recent insights from the field of neuroeconomics that may aid in understanding these processes. Although altered reward processing in psychopathology has often been treated as a general hypo- or hyperresponsivity to reward, increasing data indicate that a comprehensive understanding of reward dysfunction requires characterization within more specific reward-processing domains, including subjective valuation, discounting, hedonics, reward anticipation and facilitation, and reinforcement learning. As such, more nuanced models of the nature of these abnormalities are needed. We describe several processing abnormalities capable of producing the types of selective alterations in reward-related behavior observed in different forms of psychopathology, including (mal)adaptive scaling and anchoring, dysfunctional weighting of reward and cost variables, competition between valuation systems, and reward prediction error signaling.

Rewarded visual items capture attention only in heterogeneous contexts.

PubMed

Feldmann-Wüstefeld, Tobias; Brandhofer, Ruben; Schubö, Anna

2016-07-01

Reward is known to affect visual search performance. Rewarding targets can increase search performance, whereas rewarding distractors can decrease search performance. We used subcomponents of the N2pc in the event-related EEG, the NT (target negativity) and ND /PD (distractor negativity/positivity), in a visual search task to disentangle target and distractor processing related to reward. The visual search task comprised homogeneous and heterogeneous contexts in which a target and a colored distractor were embedded. After each correct trial, participants were given a monetary reward that depended on the color of the distractor. We found longer response times for displays with high-reward distractors compared to displays with low-reward distractors, indicating reward-induced interference, however, only for heterogeneous contexts. The NT component, indicative of attention deployment to the target, showed that target selection was impaired by high-reward distractors, regardless of the context homogeneity. Processing of distractors was not affected by reward in homogeneous contexts. In heterogeneous contexts, however, high-reward distractors were more likely to capture attention (ND ) and required more effort to be suppressed (PD ) than low-reward distractors. In sum the results showed that, despite the fact that target selection is impaired by high-reward distractors in both homogeneous and heterogeneous background contexts, high-reward distractors capture attention only in scenarios that foster attentional capture. © 2016 Society for Psychophysiological Research.

Monetary, Food, and Social Rewards Induce Similar Pavlovian-to-Instrumental Transfer Effects

PubMed Central

Lehner, Rea; Balsters, Joshua H.; Herger, Andreas; Hare, Todd A.; Wenderoth, Nicole

2017-01-01

Multiple types of reward, such as money, food or social approval, are capable of driving behavior. However, most previous investigations have only focused on one of these reward classes in isolation, as such it is not clear whether different reward classes have a unique influence on instrumental responding or whether the subjective value of the reward, rather than the reward type per se, is most important in driving behavior. Here, we investigate behavior using a well-established reward paradigm, Pavlovian-to-instrumental transfer (PIT), and three different reward types: monetary, food and social rewards. The subjective value of each reward type was matched using a modified Becker-DeGroot-Marschak (BDM) auction where subjective reward value was expressed through physical effort using a bimanual grip force task. We measured the influence of reward-associated stimuli on how participants distributed forces between hands when reaching a target effort range on the screen bimanually and on how much time participants spent in this target range. Participants spent significantly more time in the target range (15% ± 2% maximal voluntary contraction) when a stimulus was presented that was associated with a reward used during instrumental conditioning or Pavlovian conditioning compared to a stimulus associated with a neutral outcome (i.e., general PIT). The strength of the PIT effect was modulated by subjective value (i.e., individuals who showed a stronger PIT effect rated the value of rewards more highly), but not by reward type, demonstrating that stimuli of all reward types were able to act as appetitive reinforcers and influenced instrumental responding, when matched to the same subjective reward value. This is the first demonstration that individually matched monetary, food and social rewards are equally effective as appetitive reinforcers in PIT. These findings strengthen the hypotheses that the subjective value is crucial for how much reward-associated stimuli influence behavior. PMID:28101010

CIFO 3.0

NASA Technical Reports Server (NTRS)

Rogers, Pat

1992-01-01

The Ada Runtime Environment Working Group has, since 1985, developed and published the Catalog of Interface Features and Options (CFIO) for Ada runtime environments. These interfaces, expressed in legal Ada, provide 'hooks' into the runtime system to export both functionality and enhanced performance beyond that of 'vanilla' Ada implementations. Such enhancements include high- and low-level scheduling control, asynchronous communications facilities, predictable storage management facilities, and fast interrupt response. CIFO 3.0 represents the latest release, which incorporates the efforts of the European real time community as well as new interfaces and expansions of previous catalog entries. This presentation will give both an overview of the Catalog's contents and an 'insider's' view of the Catalog as a whole.

When performance and risk taking are related: Working for rewards is related to risk taking when the value of rewards is presented briefly.

PubMed

Veling, Harm; Bijleveld, Erik

2015-12-01

Valuable monetary rewards can boost human performance on various effortful tasks even when the value of the rewards is presented too briefly to allow for strategic decision making. However, the mechanism by which briefly-presented reward information influences performance has remained unclear. One possibility is that performance after briefly-presented reward information is primarily boosted via activation of the dopamine reward system, whereas performance after very visible reward information is driven more by strategic processes. To examine this hypothesis, we first presented participants with a task in which they could earn rewards of relatively low (1 cent) or high (10 cents) value, and the value information was presented either briefly (17 ms) or for an extended duration (300 ms). Furthermore, responsiveness of the dopamine system was indirectly estimated with a measure of risk taking, the Balloon Analogue Risk Task (BART). Results showed that performance after high- compared to low-value rewards was indeed related to the BART scores only when reward information was presented briefly. These results are suggestive of the possibility that brief presentation of reward information boosts performance directly via activating the dopamine system, whereas extended presentation of reward information leads to more strategic reward-driven behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

Differential patterns of nucleus accumbens activation during anticipation of monetary and social reward in young and older adults

PubMed Central

Salama, Aallaa; Gründer, Gerhard; Spreckelmeyer, Katja N.

2014-01-01

Recent studies have reported inconsistent results regarding the loss of reward sensitivity in the aging brain. Although such an age effect might be due to a decline of physiological processes, it may also be a consequence of age-related changes in motivational preference for different rewards. Here, we examined whether the age effects on neural correlates of reward anticipation are modulated by the type of expected reward. Functional magnetic resonance images were acquired in 24 older (60–78 years) and 24 young participants (20–28 years) while they performed an incentive delay task offering monetary or social rewards. Anticipation of either reward type recruited brain structures associated with reward, including the nucleus accumbens (NAcc). Region of interest analysis revealed an interaction effect of reward type and age group in the right NAcc: enhanced activation to cues of social reward was detected in the older subsample while enhanced activation to cues of monetary reward was detected in the younger subsample. Our results suggest that neural sensitivity to reward-predicting cues does not generally decrease with age. Rather, neural responses in the NAcc appear to be modulated by the type of reward, presumably reflecting age-related changes in motivational value attributed to different types of reward. PMID:23547243

Reward-based plasticity of spatial priority maps: Exploiting inter-subject variability to probe the underlying neurobiology.

PubMed

Della Libera, Chiara; Calletti, Riccardo; Eštočinová, Jana; Chelazzi, Leonardo; Santandrea, Elisa

2017-04-01

Recent evidence indicates that the attentional priority of objects and locations is altered by the controlled delivery of reward, reflecting reward-based attentional learning. Here, we take an approach hinging on intersubject variability to probe the neurobiological bases of the reward-driven plasticity of spatial priority maps. Specifically, we ask whether an individual's susceptibility to the reward-based treatment can be accounted for by specific predictors, notably personality traits that are linked to reward processing (along with more general personality traits), but also gender. Using a visual search protocol, we show that when different target locations are associated with unequal reward probability, different priorities are acquired by the more rewarded relative to the less rewarded locations. However, while males exhibit the expected pattern of results, with greater priority for locations associated with higher reward, females show an opposite trend. Critically, both the extent and the direction of reward-based adjustments are further predicted by personality traits indexing reward sensitivity, indicating that not only male and female brains are differentially sensitive to reward, but also that specific personality traits further contribute to shaping their learning-dependent attentional plasticity. These results contribute to a better understanding of the neurobiology underlying reward-dependent attentional learning and cross-subject variability in this domain.

Reward inference by primate prefrontal and striatal neurons.

PubMed

Pan, Xiaochuan; Fan, Hongwei; Sawa, Kosuke; Tsuda, Ichiro; Tsukada, Minoru; Sakagami, Masamichi

2014-01-22

The brain contains multiple yet distinct systems involved in reward prediction. To understand the nature of these processes, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum in monkeys performing a reward inference task using an asymmetric reward schedule. We found that neurons both in the LPFC and in the striatum predicted reward values for stimuli that had been previously well experienced with set reward quantities in the asymmetric reward task. Importantly, these LPFC neurons could predict the reward value of a stimulus using transitive inference even when the monkeys had not yet learned the stimulus-reward association directly; whereas these striatal neurons did not show such an ability. Nevertheless, because there were two set amounts of reward (large and small), the selected striatal neurons were able to exclusively infer the reward value (e.g., large) of one novel stimulus from a pair after directly experiencing the alternative stimulus with the other reward value (e.g., small). Our results suggest that although neurons that predict reward value for old stimuli in the LPFC could also do so for new stimuli via transitive inference, those in the striatum could only predict reward for new stimuli via exclusive inference. Moreover, the striatum showed more complex functions than was surmised previously for model-free learning.

Reward Inference by Primate Prefrontal and Striatal Neurons

PubMed Central

Pan, Xiaochuan; Fan, Hongwei; Sawa, Kosuke; Tsuda, Ichiro; Tsukada, Minoru

2014-01-01

The brain contains multiple yet distinct systems involved in reward prediction. To understand the nature of these processes, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum in monkeys performing a reward inference task using an asymmetric reward schedule. We found that neurons both in the LPFC and in the striatum predicted reward values for stimuli that had been previously well experienced with set reward quantities in the asymmetric reward task. Importantly, these LPFC neurons could predict the reward value of a stimulus using transitive inference even when the monkeys had not yet learned the stimulus–reward association directly; whereas these striatal neurons did not show such an ability. Nevertheless, because there were two set amounts of reward (large and small), the selected striatal neurons were able to exclusively infer the reward value (e.g., large) of one novel stimulus from a pair after directly experiencing the alternative stimulus with the other reward value (e.g., small). Our results suggest that although neurons that predict reward value for old stimuli in the LPFC could also do so for new stimuli via transitive inference, those in the striatum could only predict reward for new stimuli via exclusive inference. Moreover, the striatum showed more complex functions than was surmised previously for model-free learning. PMID:24453328

Science communication: a career where PhDs can make a difference

PubMed Central

Irion, Robert

2015-01-01

Among careers for biologists with PhDs, science communication is one of the most diverse and rewarding pathways. Myriad options exist, from traditional journalism to new media, from writing for specialists to working in public outreach. Textbooks, mass-market books, and freelance writing that combines many of these pursuits are all viable choices. Communicating about science allows researchers to step away from the minutiae of a subdiscipline and to once again explore the breadth of science more fully through an ever-evolving array of stories. A doctoral degree can confer distinct advantages in the eyes of prospective editors and employers. Here I describe those advantages, possible career directions, and steps toward making such a transition. PMID:25678584

Reciprocating living kidney donor generosity: tax credits, health insurance and an outcomes registry

PubMed Central

Joshi, Shivam; Joshi, Sheela; Kupin, Warren

2016-01-01

Kidney transplantation significantly improves patient survival, and is the most cost effective renal replacement option compared with dialysis therapy. Living kidney donors provide a valuable societal gift, but face many formidable disincentive barriers that include not only short- and long-term health risks, but also concerns regarding financial expenditures and health insurance. Other than governmental coverage for their medical evaluation and surgical expenses, donors are often asked to personally bear a significant financial responsibility due to lost work wages and travel expenses. In order to alleviate this economic burden for donors, we advocate for the consideration of tax credits, lifelong health insurance coverage, and an outcomes registry as societal reciprocity to reward their altruistic act of kidney donation. PMID:26798480

A causal role for right frontopolar cortex in directed, but not random, exploration

PubMed Central

Zajkowski, Wojciech K; Kossut, Malgorzata

2017-01-01

The explore-exploit dilemma occurs anytime we must choose between exploring unknown options for information and exploiting known resources for reward. Previous work suggests that people use two different strategies to solve the explore-exploit dilemma: directed exploration, driven by information seeking, and random exploration, driven by decision noise. Here, we show that these two strategies rely on different neural systems. Using transcranial magnetic stimulation to inhibit the right frontopolar cortex, we were able to selectively inhibit directed exploration while leaving random exploration intact. This suggests a causal role for right frontopolar cortex in directed, but not random, exploration and that directed and random exploration rely on (at least partially) dissociable neural systems. PMID:28914605

The Effort Paradox: Effort Is Both Costly and Valued.

PubMed

Inzlicht, Michael; Shenhav, Amitai; Olivola, Christopher Y

2018-04-01

According to prominent models in cognitive psychology, neuroscience, and economics, effort (be it physical or mental) is costly: when given a choice, humans and non-human animals alike tend to avoid effort. Here, we suggest that the opposite is also true and review extensive evidence that effort can also add value. Not only can the same outcomes be more rewarding if we apply more (not less) effort, sometimes we select options precisely because they require effort. Given the increasing recognition of effort's role in motivation, cognitive control, and value-based decision-making, considering this neglected side of effort will not only improve formal computational models, but also provide clues about how to promote sustained mental effort across time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparative study of stock trend prediction using time delay, recurrent and probabilistic neural networks.

PubMed

Saad, E W; Prokhorov, D V; Wunsch, D C

1998-01-01

Three networks are compared for low false alarm stock trend predictions. Short-term trends, particularly attractive for neural network analysis, can be used profitably in scenarios such as option trading, but only with significant risk. Therefore, we focus on limiting false alarms, which improves the risk/reward ratio by preventing losses. To predict stock trends, we exploit time delay, recurrent, and probabilistic neural networks (TDNN, RNN, and PNN, respectively), utilizing conjugate gradient and multistream extended Kalman filter training for TDNN and RNN. We also discuss different predictability analysis techniques and perform an analysis of predictability based on a history of daily closing price. Our results indicate that all the networks are feasible, the primary preference being one of convenience.

Solid waste management practices in wet coffee processing industries of Gidabo watershed, Ethiopia.

PubMed

Ulsido, Mihret D; Li, Meng

2016-07-01

The financial and social contributions of coffee processing industries within most coffee export-based national economies like Ethiopia are generally high. The type and amount of waste produced and the waste management options adopted by these industries can have negative effects on the environment. This study investigated the solid waste management options adopted in wet coffee processing industries in the Gidabo watershed of Ethiopia. A field observation and assessment were made to identify whether the operational characteristics of the industries have any effect on the waste management options that were practiced. The investigation was conducted on 125 wet coffee processing industries about their solid waste handling techniques. Focus group discussion, structured questionnaires, key informant interview and transect walks are some of the tools employed during the investigation. Two major types of wastes, namely hull-bean-pulp blended solid waste and wastewater rich in dissolved and suspended solids were generated in the industries. Wet mills, on average, released 20.69% green coffee bean, 18.58% water and 60.74% pulp by weight. Even though these wastes are rich in organic matter and recyclables; the most favoured solid waste management options in the watershed were disposal (50.4%) and industrial or household composting (49.6%). Laxity and impulsive decision are the driving motives behind solid waste management in Gidabo watershed. Therefore, to reduce possible contamination of the environment, wastes generated during the processing of red coffee cherries, such as coffee wet mill solid wastes, should be handled properly and effectively through maximisation of their benefits with minimised losses. © The Author(s) 2016.

Components of reward-driven attentional capture.

PubMed

Sha, Li Z; Jiang, Yuhong V

2016-02-01

Recent research reported that task-irrelevant colors captured attention if these colors previously served as search targets and received high monetary reward. We showed that both monetary reward and value-independent mechanisms influenced selective attention. Participants searched for two potential target colors among distractor colors in the training phase. Subsequently, they searched for a shape singleton in a testing phase. Experiment 1 found that participants were slower in the testing phase if a distractor of a previous target color was present rather than absent. Such slowing was observed even when no monetary reward was used during training. Experiment 2 associated monetary rewards with the target colors during the training phase. Participants were faster finding the target associated with higher monetary reward. However, reward training did not yield value-dependent attentional capture in the testing phase. Attentional capture by the previous target colors was not significantly greater for the previously high-reward color than the previously low or no-reward color. These findings revealed both the power and limitations of monetary reward on attention. Although monetary reward can increase attentional priority for the high-reward target during training, subsequent attentional capture effects may not be reward-based, but reflect, in part, attentional capture by previous targets.

Extinction and renewal of cue-elicited reward-seeking.

PubMed

Bezzina, Louise; Lee, Jessica C; Lovibond, Peter F; Colagiuri, Ben

2016-12-01

Reward cues can contribute to overconsumption of food and drugs and can relapse. The failure of exposure therapies to reduce overconsumption and relapse is generally attributed to the context-specificity of extinction. However, no previous study has examined whether cue-elicited reward-seeking (as opposed to cue-reactivity) is sensitive to context renewal. We tested this possibility in 160 healthy volunteers using a Pavlovian-instrumental transfer (PIT) design involving voluntary responding for a high value natural reward (chocolate). One reward cue underwent Pavlovian extinction in the same (Group AAA) or different context (Group ABA) to all other phases. This cue was compared with a second non-extinguished reward cue and an unpaired control cue. There was a significant overall PIT effect with both reward cues eliciting reward-seeking on test relative to the unpaired cue. Pavlovian extinction substantially reduced this effect, with the extinguished reward cue eliciting less reward-seeking than the non-extinguished reward cue. Most interestingly, extinction of cue-elicited reward-seeking was sensitive to renewal, with extinction less effective for reducing PIT when conducted in a different context. These findings have important implications for extinction-based interventions for reducing maladaptive reward-seeking in practice. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reward Draws the Eye, Uncertainty Holds the Eye: Associative Learning Modulates Distractor Interference in Visual Search

PubMed Central

Koenig, Stephan; Kadel, Hanna; Uengoer, Metin; Schubö, Anna; Lachnit, Harald

2017-01-01

Stimuli in our sensory environment differ with respect to their physical salience but moreover may acquire motivational salience by association with reward. If we repeatedly observed that reward is available in the context of a particular cue but absent in the context of another cue the former typically attracts more attention than the latter. However, we also may encounter cues uncorrelated with reward. A cue with 50% reward contingency may induce an average reward expectancy but at the same time induces high reward uncertainty. In the current experiment we examined how both values, reward expectancy and uncertainty, affected overt attention. Two different colors were established as predictive cues for low reward and high reward respectively. A third color was followed by high reward on 50% of the trials and thus induced uncertainty. Colors then were introduced as distractors during search for a shape target, and we examined the relative potential of the color distractors to capture and hold the first fixation. We observed that capture frequency corresponded to reward expectancy while capture duration corresponded to uncertainty. The results may suggest that within trial reward expectancy is represented at an earlier time window than uncertainty. PMID:28744206

Energy Storage Systems

NASA Astrophysics Data System (ADS)

Elliott, David

2017-07-01

As renewable energy use expands there will be a need to develop ways to balance its variability. Storage is one of the options. Presently the main emphasis is for systems storing electrical power in advanced batteries (many of them derivatives of parallel developments in the electric vehicle field), as well as via liquid air storage, compressed air storage, super-capacitors and flywheels, and, the leader so far, pumped hydro reservoirs. In addition, new systems are emerging for hydrogen generation and storage, feeding fuel cell power production. Heat (and cold) is also a storage medium and some systems exploit thermal effects as part of wider energy management activity. Some of the more exotic ones even try to use gravity on a large scale. This short book looks at all the options, their potentials and their limits. There are no clear winners, with some being suited to short-term balancing and others to longer-term storage. The eventual mix adopted will be shaped by the pattern of development of other balancing measures, including smart-grid demand management and super-grid imports and exports.

PubMed searches: overview and strategies for clinicians.

PubMed

Lindsey, Wesley T; Olin, Bernie R

2013-04-01

PubMed is a biomedical and life sciences database maintained by a division of the National Library of Medicine known as the National Center for Biotechnology Information (NCBI). It is a large resource with more than 5600 journals indexed and greater than 22 million total citations. Searches conducted in PubMed provide references that are more specific for the intended topic compared with other popular search engines. Effective PubMed searches allow the clinician to remain current on the latest clinical trials, systematic reviews, and practice guidelines. PubMed continues to evolve by allowing users to create a customized experience through the My NCBI portal, new arrangements and options in search filters, and supporting scholarly projects through exportation of citations to reference managing software. Prepackaged search options available in the Clinical Queries feature also allow users to efficiently search for clinical literature. PubMed also provides information regarding the source journals themselves through the Journals in NCBI Databases link. This article provides an overview of the PubMed database's structure and features as well as strategies for conducting an effective search.

Attention to nurses' rewarding - an interview study of registered nurses working in primary and private healthcare in Finland.

PubMed

Seitovirta, Jaana; Vehviläinen-Julkunen, Katri; Mitronen, Lasse; De Gieter, Sara; Kvist, Tarja

2017-04-01

To identify meaningful types of rewards and the consequences of rewards as expressed by Finnish registered nurses working in primary and private healthcare. Previous studies have found significant associations between nurses' rewards and both their commitment and job satisfaction. Furthermore, appropriate rewards can have beneficial effects on factors including workforce stability and occupational satisfaction that are highly important in times of nurse shortages. A cross-sectional, qualitative interview study. Data were collected via individual semi-structured interviews (n = 20) with registered nurses working in Finland's primary and private healthcare, and subjected to qualitative content analysis. Six meaningful types of rewards were identified by the registered nurses: Financial compensation and benefits, Work-Life balance, Work content, Professional development, Recognition, and Supportive leadership. Rewards encouraged respondents to perform their work correctly and reinforced occupational satisfaction, but also caused feelings of envy and stress. It is essential to pay attention to nurses' preferences for particular rewards and to reward management. When designing effective reward systems for registered nurses, it is not sufficient to provide financial rewards alone, as various kinds of non-financial rewards are both meaningful and necessary. When trying to improve registered nurses' commitment and job satisfaction through reward management, it is important to listen to nurses' opinions to create a reward system that integrates financial and non-financial rewards and is fair from their perspective. Healthcare organisations that offer registered nurses a holistic reward system are more likely to retain satisfied and committed nurses at a time of increasing nursing shortages. © 2016 John Wiley & Sons Ltd.

Mesolimbic recruitment by nondrug rewards in detoxified alcoholics: effort anticipation, reward anticipation, and reward delivery.

PubMed

Bjork, James M; Smith, Ashley R; Chen, Gang; Hommer, Daniel W

2012-09-01

Aberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol-dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: (1) cues to respond for monetary rewards, (2) post-response anticipation of rewards, or (3) delivery of rewards. Using an instrumental task with two-stage presentation of reward-predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”) or by delivery of a monetary reward (“Win?”). After a variable interval, subjects then viewed the trial outcome. We found no significant group differences in voxelwise activation by task contrasts, or in signal change extracted from VS. Both ADP and controls showed significant VS and other limbic recruitment by pre-response reward anticipation. In addition, controls also showed VS recruitment by post-response reward-anticipation, and ADP had appreciable subthreshold VS activation. Both groups also showed similar mesolimbic responses to reward deliveries. Across all subjects, a questionnaire measure of “hot” impulsivity correlated with VS recruitment by post-response anticipation of low rewards and with VS recruitment by delivery of low rewards. These findings indicate that incentive-motivational processing of nondrug rewards is substantially maintained in recovering alcoholics, and that reward-elicited VS recruitment correlates more with individual differences in trait impulsivity irrespective of addiction.

Cigarette craving is associated with blunted reward processing in nicotine-dependent smokers.

PubMed

Peechatka, Alyssa L; Whitton, Alexis E; Farmer, Stacey L; Pizzagalli, Diego A; Janes, Amy C

2015-10-01

Dysfunctional reward processing leading to the undervaluation of non-drug rewards is hypothesized to play a crucial role in nicotine dependence. However, it is unclear if blunted reward responsivity and the desire to use nicotine are directly linked after a brief period of abstinence. Such an association would suggest that individuals with reduced reward responsivity may be at increased risk to experience nicotine craving. Reward function was evaluated with a probabilistic reward task (PRT), which measures reward responsivity to monetary incentives. To identify whether smoking status influenced reward function, PRT performance was compared between non-depressed, nicotine-dependent smokers and non-smokers. Within smokers, correlations were conducted to determine if blunted reward responsivity on the PRT was associated with increased nicotine craving. Time since last nicotine exposure was standardized to 4h for all smokers. Smokers and non-smokers did not differ in reward responsivity on the PRT. However, within smokers, a significant negative correlation was found between reward responsivity and intensity of nicotine craving. The current findings show that, among smokers, the intensity of nicotine craving is linked to lower sensitivity to non-drug rewards. This finding is in line with prior theories that suggest reward dysfunction in some clinical populations (e.g., depressive disorders, schizophrenia) may facilitate nicotine use. The current study expands on such theories by indicating that sub-clinical variations in reward function are related to motivation for nicotine use. Identifying smokers who show blunted sensitivity to non-drug rewards may help guide treatments aimed at mitigating the motivation to smoke. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Monetary reward magnitude effects on behavior and brain function during goal-directed behavior.

PubMed

Rosell-Negre, P; Bustamante, J C; Fuentes-Claramonte, P; Costumero, V; Benabarre, S; Barrós-Loscertales, A

2017-08-01

Reward may modulate the cognitive processes required for goal achievement, while individual differences in personality may affect reward modulation. Our aim was to test how different monetary reward magnitudes modulate brain activation and performance during goal-directed behavior, and whether individual differences in reward sensitivity affect this modulation. For this purpose, we scanned 37 subjects with a parametric design in which we varied the magnitude of monetary rewards (€0, €0.01, €0.5, €1 or €1.5) in a blocked fashion while participants performed an interference counting-Stroop condition. The results showed that the brain activity of left dorsolateral prefrontal cortex (DLPFC) and the striatum were modulated by increasing and decreasing reward magnitudes, respectively. Behavioral performance improved as the magnitude of monetary reward increased while comparing the non reward (€0) condition to any other reward condition, or the lower €0.01 to any other reward condition, and this improvement was related with individual differences in reward sensitivity. In conclusion, the locus of influence of monetary incentives overlaps the activity of the regions commonly involved in cognitive control.

Adaptive neural reward processing during anticipation and receipt of monetary rewards in mindfulness meditators.

PubMed

Kirk, Ulrich; Brown, Kirk Warren; Downar, Jonathan

2015-05-01

Reward seeking is ubiquitous and adaptive in humans. But excessive reward seeking behavior, such as chasing monetary rewards, may lead to diminished subjective well-being. This study examined whether individuals trained in mindfulness meditation show neural evidence of lower susceptibility to monetary rewards. Seventy-eight participants (34 meditators, 44 matched controls) completed the monetary incentive delay task while undergoing functional magnetic resonance imaging. The groups performed equally on the task, but meditators showed lower neural activations in the caudate nucleus during reward anticipation, and elevated bilateral posterior insula activation during reward anticipation. Meditators also evidenced reduced activations in the ventromedial prefrontal cortex during reward receipt compared with controls. Connectivity parameters between the right caudate and bilateral anterior insula were attenuated in meditators during incentive anticipation. In summary, brain regions involved in reward processing-both during reward anticipation and receipt of reward-responded differently in mindfulness meditators than in nonmeditators, indicating that the former are less susceptible to monetary incentives. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Common and distinct networks underlying reward valence and processing stages: A meta-analysis of functional neuroimaging studies

PubMed Central

Liu, Xun; Hairston, Jacqueline; Schrier, Madeleine; Fan, Jin

2011-01-01

To better understand the reward circuitry in human brain, we conducted activation likelihood estimation (ALE) and parametric voxel-based meta-analyses (PVM) on 142 neuroimaging studies that examined brain activation in reward-related tasks in healthy adults. We observed several core brain areas that participated in reward-related decision making, including the nucleus accumbens (NAcc), caudate, putamen, thalamus, orbitofrontal cortex (OFC), bilateral anterior insula, anterior (ACC) and posterior (PCC) cingulate cortex, as well as cognitive control regions in the inferior parietal lobule and prefrontal cortex (PFC). The NAcc was commonly activated by both positive and negative rewards across various stages of reward processing (e.g., anticipation, outcome, and evaluation). In addition, the medial OFC and PCC preferentially responded to positive rewards, whereas the ACC, bilateral anterior insula, and lateral PFC selectively responded to negative rewards. Reward anticipation activated the ACC, bilateral anterior insula, and brain stem, whereas reward outcome more significantly activated the NAcc, medial OFC, and amygdala. Neurobiological theories of reward-related decision making should therefore distributed and interrelated representations of reward valuation and valence assessment into account. PMID:21185861

Neural dynamics of reward probability coding: a Magnetoencephalographic study in humans

PubMed Central

Thomas, Julie; Vanni-Mercier, Giovanna; Dreher, Jean-Claude

2013-01-01

Prediction of future rewards and discrepancy between actual and expected outcomes (prediction error) are crucial signals for adaptive behavior. In humans, a number of fMRI studies demonstrated that reward probability modulates these two signals in a large brain network. Yet, the spatio-temporal dynamics underlying the neural coding of reward probability remains unknown. Here, using magnetoencephalography, we investigated the neural dynamics of prediction and reward prediction error computations while subjects learned to associate cues of slot machines with monetary rewards with different probabilities. We showed that event-related magnetic fields (ERFs) arising from the visual cortex coded the expected reward value 155 ms after the cue, demonstrating that reward value signals emerge early in the visual stream. Moreover, a prediction error was reflected in ERF peaking 300 ms after the rewarded outcome and showing decreasing amplitude with higher reward probability. This prediction error signal was generated in a network including the anterior and posterior cingulate cortex. These findings pinpoint the spatio-temporal characteristics underlying reward probability coding. Together, our results provide insights into the neural dynamics underlying the ability to learn probabilistic stimuli-reward contingencies. PMID:24302894

A neuronal reward inequity signal in primate striatum

PubMed Central

van Coeverden, Charlotte R.; Schultz, Wolfram

2015-01-01

Primates are social animals, and their survival depends on social interactions with others. Especially important for social interactions and welfare is the observation of rewards obtained by other individuals and the comparison with own reward. The fundamental social decision variable for the comparison process is reward inequity, defined by an asymmetric reward distribution among individuals. An important brain structure for coding reward inequity may be the striatum, a component of the basal ganglia involved in goal-directed behavior. Two rhesus monkeys were seated opposite each other and contacted a touch-sensitive table placed between them to obtain specific magnitudes of reward that were equally or unequally distributed among them. Response times in one of the animals demonstrated differential behavioral sensitivity to reward inequity. A group of neurons in the striatum showed distinct signals reflecting disadvantageous and advantageous reward inequity. These neuronal signals occurred irrespective of, or in conjunction with, own reward coding. These data demonstrate that striatal neurons of macaque monkeys sense the differences between other's and own reward. The neuronal activities are likely to contribute crucial reward information to neuronal mechanisms involved in social interactions. PMID:26378202

"I'll have one of each": how separating rewards into (meaningless) categories increases motivation.

PubMed

Wiltermuth, Scott S; Gino, Francesca

2013-01-01

We propose that separating rewards into categories can increase motivation, even when those categories are meaningless. Across six experiments, people were more motivated to obtain one reward from one category and another reward from another category than they were to obtain two rewards from a pool that included all items from either reward category. As a result, they worked longer when potential rewards for their work were separated into meaningless categories. This categorization effect persisted regardless of whether the rewards were presented using a gain or loss frame. Using both moderation and mediation analyses, we found that categorizing rewards had these positive effects on motivation by increasing the degree to which people felt they would "miss out" if they did not obtain the second reward. We discuss implications for research on motivation and incentives.

Three real-time architectures - A study using reward models

NASA Technical Reports Server (NTRS)

Sjogren, J. A.; Smith, R. M.

1990-01-01

Numerous applications in the area of computer system analysis can be effectively studied with Markov reward models. These models describe the evolutionary behavior of the computer system by a continuous-time Markov chain, and a reward rate is associated with each state. In reliability/availability models, upstates have reward rate 1, and down states have reward rate zero associated with them. In a combined model of performance and reliability, the reward rate of a state may be the computational capacity, or a related performance measure. Steady-state expected reward rate and expected instantaneous reward rate are clearly useful measures which can be extracted from the Markov reward model. The diversity of areas where Markov reward models may be used is illustrated with a comparative study of three examples of interest to the fault tolerant computing community.

Reward modulates oculomotor competition between differently valued stimuli.

PubMed

Bucker, Berno; Silvis, Jeroen D; Donk, Mieke; Theeuwes, Jan

2015-03-01

The present work explored the effects of reward in the well-known global effect paradigm in which two objects appear simultaneously in close spatial proximity. The experiment consisted of three phases (i) a pre-training phase that served as a baseline, (ii) a reward-training phase to associate differently colored stimuli with high, low and no reward value, and (iii) a post-training phase in which rewards were no longer delivered, to examine whether objects previously associated with higher reward value attracted the eyes more strongly than those associated with low or no reward value. Unlike previous reward studies, the differently valued objects directly competed with each other on the same trial. The results showed that initially eye movements were not biased towards any particular stimulus, while in the reward-training phase, eye movements started to land progressively closer towards stimuli that were associated with a high reward value. Even though rewards were no longer delivered, this bias remained robustly present in the post-training phase. A time course analysis showed that the effect of reward was present for the fastest saccades (around 170 ms) and increased with increasing latency. Although strategic effects for slower saccades cannot be ruled out, we suggest that fast oculomotor responses became habituated and were no longer under strategic attentional control. Together the results imply that reward affects oculomotor competition in favor of stimuli previously associated high reward, when multiple reward associated objects compete for selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Atypical valuation of monetary and cigarette rewards in substance dependent smokers.

PubMed

Baker, Travis E; Wood, Jonathan M A; Holroyd, Clay B

2016-02-01

Substance dependent (SD) relative to non-dependent (ND) individuals exhibit an attenuated reward positivity, an electrophysiological signal believed to index sensitivity of anterior cingulate cortex (ACC) to rewards. Here we asked whether this altered neural response reflects a specific devaluation of monetary rewards relative to drug-related rewards by ACC. We recorded the reward positivity from SD and ND individuals who currently smoke, following an overnight period of abstinence, while they engaged in two feedback tasks. In a money condition the feedback indicated either a monetary reward or no reward, and in a cigarette condition the feedback indicated either a drug-related reward or no reward. Overall, cigarette relative to monetary rewards elicited a larger reward positivity. Further, for the subjects who engaged in the money condition first, the reward positivity was smaller for the SD compared to the ND participants, but for the subjects who engaged in the cigarette condition first, the reward positivity was larger for the SD compared to the ND participants. Our results suggest that the initial category of feedback "primed" the response of the ACC to the alternative feedback type on subsequent trials, and that SD and ND individuals responded differently to this priming effect. We propose that for people who misuse addictive substances, the prospect of obtaining drug-related rewards engages the ACC to exert control over extended behaviors. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Deficits in context-dependent adaptive coding of reward in schizophrenia

PubMed Central

Kirschner, Matthias; Hager, Oliver M; Bischof, Martin; Hartmann-Riemer, Matthias N; Kluge, Agne; Seifritz, Erich; Tobler, Philippe N; Kaiser, Stefan

2016-01-01

Theoretical principles of information processing and empirical findings suggest that to efficiently represent all possible rewards in the natural environment, reward-sensitive neurons have to adapt their coding range dynamically to the current reward context. Adaptation ensures that the reward system is most sensitive for the most likely rewards, enabling the system to efficiently represent a potentially infinite range of reward information. A deficit in neural adaptation would prevent precise representation of rewards and could have detrimental effects for an organism’s ability to optimally engage with its environment. In schizophrenia, reward processing is known to be impaired and has been linked to different symptom dimensions. However, despite the fundamental significance of coding reward adaptively, no study has elucidated whether adaptive reward processing is impaired in schizophrenia. We therefore studied patients with schizophrenia (n=27) and healthy controls (n=25), using functional magnetic resonance imaging in combination with a variant of the monetary incentive delay task. Compared with healthy controls, patients with schizophrenia showed less efficient neural adaptation to the current reward context, which leads to imprecise neural representation of reward. Importantly, the deficit correlated with total symptom severity. Our results suggest that some of the deficits in reward processing in schizophrenia might be due to inefficient neural adaptation to the current reward context. Furthermore, because adaptive coding is a ubiquitous feature of the brain, we believe that our findings provide an avenue in defining a general impairment in neural information processing underlying this debilitating disorder. PMID:27430009

7 CFR 1493.80 - Evidence of export.

Code of Federal Regulations, 2014 CFR

2014-01-01

... OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS CCC Export Credit Guarantee Program (GSM-102) and CCC Intermediate Export Credit Guarantee Program (GSM-103) Operations § 1493.80 Evidence of export. (a) Report of export. The exporter is required to provide CCC an evidence of export...

7 CFR 1493.80 - Evidence of export.

Code of Federal Regulations, 2013 CFR

2013-01-01

... OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS CCC Export Credit Guarantee Program (GSM-102) and CCC Intermediate Export Credit Guarantee Program (GSM-103) Operations § 1493.80 Evidence of export. (a) Report of export. The exporter is required to provide CCC an evidence of export...

7 CFR 1493.80 - Evidence of export.

Code of Federal Regulations, 2012 CFR

2012-01-01

... OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS CCC Export Credit Guarantee Program (GSM-102) and CCC Intermediate Export Credit Guarantee Program (GSM-103) Operations § 1493.80 Evidence of export. (a) Report of export. The exporter is required to provide CCC an evidence of export...

Materials flow analysis of neodymium, status of rare earth metal in the Republic of Korea.

PubMed

Swain, Basudev; Kang, Leeseung; Mishra, Chinmayee; Ahn, JoongWoo; Hong, Hyun Seon

2015-11-01

Materials flow analysis of neodymium, status of rare earth elements (REEs) in the Republic of Korea has been investigated. Information from various resources like the Korean Ministry of Environment, Korea international trade association, United Nations Commodity Trade Statistics Database and from individual industry were collected and analyzed for materials flow analysis of neodymium. Demand of neodymium in the Republic of Korea for the year 2010 was 409.5 tons out of which the majority of neodymium, i.e., 68.41% was consumed by domestic electronics industry followed by medical appliances manufacturing (13.36%). The Republic Korea is one of the biggest consumer and leading exporter of these industrial products, absolutely depends on import of neodymium, as the country is lacking natural resources. The Republic of Korea has imported 325.9 tons of neodymium permanent magnet and 79.5 tons of neodymium containing equipment parts mainly for electronics, medical appliances, and heavy/light vehicles manufacturing industry. Out of which 95.4 tons of neodymium permanent magnet get exported as an intermediate product and 140.6 tons of neodymium in the form of consumable products get exported. Worldwide the neodymium is at the high end of supply chain critical metal because of increasing demand, scarcity and irreplaceable for technological application. To bring back the neodymium to supply stream the recycling of end of life neodymium-bearing waste can be a feasible option. Out of total domestic consumption, only 21.9 tons of neodymium have been collected and subsequently recycled. From material flow analysis, the requirement for an efficient recycling system and element-wise material flow management for these REEs in the Republic of Korea were realized and recommended. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accelerating adoption of genetically modified crops in Africa through a trade liability regime.

PubMed

Smyth, Stuart J; Kerr, William A; Phillips, Peter W B

2013-06-01

Given the apparently unbridgeable divide that has developed between the 25 odd countries that grow and trade GM crops and the evolving EU regulatory hurdles, it may be time to consider alternative strategies for realizing a global market for agricultural products. Africa is one area of the world where the battle over GM agriculture is being played out, yet it is the continent where GM could have the greatest positive impact. Numerous African nations, given their long-standing trade connections to European nations, fear that allowing the commercialization of GM crops could lead to comingling of GM and conventional products and, hence, the loss of export opportunities to the EU. These are legitimate concerns. One potential solution that warrants serious consideration would be to establish a pool of funds that could be accessed by African agricultural commodity exporters in instances where exports to Europe are rejected. A production levy could be imposed in leading industrial adopting nations (i.e., Australia, Canada and the United States). The revenue raised would provide an endowment fund that could be used to offset the costs arising from import refusals. African-sourced shipments rejected by the EU will most certainly have alternate markets, but could receive a reduced price or incur higher costs associated with serving alternate markets. The intent of the fund would be to compensate for the real difference between the net returns contracted with European importers and the final market price received. This article examines the feasibility of establishing such a fund and discusses the funding options. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Reward Anticipation in Ventral Striatum and Individual Sensitivity to Reward: A Pilot Study of a Child-Friendly fMRI Task.

PubMed

van Hulst, Branko M; de Zeeuw, Patrick; Lupas, Kellina; Bos, Dienke J; Neggers, Sebastiaan F W; Durston, Sarah

2015-01-01

Reward processing has been implicated in developmental disorders. However, the classic task to probe reward anticipation, the monetary incentive delay task, has an abstract coding of reward and no storyline and may therefore be less appropriate for use with developmental populations. We modified the task to create a version appropriate for use with children. We investigated whether this child-friendly version could elicit ventral striatal activation during reward anticipation in typically developing children and young adolescents (aged 9.5-14.5). In addition, we tested whether our performance-based measure of reward sensitivity was associated with anticipatory activity in ventral striatum. Reward anticipation was related to activity in bilateral ventral striatum. Moreover, we found an association between individual reward sensitivity and activity in ventral striatum. We conclude that this task assesses ventral striatal activity in a child-friendly paradigm. The combination with a performance-based measure of reward sensitivity potentially makes the task a powerful tool for developmental imaging studies of reward processing.

It's about time: Earlier rewards increase intrinsic motivation.

PubMed

Woolley, Kaitlin; Fishbach, Ayelet

2018-06-01

Can immediate (vs. delayed) rewards increase intrinsic motivation? Prior research compared the presence versus absence of rewards. By contrast, this research compared immediate versus delayed rewards, predicting that more immediate rewards increase intrinsic motivation by creating a perceptual fusion between the activity and its goal (i.e., the reward). In support of the hypothesis, framing a reward from watching a news program as more immediate (vs. delayed) increased intrinsic motivation to watch the program (Study 1), and receiving more immediate bonus (vs. delayed, Study 2; and vs. delayed and no bonus, Study 3) increased intrinsic motivation in an experimental task. The effect of reward timing was mediated by the strength of the association between an activity and a reward, and was specific to intrinsic (vs. extrinsic) motivation-immediacy influenced the positive experience of an activity, but not perceived outcome importance (Study 4). In addition, the effect of the timing of rewards was independent of the effect of the magnitude of the rewards (Study 5). (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Distinct Roles for the Amygdala and Orbitofrontal Cortex in Representing the Relative Amount of Expected Reward.

PubMed

Saez, Rebecca A; Saez, Alexandre; Paton, Joseph J; Lau, Brian; Salzman, C Daniel

2017-07-05

The same reward can possess different motivational meaning depending upon its magnitude relative to other rewards. To study the neurophysiological mechanisms mediating assignment of motivational meaning, we recorded the activity of neurons in the amygdala and orbitofrontal cortex (OFC) of monkeys during a Pavlovian task in which the relative amount of liquid reward associated with one conditioned stimulus (CS) was manipulated by changing the reward amount associated with a second CS. Anticipatory licking tracked relative reward magnitude, implying that monkeys integrated information about recent rewards to adjust the motivational meaning of a CS. Upon changes in relative reward magnitude, neural responses to reward-predictive cues updated more rapidly in OFC than amygdala, and activity in OFC but not the amygdala was modulated by recent reward history. These results highlight a distinction between the amygdala and OFC in assessing reward history to support the flexible assignment of motivational meaning to sensory cues. Copyright © 2017 Elsevier Inc. All rights reserved.

Facilitation of voluntary goal-directed action by reward cues.

PubMed

Lovibond, Peter F; Colagiuri, Ben

2013-10-01

Reward-associated cues are known to influence motivation to approach both natural and man-made rewards, such as food and drugs. However, the mechanisms underlying these effects are not well understood. To model these processes in the laboratory with humans, we developed an appetitive Pavlovian-instrumental transfer procedure with a chocolate reward. We used a single unconstrained response that led to an actual rather than symbolic reward to assess the strength of reward motivation. Presentation of a chocolate-paired cue, but not an unpaired cue, markedly enhanced instrumental responding over a 30-s period. The same pattern was observed with 10-s and 30-s cues, showing that close cue-reward contiguity is not necessary for facilitation of reward-directed action. The results confirm that reward-related cues can instigate voluntary action to obtain that reward. The effectiveness of long-duration cues suggests that in clinical settings, attention should be directed to both proximal and distal cues for reward.

Nectar quality perception by honey bees (Apis mellifera ligustica).

PubMed

Sanderson, Charlotte E; Cook, Peyton; Hill, Peggy S M; Orozco, Benjamin S; Abramson, Charles I; Wells, Harrington

2013-11-01

In exploring how foragers perceive rewards, we often find that well-motivated individuals are not too choosy and unmotivated individuals are unreliable and inconsistent. Nevertheless, when given a choice we see that individuals can clearly distinguish between rewards. Here we develop the logic of using responses to two-choice problems as a derivative function of perceived reward, and utilize this model to examine honey bee perception of nectar quality. Measuring the derivative allows us to deduce the perceived reward function. The derivative function of the perceived reward equation gives the rate of change of the reward perceived for each reward value. This approach depends on presenting free-flying foragers with a series of two different rewards presented simultaneously (i.e., two-choice, binomial tests). We also examine how honey bees integrate information from a range of reward qualities to formulate a functional response. Results suggest that honey bees overestimate higher quality rewards and that direct comparison is an important step in the integration of information from a range of rewards.

Differential patterns of nucleus accumbens activation during anticipation of monetary and social reward in young and older adults.

PubMed

Rademacher, Lena; Salama, Aallaa; Gründer, Gerhard; Spreckelmeyer, Katja N

2014-06-01

Recent studies have reported inconsistent results regarding the loss of reward sensitivity in the aging brain. Although such an age effect might be due to a decline of physiological processes, it may also be a consequence of age-related changes in motivational preference for different rewards. Here, we examined whether the age effects on neural correlates of reward anticipation are modulated by the type of expected reward. Functional magnetic resonance images were acquired in 24 older (60-78 years) and 24 young participants (20-28 years) while they performed an incentive delay task offering monetary or social rewards. Anticipation of either reward type recruited brain structures associated with reward, including the nucleus accumbens (NAcc). Region of interest analysis revealed an interaction effect of reward type and age group in the right NAcc: enhanced activation to cues of social reward was detected in the older subsample while enhanced activation to cues of monetary reward was detected in the younger subsample. Our results suggest that neural sensitivity to reward-predicting cues does not generally decrease with age. Rather, neural responses in the NAcc appear to be modulated by the type of reward, presumably reflecting age-related changes in motivational value attributed to different types of reward. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Impaired Learning of Social Compared to Monetary Rewards in Autism

PubMed Central

Lin, Alice; Rangel, Antonio; Adolphs, Ralph

2012-01-01

A leading hypothesis to explain the social dysfunction in people with autism spectrum disorders (ASD) is that they exhibit a deficit in reward processing and motivation specific to social stimuli. However, there have been few direct tests of this hypothesis to date. Here we used an instrumental reward learning task that contrasted learning with social rewards (pictures of positive and negative faces) against learning with monetary reward (winning and losing money). The two tasks were structurally identical except for the type of reward, permitting direct comparisons. We tested 10 high-functioning people with ASD (7M, 3F) and 10 healthy controls who were matched on gender, age, and education. We found no significant differences between the two groups in terms of overall ability behaviorally to discriminate positive from negative slot machines, reaction-times, and valence ratings, However, there was a specific impairment in the ASD group in learning to choose social rewards, compared to monetary rewards: they had a significantly lower cumulative number of choices of the most rewarding social slot machine, and had a significantly slower initial learning rate for the socially rewarding slot machine, compared to the controls. The findings show a deficit in reward learning in ASD that is greater for social rewards than for monetary rewards, and support the hypothesis of a disproportionate impairment in social reward processing in ASD. PMID:23060743

75 FR 29514 - Export Trade Certificate of Review

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-26

... Operation described below in the following Export Trade and Export Markets: Export Trade Export Product ALCC... being headed and gutted. Export Markets The Export Markets include all parts of the world except the... engage in Export Trade in the Export Markets, ALCC and its Members may undertake the following activities...

Feasibility study for the Swaziland/Mozambique interconnector. Final report. Export trade information

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-11-01

This study, conducted by Black & Veatch, was funded by the U.S. Trade and Development Agency. The report, produced for the Ministry of National Resources, Energy and Environment (MNRE) of Swaziland, determines the least cost capacity expansion option to meet the future power demand and system reliability criteria of Swaziland, with particular emphasis on the proposed interconnector between Swaziland and Mozambique. Volume 2, the Final Report, contains the following sections: (1.0) Introduction; (2.0) Review of SEB Power System; (3.0) SEB Load Forecast and Review; (4.0) SEB Load Forecast Revision; (5.0) The SEB Need for Power; (6.0) SEB System Development Planmore » Review; (7.0) Southern Mozambique EdM power System Review; (8.0) Southern Mozambique EdM Energy and Demand; (9.0) Supply Side Capacity Options for Swaziland and Mozambique; (10.0) SEB Expansion Plan Development; (11.0) EdM Expansion Plan Development; (12.0) Cost Sharing of the Interconnector; (13.0) Enviroinmental Evaluation of Interconnector Options; (14.0) Generation/Transmission Trade Offs; (15.0) Draft Interconnection Agreement and Contract Packages; (16.0) Transmission System Study; (17.0) Automatic General Control; (18.0) Automatic Startup and Shutdown of Hydro Electric Power Plants; (19.0) Communications and Metering; (20.0) Conclusions and Recommendations; Appendix A: Demand Side Management Primer; Appendix B. PURPA and Avoided Cost Calculations.« less

Altered Reward Function in Adolescent Depression: What, When, and How?

PubMed Central

Forbes, Erika E.; Dahl, Ronald E.

2011-01-01

Background Conceptual models and recent evidence indicate that neural response to reward is altered in depression. Taking a developmental approach to investigating reward function in adolescent depression can elucidate the etiology, pathophysiology, and course of depression, a disorder that typically begins during adolescence and has high rates of recurrence. Methods This conceptual review describes the what, when, and how of altered reward function in adolescent depression. With the goal of generating new, testable hypotheses within a developmental affective neuroscience framework, we critically review findings and suggest future directions. Peer-reviewed empirical papers for inclusion in this critical review were obtained by searching PubMed, PsycInfo, and ScienceDirect for the years 1990–2010. Results A pattern of low striatal response and high medial prefrontal response to reward is evident in adolescents and adults with depression. Given the salience of social stimuli for positive affect and depression, reward function might be especially disrupted in response to social rewards. Because of changes in the dopamine system and reward function with aging, altered reward function in depression might be more evident during adolescence than later in life; however, low reward function may also be a stable characteristic of people who experience depression. Mechanisms of altered reward function in depression could include disrupted balance of corticostriatal circuit function, with disruption occurring as aberrant adolescent brain development. Conclusions Future studies should examine responses to social rewards; employ longitudinal and prospective designs; and investigate patterns of functional connectivity in reward circuits. Understanding altered reward function in depression has potential implications for treatment development. A more rigorous approach to investigating anhedonia, threat-reward interactions, and comorbid anxiety will be valuable to future progress in describing the role of reward function in the pathophysiology of depression. PMID:22117893

Effects of reward and punishment on brain activations associated with inhibitory control in cigarette smokers.

PubMed

Luijten, Maartje; O'Connor, David A; Rossiter, Sarah; Franken, Ingmar H A; Hester, Robert

2013-11-01

Susceptibility to use of addictive substances may result, in part, from a greater preference for an immediate small reward relative to a larger delayed reward or relative insensitivity to punishment. This functional magnetic resonance imaging (fMRI) study examined the neural basis of inhibiting an immediately rewarding stimulus to obtain a larger delayed reward in smokers. We also investigated whether punishment could modulate inhibitory control. The Monetary Incentive Go/NoGo (MI-Go/NoGo) task was administered that provided three types of reward outcomes contingent upon inhibitory control performance over rewarding stimuli: inhibition failure was either followed by no monetary reward (neutral condition), a small monetary reward with immediate feedback (reward condition) or immediate monetary punishment (punishment condition). In the reward and punishment conditions, successful inhibitory control resulted in larger delayed rewards. Community sample of smokers in the Melbourne (Australia) area. Nineteen smokers were compared with 17 demographically matched non-smoking controls. Accuracy, reaction times and brain activation associated with the MI-Go/NoGo task. Smokers showed hyperactivation in the right insula (P < 0.01), inferior and middle frontal gyrus (P < 0.01), dorsolateral prefrontal cortex (P = 0.001) and inferior parietal lobe (P < 0.01) both during inhibition of an immediately rewarding stimulus to obtain a larger delayed reward, and during inhibition of neutral stimuli. Group differences in brain activity were not significant in the punishment condition in the right insula and dorsolateral prefrontal cortex, most probably as a result of increased activation in non-smoking controls. Compared with non-smokers, smokers showed increased neural activation when resisting immediately rewarding stimuli and may be less sensitive to punishment as a strategy to increase control over rewarding stimuli. © 2013 Society for the Study of Addiction.

Mesolimbic recruitment by nondrug rewards in detoxified alcoholics: effort anticipation, reward anticipation and reward delivery

PubMed Central

Bjork, James M.; Smith, Ashley R.; Chen, Gang; Hommer, Daniel W.

2011-01-01

Aberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol-dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: 1) cues to respond for monetary rewards, 2) post-response anticipation of rewards, or 3) delivery of rewards. Using an instrumental task with two-stage presentation of reward-predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”) or by delivery of a monetary reward (“Win?”). After a variable interval, subjects then viewed the trial outcome. We found no significant group differences in voxelwise activation by task contrasts, or in signal change extracted from VS. Both ADP and controls showed significant VS and other limbic recruitment by pre-response reward anticipation. In addition, controls also showed VS recruitment by post-response reward-anticipation, and ADP had appreciable subthreshold VS activation. Both groups also showed similar mesolimbic responses to reward deliveries. Across all subjects, a questionnaire measure of “hot” impulsivity correlated with VS recruitment by post-response anticipation of low rewards and with VS recruitment by delivery of low rewards. These findings indicate that incentive-motivational processing of nondrug rewards is substantially maintained in recovering alcoholics, and that reward-elicited VS recruitment correlates more with individual differences in trait impulsivity irrespective of addiction. PMID:22281932

Effects of motivation on reward and attentional networks: an fMRI study.

PubMed

Ivanov, Iliyan; Liu, Xun; Clerkin, Suzanne; Schulz, Kurt; Friston, Karl; Newcorn, Jeffrey H; Fan, Jin

2012-11-01

Existing evidence suggests that reward and attentional networks function in concert and that activation in one system influences the other in a reciprocal fashion; however, the nature of these influences remains poorly understood. We therefore developed a three-component task to assess the interaction effects of reward anticipation and conflict resolution on the behavioral performance and the activation of brain reward and attentional systems. Sixteen healthy adult volunteers aged 21-45 years were scanned with functional magnetic resonance imaging (fMRI) while performing the task. A two-way repeated measures analysis of variance (ANOVA) with cue (reward vs. non-reward) and target (congruent vs. incongruent) as within-subjects factors was used to test for main and interaction effects. Neural responses to anticipation, conflict, and reward outcomes were tested. Behaviorally there were main effects of both reward cue and target congruency on reaction time. Neuroimaging results showed that reward anticipation and expected reward outcomes activated components of the attentional networks, including the inferior parietal and occipital cortices, whereas surprising non-rewards activated the frontoinsular cortex bilaterally and deactivated the ventral striatum. In turn, conflict activated a broad network associated with cognitive control and motor functions. Interaction effects showed decreased activity in the thalamus, anterior cingulated gyrus, and middle frontal gyrus bilaterally when difficult conflict trials (e.g., incongruent targets) were preceded by reward cues; in contrast, the ventral striatum and orbitofrontal cortex showed greater activation during congruent targets preceded by reward cues. These results suggest that reward anticipation is associated with lower activation in attentional networks, possibly due to increased processing efficiency, whereas more difficult, conflict trials are associated with lower activity in regions of the reward system, possibly because such trials are experienced as less rewarding.

Common alterations in sensitivity to type but not amount of reward in ADHD and autism spectrum disorders.

PubMed

Demurie, Ellen; Roeyers, Herbert; Baeyens, Dieter; Sonuga-Barke, Edmund

2011-11-01

Children with attention deficit/hyperactivity disorder (ADHD) display abnormalities in reward processing. Most reward studies have focused on the effects of material or monetary rewards. Studies with autism spectrum disorder (ASD) have focused on social rewards. In this study we compared the effects of amount and type of reward in children with ADHD and those with ASD. Two adapted versions of the Monetary Incentive Delay Task were used to study the effects of monetary and social reward anticipation on performance in 40 typically developing (TD) children and adolescents (8-16y), 35 children and adolescents with ADHD and 31 children and adolescents with ASD. Monetary and social reward improved accuracy and response time (RT) in all groups. The higher the anticipated reward, the more accurate and faster were responses. Independent of these effects, there was a differential effect of reward type. Both clinical groups, but not TD, responded faster for monetary than social rewards. The results, while not supporting hyposensitivity to changes in reward amount in ADHD and ASD, do suggest that both groups are generally less motivated in settings where social as opposed to monetary rewards can be earned. © 2011 The Authors. Journal of Child Psychology and Psychiatry. © 2011 Association for Child and Adolescent Mental Health.

Common and distinct neural features of social and non-social reward processing in autism and social anxiety disorder.

PubMed

Richey, John A; Rittenberg, Alison; Hughes, Lauren; Damiano, Cara R; Sabatino, Antoinette; Miller, Stephanie; Hanna, Eleanor; Bodfish, James W; Dichter, Gabriel S

2014-03-01

Autism spectrum disorders (ASDs) and social anxiety disorder (SAD) are both characterized by social dysfunction, but no study to date has compared neural responses to social rewards in ASDs and SAD. Neural responses during social and non-social reward anticipation and outcomes were examined in individuals with ASD (n = 16), SAD (n = 15) and a control group (n = 19) via functional magnetic resonance imaging. Analyses modeling all three groups revealed increased nucleus accumbens (NAc) activation in SAD relative to ASD during monetary reward anticipation, whereas both the SAD and ASD group demonstrated decreased bilateral NAc activation relative to the control group during social reward anticipation. During reward outcomes, the SAD group did not differ significantly from the other two groups in ventromedial prefrontal cortex activation to either reward type. Analyses comparing only the ASD and SAD groups revealed greater bilateral amygdala activation to social rewards in SAD relative to ASD during both anticipation and outcome phases, and the magnitude of left amygdala hyperactivation in the SAD group during social reward anticipation was significantly correlated with the severity of trait anxiety symptoms. Results suggest reward network dysfunction to both monetary and social rewards in SAD and ASD during reward anticipation and outcomes, but that NAc hypoactivation during monetary reward anticipation differentiates ASD from SAD.

Immaturities in Reward Processing and Its Influence on Inhibitory Control in Adolescence

PubMed Central

Terwilliger, R.; Teslovich, T.; Velanova, K.; Luna, B.

2010-01-01

The nature of immature reward processing and the influence of rewards on basic elements of cognitive control during adolescence are currently not well understood. Here, during functional magnetic resonance imaging, healthy adolescents and adults performed a modified antisaccade task in which trial-by-trial reward contingencies were manipulated. The use of a novel fast, event-related design enabled developmental differences in brain function underlying temporally distinct stages of reward processing and response inhibition to be assessed. Reward trials compared with neutral trials resulted in faster correct inhibitory responses across ages and in fewer inhibitory errors in adolescents. During reward trials, the blood oxygen level–dependent signal was attenuated in the ventral striatum in adolescents during cue assessment, then overactive during response preparation, suggesting limitations during adolescence in reward assessment and heightened reactivity in anticipation of reward compared with adults. Importantly, heightened activity in the frontal cortex along the precentral sulcus was also observed in adolescents during reward-trial response preparation, suggesting reward modulation of oculomotor control regions supporting correct inhibitory responding. Collectively, this work characterizes specific immaturities in adolescent brain systems that support reward processing and describes the influence of reward on inhibitory control. In sum, our findings suggest mechanisms that may underlie adolescents’ vulnerability to poor decision-making and risk-taking behavior. PMID:19875675

I endeavor to make it: effort increases valuation of subsequent monetary reward.

PubMed

Ma, Qingguo; Meng, Liang; Wang, Lei; Shen, Qiang

2014-03-15

Although it is commonly accepted that the amount of effort we put into accomplishing a task would exert an influence on subsequent reward processing and outcome evaluation, whether effort is incorporated as a cost or it would increase the valuation of concomitant reward is still under debate. In this study, EEGs were recorded while subjects performed calculation tasks that required different amount of effort, correct responses of which were followed by either no reward or fixed compensation. Results showed that high effort induced larger differentiated FRN responses to the reward and non-reward discrepancy across two experimental conditions. Furthermore, P300 manifested valence effect during reward feedback, with more positive amplitudes for reward than for non-reward only in the high effort condition. These results suggest that effort might increase subjective evaluation toward subsequent reward. Copyright © 2013 Elsevier B.V. All rights reserved.

Neural coding of basic reward terms of animal learning theory, game theory, microeconomics and behavioural ecology.

PubMed

Schultz, Wolfram

2004-04-01

Neurons in a small number of brain structures detect rewards and reward-predicting stimuli and are active during the expectation of predictable food and liquid rewards. These neurons code the reward information according to basic terms of various behavioural theories that seek to explain reward-directed learning, approach behaviour and decision-making. The involved brain structures include groups of dopamine neurons, the striatum including the nucleus accumbens, the orbitofrontal cortex and the amygdala. The reward information is fed to brain structures involved in decision-making and organisation of behaviour, such as the dorsolateral prefrontal cortex and possibly the parietal cortex. The neural coding of basic reward terms derived from formal theories puts the neurophysiological investigation of reward mechanisms on firm conceptual grounds and provides neural correlates for the function of rewards in learning, approach behaviour and decision-making.

Reward Processing, Neuroeconomics, and Psychopathology

PubMed Central

Zald, David H.; Treadway, Michael

2018-01-01

Abnormal reward processing is a prominent transdiagnostic feature of psychopathology. The present review provides a framework for considering the different aspects of reward processing and their assessment and highlight recent insights from the field of neuroeconomics that may aid in understanding these processes. Although altered reward processing in psychopathology has often been treated as a general hypo- or hyper-responsivity to reward, increasing data indicate that a comprehensive understanding of reward dysfunction requires characterization within more specific reward processing domains, including subjective valuation, discounting, hedonics, reward anticipation and facilitation, and reinforcement learning. As such, more nuanced models of the nature of these abnormalities are needed. We describe several processing abnormalities capable of producing the types of selective alterations in reward related behavior observed in different forms of psychopathology, including (mal)adaptive scaling and anchoring, dysfunctional weighting of reward and cost variables, completion between valuation systems, and positive prediction error signaling. PMID:28301764

Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively.

PubMed

Leon, M I; Gallistel, C R

1998-07-01

For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude.

What's the Point?: A Review of Reward Systems Implemented in Gamification Interventions.

PubMed

Lewis, Zakkoyya H; Swartz, Maria C; Lyons, Elizabeth J

2016-04-01

Rewards are commonly used in interventions to change behavior, but they can inhibit development of intrinsic motivation, which is associated with long-term behavior maintenance. Gamification is a novel intervention strategy that may target intrinsic motivation through fun and enjoyment. Before the effects of gamified interventions on motivation can be determined, there must be an understanding of how gamified interventions operationalize rewards, such as point systems. The purpose of this review is to determine the prevalence of different reward types, specifically point systems, within gamified interventions. Electronic databases were searched for relevant articles. Data sources included Medline OVID, Medline PubMed, Web of Science, CINAHL, Cochrane Central, and PsycINFO. Out of the 21 articles retrieved, 18 studies described a reward system and were included in this review. Gamified interventions were designed to target a myriad of clinical outcomes across diverse populations. Rewards included points (n = 14), achievements/badges/medals (n = 7), tangible rewards (n = 7), currency (n = 4), other unspecified rewards (n = 3), likes (n = 2), animated feedback (n = 1), and kudos (n = 1). Rewards, and points in particular, appear to be a foundational component of gamified interventions. Despite their prevalence, authors seldom described the use of noncontingent rewards or how the rewards interacted with other game features. The reward systems relying on tangible rewards and currency may have been limited by inhibited intrinsic motivation. As gamification proliferates, future research should explicitly describe how rewards were operationalized in the intervention and evaluate the effects of gamified rewards on motivation across populations and research outcomes.

Reward loss and the basolateral amygdala: A function in reward comparisons.

PubMed

Kawasaki, Katsuyoshi; Annicchiarico, Iván; Glueck, Amanda C; Morón, Ignacio; Papini, Mauricio R

2017-07-28

The neural circuitry underlying behavior in reward loss situations is poorly understood. We considered two such situations: reward devaluation (from large to small rewards) and reward omission (from large rewards to no rewards). There is evidence that the central nucleus of the amygdala (CeA) plays a role in the negative emotion accompanying reward loss. However, little is known about the function of the basolateral nucleus (BLA) in reward loss. Two hypotheses of BLA function in reward loss, negative emotion and reward comparisons, were tested in an experiment involving pretraining excitotoxic BLA lesions followed by training in four tasks: consummatory successive negative contrast (cSNC), autoshaping (AS) acquisition and extinction, anticipatory negative contrast (ANC), and open field testing (OF). Cell counts in the BLA (but not in the CeA) were significantly lower in animals with lesions vs. shams. BLA lesions eliminated cSNC and ANC, and accelerated extinction of lever pressing in AS. BLA lesions had no effect on OF testing: higher activity in the periphery than in the central area. This pattern of results provides support for the hypothesis that BLA neurons are important for reward comparison. The three affected tasks (cSNC, ANC, and AS extinction) involve reward comparisons. However, ANC does not seem to involve negative emotions and it was affected, whereas OF activity is known to involve negative emotion, but it was not affected. It is hypothesized that a circuit involving the thalamus, insular cortex, and BLA is critically involved in the mechanism comparing current and expected rewards. Copyright © 2017 Elsevier B.V. All rights reserved.

The tissue microarray data exchange specification: A document type definition to validate and enhance XML data

PubMed Central

Nohle, David G; Ayers, Leona W

2005-01-01

Background The Association for Pathology Informatics (API) Extensible Mark-up Language (XML) TMA Data Exchange Specification (TMA DES) proposed in April 2003 provides a community-based, open source tool for sharing tissue microarray (TMA) data in a common format. Each tissue core within an array has separate data including digital images; therefore an organized, common approach to produce, navigate and publish such data facilitates viewing, sharing and merging TMA data from different laboratories. The AIDS and Cancer Specimen Resource (ACSR) is a HIV/AIDS tissue bank consortium sponsored by the National Cancer Institute (NCI) Division of Cancer Treatment and Diagnosis (DCTD). The ACSR offers HIV-related malignancies and uninfected control tissues in microarrays (TMA) accompanied by de-identified clinical data to approved researchers. Exporting our TMA data into the proposed API specified format offers an opportunity to evaluate the API specification in an applied setting and to explore its usefulness. Results A document type definition (DTD) that governs the allowed common data elements (CDE) in TMA DES export XML files was written, tested and evolved and is in routine use by the ACSR. This DTD defines TMA DES CDEs which are implemented in an external file that can be supplemented by internal DTD extensions for locally defined TMA data elements (LDE). Conclusion ACSR implementation of the TMA DES demonstrated the utility of the specification and allowed application of a DTD to validate the language of the API specified XML elements and to identify possible enhancements within our TMA data management application. Improvements to the specification have additionally been suggested by our experience in importing other institution's exported TMA data. Enhancements to TMA DES to remove ambiguous situations and clarify the data should be considered. Better specified identifiers and hierarchical relationships will make automatic use of the data possible. Our tool can be used to reorder data and add identifiers; upgrading data for changes in the specification can be automatically accomplished. Using a DTD (optionally reflecting our proposed enhancements) can provide stronger validation of exported TMA data. PMID:15871741

Common Alterations in Sensitivity to Type but Not Amount of Reward in ADHD and Autism Spectrum Disorders

ERIC Educational Resources Information Center

Demurie, Ellen; Roeyers, Herbert; Baeyens, Dieter; Sonuga-Barke, Edmund

2011-01-01

Background: Children with attention deficit/hyperactivity disorder (ADHD) display abnormalities in reward processing. Most reward studies have focused on the effects of material or monetary rewards. Studies with autism spectrum disorder (ASD) have focused on social rewards. In this study we compared the effects of amount and type of reward in…

Social Influences on Creativity: Interactive Effects of Reward and Choice.

ERIC Educational Resources Information Center

Amabile, Teresa M.

In a test of intrinsic motivation hypothesis of creativity, 60 undergraduate women did an artistic creativity task with either the expectation of receiving a reward or no expectation of reward. Reward was crossed with choice in task engagement, such that half of the reward Ss contracted to do the task in order to receive reward, and half simply…

Registered nurses' experiences of rewarding in a Finnish University Hospital - an interview study.

PubMed

Seitovirta, Jaana; Partanen, Pirjo; Vehviläinen-Julkunen, Katri; Kvist, Tarja

2015-10-01

The purpose was to describe Finnish registered nurses' experiences of rewarding. The aim was to gather detailed information on the rewarding of nurses to help nurse managers and leaders to update existing reward strategy and to develop an effective reward system. Rewarding has been found positively to influence nurses' occupational well-being and commitment to their work, and the attractiveness of the health care field. A series of focused interviews with 10 registered nurses was conducted in 2011. Qualitative content analysis method was used. The nurses reported positive experiences with rewarding in the form of monetary compensation and other benefits, the positive aspects of nursing work and opportunities for professional development. The experiences of unsatisfactory rewarding generally stemmed from negative emotional experiences, lacking rewards and inequality in rewarding. It is essential to listen to nurses and to provide appropriate acknowledgement and appreciation of their work in order to develop an effective reward system. It is important to listen to nurses' experiences of rewarding because it enables nurse managers to maintain and increase the attractiveness of nursing and health care work in general. © 2014 John Wiley & Sons Ltd.

Real and hypothetical monetary rewards modulate risk taking in the brain.

PubMed

Xu, Sihua; Pan, Yu; Wang, You; Spaeth, Andrea M; Qu, Zhe; Rao, Hengyi

2016-07-07

Both real and hypothetical monetary rewards are widely used as reinforcers in risk taking and decision making studies. However, whether real and hypothetical monetary rewards modulate risk taking and decision making in the same manner remains controversial. In this study, we used event-related potentials (ERP) with a balloon analogue risk task (BART) paradigm to examine the effects of real and hypothetical monetary rewards on risk taking in the brain. Behavioral data showed reduced risk taking after negative feedback (money loss) during the BART with real rewards compared to those with hypothetical rewards, suggesting increased loss aversion with real monetary rewards. The ERP data demonstrated a larger feedback-related negativity (FRN) in response to money loss during risk taking with real rewards compared to those with hypothetical rewards, which may reflect greater prediction error or regret emotion after real monetary losses. These findings demonstrate differential effects of real versus hypothetical monetary rewards on risk taking behavior and brain activity, suggesting a caution when drawing conclusions about real choices from hypothetical studies of intended behavior, especially when large rewards are used. The results have implications for future utility of real and hypothetical monetary rewards in studies of risk taking and decision making.

Domain independence and stability in young and older adults' discounting of delayed rewards

PubMed Central

Jimura, Koji; Myerson, Joel; Hilgard, Joseph; Keighley, Julia; Braver, Todd S.; Green, Leonard

2011-01-01

Individual discounting rates for different types of delayed reward are typically assumed to reflect a single, underlying trait of impulsivity. Recently, we showed that discounting rates are orders of magnitude steeper for directly consumable liquid rewards than for monetary rewards (Jimura et al. 2009), raising the question of whether discounting rates for different types of reward covary at the individual level. Accordingly, the present study examined the relation between discounting of hypothetical money and real liquid rewards in young adults (Experiment 1) and older adults (Experiment 2). At the group level, young adults discounted monetary rewards more steeply than the older adults, but the reverse pattern was observed with liquid rewards. At the individual level, the rates at which young and older participants discounted each reward type were stable over a two- to fifteen-week interval (rs >.70), but there was no significant correlation between the rates at which they discounted the two reward types. These results suggest that although similar decision-making processes may underlie the discounting of different types of rewards, the rates at which individuals discount money and directly consumable rewards may reflect separate, stable traits, rather than a single trait of impulsivity. PMID:21550384

Facilitating or undermining? The effect of reward on food acceptance. A narrative review.

PubMed

Cooke, Lucy J; Chambers, Lucy C; Añez, Elizabeth V; Wardle, Jane

2011-10-01

Using rewards in child feeding is commonplace and viewed as effective by parents, although some express concern about using 'bribery'. Psychological and economic theorists emphasize the beneficial effects of rewards in enhancing performance, although, there is evidence that the offer of rewards undermines intrinsic motivation and decreases enjoyment of the rewarded task. In the food domain, results have been mixed, but this may be explained, at least partly in terms of the measured outcome (liking vs intake) and the initial level of motivation towards the target foods (liked vs disliked). Where intake is the outcome, rewards have had broadly positive effects, but when it is liking, rewards can have negative effects if the target food is already liked. Another issue concerns the type of reward offered. While offering food as a reward appear to be universally negative, there is evidence to suggest that non-food tangible rewards (e.g., stickers), or non-tangible rewards (praise) can be highly effective in encouraging children to taste new or less liked foods sufficiently often to benefit from the 'mere exposure' effect. We suggest that the judicious use of rewards may facilitate children's acceptance of healthy foods. Copyright © 2011 Elsevier Ltd. All rights reserved.

Role of Reward Sensitivity and Processing in Major Depressive and Bipolar Spectrum Disorders

PubMed Central

Alloy, Lauren B.; Olino, Thomas; Freed, Rachel D.; Nusslock, Robin

2016-01-01

Since Costello’s (1972) seminal Behavior Therapy article on loss of reinforcers or reinforcer effectiveness in depression, the role of reward sensitivity and processing in both depression and bipolar disorder has become a central area of investigation. In this article, we review the evidence for a model of reward sensitivity in mood disorders, with unipolar depression characterized by reward hyposensitivity and bipolar disorders by reward hypersensitivity. We address whether aberrant reward sensitivity and processing are correlates of, mood-independent traits of, vulnerabilities for, and/or predictors of the course of depression and bipolar spectrum disorders, covering evidence from self-report, behavioral, neurophysiological, and neural levels of analysis. We conclude that substantial evidence documents that blunted reward sensitivity and processing are involved in unipolar depression and heightened reward sensitivity and processing are characteristic of hypomania/mania. We further conclude that aberrant reward sensitivity has a trait component, but more research is needed to clearly demonstrate that reward hyposensitivity and hypersensitivity are vulnerabilities for depression and bipolar disorder, respectively. Moreover, additional research is needed to determine whether bipolar depression is similar to unipolar depression and characterized by reward hyposensitivity, or whether like bipolar hypomania/mania, it involves reward hypersensitivity. PMID:27816074

Altered neural reward representations in pathological gamblers revealed by delay and probability discounting.

PubMed

Miedl, Stephan F; Peters, Jan; Büchel, Christian

2012-02-01

The neural basis of excessive delay discounting and reduced risk sensitivity of pathological gamblers with a particular focus on subjective neural reward representations has not been previously examined. To examine how pathological gamblers represent subjective reward value at a neural level and how this is affected by gambling severity. Model-based functional magnetic resonance imaging study with patients and control subjects. Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf. Participants were recruited from the local community by advertisement and through self-help groups. A sample of 16 pathological gamblers (according to the DSM-IV definition) was matched by age, sex, smoking status, income, educational level, and handedness to 16 healthy controls. Pathological gamblers showed increased discounting of delayed rewards and a trend toward decreased discounting of probabilistic rewards compared with matched controls. At the neural level, a significant group × condition interaction indicated that reward representations in the gamblers were modulated in a condition-specific manner, such that they exhibited increased (delay discounting) and decreased (probability discounting) neural value correlations in the reward system. In addition, throughout the reward system, neuronal value signals for delayed rewards were negatively correlated with gambling severity. The results extend previous reports of a generally hypoactive reward system in pathological gamblers by showing that, even when subjective reward valuation is accounted for, gamblers still show altered reward representations. Furthermore, results point toward a gradual degradation of mesolimbic reward representations for delayed rewards during the course of pathological gambling.

Neural activation to monetary reward is associated with amphetamine reward sensitivity.

PubMed

Crane, Natania A; Gorka, Stephanie M; Weafer, Jessica; Langenecker, Scott A; de Wit, Harriet; Phan, K Luan

2018-03-14

One known risk factor for drug use and abuse is sensitivity to rewarding effects of drugs. It is not known whether this risk factor extends to sensitivity to non-drug rewards. In this study with healthy young adults, we examined the association between sensitivity to the subjective rewarding effects of amphetamine and a neural indicator of anticipation of monetary reward. We hypothesized that greater euphorigenic response to amphetamine would be associated with greater neural activation to anticipation of monetary reward (Win > Loss). Healthy participants (N = 61) completed four laboratory sessions in which they received d-amphetamine (20 mg) and placebo in alternating order, providing self-report measures of euphoria and stimulation at regular intervals. At a separate visit 1-3 weeks later, participants completed the guessing reward task (GRT) during fMRI in a drug-free state. Participants reporting greater euphoria after amphetamine also exhibited greater neural activation during monetary reward anticipation in mesolimbic reward regions, including the bilateral caudate and putamen. This is the first study to show a relationship between neural correlates of monetary reward and sensitivity to the subjective rewarding effects of amphetamine in humans. These findings support growing evidence that sensitivity to reward in general is a risk factor for drug use and abuse, and suggest that sensitivity of drug-induced euphoria may reflect a general sensitivity to rewards. This may be an index of vulnerability for drug use or abuse.

Differences in delay discounting between smokers and nonsmokers remain when both rewards are delayed

PubMed Central

Mitchell, Suzanne H.; Wilson, Vanessa B.

2013-01-01

Rationale When offered a choice between a small monetary reward available immediately (SmallNow) versus a larger reward available after a delay (LargeLater), smokers select the SmallNow alternative more than nonsmokers. That is, smokers discount the value of the LargeLater reward more than nonsmokers. Objectives To investigate whether this group difference was due to smokers overweighing the value of rewards available immediately compared with nonsmokers, we examined whether the group difference was also seen when both alternatives were delayed, i.e., when choosing between a SmallSoon reward and a LargeLater reward. Methods In Experiment 1, smokers and nonsmokers completed a task including SmallNow versus LargeLater choices and SmallSoon versus LargeLater choices. In Experiment 2, smokers and nonsmokers completed the same task but with hypothetical choices. Results Analyses using hyperbolic and double exponential (β-δ) models replicate prior findings that smokers discount the LargeLater reward more than nonsmokers when the smaller reward is available immediately. The smoker-nonsmoker difference was also seen when the smaller reward was slightly delayed, though this effect was primarily driven by heightened discounting in male smokers. However, for potentially real rewards only, this smoker-nonsmoker difference was significantly reduced when the smaller reward was delayed. Conclusions The smoker-nonsmoker difference in discounting is not confined to situations involving immediate rewards. Differences associated with potentially real vs. hypothetical rewards and gender underscore the complexity of the smoking-delay discounting relationship. PMID:21983917