The influence of spatial congruency and movement preparation time on saccade curvature in simultaneous and sequential dual-tasks.

PubMed

Moehler, Tobias; Fiehler, Katja

2015-11-01

Saccade curvature represents a sensitive measure of oculomotor inhibition with saccades curving away from covertly attended locations. Here we investigated whether and how saccade curvature depends on movement preparation time when a perceptual task is performed during or before saccade preparation. Participants performed a dual-task including a visual discrimination task at a cued location and a saccade task to the same location (congruent) or to a different location (incongruent). Additionally, we varied saccade preparation time (time between saccade cue and Go-signal) and the occurrence of the discrimination task (during saccade preparation=simultaneous vs. before saccade preparation=sequential). We found deteriorated perceptual performance in incongruent trials during simultaneous task performance while perceptual performance was unaffected during sequential task performance. Saccade accuracy and precision were deteriorated in incongruent trials during simultaneous and, to a lesser extent, also during sequential task performance. Saccades consistently curved away from covertly attended non-saccade locations. Saccade curvature was unaffected by movement preparation time during simultaneous task performance but decreased and finally vanished with increasing movement preparation time during sequential task performance. Our results indicate that the competing saccade plan to the covertly attended non-saccade location is maintained during simultaneous task performance until the perceptual task is solved while in the sequential condition, in which the discrimination task is solved prior to the saccade task, oculomotor inhibition decays gradually with movement preparation time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selective Impairments in Covert Shifts of Attention in Chinese Dyslexic Children.

PubMed

Ding, Yun; Zhao, Jing; He, Tao; Tan, Yufei; Zheng, Lingshuang; Wang, Zhiguo

2016-11-01

Reading depends heavily on the efficient shift of attention. Mounting evidence has suggested that dyslexics have deficits in covert attentional shift. However, it remains unclear whether dyslexics also have deficits in overt attentional shift. With the majority of relevant studies carried out in alphabetic writing systems, it is also unknown whether the attentional deficits observed in dyslexics are restricted to a particular writing system. The present study examined inhibition of return (IOR)-a major driving force of attentional shifts-in dyslexic children learning to read a logographic script (i.e., Chinese). Robust IOR effects were observed in both covert and overt attentional tasks in two groups of typically developing children, who were age- or reading ability-matched to the dyslexic children. In contrast, the dyslexic children showed IOR in the overt but not in the covert attentional task. We conclude that covert attentional shift is selectively impaired in dyslexic children. This impairment is not restricted to alphabetic writing systems, and it could be a significant contributor to the difficulties encountered by children learning to read. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Manipulating the disengage operation of covert visual spatial attention.

PubMed

Danckert, J; Maruff, P

1997-05-01

Processes of covert visual spatial attention have been closely linked to the programming of saccadic eye movements. In particular, it has been hypothesized that the reduction in saccadic latency that occurs in the gap paradigm is due to the prior disengagement of covert visual spatial attention. This explanation has received considerable criticism. No study as yet as attempted to demonstrate a facilitation of the disengagement of attention from a covertly attended object. If such facilitation were possible, it would support the hypothesis that the predisengagement of covert attention is necessary for the generation of express saccades. In two experiments using covert orienting of visual attention tasks (COVAT), with a high probability that targets would appear contralateral to the cued location, we attempted to facilitate the disengagement of covert attention by extinguishing peripheral cues prior to the appearance of targets. We hypothesized that the gap between cue offset and target onset would facilitate disengagement of attention from a covertly attended object. For both experiments, responses to targets appearing after a gap were slower than were responses in the no-gap condition. These results suggest that the prior offset of a covertly attended object does not facilitate the disengagement of attention.

The relationship between visual attention and visual working memory encoding: A dissociation between covert and overt orienting.

PubMed

Tas, A Caglar; Luck, Steven J; Hollingworth, Andrew

2016-08-01

There is substantial debate over whether visual working memory (VWM) and visual attention constitute a single system for the selection of task-relevant perceptual information or whether they are distinct systems that can be dissociated when their representational demands diverge. In the present study, we focused on the relationship between visual attention and the encoding of objects into VWM. Participants performed a color change-detection task. During the retention interval, a secondary object, irrelevant to the memory task, was presented. Participants were instructed either to execute an overt shift of gaze to this object (Experiments 1-3) or to attend it covertly (Experiments 4 and 5). Our goal was to determine whether these overt and covert shifts of attention disrupted the information held in VWM. We hypothesized that saccades, which typically introduce a memorial demand to bridge perceptual disruption, would lead to automatic encoding of the secondary object. However, purely covert shifts of attention, which introduce no such demand, would not result in automatic memory encoding. The results supported these predictions. Saccades to the secondary object produced substantial interference with VWM performance, but covert shifts of attention to this object produced no interference with VWM performance. These results challenge prevailing theories that consider attention and VWM to reflect a common mechanism. In addition, they indicate that the relationship between attention and VWM is dependent on the memorial demands of the orienting behavior. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The Relationship between Visual Attention and Visual Working Memory Encoding: A Dissociation between Covert and Overt Orienting

PubMed Central

Tas, A. Caglar; Luck, Steven J.; Hollingworth, Andrew

2016-01-01

There is substantial debate over whether visual working memory (VWM) and visual attention constitute a single system for the selection of task-relevant perceptual information or whether they are distinct systems that can be dissociated when their representational demands diverge. In the present study, we focused on the relationship between visual attention and the encoding of objects into visual working memory (VWM). Participants performed a color change-detection task. During the retention interval, a secondary object, irrelevant to the memory task, was presented. Participants were instructed either to execute an overt shift of gaze to this object (Experiments 1–3) or to attend it covertly (Experiments 4 and 5). Our goal was to determine whether these overt and covert shifts of attention disrupted the information held in VWM. We hypothesized that saccades, which typically introduce a memorial demand to bridge perceptual disruption, would lead to automatic encoding of the secondary object. However, purely covert shifts of attention, which introduce no such demand, would not result in automatic memory encoding. The results supported these predictions. Saccades to the secondary object produced substantial interference with VWM performance, but covert shifts of attention to this object produced no interference with VWM performance. These results challenge prevailing theories that consider attention and VWM to reflect a common mechanism. In addition, they indicate that the relationship between attention and VWM is dependent on the memorial demands of the orienting behavior. PMID:26854532

Decoding spectrotemporal features of overt and covert speech from the human cortex

PubMed Central

Martin, Stéphanie; Brunner, Peter; Holdgraf, Chris; Heinze, Hans-Jochen; Crone, Nathan E.; Rieger, Jochem; Schalk, Gerwin; Knight, Robert T.; Pasley, Brian N.

2014-01-01

Auditory perception and auditory imagery have been shown to activate overlapping brain regions. We hypothesized that these phenomena also share a common underlying neural representation. To assess this, we used electrocorticography intracranial recordings from epileptic patients performing an out loud or a silent reading task. In these tasks, short stories scrolled across a video screen in two conditions: subjects read the same stories both aloud (overt) and silently (covert). In a control condition the subject remained in a resting state. We first built a high gamma (70–150 Hz) neural decoding model to reconstruct spectrotemporal auditory features of self-generated overt speech. We then evaluated whether this same model could reconstruct auditory speech features in the covert speech condition. Two speech models were tested: a spectrogram and a modulation-based feature space. For the overt condition, reconstruction accuracy was evaluated as the correlation between original and predicted speech features, and was significant in each subject (p < 10−5; paired two-sample t-test). For the covert speech condition, dynamic time warping was first used to realign the covert speech reconstruction with the corresponding original speech from the overt condition. Reconstruction accuracy was then evaluated as the correlation between original and reconstructed speech features. Covert reconstruction accuracy was compared to the accuracy obtained from reconstructions in the baseline control condition. Reconstruction accuracy for the covert condition was significantly better than for the control condition (p < 0.005; paired two-sample t-test). The superior temporal gyrus, pre- and post-central gyrus provided the highest reconstruction information. The relationship between overt and covert speech reconstruction depended on anatomy. These results provide evidence that auditory representations of covert speech can be reconstructed from models that are built from an overt speech data set, supporting a partially shared neural substrate. PMID:24904404

Covert colour processing in colour agnosia.

PubMed

Nijboer, Tanja C W; van Zandvoort, Martine J E; de Haan, Edward H F

2006-01-01

Patients with colour agnosia can perceive colours and are able to match coloured patches on hue, but are unable to identify or categorise colours. It is a rare condition and there is as yet no agreement on the clinical definition or a generally accepted explanation. In line with observations from object agnosia and prosopagnosia, we hypothesised that (some of) these patients might still be able to process colour information at an implicit level. In this study, we investigated this possibility of implicit access to colour semantics and colour names in a man (MAH) who suffers from developmental colour agnosia. We designed two experimental computer tasks: an associative colour priming task with a lexical decision response and a reversed Stroop task. The results of these experiments suggest that there is indeed automatic processing of colour, although MAH was unable to explicitly use colour information.

Multichannel fNIRS Assessment of Overt and Covert Confrontation Naming

ERIC Educational Resources Information Center

Moriai-Izawa, Ayano; Dan, Haruka; Dan, Ippeita; Sano, Toshifumi; Oguro, Keiji; Yokota, Hidenori; Tsuzuki, Daisuke; Watanabe, Eiju

2012-01-01

Confrontation naming tasks assess cognitive processes involved in the main stage of word production. However, in fMRI, the occurrence of movement artifacts necessitates the use of covert paradigms, which has limited clinical applications. Thus, we explored the feasibility of adopting multichannel functional near-infrared spectroscopy (fNIRS) to…

Online EEG Classification of Covert Speech for Brain-Computer Interfacing.

PubMed

Sereshkeh, Alborz Rezazadeh; Trott, Robert; Bricout, Aurélien; Chau, Tom

2017-12-01

Brain-computer interfaces (BCIs) for communication can be nonintuitive, often requiring the performance of hand motor imagery or some other conversation-irrelevant task. In this paper, electroencephalography (EEG) was used to develop two intuitive online BCIs based solely on covert speech. The goal of the first BCI was to differentiate between 10[Formula: see text]s of mental repetitions of the word "no" and an equivalent duration of unconstrained rest. The second BCI was designed to discern between 10[Formula: see text]s each of covert repetition of the words "yes" and "no". Twelve participants used these two BCIs to answer yes or no questions. Each participant completed four sessions, comprising two offline training sessions and two online sessions, one for testing each of the BCIs. With a support vector machine and a combination of spectral and time-frequency features, an average accuracy of [Formula: see text] was reached across participants in the online classification of no versus rest, with 10 out of 12 participants surpassing the chance level (60.0% for [Formula: see text]). The online classification of yes versus no yielded an average accuracy of [Formula: see text], with eight participants exceeding the chance level. Task-specific changes in EEG beta and gamma power in language-related brain areas tended to provide discriminatory information. To our knowledge, this is the first report of online EEG classification of covert speech. Our findings support further study of covert speech as a BCI activation task, potentially leading to the development of more intuitive BCIs for communication.

People and Planned Change/Manipulation versus Modification.

ERIC Educational Resources Information Center

West, Bob; Dormant, Diane

1979-01-01

Presents excerpts from a workshop (on change agentry) participant's letter in which he disagrees with equating "covert,""overt," and "infiltrate" with the unethical manipulation of people. He defines covert and overt methods of influencing decision makers and identifies methods that could be borrowed from other areas to broaden options. (Author/JD)

Reward-dependent learning in neuronal networks for planning and decision making.

PubMed

Dehaene, S; Changeux, J P

2000-01-01

Neuronal network models have been proposed for the organization of evaluation and decision processes in prefrontal circuitry and their putative neuronal and molecular bases. The models all include an implementation and simulation of an elementary reward mechanism. Their central hypothesis is that tentative rules of behavior, which are coded by clusters of active neurons in prefrontal cortex, are selected or rejected based on an evaluation by this reward signal, which may be conveyed, for instance, by the mesencephalic dopaminergic neurons with which the prefrontal cortex is densely interconnected. At the molecular level, the reward signal is postulated to be a neurotransmitter such as dopamine, which exerts a global modulatory action on prefrontal synaptic efficacies, either via volume transmission or via targeted synaptic triads. Negative reinforcement has the effect of destabilizing the currently active rule-coding clusters; subsequently, spontaneous activity varies again from one cluster to another, giving the organism the chance to discover and learn a new rule. Thus, reward signals function as effective selection signals that either maintain or suppress currently active prefrontal representations as a function of their current adequacy. Simulations of this variation-selection have successfully accounted for the main features of several major tasks that depend on prefrontal cortex integrity, such as the delayed-response test, the Wisconsin card sorting test, the Tower of London test and the Stroop test. For the more complex tasks, we have found it necessary to supplement the external reward input with a second mechanism that supplies an internal reward; it consists of an auto-evaluation loop which short-circuits the reward input from the exterior. This allows for an internal evaluation of covert motor intentions without actualizing them as behaviors, by simply testing them covertly by comparison with memorized former experiences. This element of architecture gives access to enhanced rates of learning via an elementary process of internal or covert mental simulation. We have recently applied these ideas to a new model, developed with M. Kerszberg, which hypothesizes that prefrontal cortex and its reward-related connections contribute crucially to conscious effortful tasks. This model distinguishes two main computational spaces within the human brain: a unique global workspace composed of distributed and heavily interconnected neurons with long-range axons, and a set of specialized and modular perceptual, motor, memory, evaluative and attentional processors. We postulate that workspace neurons are mobilized in effortful tasks for which the specialized processors do not suffice; they selectively mobilize or suppress, through descending connections, the contribution of specific processor neurons. In the course of task performance, workspace neurons become spontaneously co-activated, forming discrete though variable spatio-temporal patterns subject to modulation by vigilance signals and to selection by reward signals. A computer simulation of the Stroop task shows workspace activation to increase during acquisition of a novel task, effortful execution, and after errors. This model makes predictions concerning the spatio-temporal activation patterns during brain imaging of cognitive tasks, particularly concerning the conditions of activation of dorsolateral prefrontal cortex and anterior cingulate, their relation to reward mechanisms, and their specific reaction during error processing.

Color vision in ADHD: part 2--does attention influence color perception?

PubMed

Kim, Soyeon; Al-Haj, Mohamed; Fuller, Stuart; Chen, Samantha; Jain, Umesh; Carrasco, Marisa; Tannock, Rosemary

2014-10-24

To investigate the impact of exogenous covert attention on chromatic (blue and red) and achromatic visual perception in adults with and without Attention Deficit Hyperactivity Disorder (ADHD). Exogenous covert attention, which is a transient, automatic, stimulus-driven form of attention, is a key mechanism for selecting relevant information in visual arrays. 30 adults diagnosed with ADHD and 30 healthy adults, matched on age and gender, performed a psychophysical task designed to measure the effects of exogenous covert attention on perceived color saturation (blue, red) and contrast sensitivity. The effects of exogenous covert attention on perceived blue and red saturation levels and contrast sensitivity were similar in both groups, with no differences between males and females. Specifically, exogenous covert attention enhanced the perception of blue saturation and contrast sensitivity, but it had no effect on the perception of red saturation. The findings suggest that exogenous covert attention is intact in adults with ADHD and does not account for the observed impairments in the perception of chromatic (blue and red) saturation.

Inhibition of return in the covert deployment of attention: evidence from human electrophysiology.

PubMed

McDonald, John J; Hickey, Clayton; Green, Jessica J; Whitman, Jennifer C

2009-04-01

People are slow to react to objects that appear at recently attended locations. This delay-known as inhibition of return (IOR)-is believed to aid search of the visual environment by discouraging inspection of recently inspected objects. However, after two decades of research, there is no evidence that IOR reflects an inhibition in the covert deployment of attention. Here, observers participated in a modified visual-search task that enabled us to measure IOR and an ERP component called the posterior contralateral N2 (N2pc) that reflects the covert deployment of attention. The N2pc was smaller when a target appeared at a recently attended location than when it appeared at a recently unattended location. This reduction was due to modulation of neural processing in the visual cortex and the right parietal lobe. Importantly, there was no evidence for a delay in the N2pc. We conclude that in our task, the inhibitory processes underlying IOR reduce the probability of shifting attention to recently attended locations but do not delay the covert deployment of attention itself.

Covert spatial attention is functionally intact in amblyopic human adults.

PubMed

Roberts, Mariel; Cymerman, Rachel; Smith, R Theodore; Kiorpes, Lynne; Carrasco, Marisa

2016-12-01

Certain abnormalities in behavioral performance and neural signaling have been attributed to a deficit of visual attention in amblyopia, a neurodevelopmental disorder characterized by a diverse array of visual deficits following abnormal binocular childhood experience. Critically, most have inferred attention's role in their task without explicitly manipulating and measuring its effects against a baseline condition. Here, we directly investigate whether human amblyopic adults benefit from covert spatial attention-the selective processing of visual information in the absence of eye movements-to the same degree as neurotypical observers. We manipulated both involuntary (Experiment 1) and voluntary (Experiment 2) attention during an orientation discrimination task for which the effects of covert spatial attention have been well established in neurotypical and special populations. In both experiments, attention significantly improved accuracy and decreased reaction times to a similar extent (a) between the eyes of the amblyopic adults and (b) between the amblyopes and their age- and gender-matched controls. Moreover, deployment of voluntary attention away from the target location significantly impaired task performance (Experiment 2). The magnitudes of the involuntary and voluntary attention benefits did not correlate with amblyopic depth or severity. Both groups of observers showed canonical performance fields (better performance along the horizontal than vertical meridian and at the lower than upper vertical meridian) and similar effects of attention across locations. Despite their characteristic low-level vision impairments, covert spatial attention remains functionally intact in human amblyopic adults.

Covert Auditory Spatial Orienting: An Evaluation of the Spatial Relevance Hypothesis

ERIC Educational Resources Information Center

Roberts, Katherine L.; Summerfield, A. Quentin; Hall, Deborah A.

2009-01-01

The spatial relevance hypothesis (J. J. McDonald & L. M. Ward, 1999) proposes that covert auditory spatial orienting can only be beneficial to auditory processing when task stimuli are encoded spatially. We present a series of experiments that evaluate 2 key aspects of the hypothesis: (a) that "reflexive activation of location-sensitive neurons is…

Pupillary correlates of covert shifts of attention during working memory maintenance.

PubMed

Unsworth, Nash; Robison, Matthew K

2017-04-01

The pupillary light reflex (PLR) was used to track covert shifts of attention to items maintained in visual working memory (VWM). In three experiments, participants performed a change detection task in which rectangles appeared on either side of fixation and at test participants indicated if the cued rectangle changed its orientation. Prior to presentation or during the delay, participants were cued to the light or dark side of the screen. When cued to the light side, the pupil constricted, and when cued to the dark side, the pupil dilated, suggesting that the PLR tracked covert shifts of attention. Similar covert shifts of attention were seen when the target stimuli remained onscreen and during a blank delay period, suggesting similar effects for attention to perceptual stimuli and attention to stimuli maintained in VWM. Furthermore, similar effects were demonstrated when participants were pre-cued or retro-cued to the prioritized location, suggesting that shifts of covert attention can occur both before and after target presentation. These results are consistent with prior research, suggesting an important role of covert shifts of attention during VWM maintenance and that the PLR can be used to track these covert shifts of attention.

A Multi-Area Stochastic Model for a Covert Visual Search Task.

PubMed

Schwemmer, Michael A; Feng, Samuel F; Holmes, Philip J; Gottlieb, Jacqueline; Cohen, Jonathan D

2015-01-01

Decisions typically comprise several elements. For example, attention must be directed towards specific objects, their identities recognized, and a choice made among alternatives. Pairs of competing accumulators and drift-diffusion processes provide good models of evidence integration in two-alternative perceptual choices, but more complex tasks requiring the coordination of attention and decision making involve multistage processing and multiple brain areas. Here we consider a task in which a target is located among distractors and its identity reported by lever release. The data comprise reaction times, accuracies, and single unit recordings from two monkeys' lateral interparietal area (LIP) neurons. LIP firing rates distinguish between targets and distractors, exhibit stimulus set size effects, and show response-hemifield congruence effects. These data motivate our model, which uses coupled sets of leaky competing accumulators to represent processes hypothesized to occur in feature-selective areas and limb motor and pre-motor areas, together with the visual selection process occurring in LIP. Model simulations capture the electrophysiological and behavioral data, and fitted parameters suggest that different connection weights between LIP and the other cortical areas may account for the observed behavioral differences between the animals.

Covert spatial attention is functionally intact in amblyopic human adults

PubMed Central

Roberts, Mariel; Cymerman, Rachel; Smith, R. Theodore; Kiorpes, Lynne; Carrasco, Marisa

2016-01-01

Certain abnormalities in behavioral performance and neural signaling have been attributed to a deficit of visual attention in amblyopia, a neurodevelopmental disorder characterized by a diverse array of visual deficits following abnormal binocular childhood experience. Critically, most have inferred attention's role in their task without explicitly manipulating and measuring its effects against a baseline condition. Here, we directly investigate whether human amblyopic adults benefit from covert spatial attention—the selective processing of visual information in the absence of eye movements—to the same degree as neurotypical observers. We manipulated both involuntary (Experiment 1) and voluntary (Experiment 2) attention during an orientation discrimination task for which the effects of covert spatial attention have been well established in neurotypical and special populations. In both experiments, attention significantly improved accuracy and decreased reaction times to a similar extent (a) between the eyes of the amblyopic adults and (b) between the amblyopes and their age- and gender-matched controls. Moreover, deployment of voluntary attention away from the target location significantly impaired task performance (Experiment 2). The magnitudes of the involuntary and voluntary attention benefits did not correlate with amblyopic depth or severity. Both groups of observers showed canonical performance fields (better performance along the horizontal than vertical meridian and at the lower than upper vertical meridian) and similar effects of attention across locations. Despite their characteristic low-level vision impairments, covert spatial attention remains functionally intact in human amblyopic adults. PMID:28033433

EEG predictors of covert vigilant attention

NASA Astrophysics Data System (ADS)

Martel, Adrien; Dähne, Sven; Blankertz, Benjamin

2014-06-01

Objective. The present study addressed the question whether neurophysiological signals exhibit characteristic modulations preceding a miss in a covert vigilant attention task which mimics a natural environment in which critical stimuli may appear in the periphery of the visual field. Approach. Subjective, behavioural and encephalographic (EEG) data of 12 participants performing a modified Mackworth Clock task were obtained and analysed offline. The stimulus consisted of a pointer performing regular ticks in a clockwise sequence across 42 dots arranged in a circle. Participants were requested to covertly attend to the pointer and press a response button as quickly as possible in the event of a jump, a rare and random event. Main results. Significant increases in response latencies and decreases in the detection rates were found as a function of time-on-task, a characteristic effect of sustained attention tasks known as the vigilance decrement. Subjective sleepiness showed a significant increase over the duration of the experiment. Increased activity in the α-frequency range (8-14 Hz) was observed emerging and gradually accumulating 10 s before a missed target. Additionally, a significant gradual attenuation of the P3 event-related component was found to antecede misses by 5 s. Significance. The results corroborate recent findings that behavioural errors are presaged by specific neurophysiological activity and demonstrate that lapses of attention can be predicted in a covert setting up to 10 s in advance reinforcing the prospective use of brain-computer interface (BCI) technology for the detection of waning vigilance in real-world scenarios. Combining these findings with real-time single-trial analysis from BCI may pave the way for cognitive states monitoring systems able to determine the current, and predict the near-future development of the brain's attentional processes.

Exercise-Induced Fatigue and Caffeine Supplementation Affect Psychomotor Performance but Not Covert Visuo-Spatial Attention

PubMed Central

Connell, Charlotte J. W.; Thompson, Benjamin; Kuhn, Gustav; Gant, Nicholas

2016-01-01

Fatigue resulting from strenuous exercise can impair cognition and oculomotor control. These impairments can be prevented by administering psychostimulants such as caffeine. This study used two experiments to explore the influence of caffeine administered at rest and during fatiguing physical exercise on spatial attention—a cognitive function that is crucial for task-based visually guided behavior. In independent placebo-controlled studies, cohorts of 12 healthy participants consumed caffeine and rested or completed 180 min of stationary cycling. Covert attentional orienting was measured in both experiments using a spatial cueing paradigm. We observed no alterations in attentional facilitation toward spatial cues suggesting that covert attentional orienting is not influenced by exercise fatigue or caffeine supplementation. Response times were increased (impaired) after exercise and this deterioration was prevented by caffeine supplementation. In the resting experiment, response times across all conditions and cues were decreased (improved) with caffeine. Covert spatial attention was not influenced by caffeine. Together, the results of these experiments suggest that covert attentional orienting is robust to the effects of fatiguing exercise and not influenced by caffeine. However, exercise fatigue impairs response times, which can be prevented by caffeine, suggesting that pre-motor planning and execution of the motor responses required for performance of the cueing task are sensitive to central nervous system fatigue. Caffeine improves response time in both fatigued and fresh conditions, most likely through action on networks controlling motor function. PMID:27768747

Exercise-Induced Fatigue and Caffeine Supplementation Affect Psychomotor Performance but Not Covert Visuo-Spatial Attention.

PubMed

Connell, Charlotte J W; Thompson, Benjamin; Kuhn, Gustav; Gant, Nicholas

2016-01-01

Fatigue resulting from strenuous exercise can impair cognition and oculomotor control. These impairments can be prevented by administering psychostimulants such as caffeine. This study used two experiments to explore the influence of caffeine administered at rest and during fatiguing physical exercise on spatial attention-a cognitive function that is crucial for task-based visually guided behavior. In independent placebo-controlled studies, cohorts of 12 healthy participants consumed caffeine and rested or completed 180 min of stationary cycling. Covert attentional orienting was measured in both experiments using a spatial cueing paradigm. We observed no alterations in attentional facilitation toward spatial cues suggesting that covert attentional orienting is not influenced by exercise fatigue or caffeine supplementation. Response times were increased (impaired) after exercise and this deterioration was prevented by caffeine supplementation. In the resting experiment, response times across all conditions and cues were decreased (improved) with caffeine. Covert spatial attention was not influenced by caffeine. Together, the results of these experiments suggest that covert attentional orienting is robust to the effects of fatiguing exercise and not influenced by caffeine. However, exercise fatigue impairs response times, which can be prevented by caffeine, suggesting that pre-motor planning and execution of the motor responses required for performance of the cueing task are sensitive to central nervous system fatigue. Caffeine improves response time in both fatigued and fresh conditions, most likely through action on networks controlling motor function.

The Necessity for the Military Assistance Command--Vietnam Studies and Observations Group

DTIC Science & Technology

2015-06-12

officials, as well as then-Colonel Edward Lansdale. An opponent of President Eisenhower’s laissez - faire attitude towards French Colonialism, the... leadership since the military was now tasked to 3 John Plaster, SOG: The Secret Wars of America’s...University of California Press Berkeley, 1972), 2. 9 oversee covert military actions. The military leadership argued that covert actions were not

Bayesian accounts of covert selective attention: A tutorial review.

PubMed

Vincent, Benjamin T

2015-05-01

Decision making and optimal observer models offer an important theoretical approach to the study of covert selective attention. While their probabilistic formulation allows quantitative comparison to human performance, the models can be complex and their insights are not always immediately apparent. Part 1 establishes the theoretical appeal of the Bayesian approach, and introduces the way in which probabilistic approaches can be applied to covert search paradigms. Part 2 presents novel formulations of Bayesian models of 4 important covert attention paradigms, illustrating optimal observer predictions over a range of experimental manipulations. Graphical model notation is used to present models in an accessible way and Supplementary Code is provided to help bridge the gap between model theory and practical implementation. Part 3 reviews a large body of empirical and modelling evidence showing that many experimental phenomena in the domain of covert selective attention are a set of by-products. These effects emerge as the result of observers conducting Bayesian inference with noisy sensory observations, prior expectations, and knowledge of the generative structure of the stimulus environment.

Covert retrieval in working memory impacts the phenomenological characteristics remembered during episodic memory.

PubMed

Loaiza, Vanessa M; Borovanska, Borislava M

2018-01-01

Much research has investigated the qualitative experience of retrieving events from episodic memory (EM). The present study investigated whether covert retrieval in WM increases the phenomenological characteristics that participants find memorable in EM using tasks that distract attention from the maintenance of memoranda (i.e., complex span; Experiment 1) relative to tasks that do not (i.e., short or long list lengths of simple span; Experiments 1 and 2). Participants rated the quality of the phonological, semantic, and temporal-contextual characteristics remembered during a delayed memory characteristics questionnaire (MCQ). Whereas an advantage of the complex over simple span items was observed for each characteristic (Experiment 1), no such difference was observed between short and long trials of simple span (Experiment 2). These results are consistent with the view that covert retrieval in WM promotes content-context bindings that are later accessible from EM for both objective performance and subjective details of the remembered information. Copyright © 2017 Elsevier Inc. All rights reserved.

Adults with Dyslexia Demonstrate Space-Based and Object-Based Covert Attention Deficits: Shifting Attention to the Periphery and Shifting Attention between Objects in the Left Visual Field

ERIC Educational Resources Information Center

Buchholz, J.; Davies, A.A.

2005-01-01

Performance on a covert visual attention task is compared between a group of adults with developmental dyslexia (specifically phonological difficulties) and a group of age and IQ matched controls. The group with dyslexia were generally slower to detect validly-cued targets. Costs of shifting attention toward the periphery when the target was…

Attention Dysfunction Subtypes of Developmental Dyslexia

PubMed Central

Lewandowska, Monika; Milner, Rafał; Ganc, Małgorzata; Włodarczyk, Elżbieta; Skarżyński, Henryk

2014-01-01

Background Previous studies indicate that many different aspects of attention are impaired in children diagnosed with developmental dyslexia (DD). The objective of the present study was to identify cognitive profiles of DD on the basis of attentional test performance. Material/Methods 78 children with DD (30 girls, 48 boys, mean age of 12 years ±8 months) and 32 age- and sex-matched non-dyslexic children (14 girls, 18 boys) were examined using a battery of standardized tests of reading, phonological and attentional processes (alertness, covert shift of attention, divided attention, inhibition, flexibility, vigilance, and visual search). Cluster analysis was used to identify subtypes of DD. Results Dyslexic children showed deficits in alertness, covert shift of attention, divided attention, flexibility, and visual search. Three different subtypes of DD were identified, each characterized by poorer performance on the reading, phonological awareness, and visual search tasks. Additionally, children in cluster no. 1 displayed deficits in flexibility and divided attention. In contrast to non-dyslexic children, cluster no. 2 performed poorer in tasks involving alertness, covert shift of attention, divided attention, and vigilance. Cluster no. 3 showed impaired covert shift of attention. Conclusions These results indicate different patterns of attentional impairments in dyslexic children. Remediation programs should address the individual child’s deficit profile. PMID:25387479

Fixations to the eyes aids in facial encoding; covertly attending to the eyes does not.

PubMed

Laidlaw, Kaitlin E W; Kingstone, Alan

2017-02-01

When looking at images of faces, people will often focus their fixations on the eyes. It has previously been demonstrated that the eyes convey important information that may improve later facial recognition. Whether this advantage requires that the eyes be fixated, or merely attended to covertly (i.e. while looking elsewhere), is unclear from previous work. While attending to the eyes covertly without fixating them may be sufficient, the act of using overt attention to fixate the eyes may improve the processing of important details used for later recognition. In the present study, participants were shown a series of faces and, in Experiment 1, asked to attend to them normally while avoiding looking at either the eyes or, as a control, the mouth (overt attentional avoidance condition); or in Experiment 2 fixate the center of the face while covertly attending to either the eyes or the mouth (covert attention condition). After the first phase, participants were asked to perform an old/new face recognition task. We demonstrate that a) when fixations to the eyes are avoided during initial viewing then subsequent face discrimination suffers, and b) covert attention to the eyes alone is insufficient to improve face discrimination performance. Together, these findings demonstrate that fixating the eyes provides an encoding advantage that is not availed by covert attention alone. Copyright © 2016 Elsevier B.V. All rights reserved.

Neuronal basis of covert spatial attention in the frontal eye field.

PubMed

Thompson, Kirk G; Biscoe, Keri L; Sato, Takashi R

2005-10-12

The influential "premotor theory of attention" proposes that developing oculomotor commands mediate covert visual spatial attention. A likely source of this attentional bias is the frontal eye field (FEF), an area of the frontal cortex involved in converting visual information into saccade commands. We investigated the link between FEF activity and covert spatial attention by recording from FEF visual and saccade-related neurons in monkeys performing covert visual search tasks without eye movements. Here we show that the source of attention signals in the FEF is enhanced activity of visually responsive neurons. At the time attention is allocated to the visual search target, nonvisually responsive saccade-related movement neurons are inhibited. Therefore, in the FEF, spatial attention signals are independent of explicit saccade command signals. We propose that spatially selective activity in FEF visually responsive neurons corresponds to the mental spotlight of attention via modulation of ongoing visual processing.

Speed-Accuracy Tradeoff Operator Characteristics of Endogenous and Exogenous Covert Orienting of Attention

PubMed Central

McCormick, Peter A.; Francis, Lori

2005-01-01

There is debate over the mechanisms that govern the orienting of attention. Some argue that the enhanced performance observed at a cued location is the result of increased perceptual sensitivity or preferential access to decision-making processes. It has also been suggested that these effects may be the result of trades in speed for accuracy on the part of the observers. In the present study, observers performed either an exogenous or an endogenous orienting of attention task under both normal instructions (respond as quickly and as accurately as possible) and speeded instructions that used a deadline procedure to limit the amount of time observers had to complete a choice reaction time (CRT) task. An examination of the speed-accuracy operating characteristics (SAOCs) yielded evidence against the notion that CRT precuing effects are due primarily to a tradeoff of accuracy for speed. PMID:15759078

Spatial frequency characteristics at image decision-point locations for observers with different radiological backgrounds in lung nodule detection

NASA Astrophysics Data System (ADS)

Pietrzyk, Mariusz W.; Manning, David J.; Dix, Alan; Donovan, Tim

2009-02-01

Aim: The goal of the study is to determine the spatial frequency characteristics at locations in the image of overt and covert observers' decisions and find out if there are any similarities in different observers' groups: the same radiological experience group or the same accuracy scored level. Background: The radiological task is described as a visual searching decision making procedure involving visual perception and cognitive processing. Humans perceive the world through a number of spatial frequency channels, each sensitive to visual information carried by different spatial frequency ranges and orientations. Recent studies have shown that particular physical properties of local and global image-based elements are correlated with the performance and the level of experience of human observers in breast cancer and lung nodule detections. Neurological findings in visual perception were an inspiration for wavelet applications in vision research because the methodology tries to mimic the brain processing algorithms. Methods: The wavelet approach to the set of postero-anterior chest radiographs analysis has been used to characterize perceptual preferences observers with different levels of experience in the radiological task. Psychophysical methodology has been applied to track eye movements over the image, where particular ROIs related to the observers' fixation clusters has been analysed in the spaces frame by Daubechies functions. Results: Significance differences have been found between the spatial frequency characteristics at the location of different decisions.

covert contrast: The acquisition of Mandarin tone 2 and tone 3 in L2 production and perception

NASA Astrophysics Data System (ADS)

Mar, Li-Ya

This dissertation investigates the occurrence of an intermediate stage, termed a covert contrast, in the acquisition of Mandarin Tone 2 (T2) and Tone 3 (T3) by adult speakers of American English. A covert contrast is a statistically reliable distinction produced by language learners that is not perceived by native speakers of the target language (TL). In second language (L2) acquisition, whether a learner is judged as having acquired a TL phonemic contrast has largely depended on whether the contrast was perceived and transcribed by native speakers of the TL. However, categorical perception has shown that native listeners cannot perceive a distinction between two sounds that fall within the same perceptual boundaries on the continuum of the relevant acoustic cues. In other words, it is possible that native speakers of the TL do not perceive a phonemic distinction that is produced by L2 learners when that distinction occurs within a phonemic boundary of TL. The data for the study were gathered through two elicitations of tone production, a longitudinal analysis, and two perception tasks. There were three key findings. First, both elicitations showed that most of the L2 participants produced a covert contrast between T2 and T3 on at least one of the three acoustic measures used in the study. Second, the longitudinal analysis reveals that some L2 participants progressed from making a covert contrast to a later stage of implementing an overt one, thereby supporting the claim that making a covert contrast is an intermediate stage in the process of acquiring a L2 phonemic contrast. Third, results of the perceptual tasks showed no reliable difference in identifying and discriminating Mandarin T2 and T3 on the part of the L2 learners who produced a covert contrast and those who produced an overt contrast, indicating that there was no reliable difference in the two groups' ability to perceive the target tones. In all, the occurrence of a covert contrast in the process of acquiring Mandarin T2 and T3 suggests that L2 acquisition of a tonal contrast is a gradient process, one in which an intermediate step occurs before a L2 learner reaches the final stage of implementing an overt contrast that is perceived as target-like by the native speakers of the TL.

Content-Based Covert Group Detection in Social Networks

DTIC Science & Technology

2017-09-06

these features to learn a model that could be applied to the holdout set. This model was then used to test on the remaining posts . Accuracy: 51.4...Content-based Covert Group Detection in Social Networks The views, opinions and/or findings contained in this report are those of the author(s) and...should not contrued as an official Department of the Army position, policy or decision, unless so designated by other documentation. 9. SPONSORING

Enhancing the prediction of self-handicapping.

PubMed

Harris, R N; Snyder, C R; Higgins, R L; Schrag, J L

1986-12-01

Levels of test anxiety, Type A and Type B coronary-prone behavior, fear of failure, and covert self-esteem were studied as predictors of self-handicapping performance attributions for college women who were placed in either a high- (N = 49) or low- (N = 49) evaluative test or task situation. We hypothesized that test anxiety. Type A or Type B level, and their interaction would account for reliable variance in the prediction of self-handicapping. However, we also theorized that underlying high fear of failure and low covert self-esteem would explain the self-handicapping claims of test-anxious and Type A subjects. The results indicated that only high levels of test anxiety and high levels of covert self-esteem were related to women's self-handicapping attributions.

The Role of Covert Retrieval in Working Memory Span Tasks: Evidence from Delayed Recall Tests

ERIC Educational Resources Information Center

McCabe, David P.

2008-01-01

The current study examined delayed recall of items that had been processed during simple and complex span tasks. Three experiments were reported showing that despite more items being recalled initially from a simple span task (i.e., word span) than a complex span task (i.e., operation span), on a delayed recall test more items were recalled that…

Associations between narcissism and emotion regulation difficulties: Respiratory sinus arrhythmia reactivity as a moderator.

PubMed

Zhang, Hui; Wang, Zhenhong; You, Xuqun; Lü, Wei; Luo, Yun

2015-09-01

The aim of the current study was to examine the direct and interactive effects of two types of narcissism (overt and covert) and respiratory sinus arrhythmia (RSA) reactivity on emotion regulation difficulties in 227 undergraduate students. Overt and covert narcissism and emotion regulation difficulties were assessed with self-report measures (narcissistic personality inventory (NPI)-16, hypersensitive narcissism scale (HSNS), and difficulties in emotion regulation scale (DERS)), and physiological data were measured during the baseline, stress (a public-speaking task), and recovery periods in the laboratory. Results indicated that overt narcissism was negatively related to a lack of emotional awareness and emotional clarity, whereas covert narcissism was positively related to overall emotion regulation difficulties, nonacceptance of emotional responses, impulse control difficulties, limited access to emotion regulation strategies, and a lack of emotional clarity. RSA reactivity in response to a mock job interview moderated the associations between covert narcissism (as a predictor) and overall emotion regulation difficulties and impulse control difficulties (as outcomes). This finding showed that a greater stress-induced RSA decrease may serve as a protective factor and ameliorate the effect of covert narcissism on individuals' emotion regulation difficulties. Copyright © 2015 Elsevier B.V. All rights reserved.

Adaptive attunement of selective covert attention to evolutionary-relevant emotional visual scenes.

PubMed

Fernández-Martín, Andrés; Gutiérrez-García, Aída; Capafons, Juan; Calvo, Manuel G

2017-05-01

We investigated selective attention to emotional scenes in peripheral vision, as a function of adaptive relevance of scene affective content for male and female observers. Pairs of emotional-neutral images appeared peripherally-with perceptual stimulus differences controlled-while viewers were fixating on a different stimulus in central vision. Early selective orienting was assessed by the probability of directing the first fixation towards either scene, and the time until first fixation. Emotional scenes selectively captured covert attention even when they were task-irrelevant, thus revealing involuntary, automatic processing. Sex of observers and specific emotional scene content (e.g., male-to-female-aggression, families and babies, etc.) interactively modulated covert attention, depending on adaptive priorities and goals for each sex, both for pleasant and unpleasant content. The attentional system exhibits domain-specific and sex-specific biases and attunements, probably rooted in evolutionary pressures to enhance reproductive and protective success. Emotional cues selectively capture covert attention based on their bio-social significance. Copyright © 2017 Elsevier Inc. All rights reserved.

Metacognitive deficits in categorization tasks in a population with impaired inner speech.

PubMed

Langland-Hassan, Peter; Gauker, Christopher; Richardson, Michael J; Dietz, Aimee; Faries, Frank R

2017-11-01

This study examines the relation of language use to a person's ability to perform categorization tasks and to assess their own abilities in those categorization tasks. A silent rhyming task was used to confirm that a group of people with post-stroke aphasia (PWA) had corresponding covert language production (or "inner speech") impairments. The performance of the PWA was then compared to that of age- and education-matched healthy controls on three kinds of categorization tasks and on metacognitive self-assessments of their performance on those tasks. The PWA showed no deficits in their ability to categorize objects for any of the three trial types (visual, thematic, and categorial). However, on the categorial trials, their metacognitive assessments of whether they had categorized correctly were less reliable than those of the control group. The categorial trials were distinguished from the others by the fact that the categorization could not be based on some immediately perceptible feature or on the objects' being found together in a type of scenario or setting. This result offers preliminary evidence for a link between covert language use and a specific form of metacognition. Copyright © 2017 Elsevier B.V. All rights reserved.

Examining the contribution of motor movement and language dominance to increased left lateralization during sign generation in native signers.

PubMed

Gutierrez-Sigut, Eva; Payne, Heather; MacSweeney, Mairéad

2016-08-01

The neural systems supporting speech and sign processing are very similar, although not identical. In a previous fTCD study of hearing native signers (Gutierrez-Sigut, Daws, et al., 2015) we found stronger left lateralization for sign than speech. Given that this increased lateralization could not be explained by hand movement alone, the contribution of motor movement versus 'linguistic' processes to the strength of hemispheric lateralization during sign production remains unclear. Here we directly contrast lateralization strength of covert versus overt signing during phonological and semantic fluency tasks. To address the possibility that hearing native signers' elevated lateralization indices (LIs) were due to performing a task in their less dominant language, here we test deaf native signers, whose dominant language is British Sign Language (BSL). Signers were more strongly left lateralized for overt than covert sign generation. However, the strength of lateralization was not correlated with the amount of time producing movements of the right hand. Comparisons with previous data from hearing native English speakers suggest stronger laterality indices for sign than speech in both covert and overt tasks. This increased left lateralization may be driven by specific properties of sign production such as the increased use of self-monitoring mechanisms or the nature of phonological encoding of signs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Using task effort and pupil size to track covert shifts of visual attention independently of a pupillary light reflex.

PubMed

Brocher, Andreas; Harbecke, Raphael; Graf, Tim; Memmert, Daniel; Hüttermann, Stefanie

2018-03-07

We tested the link between pupil size and the task effort involved in covert shifts of visual attention. The goal of this study was to establish pupil size as a marker of attentional shifting in the absence of luminance manipulations. In three experiments, participants evaluated two stimuli that were presented peripherally, appearing equidistant from and on opposite sides of eye fixation. The angle between eye fixation and the peripherally presented target stimuli varied from 12.5° to 42.5°. The evaluation of more distant stimuli led to poorer performance than did the evaluation of more proximal stimuli throughout our study, confirming that the former required more effort than the latter. In addition, in Experiment 1 we found that pupil size increased with increasing angle and that this effect could not be reduced to the operation of low-level visual processes in the task. In Experiment 2 the pupil dilated more strongly overall when participants evaluated the target stimuli, which required shifts of attention, than when they merely reported on the target's presence versus absence. Both conditions yielded larger pupils for more distant than for more proximal stimuli, however. In Experiment 3, we manipulated task difficulty more directly, by changing the contrast at which the target stimuli were presented. We replicated the results from Experiment 1 only with the high-contrast stimuli. With stimuli of low contrast, ceiling effects in pupil size were observed. Our data show that the link between task effort and pupil size can be used to track the degree to which an observer covertly shifts attention to or detects stimuli in peripheral vision.

Increased effect of target eccentricity on covert shifts of visual attention in patients with neglect.

PubMed

Hamilton, Roy H; Stark, Marianna; Coslett, H Branch

2010-01-01

Debate continues regarding the mechanisms underlying covert shifts of visual attention. We examined the relationship between target eccentricity and the speed of covert shifts of attention in normal subjects and patients with brain lesions using a cued-response task in which cues and targets were presented at 2 degrees or 8 degrees lateral to the fixation point. Normal subjects were slower on invalid trials in the 8 degrees as compared to 2 degrees condition. Patients with right-hemisphere stroke with neglect were slower in their responses to left-sided invalid targets compared to valid targets, and demonstrated a significant increase in the effect of target validity as a function of target eccentricity. Additional data from one neglect patient (JM) demonstrated an exaggerated validity x eccentricity x side interaction for contralesional targets on a cued reaction time task with a central (arrow) cue. We frame these results in the context of a continuous 'moving spotlight' model of attention, and also consider the potential role of spatial saliency maps. By either account, we argue that neglect is characterized by an eccentricity-dependent deficit in the allocation of attention.

A covert attention P300-based brain-computer interface: Geospell.

PubMed

Aloise, Fabio; Aricò, Pietro; Schettini, Francesca; Riccio, Angela; Salinari, Serenella; Mattia, Donatella; Babiloni, Fabio; Cincotti, Febo

2012-01-01

The Farwell and Donchin P300 speller interface is one of the most widely used brain-computer interface (BCI) paradigms for writing text. Recent studies have shown that the recognition accuracy of the P300 speller decreases significantly when eye movement is impaired. This report introduces the GeoSpell interface (Geometric Speller), which implements a stimulation framework for a P300-based BCI that has been optimised for operation in covert visual attention. We compared the Geospell with the P300 speller interface under overt attention conditions with regard to effectiveness, efficiency and user satisfaction. Ten healthy subjects participated in the study. The performance of the GeoSpell interface in covert attention was comparable with that of the P300 speller in overt attention. As expected, the effectiveness of the spelling decreased with the new interface in covert attention. The NASA task load index (TLX) for workload assessment did not differ significantly between the two modalities. This study introduces and evaluates a gaze-independent, P300-based brain-computer interface, the efficacy and user satisfaction of which were comparable with those off the classical P300 speller. Despite a decrease in effectiveness due to the use of covert attention, the performance of the GeoSpell far exceeded the threshold of accuracy with regard to effective spelling.

Visual attention: The past 25 years

PubMed Central

Carrasco, Marisa

2012-01-01

This review focuses on covert attention and how it alters early vision. I explain why attention is considered a selective process, the constructs of covert attention, spatial endogenous and exogenous attention, and feature-based attention. I explain how in the last 25 years research on attention has characterized the effects of covert attention on spatial filters and how attention influences the selection of stimuli of interest. This review includes the effects of spatial attention on discriminability and appearance in tasks mediated by contrast sensitivity and spatial resolution; the effects of feature-based attention on basic visual processes, and a comparison of the effects of spatial and feature-based attention. The emphasis of this review is on psychophysical studies, but relevant electrophysiological and neuroimaging studies and models regarding how and where neuronal responses are modulated are also discussed. PMID:21549742

Investigating language lateralization during phonological and semantic fluency tasks using functional transcranial Doppler sonography

PubMed Central

Gutierrez-Sigut, Eva; Payne, Heather; MacSweeney, Mairéad

2015-01-01

Although there is consensus that the left hemisphere plays a critical role in language processing, some questions remain. Here we examine the influence of overt versus covert speech production on lateralization, the relationship between lateralization and behavioural measures of language performance and the strength of lateralization across the subcomponents of language. The present study used functional transcranial Doppler sonography (fTCD) to investigate lateralization of phonological and semantic fluency during both overt and covert word generation in right-handed adults. The laterality index (LI) was left lateralized in all conditions, and there was no difference in the strength of LI between overt and covert speech. This supports the validity of using overt speech in fTCD studies, another benefit of which is a reliable measure of speech production. PMID:24875468

Visual attention: the past 25 years.

PubMed

Carrasco, Marisa

2011-07-01

This review focuses on covert attention and how it alters early vision. I explain why attention is considered a selective process, the constructs of covert attention, spatial endogenous and exogenous attention, and feature-based attention. I explain how in the last 25 years research on attention has characterized the effects of covert attention on spatial filters and how attention influences the selection of stimuli of interest. This review includes the effects of spatial attention on discriminability and appearance in tasks mediated by contrast sensitivity and spatial resolution; the effects of feature-based attention on basic visual processes, and a comparison of the effects of spatial and feature-based attention. The emphasis of this review is on psychophysical studies, but relevant electrophysiological and neuroimaging studies and models regarding how and where neuronal responses are modulated are also discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Toward a reliable gaze-independent hybrid BCI combining visual and natural auditory stimuli.

PubMed

Barbosa, Sara; Pires, Gabriel; Nunes, Urbano

2016-03-01

Brain computer interfaces (BCIs) are one of the last communication options for patients in the locked-in state (LIS). For complete LIS patients, interfaces must be gaze-independent due to their eye impairment. However, unimodal gaze-independent approaches typically present levels of performance substantially lower than gaze-dependent approaches. The combination of multimodal stimuli has been pointed as a viable way to increase users' performance. A hybrid visual and auditory (HVA) P300-based BCI combining simultaneously visual and auditory stimulation is proposed. Auditory stimuli are based on natural meaningful spoken words, increasing stimuli discrimination and decreasing user's mental effort in associating stimuli to the symbols. The visual part of the interface is covertly controlled ensuring gaze-independency. Four conditions were experimentally tested by 10 healthy participants: visual overt (VO), visual covert (VC), auditory (AU) and covert HVA. Average online accuracy for the hybrid approach was 85.3%, which is more than 32% over VC and AU approaches. Questionnaires' results indicate that the HVA approach was the less demanding gaze-independent interface. Interestingly, the P300 grand average for HVA approach coincides with an almost perfect sum of P300 evoked separately by VC and AU tasks. The proposed HVA-BCI is the first solution simultaneously embedding natural spoken words and visual words to provide a communication lexicon. Online accuracy and task demand of the approach compare favorably with state-of-the-art. The proposed approach shows that the simultaneous combination of visual covert control and auditory modalities can effectively improve the performance of gaze-independent BCIs. Copyright © 2015 Elsevier B.V. All rights reserved.

Algorithm for covert convoy of a moving target using a group of autonomous robots

NASA Astrophysics Data System (ADS)

Polyakov, Igor; Shvets, Evgeny

2018-04-01

An important application of autonomous robot systems is to substitute human personnel in dangerous environments to reduce their involvement and subsequent risk on human lives. In this paper we solve the problem of covertly convoying a civilian in a dangerous area with a group of unmanned ground vehicles (UGVs) using social potential fields. The novelty of our work lies in the usage of UGVs as compared to the unmanned aerial vehicles typically employed for this task in the approaches described in literature. Additionally, in our paper we assume that the group of UGVs should simultaneously solve the problem of patrolling to detect intruders on the area. We develop a simulation system to test our algorithms, provide numerical results and give recommendations on how to tune the potentials governing robots' behaviour to prioritize between patrolling and convoying tasks.

Functional Brain Activation Differences in Stuttering Identified with a Rapid fMRI Sequence

ERIC Educational Resources Information Center

Loucks, Torrey; Kraft, Shelly Jo; Choo, Ai Leen; Sharma, Harish; Ambrose, Nicoline G.

2011-01-01

The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech…

Signal detection theory applied to three visual search tasks--identification, yes/no detection and localization.

PubMed

Cameron, E Leslie; Tai, Joanna C; Eckstein, Miguel P; Carrasco, Marisa

2004-01-01

Adding distracters to a display impairs performance on visual tasks (i.e. the set-size effect). While keeping the display characteristics constant, we investigated this effect in three tasks: 2 target identification, yes-no detection with 2 targets, and 8-alternative localization. A Signal Detection Theory (SDT) model, tailored for each task, accounts for the set-size effects observed in identification and localization tasks, and slightly under-predicts the set-size effect in a detection task. Given that sensitivity varies as a function of spatial frequency (SF), we measured performance in each of these three tasks in neutral and peripheral precue conditions for each of six spatial frequencies (0.5-12 cpd). For all spatial frequencies tested, performance on the three tasks decreased as set size increased in the neutral precue condition, and the peripheral precue reduced the effect. Larger set-size effects were observed at low SFs in the identification and localization tasks. This effect can be described using the SDT model, but was not predicted by it. For each of these tasks we also established the extent to which covert attention modulates performance across a range of set sizes. A peripheral precue substantially diminished the set-size effect and improved performance, even at set size 1. These results provide support for distracter exclusion, and suggest that signal enhancement may also be a mechanism by which covert attention can impose its effect.

Different patterns of language activation in post-stroke aphasia are detected by overt and covert versions of the verb generation fMRI task

PubMed Central

Allendorfer, Jane B.; Kissela, Brett M.; Holland, Scott K.; Szaflarski, Jerzy P.

2012-01-01

Summary Background Post-stroke language functions depend on the relative contributions of the dominant and non-dominant hemispheres. Thus, we aimed to identify the neural correlates of overt and covert verb generation in adult post-stroke aphasia. Material/Methods Sixteen aphasic LMCA stroke patients (SPs) and 32 healthy controls (HCs) underwent language testing followed by fMRI while performing an overt event-related verb generation task (ER-VGT) isolating activations related to noun-verb semantic processing or to articulation and auditory processing, and a covert block design verb generation task (BD-VGT). Results BD-VGT activation patterns were consistent with previous studies, while ER-VGT showed different patterns in SPs relative to HCs including less left-hemispheric involvement during semantic processing and predominantly right-sided activation related to articulation and auditory processing. ER-VGT intra-scanner performance was positively associated with activation during semantic associations in the left middle temporal gyrus for HCs (p=0.031) and left middle frontal gyrus for SPs (p=0.042). Increased activation in superior frontal/cingulate gyri was associated with better intra-scanner performance (p=0.020). Lesion size negatively impacted verbal fluency tested with Controlled Oral Word Association Test (p=0.0092) and the Semantic Fluency Test (p=0.033) and trended towards a negative association with verb generation performance on the event-related verb generation task (p=0.081). Conclusions Greater retention of pre-stroke language skills is associated with greater involvement of the left hemisphere with different cortical recruitment patterns observed in SPs versus HCs. Post-stroke verbal fluency may depend more upon the structural and functional integrity of the dominant left hemisphere language network rather than the shift to contralateral homologues. PMID:22367124

Somatosensory attention identifies both overt and covert awareness in disorders of consciousness.

PubMed

Gibson, Raechelle M; Chennu, Srivas; Fernández-Espejo, Davinia; Naci, Lorina; Owen, Adrian M; Cruse, Damian

2016-09-01

Some patients diagnosed with disorders of consciousness retain sensory and cognitive abilities beyond those apparent from their overt behavior. Characterizing these covert abilities is crucial for diagnosis, prognosis, and medical ethics. This multimodal study investigates the relationship between electroencephalographic evidence for perceptual/cognitive preservation and both overt and covert markers of awareness. Fourteen patients with severe brain injuries were evaluated with an electroencephalographic vibrotactile attention task designed to identify a hierarchy of residual somatosensory and cognitive abilities: (1) somatosensory steady-state evoked responses, (2) bottom-up attention orienting (P3a event-related potential), and (3) top-down attention (P3b event-related potential). Each patient was also assessed with a clinical behavioral scale and 2 functional magnetic resonance imaging assessments of covert command following. Six patients produced only sensory responses, with no evidence of cognitive event-related potentials. A further 8 patients demonstrated reliable bottom-up attention-orienting responses (P3a). No patient showed evidence of top-down attention (P3b). Only those patients who followed commands, whether overtly with behavior or covertly with functional neuroimaging, also demonstrated event-related potential evidence of attentional orienting. Somatosensory attention-orienting event-related potentials differentiated patients who could follow commands from those who could not. Crucially, this differentiation was irrespective of whether command following was evident through overt external behavior, or through covert functional neuroimaging methods. Bedside electroencephalographic methods may corroborate more expensive and challenging methods such as functional neuroimaging, and thereby assist in the accurate diagnosis of awareness. Ann Neurol 2016;80:412-423. © 2016 American Neurological Association.

Covert rapid action-memory simulation (CRAMS): a hypothesis of hippocampal-prefrontal interactions for adaptive behavior.

PubMed

Wang, Jane X; Cohen, Neal J; Voss, Joel L

2015-01-01

Effective choices generally require memory, yet little is known regarding the cognitive or neural mechanisms that allow memory to influence choices. We outline a new framework proposing that covert memory processing of hippocampus interacts with action-generation processing of prefrontal cortex in order to arrive at optimal, memory-guided choices. Covert, rapid action-memory simulation (CRAMS) is proposed here as a framework for understanding cognitive and/or behavioral choices, whereby prefrontal-hippocampal interactions quickly provide multiple simulations of potential outcomes used to evaluate the set of possible choices. We hypothesize that this CRAMS process is automatic, obligatory, and covert, meaning that many cycles of action-memory simulation occur in response to choice conflict without an individual's necessary intention and generally without awareness of the simulations, leading to adaptive behavior with little perceived effort. CRAMS is thus distinct from influential proposals that adaptive memory-based behavior in humans requires consciously experienced memory-based construction of possible future scenarios and deliberate decisions among possible future constructions. CRAMS provides an account of why hippocampus has been shown to make critical contributions to the short-term control of behavior, and it motivates several new experimental approaches and hypotheses that could be used to better understand the ubiquitous role of prefrontal-hippocampal interactions in situations that require adaptively using memory to guide choices. Importantly, this framework provides a perspective that allows for testing decision-making mechanisms in a manner that translates well across human and nonhuman animal model systems. Copyright © 2014 Elsevier Inc. All rights reserved.

A test of the orthographic recoding hypothesis

NASA Astrophysics Data System (ADS)

Gaygen, Daniel E.

2003-04-01

The Orthographic Recoding Hypothesis [D. E. Gaygen and P. A. Luce, Percept. Psychophys. 60, 465-483 (1998)] was tested. According to this hypothesis, listeners recognize spoken words heard for the first time by mapping them onto stored representations of the orthographic forms of the words. Listeners have a stable orthographic representation of words, but no phonological representation, when those words have been read frequently but never heard or spoken. Such may be the case for low frequency words such as jargon. Three experiments using visually and auditorily presented nonword stimuli tested this hypothesis. The first two experiments were explicit tests of memory (old-new tests) for words presented visually. In the first experiment, the recognition of auditorily presented nonwords was facilitated when they previously appeared on a visually presented list. The second experiment was similar, but included a concurrent articulation task during a visual word list presentation, thus preventing covert rehearsal of the nonwords. The results were similar to the first experiment. The third experiment was an indirect test of memory (auditory lexical decision task) for visually presented nonwords. Auditorily presented nonwords were identified as nonwords significantly more slowly if they had previously appeared on the visually presented list accompanied by a concurrent articulation task.

Decision analysis in formulary decision making.

PubMed

Schechter, C B

1993-06-01

Although decision making about what drugs to include in an institutional formulary appears to lend itself readily to quantitative techniques such as decision analysis and cost-benefit analysis, a review of the literature reveals that very little has been published in this area. Several of the published decision analyses use non-standard techniques that are, at best, of unproved validity, and may seriously distort the underlying issues through covert under-counting or double-counting of various drug attributes. Well executed decision analyses have contributed to establishing that drug acquisition costs are not an adequate measure of the total economic impact of formulary decisions and that costs of labour and materials associated with drug administration must be calculated on an institution-specific basis to reflect unique staffing patterns, bulk purchasing practices, and the availability of surplus capacity within the institution which might be mobilised at little marginal cost. Clinical studies of newly introduced drugs frequently fail to answer the questions that weigh most heavily on the structuring of a formal assessment of a proposed formulary acquisition. Studies comparing a full spectrum of therapeutically equivalent drugs are rarely done, and individual studies of particular pairs of drugs can rarely be used together because of differences in methodology or patient populations studied. Gathering of institution-specific economic and clinical data is a daunting, labour-intensive task. In many institutions, incentive and reward structures discourage behaviour that takes the broad institutional perspective that is intrinsic to a good decision analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Concept priming and pain: an experimental approach to understanding gender roles in sex-related pain differences.

PubMed

Fowler, Stephanie L; Rasinski, Heather M; Geers, Andrew L; Helfer, Suzanne G; France, Christopher R

2011-04-01

Prior research has found that sex differences in pain are partially due to individual variations in gender roles. In a laboratory study, we tested the hypothesis that the presence of covert gender role cues can also moderate the extent to which women and men experience pain. Specifically, we varied gender role cues by asking male and female participants to write about instances in which they behaved in a stereotypically feminine, masculine, or neutral manner. Pain and cardiovascular reactivity to the cold pressor task were then assessed. Results revealed that, when primed with femininity, men reported less pain and anxiety from the cold pressor task than women. However, no differences existed between the sexes in the masculine or neutral prime conditions. The results indicate that covert gender cues can alter pain reports. Further, at least in some situations, feminine role cues may be more influential on pain reports than masculine role cues.

Developmental Trends for Object and Spatial Working Memory: A Psychophysiological Analysis

ERIC Educational Resources Information Center

Van Leijenhorst, Linda; Crone, Eveline A.; Van der Molen, Maurits W.

2007-01-01

This study examined developmental trends in object and spatial working memory (WM) using heart rate (HR) to provide an index of covert cognitive processes. Participants in 4 age groups (6-7, 9-10, 11-12, 18-26, n=20 each) performed object and spatial WM tasks, in which each trial was followed by feedback. Spatial WM task performance reached adult…

An Overt Chemical Protective Garment Reduces Thermal Strain Compared with a Covert Garment in Warm-Wet but Not Hot-Dry Environments.

PubMed

Maley, Matthew J; Costello, Joseph T; Borg, David N; Bach, Aaron J E; Hunt, Andrew P; Stewart, Ian B

2017-01-01

Objectives: A commercial chemical, biological, radiological and nuclear (CBRN) protective covert garment has recently been developed with the aim of reducing thermal strain. A covert CBRN protective layer can be worn under other clothing, with equipment added for full chemical protection when needed. However, it is unknown whether the covert garment offers any alleviation to thermal strain during work compared with a traditional overt ensemble. Therefore, the aim of this study was to compare thermal strain and work tolerance times during work in an overt and covert ensemble offering the same level of CBRN protection. Methods : Eleven male participants wore an overt (OVERT) or covert (COVERT) CBRN ensemble and walked (4 km·h -1 , 1% grade) for a maximum of 120 min in either a wet bulb globe temperature [WBGT] of 21, 30, or 37°C (Neutral, WarmWet and HotDry, respectively). The trials were ceased if the participants' gastrointestinal temperature reached 39°C, heart rate reached 90% of maximum, walking time reached 120 min or due to self-termination. Results: All participants completed 120 min of walking in Neutral. Work tolerance time was greater in OVERT compared with COVERT in WarmWet ( P < 0.001, 116.5[9.9] vs. 88.9[12.2] min, respectively), though this order was reversed in HotDry ( P = 0.003, 37.3[5.3] vs. 48.4[4.6] min, respectively). The rate of change in mean body temperature and mean skin temperature was greater in COVERT (0.025[0.004] and 0.045[0.010]°C·min -1 , respectively) compared with OVERT (0.014[0.004] and 0.027[0.007]°C·min -1 , respectively) in WarmWet ( P < 0.001 and P = 0.028, respectively). However, the rate of change in mean body temperature and mean skin temperature was greater in OVERT (0.068[0.010] and 0.170[0.026]°C·min -1 , respectively) compared with COVERT (0.059[0.004] and 0.120[0.017]°C·min -1 , respectively) in HotDry ( P = 0.002 and P < 0.001, respectively). Thermal sensation, thermal comfort, and ratings of perceived exertion did not differ between garments at trial cessation ( P > 0.05). Conclusion: Those dressed in OVERT experienced lower thermal strain and longer work tolerance times compared with COVERT in a warm-wet environment. However, COVERT may be an optimal choice in a hot-dry environment. These findings have practical implications for those making decisions on the choice of CBRN ensemble to be used during work.

An Overt Chemical Protective Garment Reduces Thermal Strain Compared with a Covert Garment in Warm-Wet but Not Hot-Dry Environments

PubMed Central

Maley, Matthew J.; Costello, Joseph T.; Borg, David N.; Bach, Aaron J. E.; Hunt, Andrew P.; Stewart, Ian B.

2017-01-01

Objectives: A commercial chemical, biological, radiological and nuclear (CBRN) protective covert garment has recently been developed with the aim of reducing thermal strain. A covert CBRN protective layer can be worn under other clothing, with equipment added for full chemical protection when needed. However, it is unknown whether the covert garment offers any alleviation to thermal strain during work compared with a traditional overt ensemble. Therefore, the aim of this study was to compare thermal strain and work tolerance times during work in an overt and covert ensemble offering the same level of CBRN protection. Methods: Eleven male participants wore an overt (OVERT) or covert (COVERT) CBRN ensemble and walked (4 km·h−1, 1% grade) for a maximum of 120 min in either a wet bulb globe temperature [WBGT] of 21, 30, or 37°C (Neutral, WarmWet and HotDry, respectively). The trials were ceased if the participants' gastrointestinal temperature reached 39°C, heart rate reached 90% of maximum, walking time reached 120 min or due to self-termination. Results: All participants completed 120 min of walking in Neutral. Work tolerance time was greater in OVERT compared with COVERT in WarmWet (P < 0.001, 116.5[9.9] vs. 88.9[12.2] min, respectively), though this order was reversed in HotDry (P = 0.003, 37.3[5.3] vs. 48.4[4.6] min, respectively). The rate of change in mean body temperature and mean skin temperature was greater in COVERT (0.025[0.004] and 0.045[0.010]°C·min−1, respectively) compared with OVERT (0.014[0.004] and 0.027[0.007]°C·min−1, respectively) in WarmWet (P < 0.001 and P = 0.028, respectively). However, the rate of change in mean body temperature and mean skin temperature was greater in OVERT (0.068[0.010] and 0.170[0.026]°C·min−1, respectively) compared with COVERT (0.059[0.004] and 0.120[0.017]°C·min−1, respectively) in HotDry (P = 0.002 and P < 0.001, respectively). Thermal sensation, thermal comfort, and ratings of perceived exertion did not differ between garments at trial cessation (P > 0.05). Conclusion: Those dressed in OVERT experienced lower thermal strain and longer work tolerance times compared with COVERT in a warm-wet environment. However, COVERT may be an optimal choice in a hot-dry environment. These findings have practical implications for those making decisions on the choice of CBRN ensemble to be used during work. PMID:29170644

Revising the link between microsaccades and the spatial cueing of voluntary attention.

PubMed

Meyberg, Susann; Sinn, Petra; Engbert, Ralf; Sommer, Werner

2017-04-01

Microsaccades - i.e., small fixational saccades generated in the superior colliculus (SC) - have been linked to spatial attention. While maintaining fixation, voluntary shifts of covert attention toward peripheral targets result in a sequence of attention-aligned and attention-opposing microsaccades. In most previous studies the direction of the voluntary shift is signaled by a spatial cue (e.g., a leftwards pointing arrow) that presents the most informative part of the cue (e.g., the arrowhead) in the to-be attended visual field. Here we directly investigated the influence of cue position and tested the hypothesis that microsaccades align with cue position rather than with the attention shift. In a spatial cueing task, we presented the task-relevant part of a symmetric cue either in the to-be attended visual field or in the opposite field. As a result, microsaccades were still weakly related to the covert attention shift; however, they were strongly related to the position of the cue even if that required a movement opposite to the cued attention shift. Moreover, if microsaccades aligned with cue position, we observed stronger cueing effects on manual response times. Our interpretation of the data is supported by numerical simulations of a computational model of microsaccade generation that is based on SC properties, where we explain our findings by separate attentional mechanisms for cue localization and the cued attention shift. We conclude that during cueing of voluntary attention, microsaccades are related to both - the overt attentional selection of the task-relevant part of the cue stimulus and the subsequent covert attention shift. Copyright © 2017 Elsevier Ltd. All rights reserved.

(C)overt attention and visual speller design in an ERP-based brain-computer interface.

PubMed

Treder, Matthias S; Blankertz, Benjamin

2010-05-28

In a visual oddball paradigm, attention to an event usually modulates the event-related potential (ERP). An ERP-based brain-computer interface (BCI) exploits this neural mechanism for communication. Hitherto, it was unclear to what extent the accuracy of such a BCI requires eye movements (overt attention) or whether it is also feasible for targets in the visual periphery (covert attention). Also unclear was how the visual design of the BCI can be improved to meet peculiarities of peripheral vision such as low spatial acuity and crowding. Healthy participants (N = 13) performed a copy-spelling task wherein they had to count target intensifications. EEG and eye movements were recorded concurrently. First, (c)overt attention was investigated by way of a target fixation condition and a central fixation condition. In the latter, participants had to fixate a dot in the center of the screen and allocate their attention to a target in the visual periphery. Second, the effect of visual speller layout was investigated by comparing the symbol Matrix to an ERP-based Hex-o-Spell, a two-levels speller consisting of six discs arranged on an invisible hexagon. We assessed counting errors, ERP amplitudes, and offline classification performance. There is an advantage (i.e., less errors, larger ERP amplitude modulation, better classification) of overt attention over covert attention, and there is also an advantage of the Hex-o-Spell over the Matrix. Using overt attention, P1, N1, P2, N2, and P3 components are enhanced by attention. Using covert attention, only N2 and P3 are enhanced for both spellers, and N1 and P2 are modulated when using the Hex-o-Spell but not when using the Matrix. Consequently, classifiers rely mainly on early evoked potentials in overt attention and on later cognitive components in covert attention. Both overt and covert attention can be used to drive an ERP-based BCI, but performance is markedly lower for covert attention. The Hex-o-Spell outperforms the Matrix, especially when eye movements are not permitted, illustrating that performance can be increased if one accounts for peculiarities of peripheral vision.

(C)overt attention and visual speller design in an ERP-based brain-computer interface

PubMed Central

2010-01-01

Background In a visual oddball paradigm, attention to an event usually modulates the event-related potential (ERP). An ERP-based brain-computer interface (BCI) exploits this neural mechanism for communication. Hitherto, it was unclear to what extent the accuracy of such a BCI requires eye movements (overt attention) or whether it is also feasible for targets in the visual periphery (covert attention). Also unclear was how the visual design of the BCI can be improved to meet peculiarities of peripheral vision such as low spatial acuity and crowding. Method Healthy participants (N = 13) performed a copy-spelling task wherein they had to count target intensifications. EEG and eye movements were recorded concurrently. First, (c)overt attention was investigated by way of a target fixation condition and a central fixation condition. In the latter, participants had to fixate a dot in the center of the screen and allocate their attention to a target in the visual periphery. Second, the effect of visual speller layout was investigated by comparing the symbol Matrix to an ERP-based Hex-o-Spell, a two-levels speller consisting of six discs arranged on an invisible hexagon. Results We assessed counting errors, ERP amplitudes, and offline classification performance. There is an advantage (i.e., less errors, larger ERP amplitude modulation, better classification) of overt attention over covert attention, and there is also an advantage of the Hex-o-Spell over the Matrix. Using overt attention, P1, N1, P2, N2, and P3 components are enhanced by attention. Using covert attention, only N2 and P3 are enhanced for both spellers, and N1 and P2 are modulated when using the Hex-o-Spell but not when using the Matrix. Consequently, classifiers rely mainly on early evoked potentials in overt attention and on later cognitive components in covert attention. Conclusions Both overt and covert attention can be used to drive an ERP-based BCI, but performance is markedly lower for covert attention. The Hex-o-Spell outperforms the Matrix, especially when eye movements are not permitted, illustrating that performance can be increased if one accounts for peculiarities of peripheral vision. PMID:20509913

Spatio-Temporal Progression of Cortical Activity Related to Continuous Overt and Covert Speech Production in a Reading Task.

PubMed

Brumberg, Jonathan S; Krusienski, Dean J; Chakrabarti, Shreya; Gunduz, Aysegul; Brunner, Peter; Ritaccio, Anthony L; Schalk, Gerwin

2016-01-01

How the human brain plans, executes, and monitors continuous and fluent speech has remained largely elusive. For example, previous research has defined the cortical locations most important for different aspects of speech function, but has not yet yielded a definition of the temporal progression of involvement of those locations as speech progresses either overtly or covertly. In this paper, we uncovered the spatio-temporal evolution of neuronal population-level activity related to continuous overt speech, and identified those locations that shared activity characteristics across overt and covert speech. Specifically, we asked subjects to repeat continuous sentences aloud or silently while we recorded electrical signals directly from the surface of the brain (electrocorticography (ECoG)). We then determined the relationship between cortical activity and speech output across different areas of cortex and at sub-second timescales. The results highlight a spatio-temporal progression of cortical involvement in the continuous speech process that initiates utterances in frontal-motor areas and ends with the monitoring of auditory feedback in superior temporal gyrus. Direct comparison of cortical activity related to overt versus covert conditions revealed a common network of brain regions involved in speech that may implement orthographic and phonological processing. Our results provide one of the first characterizations of the spatiotemporal electrophysiological representations of the continuous speech process, and also highlight the common neural substrate of overt and covert speech. These results thereby contribute to a refined understanding of speech functions in the human brain.

Spatio-Temporal Progression of Cortical Activity Related to Continuous Overt and Covert Speech Production in a Reading Task

PubMed Central

Brumberg, Jonathan S.; Krusienski, Dean J.; Chakrabarti, Shreya; Gunduz, Aysegul; Brunner, Peter; Ritaccio, Anthony L.; Schalk, Gerwin

2016-01-01

How the human brain plans, executes, and monitors continuous and fluent speech has remained largely elusive. For example, previous research has defined the cortical locations most important for different aspects of speech function, but has not yet yielded a definition of the temporal progression of involvement of those locations as speech progresses either overtly or covertly. In this paper, we uncovered the spatio-temporal evolution of neuronal population-level activity related to continuous overt speech, and identified those locations that shared activity characteristics across overt and covert speech. Specifically, we asked subjects to repeat continuous sentences aloud or silently while we recorded electrical signals directly from the surface of the brain (electrocorticography (ECoG)). We then determined the relationship between cortical activity and speech output across different areas of cortex and at sub-second timescales. The results highlight a spatio-temporal progression of cortical involvement in the continuous speech process that initiates utterances in frontal-motor areas and ends with the monitoring of auditory feedback in superior temporal gyrus. Direct comparison of cortical activity related to overt versus covert conditions revealed a common network of brain regions involved in speech that may implement orthographic and phonological processing. Our results provide one of the first characterizations of the spatiotemporal electrophysiological representations of the continuous speech process, and also highlight the common neural substrate of overt and covert speech. These results thereby contribute to a refined understanding of speech functions in the human brain. PMID:27875590

Inducing task-relevant responses to speech in the sleeping brain.

PubMed

Kouider, Sid; Andrillon, Thomas; Barbosa, Leonardo S; Goupil, Louise; Bekinschtein, Tristan A

2014-09-22

Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment [1]. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep [2]. For instance, sleeping participants can create novel sensory associations between tones and odors [3] or reactivate existing semantic associations, as evidenced by event-related potentials [4-7]. Yet, the extent to which the brain continues to process external stimuli remains largely unknown. In particular, it remains unclear whether sensory information can be processed in a flexible and task-dependent manner by the sleeping brain, all the way up to the preparation of relevant actions. Here, using semantic categorization and lexical decision tasks, we studied task-relevant responses triggered by spoken stimuli in the sleeping brain. Awake participants classified words as either animals or objects (experiment 1) or as either words or pseudowords (experiment 2) by pressing a button with their right or left hand, while transitioning toward sleep. The lateralized readiness potential (LRP), an electrophysiological index of response preparation, revealed that task-specific preparatory responses are preserved during sleep. These findings demonstrate that despite the absence of awareness and behavioral responsiveness, sleepers can still extract task-relevant information from external stimuli and covertly prepare for appropriate motor responses. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Adults with dyslexia demonstrate space-based and object-based covert attention deficits: shifting attention to the periphery and shifting attention between objects in the left visual field.

PubMed

Buchholz, Judy; Aimola Davies, Anne

2005-02-01

Performance on a covert visual attention task is compared between a group of adults with developmental dyslexia (specifically phonological difficulties) and a group of age and IQ matched controls. The group with dyslexia were generally slower to detect validly-cued targets. Costs of shifting attention toward the periphery when the target was invalidly cued were significantly higher for the group with dyslexia, while costs associated with shifts toward the fovea tended to be lower. Higher costs were also shown by the group with dyslexia for up-down shifts of attention in the periphery. A visual field processing difference was found, in that the group with dyslexia showed higher costs associated with shifting attention between objects in they LVF. These findings indicate that these adults with dyslexia have difficulty in both the space-based and the object-based components of covert visual attention, and more specifically to stimuli located in the periphery.

Reading Skills--What Reading Skills? The Implications of Normatively Derived Reading Skills, in Certain Occupations, for Reading Standards.

ERIC Educational Resources Information Center

Smith, Arthur De W.

The Generic Skills project is a research study being conducted in Canada to determine those overt and covert behaviors which are fundamental to the performance of many tasks and sub-tasks performed in a wide range of occupations. Data aimed at determining the needs for adult education and training have been obtained in two surveys. In the first,…

Relationship between etiology and covert cognition in the minimally conscious state

PubMed Central

Chennu, S.; Chatelle, C.; Fernández-Espejo, D.; Bekinschtein, T.A.; Pickard, J.D.; Laureys, S.; Owen, A.M.

2012-01-01

Objectives: Functional neuroimaging has shown that the absence of externally observable signs of consciousness and cognition in severely brain-injured patients does not necessarily indicate the true absence of such abilities. However, relative to traumatic brain injury, nontraumatic injury is known to be associated with a reduced likelihood of regaining overtly measurable levels of consciousness. We investigated the relationships between etiology and both overt and covert cognitive abilities in a group of patients in the minimally conscious state (MCS). Methods: Twenty-three MCS patients (15 traumatic and 8 nontraumatic) completed a motor imagery EEG task in which they were required to imagine movements of their right-hand and toes to command. When successfully performed, these imagined movements appear as distinct sensorimotor modulations, which can be used to determine the presence of reliable command-following. The utility of this task has been demonstrated previously in a group of vegetative state patients. Results: Consistent and robust responses to command were observed in the EEG of 22% of the MCS patients (5 of 23). Etiology had a significant impact on the ability to successfully complete this task, with 33% of traumatic patients (5 of 15) returning positive EEG outcomes compared with none of the nontraumatic patients (0 of 8). Conclusions: The overt behavioral signs of awareness (measured with the Coma Recovery Scale–Revised) exhibited by nontraumatic MCS patients appear to be an accurate reflection of their covert cognitive abilities. In contrast, one-third of a group of traumatically injured patients in the MCS possess a range of high-level cognitive faculties that are not evident from their overt behavior. Neurology®2012;78:816–822 PMID:22377810

Diminished neural and cognitive responses to facial expressions of disgust in patients with psoriasis: a functional magnetic resonance imaging study.

PubMed

Kleyn, C Elise; McKie, Shane; Ross, Andrew R; Montaldi, Daniela; Gregory, Lloyd J; Elliott, Rebecca; Isaacs, Clare L; Anderson, Ian M; Richards, Helen L; Deakin, J F William; Fortune, Donal G; Griffiths, Christopher E M

2009-11-01

Psoriasis produces significant psychosocial disability; however, little is understood about the neurocognitive mechanisms that mediate the adverse consequences of the social stigma associated with visible skin lesions, such as disgusted facial expressions of others. Both the feeling of disgust and the observation of disgust in others are known to activate the insula cortex. We investigated whether the social impact of psoriasis is associated with altered cognitive processing of disgust using (i) a covert recognition of faces task conducted using functional magnetic resonance imaging (fMRI) and (ii) the facial expression recognition task (FERT), a decision-making task, conducted outside the scanner to assess the ability to recognize overtly different intensities of disgust. Thirteen right-handed male patients with psoriasis and 13 age-matched male controls were included. In the fMRI study, psoriasis patients had significantly (P<0.005) smaller signal responses to disgusted faces in the bilateral insular cortex compared with healthy controls. These data were corroborated by FERT, in that patients were less able than controls to identify all intensities of disgust tested. We hypothesize that patients with psoriasis, in this case male patients, develop a coping mechanism to protect them from stressful emotional responses by blocking the processing of disgusted facial expressions.

Evaluating comparative and equality judgments in contrast perception: attention alters appearance.

PubMed

Anton-Erxleben, Katharina; Abrams, Jared; Carrasco, Marisa

2010-09-09

Covert attention not only improves performance in many visual tasks but also modulates the appearance of several visual features. Studies on attention and appearance have assessed subjective appearance using a task contingent upon a comparative judgment (e.g., M. Carrasco, S. Ling, & S. Read, 2004). Recently, K. A. Schneider and M. Komlos (2008) questioned the validity of those results because they did not find a significant effect of attention on contrast appearance using an equality task. They claim that such equality judgments are bias-free whereas comparative judgments are bias-prone and propose an alternative interpretation of the previous findings based on a decision bias. However, to date there is no empirical support for the superiority of the equality procedure. Here, we compare biases and sensitivity to shifts in perceived contrast of both paradigms. We measured contrast appearance using both a comparative and an equality judgment. Observers judged the contrasts of two simultaneously presented stimuli, while either the contrast of one stimulus was physically incremented (Experiments 1 and 2) or exogenous attention was drawn to it (Experiments 3 and 4). We demonstrate several methodological limitations of the equality paradigm. Nevertheless, both paradigms capture shifts in PSE due to physical and perceived changes in contrast and show that attention enhances apparent contrast.

Deciding Where to Turn: A Qualitative Investigation of College Students' Helpseeking Decisions After Sexual Assault.

PubMed

DeLoveh, Heidi L M; Cattaneo, Lauren Bennett

2017-03-01

Sexual assault is a widespread problem on college campuses that has been the subject of substantial attention in recent years (Ali, 2011; Krebs, Lindquist, Berzofsky, Shook-Sa, & Peterson, 2016). Resources designed to address the problem exist, but there is evidence that they are underutilized by survivors (Campbell, 2008). The current study used grounded theory to explore how sexual assault survivors make decisions about helpseeking. In-depth interviews were conducted with 14 college sexual assault survivors to develop a theoretical model for their decision-making process. The resulting model, Deciding Where to Turn, suggests that survivors engage in three key decision points: determining if there is a problem related to the sexual assault (Do I Need Help), considering options (What Can I Do), and weighing the consequences of these options (What Will I Do). This process results in one of four behavioral choices: cope on one's own, seek support from friends/family, seek support from formal resources, or covert helpseeking, where needs are met without disclosure. Deciding Where to Turn contributes to the literature by providing a framework for understanding helpseeking decisions after sexual assault, highlighting the need to match reactions to survivor perceptions. The concept of covert helpseeking in particular adds to the way researchers and practitioners think about helpseeking. Research and practice implications are discussed. © Society for Community Research and Action 2017.

Anger in brain and body: the neural and physiological perturbation of decision-making by emotion

PubMed Central

Zorab, Emma; Navaratnam, Nakulan; Engels, Miriam; Mallorquí-Bagué, Núria; Minati, Ludovico; Dowell, Nicholas G.; Brosschot, Jos F.; Thayer, Julian F.; Critchley, Hugo D.

2016-01-01

Emotion and cognition are dynamically coupled to bodily arousal: the induction of anger, even unconsciously, can reprioritise neural and physiological resources toward action states that bias cognitive processes. Here we examine behavioural, neural and bodily effects of covert anger processing and its influence on cognition, indexed by lexical decision-making. While recording beat-to-beat blood pressure, the words ANGER or RELAX were presented subliminally just prior to rapid word/non-word reaction-time judgements of letter-strings. Subliminal ANGER primes delayed the time taken to reach rapid lexical decisions, relative to RELAX primes. However, individuals with high trait anger were speeded up by subliminal anger primes. ANGER primes increased systolic blood pressure and the magnitude of this increase predicted reaction time prolongation. Within the brain, ANGER trials evoked an enhancement of activity within dorsal pons and an attenuation of activity within visual occipitotemporal and attentional parietal cortices. Activity within periaqueductal grey matter, occipital and parietal regions increased linearly with evoked blood pressure changes, indicating neural substrates through which covert anger impairs semantic decisions, putatively through its expression as visceral arousal. The behavioural and physiological impact of anger states compromises the efficiency of cognitive processing through action-ready changes in autonomic response that skew regional neural activity. PMID:26253525

Spatial covert attention increases contrast sensitivity across the CSF: support for signal enhancement

NASA Technical Reports Server (NTRS)

Carrasco, M.; Penpeci-Talgar, C.; Eckstein, M.

2000-01-01

This study is the first to report the benefits of spatial covert attention on contrast sensitivity in a wide range of spatial frequencies when a target alone was presented in the absence of a local post-mask. We used a peripheral precue (a small circle indicating the target location) to explore the effects of covert spatial attention on contrast sensitivity as assessed by orientation discrimination (Experiments 1-4), detection (Experiments 2 and 3) and localization (Experiment 3) tasks. In all four experiments the target (a Gabor patch ranging in spatial frequency from 0.5 to 10 cpd) was presented alone in one of eight possible locations equidistant from fixation. Contrast sensitivity was consistently higher for peripherally- than for neutrally-cued trials, even though we eliminated variables (distracters, global masks, local masks, and location uncertainty) that are known to contribute to an external noise reduction explanation of attention. When observers were presented with vertical and horizontal Gabor patches an external noise reduction signal detection model accounted for the cueing benefit in a discrimination task (Experiment 1). However, such a model could not account for this benefit when location uncertainty was reduced, either by: (a) Increasing overall performance level (Experiment 2); (b) increasing stimulus contrast to enable fine discriminations of slightly tilted suprathreshold stimuli (Experiment 3); and (c) presenting a local post-mask (Experiment 4). Given that attentional benefits occurred under conditions that exclude all variables predicted by the external noise reduction model, these results support the signal enhancement model of attention.

Generic Skills for Occupational Training.

ERIC Educational Resources Information Center

Smith, Arthur De W.

Generic skills are those overt and covert behaviors which are fundamental to the performance of many tasks and subtasks carried out in a wide range of occupations and which are basic to both specialized applications and job specific skills. They consist of academic, reasoning, interpersonal and manipulation skills. The generic approach is…

Investigating L2 Performance in Text Chat

ERIC Educational Resources Information Center

Sauro, Shannon; Smith, Bryan

2010-01-01

This study examines the linguistic complexity and lexical diversity of both overt and covert L2 output produced during synchronous written computer-mediated communication, also referred to as chat. Video enhanced chatscripts produced by university learners of German (N = 23) engaged in dyadic task-based chat interaction were coded and analyzed for…

Taxonomic Workstation System User Guide

DTIC Science & Technology

1993-05-01

of the Methods below: Method 1: - Type SAVELISr ACME.DEPr - From the Main Menu, select DEVOP , then M RBASE S1VIURE, then INDEX LISTS. For Missions...utility allows the user to covert downloaded IWM ASCII files to Micro SAINTr task networks . To use Hooker you nist be fully conzversant in the use and...hookc up fojllw-on tasks/ networks using a graphiic point and shoot interface (Note: All other MicroSAIWI’ variables, sixi as Release Cm-ditions

Short-term retention of a single word relies on retrieval from long-term memory when both rehearsal and refreshing are disrupted.

PubMed

Rose, Nathan S; Buchsbaum, Bradley R; Craik, Fergus I M

2014-07-01

Many working memory (WM) models propose that the focus of attention (or primary memory) has a capacity limit of one to four items, and therefore, that performance on WM tasks involves retrieving some items from long-term (or secondary) memory (LTM). In the present study, we present evidence suggesting that recall of even one item on a WM task can involve retrieving it from LTM. The WM task required participants to make a deep (living/nonliving) or shallow ("e"/no "e") level-of-processing (LOP) judgment on one word and to recall the word after a 10-s delay on each trial. During the delay, participants either rehearsed the word or performed an easy or a hard math task. When the to-be-remembered item could be rehearsed, recall was fast and accurate. When it was followed by a math task, recall was slower, error-prone, and benefited from a deeper LOP at encoding, especially for the hard math condition. The authors suggest that a covert-retrieval mechanism may have refreshed the item during easy math, and that the hard math condition shows that even a single item cannot be reliably held in WM during a sufficiently distracting task--therefore, recalling the item involved retrieving it from LTM. Additionally, performance on a final free recall (LTM) test was better for items recalled following math than following rehearsal, suggesting that initial recall following math involved elaborative retrieval from LTM, whereas rehearsal did not. The authors suggest that the extent to which performance on WM tasks involves retrieval from LTM depends on the amounts of disruption to both rehearsal and covert-retrieval/refreshing maintenance mechanisms.

Anger in brain and body: the neural and physiological perturbation of decision-making by emotion.

PubMed

Garfinkel, Sarah N; Zorab, Emma; Navaratnam, Nakulan; Engels, Miriam; Mallorquí-Bagué, Núria; Minati, Ludovico; Dowell, Nicholas G; Brosschot, Jos F; Thayer, Julian F; Critchley, Hugo D

2016-01-01

Emotion and cognition are dynamically coupled to bodily arousal: the induction of anger, even unconsciously, can reprioritise neural and physiological resources toward action states that bias cognitive processes. Here we examine behavioural, neural and bodily effects of covert anger processing and its influence on cognition, indexed by lexical decision-making. While recording beat-to-beat blood pressure, the words ANGER or RELAX were presented subliminally just prior to rapid word/non-word reaction-time judgements of letter-strings. Subliminal ANGER primes delayed the time taken to reach rapid lexical decisions, relative to RELAX primes. However, individuals with high trait anger were speeded up by subliminal anger primes. ANGER primes increased systolic blood pressure and the magnitude of this increase predicted reaction time prolongation. Within the brain, ANGER trials evoked an enhancement of activity within dorsal pons and an attenuation of activity within visual occipitotemporal and attentional parietal cortices. Activity within periaqueductal grey matter, occipital and parietal regions increased linearly with evoked blood pressure changes, indicating neural substrates through which covert anger impairs semantic decisions, putatively through its expression as visceral arousal. The behavioural and physiological impact of anger states compromises the efficiency of cognitive processing through action-ready changes in autonomic response that skew regional neural activity. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Impaired Visual Attention in Children with Dyslexia.

ERIC Educational Resources Information Center

Heiervang, Einar; Hugdahl, Kenneth

2003-01-01

A cue-target visual attention task was administered to 25 children (ages 10-12) with dyslexia. Results showed a general pattern of slower responses in the children with dyslexia compared to controls. Subjects also had longer reaction times in the short and long cue-target interval conditions (covert and overt shift of attention). (Contains…

Addressing the Assessment Dilemma of Additional Language Learners through Dynamic Assessment

ERIC Educational Resources Information Center

Omidire, M. F.; Bouwer, A. C.; Jordaan, J. C.

2011-01-01

Many learners with an additional language (AL) as their language of learning and teaching (LoLT) have not acquired the level of proficiency required for them to demonstrate their knowledge and achieve the desired outcome on assessment tasks given in that language. Using instruments designed for fully fluent learners and covertly including…

The Influence of Word Frequency on Word Retrieval: Measuring Covert Behaviors

ERIC Educational Resources Information Center

Chih, Yu-Chun; Stierwalt, Julie A. G.; LaPointe, Leonard L.; Chih, Yu-Pin

2017-01-01

Physiological activities (heart rate and respiratory rate) during a word retrieval task were measured in normal participants. Word frequency demonstrated a significant effect on naming accuracy and latencies but not on physiological activities. These data will serve as a basis for comparison for individuals with a compromised language system.

Negative induced mood influences word production: An event-related potentials study with a covert picture naming task.

PubMed

Hinojosa, J A; Fernández-Folgueiras, U; Albert, J; Santaniello, G; Pozo, M A; Capilla, A

2017-01-27

The present event-related potentials (ERPs) study investigated the effects of mood on phonological encoding processes involved in word generation. For this purpose, negative, positive and neutral affective states were induced in participants during three different recording sessions using short film clips. After the mood induction procedure, participants performed a covert picture naming task in which they searched letters. The negative compared to the neutral mood condition elicited more negative amplitudes in a component peaking around 290ms. Furthermore, results from source localization analyses suggested that this activity was potentially generated in the left prefrontal cortex. In contrast, no differences were found in the comparison between positive and neutral moods. Overall, current data suggest that processes involved in the retrieval of phonological information during speech generation are impaired when participants are in a negative mood. The mechanisms underlying these effects were discussed in relation to linguistic and attentional processes, as well as in terms of the use of heuristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

A common network of functional areas for attention and eye movements

NASA Technical Reports Server (NTRS)

Corbetta, M.; Akbudak, E.; Conturo, T. E.; Snyder, A. Z.; Ollinger, J. M.; Drury, H. A.; Linenweber, M. R.; Petersen, S. E.; Raichle, M. E.; Van Essen, D. C.;

Patient participation in palliative care decisions: An ethnographic discourse analysis

PubMed Central

Bélanger, Emmanuelle; Rodríguez, Charo; Groleau, Danielle; Légaré, France; MacDonald, Mary Ellen; Marchand, Robert

2016-01-01

The participation of patients in making decisions about their care is especially important towards the end of life because palliative care decisions involve extensive uncertainty and are heavily influenced by personal values. Yet, there is a scarcity of studies directly observing clinical interactions between palliative patients and their health care providers. In this study, we aimed to understand how patient participation in palliative care decisions is constructed through discourse in a community hospital-based palliative care team. This qualitative study combined ethnographic observations of a palliative care team with discourse analysis. Eighteen palliative care patients with cancer diagnoses, six family physicians, and two nurses were involved in the study. Multiple interactions were observed between each patient and health care providers over the course of 1 year, for a total of 101 consultations, 24 of which were audio-recorded. The analysis consisted in looking for the interpretive repertoires (i.e., familiar lines of argument used to justify actions) that were used to justify patient participation in decision-making during clinical interactions, as well as exploring their implications for decision roles and end-of-life care. Patients and their health care providers seldom addressed their decision-making roles explicitly. Rather, they constructed patient participation in palliative care decisions in a covert manner. Four interpretive repertoires were used to justify patient participation: (1) exposing uncertainty, (2) co-constructing patient preferences, (3) affirming patient autonomy, and finally (4) upholding the authority of health care providers. The results demonstrate how patients and health care providers used these arguments to negotiate their respective roles in decision-making. In conclusion, patients and health care providers used a variety of interpretive repertoires to covertly negotiate their roles in decision-making, and to legitimize decisions that shaped patients’ dying trajectories. Discourse analysis encourages awareness of the role of language in either promoting or hindering patient participation in decision-making. PMID:27882864

Patient participation in palliative care decisions: An ethnographic discourse analysis.

PubMed

Bélanger, Emmanuelle; Rodríguez, Charo; Groleau, Danielle; Légaré, France; MacDonald, Mary Ellen; Marchand, Robert

2016-01-01

The participation of patients in making decisions about their care is especially important towards the end of life because palliative care decisions involve extensive uncertainty and are heavily influenced by personal values. Yet, there is a scarcity of studies directly observing clinical interactions between palliative patients and their health care providers. In this study, we aimed to understand how patient participation in palliative care decisions is constructed through discourse in a community hospital-based palliative care team. This qualitative study combined ethnographic observations of a palliative care team with discourse analysis. Eighteen palliative care patients with cancer diagnoses, six family physicians, and two nurses were involved in the study. Multiple interactions were observed between each patient and health care providers over the course of 1 year, for a total of 101 consultations, 24 of which were audio-recorded. The analysis consisted in looking for the interpretive repertoires (i.e., familiar lines of argument used to justify actions) that were used to justify patient participation in decision-making during clinical interactions, as well as exploring their implications for decision roles and end-of-life care. Patients and their health care providers seldom addressed their decision-making roles explicitly. Rather, they constructed patient participation in palliative care decisions in a covert manner. Four interpretive repertoires were used to justify patient participation: (1) exposing uncertainty, (2) co-constructing patient preferences, (3) affirming patient autonomy, and finally (4) upholding the authority of health care providers. The results demonstrate how patients and health care providers used these arguments to negotiate their respective roles in decision-making. In conclusion, patients and health care providers used a variety of interpretive repertoires to covertly negotiate their roles in decision-making, and to legitimize decisions that shaped patients' dying trajectories. Discourse analysis encourages awareness of the role of language in either promoting or hindering patient participation in decision-making.

Females and males are highly similar in language performance and cortical activation patterns during verb generation.

PubMed

Allendorfer, Jane B; Lindsell, Christopher J; Siegel, Miriam; Banks, Christi L; Vannest, Jennifer; Holland, Scott K; Szaflarski, Jerzy P

2012-10-01

To test the existence of sex differences in cortical activation during verb generation when performance is controlled for. Twenty male and 20 female healthy adults underwent functional magnetic resonance imaging (fMRI) using a covert block-design verb generation task (BD-VGT) and its event-related version (ER-VGT) that allowed for intra-scanner recordings of overt responses. Task-specific activations were determined using the following contrasts: BD-VGT covert generation>finger-tapping; ER-VGT overt generation>repetition; ER-VGT overt>covert generation. Lateral cortical regions activated during each contrast were used for calculating language lateralization index scores. Voxelwise regressions were used to determine sex differences in activation, with and without controlling for performance. Each brain region showing male/female activation differences for ER-VGT overt generation>repetition (isolating noun-verb association) was defined as a region of interest (ROI). For each subject, the signal change in each ROI was extracted, and the association between ER-VGT activation related to noun-verb association and performance was assessed separately for each sex. Males and females performed similarly on language assessments, had similar patterns of language lateralization, and exhibited similar activation patterns for each fMRI task contrast. Regression analysis controlling for overt intra-scanner performance either abolished (BD-VGT) or reduced (ER-VGT) the observed differences in activation between sexes. The main difference between sexes occurred during ER-VGT processing of noun-verb associations, where males showed greater activation than females in the right middle/superior frontal gyrus (MFG/SFG) and the right caudate/anterior cingulate gyrus (aCG) after controlling for performance. Better verb generation performance was associated with increased right caudate/aCG activation in males and with increased right MFG/SFG activation in females. Males and females exhibit similar activation patterns during verb generation fMRI, and controlling for intra-scanner performance reduces or even abolishes sex differences in language-related activation. These results suggest that previous findings of sex differences in neuroimaging studies that did not control for task performance may reflect false positives. Copyright © 2011 Elsevier Srl. All rights reserved.

Orienting Auditory Spatial Attention Engages Frontal Eye Fields and Medial Occipital Cortex in Congenitally Blind Humans

PubMed Central

Garg, Arun; Schwartz, Daniel; Stevens, Alexander A.

2007-01-01

What happens in vision related cortical areas when congenitally blind (CB) individuals orient attention to spatial locations? Previous neuroimaging of sighted individuals has found overlapping activation in a network of frontoparietal areas including frontal eye-fields (FEF), during both overt (with eye movement) and covert (without eye movement) shifts of spatial attention. Since voluntary eye movement planning seems irrelevant in CB, their FEF neurons should be recruited for alternative functions if their attentional role in sighted individuals is only due to eye movement planning. Recent neuroimaging of the blind has also reported activation in medial occipital areas, normally associated with visual processing, during a diverse set of non-visual tasks, but their response to attentional shifts remains poorly understood. Here, we used event-related fMRI to explore FEF and medial occipital areas in CB individuals and sighted controls with eyes closed (SC) performing a covert attention orienting task, using endogenous verbal cues and spatialized auditory targets. We found robust stimulus-locked FEF activation of all CB subjects, similar but stronger than in SC, suggesting that FEF plays a role in endogenous orienting of covert spatial attention even in individuals in whom voluntary eye movements are irrelevant. We also found robust activation in bilateral medial occipital cortex in CB but not in SC subjects. The response decreased below baseline following endogenous verbal cues but increased following auditory targets, suggesting that the medial occipital area in CB does not directly engage during cued orienting of attention but may be recruited for processing of spatialized auditory targets. PMID:17397882

Evidence for a neural correlate of a framing effect: bias-specific activity in the ventromedial prefrontal cortex during credibility judgments.

PubMed

Deppe, M; Schwindt, W; Krämer, J; Kugel, H; Plassmann, H; Kenning, P; Ringelstein, E B

2005-11-15

Neural processes within the medial prefrontal cortex play a crucial role in assessing and integrating emotional and other implicit information during decision-making. Phylogenetically, it was important for the individual to assess the relevance of all kinds of environmental stimuli in order to adapt behavior in a flexible manner. Consequently, we can in principle not exclude that environmental information covertly influences the evaluation of actually decision relevant facts ("framing effect"). To test the hypothesis that the medial prefrontal cortex is involved into a framing effect we employed functional magnetic resonance imaging (fMRI) during a binary credibility judgment task. Twenty-one subjects were asked to judge 30 normalized news magazine headlines by forced answers as "true" or "false". To confound the judgments by formally irrelevant framing information we presented each of the headlines in four different news magazines characterized by varying credibility. For each subject the susceptibility to the judgment confounder (framing information) was assessed by magazine-specific modifications of the answers given. We could show that individual activity changes of the ventromedial prefrontal cortex during the judgments correlate with the degree of an individual's susceptibility to the framing information. We found (i) a neural correlate of a framing effect as postulated by behavioral decision theorists that (ii) reflects interindividual differences in the degree of the susceptibility to framing information.

Fostering Intuition in Management Education: Activities and Resources

ERIC Educational Resources Information Center

Sadler-Smith, Eugene; Burke, Lisa A.

2009-01-01

In business, there is little doubt that managers use their intuitions when making decisions. But in spite of the fact that intuition and rationality are two parallel systems of knowing, intuition is often considered the antithesis of rationality and is overlooked, disregarded, or acted on covertly by managers. What is also clear is that intuition…

Learning optimal eye movements to unusual faces

PubMed Central

Peterson, Matthew F.; Eckstein, Miguel P.

2014-01-01

Eye movements, which guide the fovea’s high resolution and computational power to relevant areas of the visual scene, are integral to efficient, successful completion of many visual tasks. How humans modify their eye movements through experience with their perceptual environments, and its functional role in learning new tasks, has not been fully investigated. Here, we used a face identification task where only the mouth discriminated exemplars to assess if, how, and when eye movement modulation may mediate learning. By interleaving trials of unconstrained eye movements with trials of forced fixation, we attempted to separate the contributions of eye movements and covert mechanisms to performance improvements. Without instruction, a majority of observers substantially increased accuracy and learned to direct their initial eye movements towards the optimal fixation point. The proximity of an observer’s default face identification eye movement behavior to the new optimal fixation point and the observer’s peripheral processing ability were predictive of performance gains and eye movement learning. After practice in a subsequent condition in which observers were directed to fixate different locations along the face, including the relevant mouth region, all observers learned to make eye movements to the optimal fixation point. In this fully learned state, augmented fixation strategy accounted for 43% of total efficiency improvements while covert mechanisms accounted for the remaining 57%. The findings suggest a critical role for eye movement planning to perceptual learning, and elucidate factors that can predict when and how well an observer can learn a new task with unusual exemplars. PMID:24291712

Insights into sleep's role for insight: Studies with the number reduction task

PubMed Central

Verleger, Rolf; Rose, Michael; Wagner, Ullrich; Yordanova, Juliana; Kolev, Vasil

2013-01-01

In recent years, vibrant research has developed on “consolidation” during sleep: To what extent are newly experienced impressions reprocessed or even restructured during sleep? We used the number reduction task (NRT) to study if and how sleep does not only reiterate new experiences but may even lead to new insights. In the NRT, covert regularities may speed responses. This implicit acquisition of regularities may become explicitly conscious at some point, leading to a qualitative change in behavior which reflects this insight. By applying the NRT at two consecutive sessions separated by an interval, we investigated the role of sleep in this interval for attaining insight at the second session. In the first study, a night of sleep was shown to triple the number of participants attaining insight above the base rate of about 20%. In the second study, this hard core of 20% discoverers differed from other participants in their task-related EEG potentials from the very beginning already. In the third study, the additional role of sleep was specified as an effect of the deep-sleep phase of slow-wave sleep on participants who had implicitly acquired the covert regularity before sleep. It was in these participants that a specific increase of EEG during slow-wave sleep in the 10-12 Hz band was obtained. These results support the view that neuronal memory reprocessing during slow-wave sleep restructures task-related representations in the brain, and that such restructuring promotes the gain of explicit knowledge. PMID:24605175

Right Hand Presence Modulates Shifts of Exogenous Visuospatial Attention in Near Perihand Space

ERIC Educational Resources Information Center

Lloyd, Donna M.; Azanon, Elena; Poliakoff, Ellen

2010-01-01

To investigate attentional shifting in perihand space, we measured performance on a covert visual orienting task under different hand positions. Participants discriminated visual shapes presented on a screen and responded using footpedals placed under their right foot. With the right hand positioned by the right side of the screen, mean cueing…

Training Preschool Children to Use Visual Imagining as a Problem-Solving Strategy for Complex Categorization Tasks

ERIC Educational Resources Information Center

Kisamore, April N.; Carr, James E.; LeBlanc, Linda A.

2011-01-01

It has been suggested that verbally sophisticated individuals engage in a series of precurrent behaviors (e.g., covert intraverbal behavior, grouping stimuli, visual imagining) to solve problems such as answering questions (Palmer, 1991; Skinner, 1953). We examined the effects of one problem solving strategy--visual imagining--on increasing…

Effects of stimulus response compatibility on covert imitation of vowels.

PubMed

Adank, Patti; Nuttall, Helen; Bekkering, Harold; Maegherman, Gwijde

2018-03-13

When we observe someone else speaking, we tend to automatically activate the corresponding speech motor patterns. When listening, we therefore covertly imitate the observed speech. Simulation theories of speech perception propose that covert imitation of speech motor patterns supports speech perception. Covert imitation of speech has been studied with interference paradigms, including the stimulus-response compatibility paradigm (SRC). The SRC paradigm measures covert imitation by comparing articulation of a prompt following exposure to a distracter. Responses tend to be faster for congruent than for incongruent distracters; thus, showing evidence of covert imitation. Simulation accounts propose a key role for covert imitation in speech perception. However, covert imitation has thus far only been demonstrated for a select class of speech sounds, namely consonants, and it is unclear whether covert imitation extends to vowels. We aimed to demonstrate that covert imitation effects as measured with the SRC paradigm extend to vowels, in two experiments. We examined whether covert imitation occurs for vowels in a consonant-vowel-consonant context in visual, audio, and audiovisual modalities. We presented the prompt at four time points to examine how covert imitation varied over the distracter's duration. The results of both experiments clearly demonstrated covert imitation effects for vowels, thus supporting simulation theories of speech perception. Covert imitation was not affected by stimulus modality and was maximal for later time points.

Lateralization patterns of covert but not overt movements change with age: An EEG neurofeedback study.

PubMed

Zich, Catharina; Debener, Stefan; De Vos, Maarten; Frerichs, Stella; Maurer, Stefanie; Kranczioch, Cornelia

2015-08-01

The mental practice of movements has been suggested as a promising add-on therapy to facilitate motor recovery after stroke. In the case of mentally practised movements, electroencephalogram (EEG) can be utilized to provide feedback about an otherwise covert act. The main target group for such an intervention are elderly patients, though research so far is largely focused on young populations (<30 years). The present study therefore aimed to examine the influence of age on the neural correlates of covert movements (CMs) in a real-time EEG neurofeedback framework. CM-induced event-related desynchronization (ERD) was studied in young (mean age: 23.6 years) and elderly (mean age: 62.7 years) healthy adults. Participants performed covert and overt hand movements. CMs were based on kinesthetic motor imagery (MI) or quasi-movements (QM). Based on previous studies investigating QM in the mu frequency range (8-13Hz) QM were expected to result in more lateralized ERD% patterns and accordingly higher classification accuracies. Independent of CM strategy the elderly were characterized by a significantly reduced lateralization of ERD%, due to stronger ipsilateral ERD%, and in consequence, reduced classification accuracies. QM were generally perceived as more vivid, but no differences were evident between MI and QM in ERD% or classification accuracies. EEG feedback enhanced task-related activity independently of strategy and age. ERD% measures of overt and covert movements were strongly related in young adults, whereas in the elderly ERD% lateralization is dissociated. In summary, we did not find evidence in support of more pronounced ERD% lateralization patterns in QM. Our finding of a less lateralized activation pattern in the elderly is in accordance to previous research and with the idea that compensatory processes help to overcome neurodegenerative changes related to normal ageing. Importantly, it indicates that EEG neurofeedback studies should place more emphasis on the age of the potential end-users. Copyright © 2015 Elsevier Inc. All rights reserved.

Covert orienting in the split brain: Right hemisphere specialization for object-based attention.

PubMed

Kingstone, Alan

2015-12-18

The present paper takes as its starting point Phil Bryden's long-standing interest in human attention and the role it can play in laterality effects. Past split-brain research has suggested that object-based attention is lateralized to the left hemisphere [e.g., Egly, R., Rafal, R. D., Driver, J., & Starreveld, Y. (1994). Covert orienting in the split brain reveals hemispheric specialization for object-based attention. Psychological Science, 5(6), 380-382]. The task used to isolate object-based attention in that previous work, however, has been found wanting [Vecera, S. P. (1994). Grouped locations and object-based attention: Comment on Egly, Driver, and Rafal (1994). Journal of Experimental Psychology: General, 123(3), 316-320]; and indeed, subsequent research with healthy participants using a different task has suggested that object-based attention is lateralized to the opposite right hemisphere (RH) [Valsangkar-Smyth, M. A., Donovan, C. L., Sinnett, S., Dawson, M. R., & Kingstone, A. (2004). Hemispheric performance in object-based attention. Psychonomic Bulletin & Review, 11(1), 84-91]. The present study tested the same split-brain as Egly, Rafal, et al. (1994) but used the object-based attention task introduced by Valsangkar-Smyth et al. (2004). The results confirm that object-based attention is lateralized to the RH. They also suggest that subcortical interhemispheric competition may occur and be dominated by the RH.

Covert leadership: notes on managing professionals. Knowledge workers respond to inspiration, not supervision.

PubMed

Mintzberg, H

1998-01-01

The orchestra conductor is a popular metaphor for managers today--up there on the podium in complete control. But that image may be misleading, says Henry Mintzberg, who recently spent a day with Bramwell Tovey, conductor of the Winnipeg Symphony Orchestra, in order to explore the metaphor. He found that Tovey does not operate like an absolute ruler but practices instead what Mintzberg calls covert leadership. Covert leadership means managing with a sense of nuances, constraints, and limitations. When a manager like Tovey guides an organization, he leads without seeming to, without his people being fully aware of all that he is doing. That's because in this world of professionals, a leader is not completely powerless--but neither does he have absolute control over others. As knowledge work grows in importance, the way an orchestra conductor really operates may serve as a good model for managers in a wide range of businesses. For example, Mintzberg found that Tovey does a lot more hands-on work than one might expect. More like a first-line supervisor than a hands-off executive, he takes direct and personal charge of what is getting done. In dealing with his musicians, his focus is on inspiring them, not empowering them. Like other professionals, the musicians don't need to be empowered--they're already secure in what they know and can do--but they do need to be infused with energy for the tasks at hand. This is the role of the covert leader: to act quietly and unobtrusively in order to exact not obedience but inspired performance.

Decreased interpretation of nonverbal cues in rape victims.

PubMed

Giannini, A J; Price, W A; Kniepple, J L

The ability to receive nonverbal facial cues was tested in twelve female victims of multiple nonserial rapes and matched controls. Subjects attempted to interpret nonverbal messages transmitted by male and female senders who were covertly taped while involved in a gambling task. Rape victims had significantly decreased ability to interpret the nonverbal facial cues of both male and female senders.

Reconciling conflicting electrophysiological findings on the guidance of attention by working memory.

PubMed

Carlisle, Nancy B; Woodman, Geoffrey F

2013-10-01

Maintaining a representation in working memory has been proposed to be sufficient for the execution of top-down attentional control. Two recent electrophysiological studies that recorded event-related potentials (ERPs) during similar paradigms have tested this proposal, but have reported contradictory findings. The goal of the present study was to reconcile these previous reports. To this end, we used the stimuli from one study (Kumar, Soto, & Humphreys, 2009) combined with the task manipulations from the other (Carlisle & Woodman, 2011b). We found that when an item matching a working memory representation was presented in a visual search array, we could use ERPs to quantify the size of the covert attention effect. When the working memory matches were consistently task-irrelevant, we observed a weak attentional bias to these items. However, when the same item indicated the location of the search target, we found that the covert attention effect was approximately four times larger. This shows that simply maintaining a representation in working memory is not equivalent to having a top-down attentional set for that item. Our findings indicate that high-level goals mediate the relationship between the contents of working memory and perceptual attention.

Modulation of Posterior Alpha Activity by Spatial Attention Allows for Controlling A Continuous Brain-Computer Interface.

PubMed

Horschig, Jörn M; Oosterheert, Wouter; Oostenveld, Robert; Jensen, Ole

2015-11-01

Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing.

Understanding the role of speech production in reading: Evidence for a print-to-speech neural network using graphical analysis.

PubMed

Cummine, Jacqueline; Cribben, Ivor; Luu, Connie; Kim, Esther; Bahktiari, Reyhaneh; Georgiou, George; Boliek, Carol A

2016-05-01

The neural circuitry associated with language processing is complex and dynamic. Graphical models are useful for studying complex neural networks as this method provides information about unique connectivity between regions within the context of the entire network of interest. Here, the authors explored the neural networks during covert reading to determine the role of feedforward and feedback loops in covert speech production. Brain activity of skilled adult readers was assessed in real word and pseudoword reading tasks with functional MRI (fMRI). The authors provide evidence for activity coherence in the feedforward system (inferior frontal gyrus-supplementary motor area) during real word reading and in the feedback system (supramarginal gyrus-precentral gyrus) during pseudoword reading. Graphical models provided evidence of an extensive, highly connected, neural network when individuals read real words that relied on coordination of the feedforward system. In contrast, when individuals read pseudowords the authors found a limited/restricted network that relied on coordination of the feedback system. Together, these results underscore the importance of considering multiple pathways and articulatory loops during language tasks and provide evidence for a print-to-speech neural network. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Functional MRI Motor Imagery Tasks to Detect Command Following in Traumatic Disorders of Consciousness.

PubMed

Bodien, Yelena G; Giacino, Joseph T; Edlow, Brian L

2017-01-01

Severe traumatic brain injury impairs arousal and awareness, the two components of consciousness. Accurate diagnosis of a patient's level of consciousness is critical for determining treatment goals, access to rehabilitative services, and prognosis. The bedside behavioral examination, the current clinical standard for diagnosis of disorders of consciousness, is prone to misdiagnosis, a finding that has led to the development of advanced neuroimaging techniques aimed at detection of conscious awareness. Although a variety of paradigms have been used in functional magnetic resonance imaging (fMRI) to reveal covert consciousness, the relative accuracy of these paradigms in the patient population is unknown. Here, we compare the rate of covert consciousness detection by hand squeezing and tennis playing motor imagery paradigms in 10 patients with traumatic disorders of consciousness [six male, six acute, mean ± SD age = 27.9 ± 9.1 years, one coma, four unresponsive wakefulness syndrome, two minimally conscious without language function, and three minimally conscious with language function, per bedside examination with the Coma Recovery Scale-Revised (CRS-R)]. We also tested the same paradigms in 10 healthy subjects (nine male, mean ± SD age = 28.5 ± 9.4 years). In healthy subjects, the hand squeezing paradigm detected covert command following in 7/10 and the tennis playing paradigm in 9/10 subjects. In patients who followed commands on the CRS-R, the hand squeezing paradigm detected covert command following in 2/3 and the tennis playing paradigm in 0/3 subjects. In patients who did not follow commands on the CRS-R, the hand squeezing paradigm detected command following in 1/7 and the tennis playing paradigm in 2/7 subjects. The sensitivity, specificity, and accuracy (ACC) of detecting covert command following in patients who demonstrated this behavior on the CRS-R was 66.7, 85.7, and 80% for the hand squeezing paradigm and 0, 71.4, and 50% for the tennis playing paradigm, respectively. Overall, the tennis paradigm performed better than the hand squeezing paradigm in healthy subjects, but in patients, the hand squeezing paradigm detected command following with greater ACC. These findings indicate that current fMRI motor imagery paradigms frequently fail to detect command following and highlight the need for paradigm optimization to improve the accuracy of covert consciousness detection.

Functional MRI Motor Imagery Tasks to Detect Command Following in Traumatic Disorders of Consciousness

PubMed Central

Bodien, Yelena G.; Giacino, Joseph T.; Edlow, Brian L.

2017-01-01

Severe traumatic brain injury impairs arousal and awareness, the two components of consciousness. Accurate diagnosis of a patient’s level of consciousness is critical for determining treatment goals, access to rehabilitative services, and prognosis. The bedside behavioral examination, the current clinical standard for diagnosis of disorders of consciousness, is prone to misdiagnosis, a finding that has led to the development of advanced neuroimaging techniques aimed at detection of conscious awareness. Although a variety of paradigms have been used in functional magnetic resonance imaging (fMRI) to reveal covert consciousness, the relative accuracy of these paradigms in the patient population is unknown. Here, we compare the rate of covert consciousness detection by hand squeezing and tennis playing motor imagery paradigms in 10 patients with traumatic disorders of consciousness [six male, six acute, mean ± SD age = 27.9 ± 9.1 years, one coma, four unresponsive wakefulness syndrome, two minimally conscious without language function, and three minimally conscious with language function, per bedside examination with the Coma Recovery Scale-Revised (CRS-R)]. We also tested the same paradigms in 10 healthy subjects (nine male, mean ± SD age = 28.5 ± 9.4 years). In healthy subjects, the hand squeezing paradigm detected covert command following in 7/10 and the tennis playing paradigm in 9/10 subjects. In patients who followed commands on the CRS-R, the hand squeezing paradigm detected covert command following in 2/3 and the tennis playing paradigm in 0/3 subjects. In patients who did not follow commands on the CRS-R, the hand squeezing paradigm detected command following in 1/7 and the tennis playing paradigm in 2/7 subjects. The sensitivity, specificity, and accuracy (ACC) of detecting covert command following in patients who demonstrated this behavior on the CRS-R was 66.7, 85.7, and 80% for the hand squeezing paradigm and 0, 71.4, and 50% for the tennis playing paradigm, respectively. Overall, the tennis paradigm performed better than the hand squeezing paradigm in healthy subjects, but in patients, the hand squeezing paradigm detected command following with greater ACC. These findings indicate that current fMRI motor imagery paradigms frequently fail to detect command following and highlight the need for paradigm optimization to improve the accuracy of covert consciousness detection. PMID:29326648

Personnel Detection Technology Assessment Final Report

DTIC Science & Technology

2003-04-16

3.1.2.1 Bioelectric Activity Nerve impulses generate very weak bioelectric signals that can be detected by external probes at short ranges. The...covert detection /tracking scenarios. It was concluded that, in general , distributed sensor networks will be required to meet the scenario...personnel detection was recognized by the US Army Research Office (ARO). The Ohio State University was tasked to assess the status of sensors and signal

Lateralized electrical brain activity reveals covert attention allocation during speaking.

PubMed

Rommers, Joost; Meyer, Antje S; Praamstra, Peter

2017-01-27

Speakers usually begin to speak while only part of the utterance has been planned. Earlier work has shown that speech planning processes are reflected in speakers' eye movements as they describe visually presented objects. However, to-be-named objects can be processed to some extent before they have been fixated upon, presumably because attention can be allocated to objects covertly, without moving the eyes. The present study investigated whether EEG could track speakers' covert attention allocation as they produced short utterances to describe pairs of objects (e.g., "dog and chair"). The processing difficulty of each object was varied by presenting it in upright orientation (easy) or in upside down orientation (difficult). Background squares flickered at different frequencies in order to elicit steady-state visual evoked potentials (SSVEPs). The N2pc component, associated with the focusing of attention on an item, was detectable not only prior to speech onset, but also during speaking. The time course of the N2pc showed that attention shifted to each object in the order of mention prior to speech onset. Furthermore, greater processing difficulty increased the time speakers spent attending to each object. This demonstrates that the N2pc can track covert attention allocation in a naming task. In addition, an effect of processing difficulty at around 200-350ms after stimulus onset revealed early attention allocation to the second to-be-named object. The flickering backgrounds elicited SSVEPs, but SSVEP amplitude was not influenced by processing difficulty. These results help complete the picture of the coordination of visual information uptake and motor output during speaking. Copyright © 2016 Elsevier Ltd. All rights reserved.

Moderation of nicotine effects on covert orienting of attention tasks by poor placebo performance and cue validity.

PubMed

Hammersley, Jonathan J; Gilbert, David G; Rzetelny, Adam; Rabinovich, Norka E

2016-10-01

Given baseline-dependent effects of nicotine on other forms of attention, there is reason to believe that inconsistent findings for the effects of nicotine on attentional orienting may be partly due to individual differences in baseline (abstinence state) functioning. Individuals with low baseline attention may benefit more from nicotine replacement. The effects of nicotine as a function of baseline performance (bottom, middle, and top third of mean reaction times during placebo) were assessed in 52 habitual abstinent smokers (26 females/26 males) utilizing an arrow-cued covert orienting of attention task. Compared to a placebo patch, a 14mg nicotine patch produced faster overall reaction times (RTs). In addition, individuals with slower RTs during the placebo condition benefitted more from nicotine on cued trials than did those who had shorter (faster) RTs during placebo. Nicotine also enhanced the validity effect (shorter RTs to validly vs. invalidly cued targets), but this nicotine benefit did not differ as a function of overall placebo-baseline performance. These findings support the view that nicotine enhances cued spatial attentional orienting in individuals who have slower RTs during placebo (nicotine-free) conditions; however, baseline-dependent effects may not generalize to all aspects of spatial attention. These findings are consistent with findings indicating that nicotine's effects vary as a function of task parameters rather than simple RT speeding or cognitive enhancement. Copyright © 2016 Elsevier Inc. All rights reserved.

Moderation of Nicotine Effects on Covert Orienting of Attention Tasks by Poor Placebo Performance and Cue Validity

PubMed Central

Gilbert, David G.; Rzetelny, Adam; Rabinovich, Norka E.

2016-01-01

Introduction and Rationale Given baseline-dependent effects of nicotine on other forms of attention, there is reason to believe that inconsistent findings for the effects of nicotine on attentional orienting may be partly due to individual differences in baseline (abstinence state) functioning. Individuals with low baseline attention may benefit more from nicotine replacement. Method The effects of nicotine as a function of baseline performance (bottom, middle, and top third of mean reaction times during placebo) were assessed in 52 habitual abstinent smokers (26 females/26 males) utilizing an arrow-cued covert orienting of attention task. Results Compared to a placebo patch, a 14 mg nicotine patch produced faster overall reaction times (RTs). In addition, individuals with slower RTs during the placebo condition benefitted more from nicotine on cued trials than did those who had shorter (faster) RTs during placebo. Nicotine also enhanced the validity effect (shorter RTs to validly vs. invalidly cued targets), but this nicotine benefit did not differ as a function of overall placebo-baseline performance. Conclusions These findings support the view that nicotine enhances cued spatial attentional orienting in individuals who have slower RTs during placebo (nicotine-free) conditions; however, baseline-dependent effects may not generalize to all aspects of spatial attention. These findings are consistent with findings indicating that nicotine’s effects vary as a function of task parameters rather than simple RT speeding or cognitive enhancement. PMID:27461547

The Call of the Sirens? The Influence of Gender in the Decision To Choose Teaching as a Career Change.

ERIC Educational Resources Information Center

Freidus, Helen

Social feminists insist on the relevance of personal experience and believe that, for changes to occur, it is essential to understand the dynamics of how and why gender roles are perpetuated. Social feminists view the career course of second-career teachers as vulnerable to the covert structures and curriculum of the schools. The social feminist…

Are Covert Saccade Functionally Relevant in Vestibular Hypofunction?

PubMed

Hermann, R; Pelisson, D; Dumas, O; Urquizar, Ch; Truy, E; Tilikete, C

2018-06-01

The vestibulo-ocular reflex maintains gaze stabilization during angular or linear head accelerations, allowing adequate dynamic visual acuity. In case of bilateral vestibular hypofunction, patients use saccades to compensate for the reduced vestibulo-ocular reflex function, with covert saccades occurring even during the head displacement. In this study, we questioned whether covert saccades help maintain dynamic visual acuity, and evaluated which characteristic of these saccades are the most relevant to improve visual function. We prospectively included 18 patients with chronic bilateral vestibular hypofunction. Subjects underwent evaluation of dynamic visual acuity in the horizontal plane as well as video recording of their head and eye positions during horizontal head impulse tests in both directions (36 ears tested). Frequency, latency, consistency of covert saccade initiation, and gain of covert saccades as well as residual vestibulo-ocular reflex gain were calculated. We found no correlation between residual vestibulo-ocular reflex gain and dynamic visual acuity. Dynamic visual acuity performance was however positively correlated with the frequency and gain of covert saccades and negatively correlated with covert saccade latency. There was no correlation between consistency of covert saccade initiation and dynamic visual acuity. Even though gaze stabilization in space during covert saccades might be of very short duration, these refixation saccades seem to improve vision in patients with bilateral vestibular hypofunction during angular head impulses. These findings emphasize the need for specific rehabilitation technics that favor the triggering of covert saccades. The physiological origin of covert saccades is discussed.

False fame prevented: avoiding fluency effects without judgmental correction.

PubMed

Topolinski, Sascha; Strack, Fritz

2010-05-01

Three studies show a way to prevent fluency effects independently of judgmental correction strategies by identifying and procedurally blocking the sources of fluency variations, which are assumed to be embodied in nature. For verbal stimuli, covert pronunciations are assumed to be the crucial source of fluency gains. As a consequence, blocking such pronunciation simulations through a secondary oral motor task decreased the false-fame effect for repeatedly presented names of actors (Experiment 1) as well as prevented increases in trust due to repetition for brand names and names of shares in the stock market (Experiment 2). Extending this evidence beyond repeated exposure, we demonstrated that blocking oral motor simulations also prevented fluency effects of word pronunciation on judgments of hazardousness (Experiment 3). Concerning the realm of judgment correction, this procedural blocking of (biasing) associative processes is a decontamination method not considered before in the literature, because it is independent of exposure control, mood, motivation, and post hoc correction strategies. The present results also have implications for applied issues, such as advertising and investment decisions. 2010 APA, all rights reserved

Video game players show higher performance but no difference in speed of attention shifts.

PubMed

Mack, David J; Wiesmann, Helene; Ilg, Uwe J

2016-09-01

Video games have become both a widespread leisure activity and a substantial field of research. In a variety of tasks, video game players (VGPs) perform better than non-video game players (NVGPs). This difference is most likely explained by an alteration of the basic mechanisms underlying visuospatial attention. More specifically, the present study hypothesizes that VGPs are able to shift attention faster than NVGPs. Such alterations in attention cannot be disentangled from changes in stimulus-response mappings in reaction time based measurements. Therefore, we used a spatial cueing task with varying cue lead times (CLTs) to investigate the speed of covert attention shifts of 98 male participants divided into 36 NVGPs and 62 VGPs based on their weekly gaming time. VGPs exhibited higher peak and mean performance than NVGPs. However, we did not find any differences in the speed of covert attention shifts as measured by the CLT needed to achieve peak performance. Thus, our results clearly rule out faster stimulus-response mappings as an explanation for the higher performance of VGPs in line with previous studies. More importantly, our data do not support the notion of faster attention shifts in VGPs as another possible explanation. Copyright © 2016 Elsevier B.V. All rights reserved.

How Attention Affects Spatial Resolution

PubMed Central

Carrasco, Marisa; Barbot, Antoine

2015-01-01

We summarize and discuss a series of psychophysical studies on the effects of spatial covert attention on spatial resolution, our ability to discriminate fine patterns. Heightened resolution is beneficial in most, but not all, visual tasks. We show how endogenous attention (voluntary, goal driven) and exogenous attention (involuntary, stimulus driven) affect performance on a variety of tasks mediated by spatial resolution, such as visual search, crowding, acuity, and texture segmentation. Exogenous attention is an automatic mechanism that increases resolution regardless of whether it helps or hinders performance. In contrast, endogenous attention flexibly adjusts resolution to optimize performance according to task demands. We illustrate how psychophysical studies can reveal the underlying mechanisms of these effects and allow us to draw linking hypotheses with known neurophysiological effects of attention. PMID:25948640

A Primer of Covert Sensitization

ERIC Educational Resources Information Center

Kearney, Albert J.

2006-01-01

Covert sensitization is the first of a family of behavior therapy procedures called covert conditioning initially developed by Joseph Cautela in the 1960s and 1970s. The covert conditioning procedures involve the use of visualized imagery and are designed to work according to operant conditioning principles. When working with cooperative clients…

Gendered power dynamics and women's negotiation of family planning in a high HIV prevalence setting: a qualitative study of couples in western Kenya.

PubMed

Harrington, Elizabeth K; Dworkin, Shari; Withers, Mellissa; Onono, Maricianah; Kwena, Zachary; Newmann, Sara J

2016-01-01

In sub-Saharan Africa, high burdens of HIV and unmet need for contraception often coexist. Research emphasises the need to engage men and couples in reproductive health, yet couples' negotiations around fertility and family planning in the context of HIV have been sparsely studied. This study examined the gendered power dynamics that frame women's and couples' negotiations of contraceptive use in western Kenya. We conducted 76 in-depth interviews with 38 couples, of whom 22 couples were concordant HIV-positive. Qualitative data were analysed using a grounded theory approach. Direct communication around contraception with men was often challenging due to perceived or expressed male resistance. A substantial minority of women avoided male reproductive decision-making authority through covert contraceptive use, with concern for severe consequences when contraceptive use was discovered. Many men assumed that family planning use signified female promiscuity and that infidelity motivated covert use. Men were more willing to use condoms to avoid HIV re-infection or on the recommendation of HIV care providers, which allowed some women leverage to insist on condom use. Our findings highlight the tension between male dominated reproductive decision making and women's agency and point to the need for gender transformative approaches seeking to challenge masculinities that negatively impact health.

Emotional Processing of Personally Familiar Faces in the Vegetative State

PubMed Central

Sharon, Haggai; Pasternak, Yotam; Ben Simon, Eti; Gruberger, Michal; Giladi, Nir; Krimchanski, Ben Zion; Hassin, David; Hendler, Talma

2013-01-01

Background The Vegetative State (VS) is a severe disorder of consciousness in which patients are awake but display no signs of awareness. Yet, recent functional magnetic resonance imaging (fMRI) studies have demonstrated evidence for covert awareness in VS patients by recording specific brain activations during a cognitive task. However, the possible existence of incommunicable subjective emotional experiences in VS patients remains largely unexplored. This study aimed to probe the question of whether VS patients retain a brain ability to selectively process external stimuli according to their emotional value and look for evidence of covert emotional awareness in patients. Methods and Findings In order to explore these questions we employed the emotive impact of observing personally familiar faces, known to provoke specific perceptual as well as emotional brain activations. Four VS patients and thirteen healthy controls first underwent an fMRI scan while viewing pictures of non-familiar faces, personally familiar faces and pictures of themselves. In a subsequent imagery task participants were asked to actively imagine one of their parent's faces. Analyses focused on face and familiarity selective regional brain activations and inter-regional functional connectivity. Similar to controls, all patients displayed face selective brain responses with further limbic and cortical activations elicited by familiar faces. In patients as well as controls, Connectivity was observed between emotional, visual and face specific areas, suggesting aware emotional perception. This connectivity was strongest in the two patients who later recovered. Notably, these two patients also displayed selective amygdala activation during familiar face imagery, with one further exhibiting face selective activations, indistinguishable from healthy controls. Conclusions Taken together, these results show that selective emotional processing can be elicited in VS patients both by external emotionally salient stimuli and by internal cognitive processes, suggesting the ability for covert emotional awareness of self and the environment in VS patients. PMID:24086365

Attention enhances contrast appearance via increased input baseline of neural responses

PubMed Central

Cutrone, Elizabeth K.; Heeger, David J.; Carrasco, Marisa

2014-01-01

Covert spatial attention increases the perceived contrast of stimuli at attended locations, presumably via enhancement of visual neural responses. However, the relation between perceived contrast and the underlying neural responses has not been characterized. In this study, we systematically varied stimulus contrast, using a two-alternative, forced-choice comparison task to probe the effect of attention on appearance across the contrast range. We modeled performance in the task as a function of underlying neural contrast-response functions. Fitting this model to the observed data revealed that an increased input baseline in the neural responses accounted for the enhancement of apparent contrast with spatial attention. PMID:25549920

The Invisibility of Covert Bullying among Students: Challenges for School Intervention

ERIC Educational Resources Information Center

Barnes, Amy; Cross, Donna; Lester, Leanne; Hearn, Lydia; Epstein, Melanie; Monks, Helen

2012-01-01

Covert bullying behaviours are at least as distressing for young people as overt forms of bullying, but often remain unnoticed or unacknowledged by adults. This "invisibility" is increased in schools by inattention to covert bullying in policy and practice, and limited staff understanding and skill to address covert behaviours. These…

Persistence, impacts and environmental drivers of covert infections in invertebrate hosts.

PubMed

Fontes, Inês; Hartikainen, Hanna; Williams, Chris; Okamura, Beth

2017-11-02

Persistent covert infections of the myxozoan, Tetracapsuloides bryosalmonae, in primary invertebrate hosts (the freshwater bryozoan, Fredericella sultana) have been proposed to represent a reservoir for proliferative kidney disease in secondary fish hosts. However, we have limited understanding of how covert infections persist and vary in bryozoan populations over time and space and how they may impact these populations. In addition, previous studies have likely underestimated covert infection prevalence. To improve our understanding of the dynamics, impacts and implications of covert infections we employed a highly sensitive polymerase chain reaction (PCR) assay and undertook the first investigation of covert infections in the field over an annual period by sampling bryozoans every 45 days from three populations within each of three rivers. Covert infections persisted throughout the year and prevalence varied within and between rivers, but were often > 50%. Variation in temperature and water chemistry were linked with changes in prevalence in a manner consistent with the maintenance of covert infections during periods of low productivity and thus poor growth conditions for both bryozoans and T. bryosalmonae. The presence and increased severity of covert infections reduced host growth but only when bryozoans were also investing in the production of overwintering propagules (statoblasts). However, because statoblast production is transitory, this effect is unlikely to greatly impact the capacity of bryozoan populations to act as persistent sources of infections and hence potential disease outbreaks in farmed and wild fish populations. We demonstrate that covert infections are widespread and persist over space and time in bryozoan populations. To our knowledge, this is the first long-term study of covert infections in a field setting. Review of the results of this and previous studies enables us to identify key questions related to the ecology and evolution of covert infection strategies and associated host-parasite interactions.

Utilizing Glove-Based Gestures and a Tactile Vest Display for Covert Communications and Robot Control

DTIC Science & Technology

2014-06-01

transmitted from a controller mechanism that contains inertial measurement unit ( IMU ) sensors to sense rotation and acceleration of movement. Earlier...assets, and standard hand signal commands can be presented to human team members via a variety of modalities. IMU sensor technologies placed on the body...obstacle event (e.g., climbing, crawling, combat roll , running) and between obstacles (i.e., walking). The following analyses are for each task

USSR Report, Military Affairs, Military History Journal, No. 4, April 1986

DTIC Science & Technology

1986-08-21

25 Oct 1944. On Cape Pikushev, in Malaya Volokovaya Bay , in Port of Linakhamari on Cape Ristiniyemi, in Suolavuono Bay , in Kobholmfjord, in...Holmengorfjord Tasks Assigned to Force Capturing port and coast of Tsemes Bay , helping units of 18th Army in liberating Novorossiysk To cut in...unexpected for the enemy, since it did not assume that the numerous launches and small boats concentrated in Gelendzhik Bay could quickly and covertly

A dissociation of dorso-lateral striatum and amygdala function on the same stimulus-response habit task.

PubMed

McDonald, R J; Hong, N S

2004-01-01

This experiment tested the idea that the amygdala-based learning and memory system covertly acquires a stimulus-reward (stimulus-outcome) association during acquisition of a stimulus-response (S-R) habit task developed for the eight-arm radial maze. Groups of rats were given dorso-lateral striatal or amygdala lesions and then trained on the S-R habit task on the eight-arm radial maze. Rats with neurotoxic damage to the dorso-lateral striatum were severely impaired on the acquisition of the S-R habit task but showed a conditioned-cue preference for the stimulus reinforced during S-R habit training. Rats with neurotoxic damage to the amygdala were able to acquire the S-R habit task but did not show a conditioned-cue preference for the stimulus reinforced during S-R habit training. This pattern of results represents a dissociation of learning and memory functions of the dorsal striatum and amygdala on the same task.

Do patients with psychogenic nonepileptic seizures have positive covert attitudes toward sickness?

PubMed

Testa, S Marc; Brandt, Jason

2010-11-01

Some individuals with psychogenic nonepileptic seizures (PNES) are seen as having adopted a "sick role" that relinquishes them of responsibility for meeting stressful life demands. Thus, patients with PNES may have positive, albeit unrecognized, attitudes toward seizures, or perhaps illness in general. Because such covert attitudes may not be amendable to self-report, the current study used the Implicit Association Test (IAT), a methodology by which attitudes toward illness and disability can be inferred from performance on an ostensibly neutral task. Individuals with PNES did not have a reduced interference effect when responding to sickness-related and pleasant words on the same response key. Exploratory analyses revealed that a pronounced somatic focus and higher extraversion were associated with more neutral attitudes toward illness among patients with PNES. This IAT methodology found little support for the notion that patients with PNES harbor positive attitudes toward illness. Limitations of the IAT methodology are reviewed and recommendations are provided. Published by Elsevier Inc.

The articulatory in-out effect resists oral motor interference.

PubMed

Lindau, Berit; Topolinski, Sascha

2018-02-01

People prefer words with inward directed consonantal patterns (e.g., MENIKA) compared to outward patterns (KENIMA), because inward (outward) articulation movements resemble positive (negative) mouth actions such as swallowing (spitting). This effect might rely on covert articulation simulations, or subvocalizations, since it occurs also under silent reading. We tested to what degree these underlying articulation simulations are disturbed by oral motor interference. In 3 experiments (total N = 465) we interfered with these articulation simulations by employing concurrent oral exercises that induce oral motor noise while judging inward and outward words (chewing gum, Experiment 1; executing meaningless tongue movements, Experiment 2; concurrent verbalizations, Experiment 3). Across several word stimulus types, the articulatory in-out effect was not modulated by these tasks. This finding introduces a theoretically interesting case, because in contrast to many previous demonstrations regarding other motor-preference effects, the covert simulations in this effect are not susceptible to selective motor interference. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Invisible Blockade and the Covert War: U.S. Relations with Chile, 1970-1973

DTIC Science & Technology

1979-06-01

U.S.- owned multinational corporations , pursued a course of action, publicly, economically and covertly, bent on discrediting, disrupting and dislodging...government, in concert with U.S.- .owned multinational corporations , pursued a course of action, publicly, economically and covertly, bent on...513 E. CONCLUSION -------------------------------------- 64 IV. COVERT GOVERNMENTAL AND CORPORATE PRESSURES-------- 67 A. ATTEMPTS TO KEEP

Covert Coercion: A Formal Analysis of Unconventional Warfare as an Interstate Coercive Policy Option

DTIC Science & Technology

2013-06-01

as the most notable of the founding game theorist patriarchs .121 Game theory’s evolution and development exploded during World War II and the...Kennan’s “containment” telegraph. Containment sought to prevent the further expansion of communism by developing a sphere of democratic influence in...the subjective cardinal value interval scaling used to model the decision behavior of the principal actors, which is resultant from the author’s

Rethinking human visual attention: spatial cueing effects and optimality of decisions by honeybees, monkeys and humans.

PubMed

Eckstein, Miguel P; Mack, Stephen C; Liston, Dorion B; Bogush, Lisa; Menzel, Randolf; Krauzlis, Richard J

2013-06-07

Visual attention is commonly studied by using visuo-spatial cues indicating probable locations of a target and assessing the effect of the validity of the cue on perceptual performance and its neural correlates. Here, we adapt a cueing task to measure spatial cueing effects on the decisions of honeybees and compare their behavior to that of humans and monkeys in a similarly structured two-alternative forced-choice perceptual task. Unlike the typical cueing paradigm in which the stimulus strength remains unchanged within a block of trials, for the monkey and human studies we randomized the contrast of the signal to simulate more real world conditions in which the organism is uncertain about the strength of the signal. A Bayesian ideal observer that weights sensory evidence from cued and uncued locations based on the cue validity to maximize overall performance is used as a benchmark of comparison against the three animals and other suboptimal models: probability matching, ignore the cue, always follow the cue, and an additive bias/single decision threshold model. We find that the cueing effect is pervasive across all three species but is smaller in size than that shown by the Bayesian ideal observer. Humans show a larger cueing effect than monkeys and bees show the smallest effect. The cueing effect and overall performance of the honeybees allows rejection of the models in which the bees are ignoring the cue, following the cue and disregarding stimuli to be discriminated, or adopting a probability matching strategy. Stimulus strength uncertainty also reduces the theoretically predicted variation in cueing effect with stimulus strength of an optimal Bayesian observer and diminishes the size of the cueing effect when stimulus strength is low. A more biologically plausible model that includes an additive bias to the sensory response from the cued location, although not mathematically equivalent to the optimal observer for the case stimulus strength uncertainty, can approximate the benefits of the more computationally complex optimal Bayesian model. We discuss the implications of our findings on the field's common conceptualization of covert visual attention in the cueing task and what aspects, if any, might be unique to humans. Copyright © 2013 Elsevier Ltd. All rights reserved.

Instruct: An Example of the Role of Artificial Intelligence in Voice-Based Training Systems.

DTIC Science & Technology

1983-01-01

Lockhart , R.S. Levels of processing : A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 1972, LT, pp. 6𔄁T-684. Ericsson...of covert student processing and knowledge levels from overt student behavior; and a curriculum driver that could use the student model to determine...concentration), then the task is said to be resource-limited. Whenever the performance level remains invariant to increased allocations of processing

Functional Similarity of Medial Superior Parietal Areas for Shift-Selective Attention Signals in Humans and Monkeys.

PubMed

Caspari, Natalie; Arsenault, John T; Vandenberghe, Rik; Vanduffel, Wim

2018-06-01

We continually shift our attention between items in the visual environment. These attention shifts are usually based on task relevance (top-down) or the saliency of a sudden, unexpected stimulus (bottom-up), and are typically followed by goal-directed actions. It could be argued that any species that can covertly shift its focus of attention will rely on similar, evolutionarily conserved neural substrates for processing such shift-signals. To address this possibility, we performed comparative fMRI experiments in humans and monkeys, combining traditional, and novel, data-driven analytical approaches. Specifically, we examined correspondences between monkey and human brain areas activated during covert attention shifts. When "shift" events were compared with "stay" events, the medial (superior) parietal lobe (mSPL) and inferior parietal lobes showed similar shift sensitivities across species, whereas frontal activations were stronger in monkeys. To identify, in a data-driven manner, monkey regions that corresponded with human shift-selective SPL, we used a novel interspecies beta-correlation strategy whereby task-related beta-values were correlated across voxels or regions-of-interest in the 2 species. Monkey medial parietal areas V6/V6A most consistently correlated with shift-selective human mSPL. Our results indicate that both species recruit corresponding, evolutionarily conserved regions within the medial superior parietal lobe for shifting spatial attention.

Neural Correlates of Visual–Spatial Attention in Electrocorticographic Signals in Humans

PubMed Central

Gunduz, Aysegul; Brunner, Peter; Daitch, Amy; Leuthardt, Eric C.; Ritaccio, Anthony L.; Pesaran, Bijan; Schalk, Gerwin

2011-01-01

Attention is a cognitive selection mechanism that allocates the limited processing resources of the brain to the sensory streams most relevant to our immediate goals, thereby enhancing responsiveness and behavioral performance. The underlying neural mechanisms of orienting attention are distributed across a widespread cortical network. While aspects of this network have been extensively studied, details about the electrophysiological dynamics of this network are scarce. In this study, we investigated attentional networks using electrocorticographic (ECoG) recordings from the surface of the brain, which combine broad spatial coverage with high temporal resolution, in five human subjects. ECoG was recorded when subjects covertly attended to a spatial location and responded to contrast changes in the presence of distractors in a modified Posner cueing task. ECoG amplitudes in the alpha, beta, and gamma bands identified neural changes associated with covert attention and motor preparation/execution in the different stages of the task. The results show that attentional engagement was primarily associated with ECoG activity in the visual, prefrontal, premotor, and parietal cortices. Motor preparation/execution was associated with ECoG activity in premotor/sensorimotor cortices. In summary, our results illustrate rich and distributed cortical dynamics that are associated with orienting attention and the subsequent motor preparation and execution. These findings are largely consistent with and expand on primate studies using intracortical recordings and human functional neuroimaging studies. PMID:22046153

Automatically Characterizing Sensory-Motor Patterns Underlying Reach-to-Grasp Movements on a Physical Depth Inversion Illusion.

PubMed

Nguyen, Jillian; Majmudar, Ushma V; Ravaliya, Jay H; Papathomas, Thomas V; Torres, Elizabeth B

2015-01-01

Recently, movement variability has been of great interest to motor control physiologists as it constitutes a physical, quantifiable form of sensory feedback to aid in planning, updating, and executing complex actions. In marked contrast, the psychological and psychiatric arenas mainly rely on verbal descriptions and interpretations of behavior via observation. Consequently, a large gap exists between the body's manifestations of mental states and their descriptions, creating a disembodied approach in the psychological and neural sciences: contributions of the peripheral nervous system to central control, executive functions, and decision-making processes are poorly understood. How do we shift from a psychological, theorizing approach to characterize complex behaviors more objectively? We introduce a novel, objective, statistical framework, and visuomotor control paradigm to help characterize the stochastic signatures of minute fluctuations in overt movements during a visuomotor task. We also quantify a new class of covert movements that spontaneously occur without instruction. These are largely beneath awareness, but inevitably present in all behaviors. The inclusion of these motions in our analyses introduces a new paradigm in sensory-motor integration. As it turns out, these movements, often overlooked as motor noise, contain valuable information that contributes to the emergence of different kinesthetic percepts. We apply these new methods to help better understand perception-action loops. To investigate how perceptual inputs affect reach behavior, we use a depth inversion illusion (DII): the same physical stimulus produces two distinct depth percepts that are nearly orthogonal, enabling a robust comparison of competing percepts. We find that the moment-by-moment empirically estimated motor output variability can inform us of the participants' perceptual states, detecting physiologically relevant signals from the peripheral nervous system that reveal internal mental states evoked by the bi-stable illusion. Our work proposes a new statistical platform to objectively separate changes in visual perception by quantifying the unfolding of movement, emphasizing the importance of including in the motion analyses all overt and covert aspects of motor behavior.

A Comparative Study on the Detection of Covert Attention in Event-Related EEG and MEG Signals to Control a BCI

PubMed Central

Reichert, Christoph; Dürschmid, Stefan; Heinze, Hans-Jochen; Hinrichs, Hermann

2017-01-01

In brain-computer interface (BCI) applications the detection of neural processing as revealed by event-related potentials (ERPs) is a frequently used approach to regain communication for people unable to interact through any peripheral muscle control. However, the commonly used electroencephalography (EEG) provides signals of low signal-to-noise ratio, making the systems slow and inaccurate. As an alternative noninvasive recording technique, the magnetoencephalography (MEG) could provide more advantageous electrophysiological signals due to a higher number of sensors and the magnetic fields not being influenced by volume conduction. We investigated whether MEG provides higher accuracy in detecting event-related fields (ERFs) compared to detecting ERPs in simultaneously recorded EEG, both evoked by a covert attention task, and whether a combination of the modalities is advantageous. In our approach, a detection algorithm based on spatial filtering is used to identify ERP/ERF components in a data-driven manner. We found that MEG achieves higher decoding accuracy (DA) compared to EEG and that the combination of both further improves the performance significantly. However, MEG data showed poor performance in cross-subject classification, indicating that the algorithm's ability for transfer learning across subjects is better in EEG. Here we show that BCI control by covert attention is feasible with EEG and MEG using a data-driven spatial filter approach with a clear advantage of the MEG regarding DA but with a better transfer learning in EEG. PMID:29085279

Disentangling working memory processes during spatial span assessment: a modeling analysis of preferred eye movement strategies.

PubMed

Patt, Virginie M; Thomas, Michael L; Minassian, Arpi; Geyer, Mark A; Brown, Gregory G; Perry, William

2014-01-01

The neurocognitive processes involved during classic spatial working memory (SWM) assessment were investigated by examining naturally preferred eye movement strategies. Cognitively healthy adult volunteers were tested in a computerized version of the Corsi Block-Tapping Task--a spatial span task requiring the short term maintenance of a series of locations presented in a specific order--coupled with eye tracking. Modeling analysis was developed to characterize eye-tracking patterns across all task phases, including encoding, retention, and recall. Results revealed a natural preference for local gaze maintenance during both encoding and retention, with fewer than 40% fixated targets. These findings contrasted with the stimulus retracing pattern expected during recall as a result of task demands, with 80% fixated targets. Along with participants' self-reported strategies of mentally "making shapes," these results suggest the involvement of covert attention shifts and higher order cognitive Gestalt processes during spatial span tasks, challenging instrument validity as a single measure of SWM storage capacity.

Secret-key expansion from covert communication

NASA Astrophysics Data System (ADS)

Arrazola, Juan Miguel; Amiri, Ryan

2018-02-01

Covert communication allows the transmission of messages in such a way that it is not possible for adversaries to detect that the communication is occurring. This provides protection in situations where knowledge that two parties are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a covert communication protocol where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions for secret key expansion to occur, showing that it is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

Gendered power dynamics and women’s negotiation of family planning in a high HIV prevalence setting: A qualitative study of couples in western Kenya

PubMed Central

Harrington, Elizabeth K.; Dworkin, Shari; Withers, Mellissa; Onono, Maricianah; Kwena, Zachary; Newmann, Sara J.

2017-01-01

In sub-Saharan Africa, high burdens of HIV and unmet need for contraception often coexist. Research emphasises the need to engage men and couples in reproductive health, yet couples’ negotiations around fertility and family planning in the context of HIV have been sparsely studied. This study examined the gendered power dynamics that frame women’s and couples’ negotiations of contraceptive use in western Kenya. We conducted 76 in-depth interviews with 38 couples, of whom 22 couples were concordant HIV-positive. Qualitative data were analysed using a grounded theory approach. Direct communication around contraception with men was often challenging due to perceived or expressed male resistance. A substantial minority of women avoided male reproductive decision-making authority through covert contraceptive use, with concern for severe consequences when contraceptive use was discovered. Many men assumed that family planning use signified female promiscuity and that infidelity motivated covert use. Men were more willing to use condoms to avoid HIV re-infection or at the recommendation of HIV care providers, which allowed some women leverage to insist on condom use. Our findings highlight the tension between male-dominated reproductive decision-making and women’s agency and point to the need for gender transformative approaches seeking to challenge masculinities that negatively impact health. PMID:26503879

Discovering what is hidden: The role of non-ritualized covert neutralizing strategies in Obsessive-Compulsive Disorder.

PubMed

Belloch, Amparo; Carrió, Carmen; Cabedo, Elena; García-Soriano, Gemma

2015-12-01

Neutralizing strategies are secondary to obsessions and an additional cause of distress and interference, but they have received little attention in theories and research, especially the non-ritualized covert strategies. This study focuses on the comparative impact of non-ritualized covert and compulsive-overt strategies in the course of OCD. Eighty-two OCD adult patients completed measures assessing distress, interference, appraisals and overt and covert neutralizing strategies to control obsessions. Thirty-eight patients who had completed cognitive therapy were assessed again after treatment. Only overt compulsions are associated with OCD severity. Nonetheless, considering the main symptom dimension, covert strategies are also associated with severity in patients with moral-based obsessions. Patients who used covert strategies more frequently, compared to those who use them less, reported more sadness, guilt, control importance, interference, and dysfunctional appraisals. Regarding the overt strategies, patients who used them more reported more anxiety and ascribed more personal meaning to their obsessions than the patients who used them less. After treatment, recovered patients decreased their use of both covert and overt strategies, while non-recovered patients did not. There was a higher rate of non-recovered patients among those who used more non-ritualized covert strategies before treatment. Emotions and appraisals were assessed with a single item. OCD symptom dimensions were only assessed by the Obsessive-Compulsive Inventory. In addition to studying overt compulsions, the impact of covert neutralizing strategies on the OCD course and severity warrants more in-depth study. Copyright © 2015 Elsevier Ltd. All rights reserved.

Visual Word Recognition in Deaf Readers: Lexicality Is Modulated by Communication Mode

PubMed Central

Barca, Laura; Pezzulo, Giovanni; Castrataro, Marianna; Rinaldi, Pasquale; Caselli, Maria Cristina

2013-01-01

Evidence indicates that adequate phonological abilities are necessary to develop proficient reading skills and that later in life phonology also has a role in the covert visual word recognition of expert readers. Impairments of acoustic perception, such as deafness, can lead to atypical phonological representations of written words and letters, which in turn can affect reading proficiency. Here, we report an experiment in which young adults with different levels of acoustic perception (i.e., hearing and deaf individuals) and different modes of communication (i.e., hearing individuals using spoken language, deaf individuals with a preference for sign language, and deaf individuals using the oral modality with less or no competence in sign language) performed a visual lexical decision task, which consisted of categorizing real words and consonant strings. The lexicality effect was restricted to deaf signers who responded faster to real words than consonant strings, showing over-reliance on whole word lexical processing of stimuli. No effect of stimulus type was found in deaf individuals using the oral modality or in hearing individuals. Thus, mode of communication modulates the lexicality effect. This suggests that learning a sign language during development shapes visuo-motor representations of words, which are tuned to the actions used to express them (phono-articulatory movements vs. hand movements) and to associated perceptions. As these visuo-motor representations are elicited during on-line linguistic processing and can overlap with the perceptual-motor processes required to execute the task, they can potentially produce interference or facilitation effects. PMID:23554976

Visual word recognition in deaf readers: lexicality is modulated by communication mode.

PubMed

Barca, Laura; Pezzulo, Giovanni; Castrataro, Marianna; Rinaldi, Pasquale; Caselli, Maria Cristina

2013-01-01

Evidence indicates that adequate phonological abilities are necessary to develop proficient reading skills and that later in life phonology also has a role in the covert visual word recognition of expert readers. Impairments of acoustic perception, such as deafness, can lead to atypical phonological representations of written words and letters, which in turn can affect reading proficiency. Here, we report an experiment in which young adults with different levels of acoustic perception (i.e., hearing and deaf individuals) and different modes of communication (i.e., hearing individuals using spoken language, deaf individuals with a preference for sign language, and deaf individuals using the oral modality with less or no competence in sign language) performed a visual lexical decision task, which consisted of categorizing real words and consonant strings. The lexicality effect was restricted to deaf signers who responded faster to real words than consonant strings, showing over-reliance on whole word lexical processing of stimuli. No effect of stimulus type was found in deaf individuals using the oral modality or in hearing individuals. Thus, mode of communication modulates the lexicality effect. This suggests that learning a sign language during development shapes visuo-motor representations of words, which are tuned to the actions used to express them (phono-articulatory movements vs. hand movements) and to associated perceptions. As these visuo-motor representations are elicited during on-line linguistic processing and can overlap with the perceptual-motor processes required to execute the task, they can potentially produce interference or facilitation effects.

Modes of Large-Scale Brain Network Organization during Threat Processing and Posttraumatic Stress Disorder Symptom Reduction during TF-CBT among Adolescent Girls.

PubMed

Cisler, Josh M; Sigel, Benjamin A; Kramer, Teresa L; Smitherman, Sonet; Vanderzee, Karin; Pemberton, Joy; Kilts, Clinton D

2016-01-01

Posttraumatic stress disorder (PTSD) is often chronic and disabling across the lifespan. The gold standard treatment for adolescent PTSD is Trauma-Focused Cognitive-Behavioral Therapy (TF-CBT), though treatment response is variable and mediating neural mechanisms are not well understood. Here, we test whether PTSD symptom reduction during TF-CBT is associated with individual differences in large-scale brain network organization during emotion processing. Twenty adolescent girls, aged 11-16, with PTSD related to assaultive violence completed a 12-session protocol of TF-CBT. Participants completed an emotion processing task, in which neutral and fearful facial expressions were presented either overtly or covertly during 3T fMRI, before and after treatment. Analyses focused on characterizing network properties of modularity, assortativity, and global efficiency within an 824 region-of-interest brain parcellation separately during each of the task blocks using weighted functional connectivity matrices. We similarly analyzed an existing dataset of healthy adolescent girls undergoing an identical emotion processing task to characterize normative network organization. Pre-treatment individual differences in modularity, assortativity, and global efficiency during covert fear vs neutral blocks predicted PTSD symptom reduction. Patients who responded better to treatment had greater network modularity and assortativity but lesser efficiency, a pattern that closely resembled the control participants. At a group level, greater symptom reduction was associated with greater pre-to-post-treatment increases in network assortativity and modularity, but this was more pronounced among participants with less symptom improvement. The results support the hypothesis that modularized and resilient brain organization during emotion processing operate as mechanisms enabling symptom reduction during TF-CBT.

Passive motion paradigm: an alternative to optimal control.

PubMed

Mohan, Vishwanathan; Morasso, Pietro

2011-01-01

IN THE LAST YEARS, OPTIMAL CONTROL THEORY (OCT) HAS EMERGED AS THE LEADING APPROACH FOR INVESTIGATING NEURAL CONTROL OF MOVEMENT AND MOTOR COGNITION FOR TWO COMPLEMENTARY RESEARCH LINES: behavioral neuroscience and humanoid robotics. In both cases, there are general problems that need to be addressed, such as the "degrees of freedom (DoFs) problem," the common core of production, observation, reasoning, and learning of "actions." OCT, directly derived from engineering design techniques of control systems quantifies task goals as "cost functions" and uses the sophisticated formal tools of optimal control to obtain desired behavior (and predictions). We propose an alternative "softer" approach passive motion paradigm (PMP) that we believe is closer to the biomechanics and cybernetics of action. The basic idea is that actions (overt as well as covert) are the consequences of an internal simulation process that "animates" the body schema with the attractor dynamics of force fields induced by the goal and task-specific constraints. This internal simulation offers the brain a way to dynamically link motor redundancy with task-oriented constraints "at runtime," hence solving the "DoFs problem" without explicit kinematic inversion and cost function computation. We argue that the function of such computational machinery is not only restricted to shaping motor output during action execution but also to provide the self with information on the feasibility, consequence, understanding and meaning of "potential actions." In this sense, taking into account recent developments in neuroscience (motor imagery, simulation theory of covert actions, mirror neuron system) and in embodied robotics, PMP offers a novel framework for understanding motor cognition that goes beyond the engineering control paradigm provided by OCT. Therefore, the paper is at the same time a review of the PMP rationale, as a computational theory, and a perspective presentation of how to develop it for designing better cognitive architectures.

The effect of monetary punishment on error evaluation in a Go/No-go task.

PubMed

Maruo, Yuya; Sommer, Werner; Masaki, Hiroaki

2017-10-01

Little is known about the effects of the motivational significance of errors in Go/No-go tasks. We investigated the impact of monetary punishment on the error-related negativity (ERN) and error positivity (Pe) for both overt errors and partial errors, that is, no-go trials without overt responses but with covert muscle activities. We compared high and low punishment conditions where errors were penalized with 50 or 5 yen, respectively, and a control condition without monetary consequences for errors. Because we hypothesized that the partial-error ERN might overlap with the no-go N2, we compared ERPs between correct rejections (i.e., successful no-go trials) and partial errors in no-go trials. We also expected that Pe amplitudes should increase with the severity of the penalty for errors. Mean error rates were significantly lower in the high punishment than in the control condition. Monetary punishment did not influence the overt-error ERN and partial-error ERN in no-go trials. The ERN in no-go trials did not differ between partial errors and overt errors; in addition, ERPs for correct rejections in no-go trials without partial errors were of the same size as in go-trial. Therefore the overt-error ERN and the partial-error ERN may share similar error monitoring processes. Monetary punishment increased Pe amplitudes for overt errors, suggesting enhanced error evaluation processes. For partial errors an early Pe was observed, presumably representing inhibition processes. Interestingly, even partial errors elicited the Pe, suggesting that covert erroneous activities could be detected in Go/No-go tasks. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Right hemispheric dysfunction in a case of pure progressive aphemia: fusion of multimodal neuroimaging.

PubMed

Vitali, Paolo; Nobili, Flavio; Raiteri, Umberto; Canfora, Michela; Rosa, Marco; Calvini, Piero; Girtler, Nicola; Regesta, Giovanni; Rodriguez, Guido

2004-01-15

This article describes the unusual case of a 60-year-old woman suffering from pure progressive aphemia. The fusion of multimodal neuroimaging (MRI, perfusion SPECT) implicated the right frontal lobe, especially the inferior frontal gyrus. This area also showed the greatest functional MRI activation during the performance of a covert phonemic fluency task. Results are discussed in terms of bihemispheric language representation. The fusion of three sets of neuroimages has aided in the interpretation of the patient's cognitive brain dysfunction.

Covert Channels within IRC

DTIC Science & Technology

2011-03-24

in the secret file in bits. Therefore, CPP is a function of the size of the secret file and amount of covert information embedded per packet, while...CPS is dependent on the size of the secret file and the rate at which the covert packets are transmitted to the IRC server. • Build a covert...and decode a secret message. • Cover. The object being used to hide the secret information; this is often in the form of pictures [FPK07], audio

Predictive distractor context facilitates attentional selection of high, but not intermediate and low, salience targets.

PubMed

Töllner, Thomas; Conci, Markus; Müller, Hermann J

2015-03-01

It is well established that we can focally attend to a specific region in visual space without shifting our eyes, so as to extract action-relevant sensory information from covertly attended locations. The underlying mechanisms that determine how fast we engage our attentional spotlight in visual-search scenarios, however, remain controversial. One dominant view advocated by perceptual decision-making models holds that the times taken for focal-attentional selection are mediated by an internal template that biases perceptual coding and selection decisions exclusively through target-defining feature coding. This notion directly predicts that search times remain unaffected whether or not participants can anticipate the upcoming distractor context. Here we tested this hypothesis by employing an illusory-figure localization task that required participants to search for an invariant target amongst a variable distractor context, which gradually changed--either randomly or predictably--as a function of distractor-target similarity. We observed a graded decrease in internal focal-attentional selection times--correlated with external behavioral latencies--for distractor contexts of higher relative to lower similarity to the target. Critically, for low but not intermediate and high distractor-target similarity, these context-driven effects were cortically and behaviorally amplified when participants could reliably predict the type of distractors. This interactive pattern demonstrates that search guidance signals can integrate information about distractor, in addition to target, identities to optimize distractor-target competition for focal-attentional selection. © 2014 Wiley Periodicals, Inc.

Comparison of Individualized Covert Modeling, Self-Control Desensitization, and Study Skills Training for Alleviation of Test Anxiety.

ERIC Educational Resources Information Center

Harris, Gina; Johhson, Suzanne Bennett

1980-01-01

Individualized covert modeling and self-control desensitization substantially reduced self-reported test anxiety. However, the individualized covert modeling group was the only treatment group that showed significant improvement in academic performance. (Author)

Covert enaction at work: Recording the continuous movements of visuospatial attention to visible or imagined targets by means of Steady-State Visual Evoked Potentials (SSVEPs).

PubMed

Gregori Grgič, Regina; Calore, Enrico; de'Sperati, Claudio

2016-01-01

Whereas overt visuospatial attention is customarily measured with eye tracking, covert attention is assessed by various methods. Here we exploited Steady-State Visual Evoked Potentials (SSVEPs) - the oscillatory responses of the visual cortex to incoming flickering stimuli - to record the movements of covert visuospatial attention in a way operatively similar to eye tracking (attention tracking), which allowed us to compare motion observation and motion extrapolation with and without eye movements. Observers fixated a central dot and covertly tracked a target oscillating horizontally and sinusoidally. In the background, the left and the right halves of the screen flickered at two different frequencies, generating two SSVEPs in occipital regions whose size varied reciprocally as observers attended to the moving target. The two signals were combined into a single quantity that was modulated at the target frequency in a quasi-sinusoidal way, often clearly visible in single trials. The modulation continued almost unchanged when the target was switched off and observers mentally extrapolated its motion in imagery, and also when observers pointed their finger at the moving target during covert tracking, or imagined doing so. The amplitude of modulation during covert tracking was ∼25-30% of that measured when observers followed the target with their eyes. We used 4 electrodes in parieto-occipital areas, but similar results were achieved with a single electrode in Oz. In a second experiment we tested ramp and step motion. During overt tracking, SSVEPs were remarkably accurate, showing both saccadic-like and smooth pursuit-like modulations of cortical responsiveness, although during covert tracking the modulation deteriorated. Covert tracking was better with sinusoidal motion than ramp motion, and better with moving targets than stationary ones. The clear modulation of cortical responsiveness recorded during both overt and covert tracking, identical for motion observation and motion extrapolation, suggests to include covert attention movements in enactive theories of mental imagery. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Evolution of Covert Signaling.

PubMed

Smaldino, Paul E; Flamson, Thomas J; McElreath, Richard

2018-03-20

Human sociality depends upon the benefits of mutual aid and extensive communication. However, diverse norms and preferences complicate mutual aid, and ambiguity in meaning hinders communication. Here we demonstrate that these two problems can work together to enhance cooperation through the strategic use of deliberately ambiguous signals: covert signaling. Covert signaling is the transmission of information that is accurately received by its intended audience but obscured when perceived by others. Such signals may allow coordination and enhanced cooperation while also avoiding the alienation or hostile reactions of individuals with different preferences. Although the empirical literature has identified potential mechanisms of covert signaling, such as encryption in humor, there is to date no formal theory of its dynamics. We introduce a novel mathematical model to assess when a covert signaling strategy will evolve, as well as how receiver attitudes coevolve with covert signals. Covert signaling plausibly serves an important function in facilitating within-group cooperative assortment by allowing individuals to pair up with similar group members when possible and to get along with dissimilar ones when necessary. This mechanism has broad implications for theories of signaling and cooperation, humor, social identity, political psychology, and the evolution of human cultural complexity.

Brutality under cover of ambiguity: activating, perpetuating, and deactivating covert retributivism.

PubMed

Fincher, Katrina M; Tetlock, Philip E

2015-05-01

Five studies tested four hypotheses on the drivers of punitive judgments. Study 1 showed that people imposed covertly retributivist physical punishments on extreme norm violators when they could plausibly deny that is what they were doing (attributional ambiguity). Studies 2 and 3 showed that covert retributivism could be suppressed by subtle accountability manipulations that cue people to the possibility that they might be under scrutiny. Studies 4 and 5 showed how covert retributivism can become self-sustaining by biasing the lessons people learn from experience. Covert retributivists did not scale back punitiveness in response to feedback that the justice system makes false-conviction errors but they did ramp up punitiveness in response to feedback that the system makes false-acquittal errors. Taken together, the results underscore the paradoxical nature of covert retributivism: It is easily activated by plausible deniability and persistent in the face of false-conviction feedback but also easily deactivated by minimalist forms of accountability. © 2015 by the Society for Personality and Social Psychology, Inc.

The Factors That Influence and Protect Against Power Imbalance in Covert Bullying Among Preadolescent Children at School: A Thematic Analysis.

PubMed

Nelson, Helen J; Burns, Sharyn K; Kendall, Garth E; Schonert-Reichl, Kimberly A

2017-01-01

In this article, the perceptions of preadolescent children (ages 9-11) regarding factors that influence and protect against power imbalance associated with covert aggression and bullying are explored. In aggression research, the term covert has been typically used to describe relational, indirect, and social acts of aggression that are hidden. These behaviors contrast with overt physical and verbal aggression. Children have previously conveyed their belief that covert aggression is harmful because adults do not see it even though children, themselves, are aware. We used focus groups to explore children's understanding of covert aggression and to identify children's experience and perception of adult support in relation to bullying. Thematic analysis supported the definition of covert aggression as that which is intentionally hidden from adults. Friendship, social exclusion, and secret from teacher were identified as factors that influence power imbalance, while support from friends and adult support protected against power imbalance.

Is scanning in probed order recall articulatory?

PubMed

Farrell, Simon; Lelièvre, Anna

2009-09-01

We consider how theories of serial recall might apply to other short-term memory tasks involving recall of order. In particular, we consider the possibility that when participants are cued to recall an item at an arbitrary position in a sequence, they covertly serially recall the list up to the cued position. One question is whether such "scanning" is articulatory in nature. Two experiments are presented in which the syllabic length of words preceding and following target positions were manipulated, to test the prediction of an articulatory-based mechanism that time to recall an item at a particular position will depend on the number of preceding long words. Although latency was dependent on target position, no word length effects on latency were observed. Additionally, the effects of word length on accuracy replicate recent demonstrations in serial recall that recall accuracy is dependent on the word length of all list items, not just that of target items, in line with distinctiveness assumptions. It is concluded that if scanning does occur, it is not carried out by covert or overt articulation.

Group Systematic Desensitization Versus Covert Positive Reinforcement in the Reduction of Test Anxiety

ERIC Educational Resources Information Center

Kostka, Marion P.; Galassi, John P.

1974-01-01

The study compared modified versions of systematic desensitization and covert positive reinforcement to a no-treatment control condition in the reduction of test anxiety. On an anagrams performance test, the covert reinforcement and control groups were superior to the desensitization group. (Author)

Predicting Individual Action Switching in Covert and Continuous Interactive Tasks Using the Fluid Events Model

PubMed Central

Radvansky, Gabriel A.; D’Mello, Sidney K.; Abbott, Robert G.; Bixler, Robert E.

2016-01-01

The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covert event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant’s current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person’s prior experience. Thus, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events. PMID:26858673

Predicting Individual Action Switching in Covert and Continuous Interactive Tasks Using the Fluid Events Model.

PubMed

Radvansky, Gabriel A; D'Mello, Sidney K; Abbott, Robert G; Bixler, Robert E

2016-01-01

The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covert event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant's current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person's prior experience. Thus, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events.

Young People Smokers' Reactions on Peer Influence Not to Smoke.

PubMed

Harakeh, Zeena; van Nijnatten, Carolus H C J

2016-11-09

Peers exert influence not to smoke but little is yet known on how this affects young people's behavior and cognitions. This experimental study investigates the impact of two types of peer influence not to smoke on the verbalized attitudes and responses of daily-smoking young people. Two conditions were conducted: 1) a peer confederate stating three times that s/he had quit smoking and was glad to have done so (covert peer influence); 2) a peer confederate making similar statements, but urging to quit smoking (overt peer influence). The participant performed a music task with the peer in order to disguise the true nature of the experiment. Thirty-one daily-smoking young people (16-24 years) participated; 44 responses in the overt and 34 responses in the covert condition were analyzed in a discourse analysis. The participants in the covert condition were more elaborative about smoking, i.e., taking an active role in a dialogue about the experiences of the peer or the participant in quitting smoking while in the overt condition participants showed more passive resistance, i.e., not showing an intention to follow the advice but avoid causing the peer embarrassment or discomfort. Open resistance, i.e., demonstration of being well-informed and indicating the redundancy of the advice, does not significantly differ in these two conditions but occurs, for both, primarily at the third discouragement. Overt and frequent discouragement seems to be less effective in stimulating young people to take an active role in the dialogue with their peers about smoking.

A gaze independent hybrid-BCI based on visual spatial attention

NASA Astrophysics Data System (ADS)

Egan, John M.; Loughnane, Gerard M.; Fletcher, Helen; Meade, Emma; Lalor, Edmund C.

2017-08-01

Objective. Brain-computer interfaces (BCI) use measures of brain activity to convey a user’s intent without the need for muscle movement. Hybrid designs, which use multiple measures of brain activity, have been shown to increase the accuracy of BCIs, including those based on EEG signals reflecting covert attention. Our study examined whether incorporating a measure of the P3 response improved the performance of a previously reported attention-based BCI design that incorporates measures of steady-state visual evoked potentials (SSVEP) and alpha band modulations. Approach. Subjects viewed stimuli consisting of two bi-laterally located flashing white boxes on a black background. Streams of letters were presented sequentially within the boxes, in random order. Subjects were cued to attend to one of the boxes without moving their eyes, and they were tasked with counting the number of target-letters that appeared within. P3 components evoked by target appearance, SSVEPs evoked by the flashing boxes, and power in the alpha band are modulated by covert attention, and the modulations can be used to classify trials as left-attended or right-attended. Main Results. We showed that classification accuracy was improved by including a P3 feature along with the SSVEP and alpha features (the inclusion of a P3 feature lead to a 9% increase in accuracy compared to the use of SSVEP and Alpha features alone). We also showed that the design improves the robustness of BCI performance to individual subject differences. Significance. These results demonstrate that incorporating multiple neurophysiological indices of covert attention can improve performance in a gaze-independent BCI.

Covert Response Patterns in Processing Language Stimuli. Final Report.

ERIC Educational Resources Information Center

McGuigan, F. Joseph

The purpose of this research project is to specify critical events within a person during linguistic processing. The experiments reported here cover such topics as the effects of increased reading rate on covert processes, covert behavior as a direct electro-myographic measure of mediating responses, enhancement of speech perception by…

The Effect of Covert Modeling on Communication Apprehension, Communication Confidence, and Performance.

ERIC Educational Resources Information Center

Nimocks, Mittie J.; Bromley, Patricia L.; Parsons, Theron E.; Enright, Corinne S.; Gates, Elizabeth A.

This study examined the effect of covert modeling on communication apprehension, public speaking anxiety, and communication competence. Students identified as highly communication apprehensive received covert modeling, a technique in which one first observes a model doing a behavior, then visualizes oneself performing the behavior and obtaining a…

Effects of spatial cues on color-change detection in humans

PubMed Central

Herman, James P.; Bogadhi, Amarender R.; Krauzlis, Richard J.

2015-01-01

Studies of covert spatial attention have largely used motion, orientation, and contrast stimuli as these features are fundamental components of vision. The feature dimension of color is also fundamental to visual perception, particularly for catarrhine primates, and yet very little is known about the effects of spatial attention on color perception. Here we present results using novel dynamic color stimuli in both discrimination and color-change detection tasks. We find that our stimuli yield comparable discrimination thresholds to those obtained with static stimuli. Further, we find that an informative spatial cue improves performance and speeds response time in a color-change detection task compared with an uncued condition, similar to what has been demonstrated for motion, orientation, and contrast stimuli. Our results demonstrate the use of dynamic color stimuli for an established psychophysical task and show that color stimuli are well suited to the study of spatial attention. PMID:26047359

Executive control processes underlying multi-item working memory

PubMed Central

Lara, Antonio H.; Wallis, Jonathan D.

2014-01-01

A dominant view of prefrontal cortex (PFC) function is that it stores task-relevant information in working memory. To examine this and determine how it applies when multiple pieces of information must be stored, we trained two macaque monkeys to perform a multi-item color change-detection task and recorded activity of neurons in PFC. Few neurons encoded the color of the items. Instead, the predominant encoding was spatial: a static signal reflecting the item's position and a dynamic signal reflecting the animal's covert attention. These findings challenge the notion that PFC stores task-relevant information. Instead, we suggest that the contribution of PFC is in controlling the allocation of resources to support working memory. In support of this, we found that increased power in the alpha and theta bands of PFC local field potentials, which are thought to reflect long-range communication with other brain areas, was correlated with more precise color representations. PMID:24747574

Preserved and attenuated electrophysiological correlates of visual spatial attention in elderly subjects.

PubMed

van der Waal, Marjolein; Farquhar, Jason; Fasotti, Luciano; Desain, Peter

2017-01-15

Healthy aging is associated with changes in many neurocognitive functions. While on the behavioral level, visual spatial attention capacities are relatively stable with increasing age, the underlying neural processes change. In this study, we investigated attention-related modulations of the stimulus-locked event-related potential (ERP) and occipital oscillations in the alpha band (8-14Hz) in young and elderly participants. Both groups performed a visual attention task equally well and the ERP showed comparable attention-related modulations in both age groups. However, in elderly subjects, oscillations in the alpha band were massively reduced both during the task and in the resting state and the typical task-related lateralized pattern of alpha activity was not observed. These differences between young and elderly participants were observed on the group level as well as on the single trial level. The results indicate that younger and older adults use different neural strategies to reach the same performance in a covert visual spatial attention task. Copyright © 2016 Elsevier B.V. All rights reserved.

A Link Between Attentional Function, Effective Eye Movements, and Driving Ability

PubMed Central

2016-01-01

The misallocation of driver visual attention has been suggested as a major contributing factor to vehicle accidents. One possible reason is that the relatively high cognitive demands of driving limit the ability to efficiently allocate gaze. We present an experiment that explores the relationship between attentional function and visual performance when driving. Drivers performed 2 variations of a multiple-object tracking task targeting aspects of cognition including sustained attention, dual-tasking, covert attention, and visuomotor skill. They also drove a number of courses in a driving simulator. Eye movements were recorded throughout. We found that individuals who performed better in the cognitive tasks exhibited more effective eye movement strategies when driving, such as scanning more of the road, and they also exhibited better driving performance. We discuss the potential link between an individual’s attentional function, effective eye movements, and driving ability. We also discuss the use of a visuomotor task in assessing driving behavior. PMID:27893270

The Neural Correlates of Hierarchical Predictions for Perceptual Decisions.

PubMed

Weilnhammer, Veith A; Stuke, Heiner; Sterzer, Philipp; Schmack, Katharina

2018-05-23

Sensory information is inherently noisy, sparse, and ambiguous. In contrast, visual experience is usually clear, detailed, and stable. Bayesian theories of perception resolve this discrepancy by assuming that prior knowledge about the causes underlying sensory stimulation actively shapes perceptual decisions. The CNS is believed to entertain a generative model aligned to dynamic changes in the hierarchical states of our volatile sensory environment. Here, we used model-based fMRI to study the neural correlates of the dynamic updating of hierarchically structured predictions in male and female human observers. We devised a crossmodal associative learning task with covertly interspersed ambiguous trials in which participants engaged in hierarchical learning based on changing contingencies between auditory cues and visual targets. By inverting a Bayesian model of perceptual inference, we estimated individual hierarchical predictions, which significantly biased perceptual decisions under ambiguity. Although "high-level" predictions about the cue-target contingency correlated with activity in supramodal regions such as orbitofrontal cortex and hippocampus, dynamic "low-level" predictions about the conditional target probabilities were associated with activity in retinotopic visual cortex. Our results suggest that our CNS updates distinct representations of hierarchical predictions that continuously affect perceptual decisions in a dynamically changing environment. SIGNIFICANCE STATEMENT Bayesian theories posit that our brain entertains a generative model to provide hierarchical predictions regarding the causes of sensory information. Here, we use behavioral modeling and fMRI to study the neural underpinnings of such hierarchical predictions. We show that "high-level" predictions about the strength of dynamic cue-target contingencies during crossmodal associative learning correlate with activity in orbitofrontal cortex and the hippocampus, whereas "low-level" conditional target probabilities were reflected in retinotopic visual cortex. Our findings empirically corroborate theorizations on the role of hierarchical predictions in visual perception and contribute substantially to a longstanding debate on the link between sensory predictions and orbitofrontal or hippocampal activity. Our work fundamentally advances the mechanistic understanding of perceptual inference in the human brain. Copyright © 2018 the authors 0270-6474/18/385008-14$15.00/0.

An analysis of the processing requirements of a complex perceptual-motor task

NASA Technical Reports Server (NTRS)

Kramer, A. F.; Wickens, C. D.; Donchin, E.

1983-01-01

Current concerns in the assessment of mental workload are discussed, and the event-related brain potential (ERP) is introduced as a promising mental-workload index. Subjects participated in a series of studies in which they were required to perform a target acquisition task while also covertly counting either auditory or visual probes. The effects of several task-difficulty manipulations on the P300 component of the ERP elicited by the counted stimulus probes were investigated. With sufficiently practiced subjects the amplitude of the P300 was found to decrease with increases in task difficulty. The second experiment also provided evidence that the P300 is selectively sensitive to task-relevant attributes. A third experiment demonstrated a convergence in the amplitude of the P300s elicited in the simple and difficult versions of the tracking task. The amplitude of the P300 was also found to covary with the measures of tracking performance. The results of the series of three experiments illustrate the sensitivity of the P300 to the processing requirements of a complex target acquisition task. The findings are discussed in terms of the multidimensional nature of processing resources.

The Modification of Covert Behavior: A Survey of the Literature.

ERIC Educational Resources Information Center

Johnson, R. Gilmore; Elson, Steven E.

This review of the research literature focuses on processes that Cautela (1972a) has called covert conditioning and Mahoney, Thoresen, and Danaher (1972) have called covert behavior modification. Both of these terms refer to processes for changing behavior through imaginal responses. Two general strategies have been employed. One has been to…

A Network Steganography Lab on Detecting TCP/IP Covert Channels

ERIC Educational Resources Information Center

Zseby, Tanja; Vázquez, Félix Iglesias; Bernhardt, Valentin; Frkat, Davor; Annessi, Robert

2016-01-01

This paper presents a network security laboratory to teach data analysis for detecting TCP/IP covert channels. The laboratory is mainly designed for students of electrical engineering, but is open to students of other technical disciplines with similar background. Covert channels provide a method for leaking data from protected systems, which is a…

Covert and Overt Dependence in Suicidal Women and Their Male Partners.

ERIC Educational Resources Information Center

Canetto, Silvia Sara; Feldman, Larry B.

1993-01-01

Explored covert mental representations and interactional context of dependence in suicidal women (n=19) and their nonsuicidal male partners. Suicidal women and their partners were similar in terms of covert dependence and different with regard to overt behavior. Male partners tended to foster dependence in suicidal women. Most suicidal women did…

Covert hepatic encephalopathy: not as minimal as you might think.

PubMed

Kappus, Matthew R; Bajaj, Jasmohan S

2012-11-01

Hepatic encephalopathy (HE) is a serious neuropsychiatric and neurocognitive complication of acute and chronic liver disease. Symptoms are often overt (confusion, disorientation, ataxia, or coma) but can also be subtle (difficulty with cognitive abilities such as executive decision-making and psychomotor speed). There is consensus that HE is characterized as a spectrum of neuropsychiatric symptoms in the absence of brain disease, ranging from overt HE (OHE) to minimal HE (MHE). The West Haven Criteria are most often used to grade HE, with scores ranging from 0-4 (4 being coma). However, it is a challenge to diagnose patients with MHE or grade 1 HE; it might be practical to combine these entities and name them covert HE for clinical use. The severity of HE is associated with the stage of liver disease. Although the pathologic mechanisms of HE are not well understood, they are believed to involve increased levels of ammonia and inflammation, which lead to low-grade cerebral edema. A diagnosis of MHE requires dedicated psychometric tests and neurophysiological techniques rather than a simple clinical assessment. Although these tests can be difficult to perform in practice, they are cost effective and important; the disorder affects patients' quality of life, socioeconomic status, and driving ability and increases their risk for falls and the development of OHE. Patients with MHE are first managed by excluding other causes of neurocognitive dysfunction. Therapy with gut-specific agents might be effective. We review management strategies and important areas of research for MHE and covert HE. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

Covert hepatic encephalopathy leads to distinct alterations in the emotional state, independently of MELD-Score.

PubMed

Greinert, Robin; Ripoll, Cristina; Zipprich, Alexander

2018-05-01

 Covert hepatic encephalopathy impairs many aspects of quality of life, although its impact on the emotional state has not been evaluated. This study aims to evaluate the impact of covert hepatic encephalopathy on the emotional state and which factors are associated with changes in the emotional state in patients with cirrhosis.  This single-center study included all patients with cirrhosis who underwent the portosystemic encephalopathy syndrome (PSE) test, critical flicker frequency, and emotional state assessment with the Eigenschaftswörterliste 60-S in 2011. Covert hepatic encephalopathy was defined by abnormal PSE. Parametric and non-parametric tests were used according to variable distribution.  One hundred seventeen patients with cirrhosis were included (median age: 59 [interquartile range: 48 - 67], 32 % female, 74 % alcohol-associated). Seventy patients had covert hepatic encephalopathy (60 %) with a higher MELD (16 [interquartile range: 13 - 21], p = 0.001) and a higher Child-Pugh score (p = 0.003) compared to patients without encephalopathy. Patients with covert encephalopathy felt reduced mental activity (p = 0.004), lower general well-being (p = 0.001), and reduced extraversion (p = 0.021). The scores in the negative domains such as general lethargy (p = 0.031) and anxiousness/depressiveness (p = 0.033) were higher in patients with covert hepatic encephalopathy. There was no correlation between MELD and the emotional state. Patients with 2 pathological tests (critical flicker frequency and PSE) showed the most distinct alterations in the emotional state in the group of patients with covert hepatic encephalopathy.  Patients with covert hepatic encephalopathy have an alteration of the emotional state, which is more marked in patients with 2 pathological tests. Interestingly, MELD had no impact on the emotional state. © Georg Thieme Verlag KG Stuttgart · New York.

Emotion, decision making, and the amygdala.

PubMed

Seymour, Ben; Dolan, Ray

2008-06-12

Emotion plays a critical role in many contemporary accounts of decision making, but exactly what underlies its influence and how this is mediated in the brain remain far from clear. Here, we review behavioral studies that suggest that Pavlovian processes can exert an important influence over choice and may account for many effects that have traditionally been attributed to emotion. We illustrate how recent experiments cast light on the underlying structure of Pavlovian control and argue that generally this influence makes good computational sense. Corresponding neuroscientific data from both animals and humans implicate a central role for the amygdala through interactions with other brain areas. This yields a neurobiological account of emotion in which it may operate, often covertly, to optimize rather than corrupt economic choice.

A new sensors-based covert channel on android.

PubMed

Al-Haiqi, Ahmed; Ismail, Mahamod; Nordin, Rosdiadee

2014-01-01

Covert channels are not new in computing systems, and have been studied since their first definition four decades ago. New platforms invoke thorough investigations to assess their security. Now is the time for Android platform to analyze its security model, in particular the two key principles: process-isolation and the permissions system. Aside from all sorts of malware, one threat proved intractable by current protection solutions, that is, collusion attacks involving two applications communicating over covert channels. Still no universal solution can countermeasure this sort of attack unless the covert channels are known. This paper is an attempt to reveal a new covert channel, not only being specific to smartphones, but also exploiting an unusual resource as a vehicle to carry covert information: sensors data. Accelerometers generate signals that reflect user motions, and malware applications can apparently only read their data. However, if the vibration motor on the device is used properly, programmatically produced vibration patterns can encode stolen data and hence an application can cause discernible effects on acceleration data to be received and decoded by another application. Our evaluations confirmed a real threat where strings of tens of characters could be transmitted errorless if the throughput is reduced to around 2.5-5 bps. The proposed covert channel is very stealthy as no unusual permissions are required and there is no explicit communication between the colluding applications.

Covert photo classification by fusing image features and visual attributes.

PubMed

Lang, Haitao; Ling, Haibin

2015-10-01

In this paper, we study a novel problem of classifying covert photos, whose acquisition processes are intentionally concealed from the subjects being photographed. Covert photos are often privacy invasive and, if distributed over Internet, can cause serious consequences. Automatic identification of such photos, therefore, serves as an important initial step toward further privacy protection operations. The problem is, however, very challenging due to the large semantic similarity between covert and noncovert photos, the enormous diversity in the photographing process and environment of cover photos, and the difficulty to collect an effective data set for the study. Attacking these challenges, we make three consecutive contributions. First, we collect a large data set containing 2500 covert photos, each of them is verified rigorously and carefully. Second, we conduct a user study on how humans distinguish covert photos from noncovert ones. The user study not only provides an important evaluation baseline, but also suggests fusing heterogeneous information for an automatic solution. Our third contribution is a covert photo classification algorithm that fuses various image features and visual attributes in the multiple kernel learning framework. We evaluate the proposed approach on the collected data set in comparison with other modern image classifiers. The results show that our approach achieves an average classification rate (1-EER) of 0.8940, which significantly outperforms other competitors as well as human's performance.

A New Sensors-Based Covert Channel on Android

PubMed Central

2014-01-01

Covert channels are not new in computing systems, and have been studied since their first definition four decades ago. New platforms invoke thorough investigations to assess their security. Now is the time for Android platform to analyze its security model, in particular the two key principles: process-isolation and the permissions system. Aside from all sorts of malware, one threat proved intractable by current protection solutions, that is, collusion attacks involving two applications communicating over covert channels. Still no universal solution can countermeasure this sort of attack unless the covert channels are known. This paper is an attempt to reveal a new covert channel, not only being specific to smartphones, but also exploiting an unusual resource as a vehicle to carry covert information: sensors data. Accelerometers generate signals that reflect user motions, and malware applications can apparently only read their data. However, if the vibration motor on the device is used properly, programmatically produced vibration patterns can encode stolen data and hence an application can cause discernible effects on acceleration data to be received and decoded by another application. Our evaluations confirmed a real threat where strings of tens of characters could be transmitted errorless if the throughput is reduced to around 2.5–5 bps. The proposed covert channel is very stealthy as no unusual permissions are required and there is no explicit communication between the colluding applications. PMID:25295311

Maternal Smoking during Pregnancy and Offspring Overt and Covert Conduct Problems: A Longitudinal Study

ERIC Educational Resources Information Center

Monuteaux, Michael C.; Blacker, Deborah; Biederman, Joseph; Fitzmaurice, Garrett; Buka, Stephen L.

2006-01-01

Background: Empirical evidence demonstrates that conduct disorder (CD) symptoms tend to cluster into covert and overt domains. We hypothesized that overt and covert CD symptoms may be distinct constructs with distinct risk factors. An important risk factor for CD is maternal smoking during pregnancy. We further investigated this association,…

Heat strain evaluation of overt and covert body armour in a hot and humid environment.

PubMed

Pyke, Andrew J; Costello, Joseph T; Stewart, Ian B

2015-03-01

The aim of this study was to elucidate the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. Eight healthy males walked on a treadmill for 120 min at 22% of their heart rate reserve in a climate chamber simulating 31 °C (60%RH) wearing either no armour (control), overt or covert PBA in addition to a security guard uniform, in a randomised controlled crossover design. No significant difference between conditions at the end of each trial was observed in core temperature, heart rate or skin temperature (P > 0.05). Covert PBA produced a significantly greater amount of body mass change (-1.81 ± 0.44%) compared to control (-1.07 ± 0.38%, P = 0.009) and overt conditions (-1.27 ± 0.44%, P = 0.025). Although a greater change in body mass was observed after the covert PBA trial; based on the physiological outcome measures recorded, the heat strain encountered while wearing lightweight, non-military overt or covert PBA was negligible compared to no PBA. The wearing of bullet proof vests or body armour is a requirement of personnel engaged in a wide range of occupations including police, security, customs and even journalists in theatres of war. This randomised controlled crossover study is the first to examine the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. We conclude that the heat strain encountered while wearing both overt and covert lightweight, non-military PBA was negligible compared to no PBA. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Covert Infection of Insects by Baculoviruses.

PubMed

Williams, Trevor; Virto, Cristina; Murillo, Rosa; Caballero, Primitivo

2017-01-01

Baculoviruses ( Baculoviridae ) are occluded DNA viruses that are lethal pathogens of the larval stages of some lepidopterans, mosquitoes, and sawflies (phytophagous Hymenoptera). These viruses have been developed as biological insecticides for control of insect pests and as expression vectors in biotechnological applications. Natural and laboratory populations frequently harbor covert infections by baculoviruses, often at a prevalence exceeding 50%. Covert infection can comprise either non-productive latency or sublethal infection involving low level production of virus progeny. Latency in cell culture systems involves the expression of a small subset of viral genes. In contrast, covert infection in lepidopterans is associated with differential infection of cell types, modulation of virus gene expression and avoidance of immune system clearance. The molecular basis for covert infection may reside in the regulation of host-virus interactions through the action of microRNAs (miRNA). Initial findings suggest that insect nudiviruses and vertebrate herpesviruses may provide useful analogous models for exploring the mechanisms of covert infection by baculoviruses. These pathogens adopt mixed-mode transmission strategies that depend on the relative fitness gains that accrue through vertical and horizontal transmission. This facilitates virus persistence when opportunities for horizontal transmission are limited and ensures virus dispersal in migratory host species. However, when host survival is threatened by environmental or physiological stressors, latent or persistent infections can be activated to produce lethal disease, followed by horizontal transmission. Covert infection has also been implicated in population level effects on host-pathogen dynamics due to the reduced reproductive capacity of infected females. We conclude that covert infections provide many opportunities to examine the complexity of insect-virus pathosystems at the organismal level and to explore the evolutionary and ecological relationships of these pathogens with major crop and forest pests.

Covert Infection of Insects by Baculoviruses

PubMed Central

Williams, Trevor; Virto, Cristina; Murillo, Rosa; Caballero, Primitivo

2017-01-01

Baculoviruses (Baculoviridae) are occluded DNA viruses that are lethal pathogens of the larval stages of some lepidopterans, mosquitoes, and sawflies (phytophagous Hymenoptera). These viruses have been developed as biological insecticides for control of insect pests and as expression vectors in biotechnological applications. Natural and laboratory populations frequently harbor covert infections by baculoviruses, often at a prevalence exceeding 50%. Covert infection can comprise either non-productive latency or sublethal infection involving low level production of virus progeny. Latency in cell culture systems involves the expression of a small subset of viral genes. In contrast, covert infection in lepidopterans is associated with differential infection of cell types, modulation of virus gene expression and avoidance of immune system clearance. The molecular basis for covert infection may reside in the regulation of host–virus interactions through the action of microRNAs (miRNA). Initial findings suggest that insect nudiviruses and vertebrate herpesviruses may provide useful analogous models for exploring the mechanisms of covert infection by baculoviruses. These pathogens adopt mixed-mode transmission strategies that depend on the relative fitness gains that accrue through vertical and horizontal transmission. This facilitates virus persistence when opportunities for horizontal transmission are limited and ensures virus dispersal in migratory host species. However, when host survival is threatened by environmental or physiological stressors, latent or persistent infections can be activated to produce lethal disease, followed by horizontal transmission. Covert infection has also been implicated in population level effects on host–pathogen dynamics due to the reduced reproductive capacity of infected females. We conclude that covert infections provide many opportunities to examine the complexity of insect–virus pathosystems at the organismal level and to explore the evolutionary and ecological relationships of these pathogens with major crop and forest pests. PMID:28769903

Emotional responses to a romantic partner's imaginary rejection: the roles of attachment anxiety, covert narcissism, and self-evaluation.

PubMed

Besser, Avi; Priel, Beatriz

2009-02-01

These studies tested the associations between responses to an induced imaginary romantic rejection and individual differences on dimensions of attachment and covert narcissism. In Study 1 (N=125), we examined the associations between attachment dimensions and emotional responses to a vignette depicting a scenario of romantic rejection, as measured by self-reported negative mood states, expressions of anger, somatic symptoms, and self-evaluation. Higher scores on attachment anxiety, but not on attachment avoidance, were associated with stronger reactions to the induced rejection. Moreover, decreased self-evaluation scores (self-esteem and pride) were found to mediate these associations. In Study 2 (N=88), the relative contributions of covert narcissism and attachment anxiety to the emotional responses to romantic rejection were explored. Higher scores on covert narcissism were associated with stronger reactions to the induced rejection. Moreover, covert narcissism seemed to constitute a specific aspect of attachment anxiety.

The decision-making of the Mental Health Review Tribunal in New Zealand.

PubMed

Thom, Katey; Black, Stella; Panther, Graham

2015-03-01

This article reports the findings of a qualitative research project that explored the decision-making of the Mental Health Review Tribunal in New Zealand, providing "thick descriptions" of the hearing process by closely focusing not only on the content of final written decisions, but also how decisions are made and delivered within the context they are formed. Drawing on interviews with tribunal members (n = 14), observation of hearings (n = 11), and review of written decisions (n = 60), the article illustrates how the MHRT attempts to practise in a way that enhances rather than damages ongoing relationships between applicants and clinicians. The factors that constrain its ability to conduct a hearing perceived as fair and participatory by the applicants is considered, and synergies with the international literature are noted in relation to the heavy use of medico-legal language, dominance of public safety concerns, and the covert interventionist practices of the MHRT. The article concludes by highlighting the value of qualitative observations of this decision-making body. While written decisions provide a justification for the outcome decided by the MHRT it leaves out nuances gleaned from in-depth clinical reporting, inquisitorial investigation and unwritten observations during hearings.

Applicability of Hydrologic Modeling to Tactical Military Decision Making

DTIC Science & Technology

1991-03-01

the continental United States. 111 DRAFT Table 4-4. Coefficient Ranges Location Range of Average Range of Average Ct Ct Cp Ct Appalachian 1.8-2.2 2.0... Mountainous --- 1.2 Watersheds Foothills --- 0.7 Areas Valley --- 0.4 Areas Eastern 0.4-1.0 0.8 0.5-1.0 0.8 Nebraska Corps of 0.4-8.0 0.3-0.9 --- Engineers...enemy to cover covert gorilla operations. b. Friendly Forces. Forces should be prepared to operate in a wet environment. c. Attachments and Detachments

The ethics of end-of-life decisions in the elderly: deliberations from the ECOPE study.

PubMed

Reiter-Theil, Stella

2003-06-01

Is age a factor underlying clinical decision-making? Should age be a criterion in the allocation of health care resources? Is it correct to criticize this approach as 'ageism'? What role does 'paternalism' play? These questions are the focus of this chapter which takes an interdisciplinary perspective of clinical ethics in order to provide an ethical evaluation of the situation of the elderly in health care. First, the text of the chapter is based on the descriptive level referring to (a) clinical ethics consultation, (b) the ECOPE study on 'Ethical Conditions of Passive Euthanasia' focusing on decision-making, and studies about age as a factor in clinical decisions, such as the American SUPPORT study. Second, at the normative level, ethical deliberations are discussed for and against age as a criterion for allocating health care resources. Finally, it is suggested that the differences in evidence to be found about the role of age as a factor in clinical decision-making may be due to the different national health policies as well as to the insufficient awareness of ethical principles violated by covert 'ageist' attitudes.

Temporal dynamics of sensorimotor integration in speech perception and production: independent component analysis of EEG data

PubMed Central

Jenson, David; Bowers, Andrew L.; Harkrider, Ashley W.; Thornton, David; Cuellar, Megan; Saltuklaroglu, Tim

2014-01-01

Activity in anterior sensorimotor regions is found in speech production and some perception tasks. Yet, how sensorimotor integration supports these functions is unclear due to a lack of data examining the timing of activity from these regions. Beta (~20 Hz) and alpha (~10 Hz) spectral power within the EEG μ rhythm are considered indices of motor and somatosensory activity, respectively. In the current study, perception conditions required discrimination (same/different) of syllables pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required covert and overt syllable productions and overt word production. Independent component analysis was performed on EEG data obtained during these conditions to (1) identify clusters of μ components common to all conditions and (2) examine real-time event-related spectral perturbations (ERSP) within alpha and beta bands. 17 and 15 out of 20 participants produced left and right μ-components, respectively, localized to precentral gyri. Discrimination conditions were characterized by significant (pFDR < 0.05) early alpha event-related synchronization (ERS) prior to and during stimulus presentation and later alpha event-related desynchronization (ERD) following stimulus offset. Beta ERD began early and gained strength across time. Differences were found between quiet and noisy discrimination conditions. Both overt syllable and word productions yielded similar alpha/beta ERD that began prior to production and was strongest during muscle activity. Findings during covert production were weaker than during overt production. One explanation for these findings is that μ-beta ERD indexes early predictive coding (e.g., internal modeling) and/or overt and covert attentional/motor processes. μ-alpha ERS may index inhibitory input to the premotor cortex from sensory regions prior to and during discrimination, while μ-alpha ERD may index sensory feedback during speech rehearsal and production. PMID:25071633

Nonword repetition ability of children who do and do not stutter and covert repair hypothesis.

PubMed

Bakhtiar, Mehdi; Abad, Ali Dehqan Ahmad; Panahi, Mohammad Sadegh Seif

2007-08-01

Stuttering has a life span incidence and it significantly impacts academic, social, emotional and vocational achievements of patients who stutter. The purpose of the present study was to examine phonological encoding in young children who stutter (CWS) during a non word repetition task and to test the covert repair hypothesis (CRH) and phonological skills in Persian native children. The study was conducted among 12 CWS and 12 children who do not stutter (CWNS) between the ages of 5.1 and 7.10 at the rehabilitation clinics in Tehran. A list of 40 bisyllabic and trisyllabic nonwords was used in a nonword repetition task to collect information about the following dependent variables: (a) reaction times (RTs), (b) the number of phonological errors (PEs) and (c) nonword length. An independent sample T-test was performed to compare means of PEs and RTs between the two groups and a paired t-test for analysis of nonword length impacts. Results indicated that the CWS had a slightly poor performance than CWNS but there was no significant difference between the groups. Also, the differences between bisyllabic and trisyllabic nonwords were significant for phonological errors but not for reaction times. In general, it is concluded that CWS might not have a gross problem in phonological retrieval of the novel phonological context even with increase in syllable length. Also, some predictions of CRH were not supported by this research. However, further research into this possibility may shed light on the emergence and characteristics of childhood stuttering.

Neural Signatures of Language Co-activation and Control in Bilingual Spoken Word Comprehension

PubMed Central

Chen, Peiyao; Bobb, Susan C.; Hoshino, Noriko; Marian, Viorica

2017-01-01

To examine the neural signatures of language co-activation and control during bilingual spoken word comprehension, Korean-English bilinguals and English monolinguals were asked to make overt or covert semantic relatedness judgments on auditorily-presented English word pairs. In two critical conditions, participants heard word pairs consisting of an English-Korean interlingual homophone (e.g., the sound /mu:n/ means “moon” in English and “door” in Korean) as the prime and an English word as the target. In the homophone-related condition, the target (e.g., “lock”) was related to the homophone’s Korean meaning, but not related to the homophone’s English meaning. In the homophone-unrelated condition, the target was unrelated to either the homophone’s Korean meaning or the homophone’s English meaning. In overtly responded situations, ERP results revealed that the reduced N400 effect in bilinguals for homophone-related word pairs correlated positively with the amount of their daily exposure to Korean. In covertly responded situations, ERP results showed a reduced late positive component for homophone-related word pairs in the right hemisphere, and this late positive effect was related to the neural efficiency of suppressing interference in a non-linguistic task. Together, these findings suggest 1) that the degree of language co-activation in bilingual spoken word comprehension is modulated by the amount of daily exposure to the non-target language; and 2) that bilinguals who are less influenced by cross-language activation may also have greater efficiency in suppressing interference in a non-linguistic task. PMID:28372943

Frontal Eye Fields Control Attentional Modulation of Alpha and Gamma Oscillations in Contralateral Occipitoparietal Cortex

PubMed Central

O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O.

2015-01-01

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8–12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. PMID:25632139

Neural signatures of language co-activation and control in bilingual spoken word comprehension.

PubMed

Chen, Peiyao; Bobb, Susan C; Hoshino, Noriko; Marian, Viorica

2017-06-15

To examine the neural signatures of language co-activation and control during bilingual spoken word comprehension, Korean-English bilinguals and English monolinguals were asked to make overt or covert semantic relatedness judgments on auditorily-presented English word pairs. In two critical conditions, participants heard word pairs consisting of an English-Korean interlingual homophone (e.g., the sound /mu:n/ means "moon" in English and "door" in Korean) as the prime and an English word as the target. In the homophone-related condition, the target (e.g., "lock") was related to the homophone's Korean meaning, but not related to the homophone's English meaning. In the homophone-unrelated condition, the target was unrelated to either the homophone's Korean meaning or the homophone's English meaning. In overtly responded situations, ERP results revealed that the reduced N400 effect in bilinguals for homophone-related word pairs correlated positively with the amount of their daily exposure to Korean. In covertly responded situations, ERP results showed a reduced late positive component for homophone-related word pairs in the right hemisphere, and this late positive effect was related to the neural efficiency of suppressing interference in a non-linguistic task. Together, these findings suggest 1) that the degree of language co-activation in bilingual spoken word comprehension is modulated by the amount of daily exposure to the non-target language; and 2) that bilinguals who are less influenced by cross-language activation may also have greater efficiency in suppressing interference in a non-linguistic task. Copyright © 2017 Elsevier B.V. All rights reserved.

Language networks in anophthalmia: maintained hierarchy of processing in 'visual' cortex.

PubMed

Watkins, Kate E; Cowey, Alan; Alexander, Iona; Filippini, Nicola; Kennedy, James M; Smith, Stephen M; Ragge, Nicola; Bridge, Holly

2012-05-01

Imaging studies in blind subjects have consistently shown that sensory and cognitive tasks evoke activity in the occipital cortex, which is normally visual. The precise areas involved and degree of activation are dependent upon the cause and age of onset of blindness. Here, we investigated the cortical language network at rest and during an auditory covert naming task in five bilaterally anophthalmic subjects, who have never received visual input. When listening to auditory definitions and covertly retrieving words, these subjects activated lateral occipital cortex bilaterally in addition to the language areas activated in sighted controls. This activity was significantly greater than that present in a control condition of listening to reversed speech. The lateral occipital cortex was also recruited into a left-lateralized resting-state network that usually comprises anterior and posterior language areas. Levels of activation to the auditory naming and reversed speech conditions did not differ in the calcarine (striate) cortex. This primary 'visual' cortex was not recruited to the left-lateralized resting-state network and showed high interhemispheric correlation of activity at rest, as is typically seen in unimodal cortical areas. In contrast, the interhemispheric correlation of resting activity in extrastriate areas was reduced in anophthalmia to the level of cortical areas that are heteromodal, such as the inferior frontal gyrus. Previous imaging studies in the congenitally blind show that primary visual cortex is activated in higher-order tasks, such as language and memory to a greater extent than during more basic sensory processing, resulting in a reversal of the normal hierarchy of functional organization across 'visual' areas. Our data do not support such a pattern of organization in anophthalmia. Instead, the patterns of activity during task and the functional connectivity at rest are consistent with the known hierarchy of processing in these areas normally seen for vision. The differences in cortical organization between bilateral anophthalmia and other forms of congenital blindness are considered to be due to the total absence of stimulation in 'visual' cortex by light or retinal activity in the former condition, and suggests development of subcortical auditory input to the geniculo-striate pathway.

Soviet objectives in the INF negotiations and European security. Master's thesis

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

Baumgardner, H.J.

1987-12-01

On 12 December 1979, NATO officials announced the decision to deploy 108 Pershing II nuclear missiles and 464 Ground Launched Cruise Missiles, in response to the Soviet deployment of SS-20 nuclear missiles. The NATO decision was met by a determined Soviet effort to prevent the deployment of the new missiles. The Soviet effort consisted of negotiations, diplomatic propaganda, and covert measures. When it was clear that the deployment was not going to be stopped, the Soviets agreed to formal INF arms-reduction talks. It is this author's opinion that the Soviet negotiation tactics, during the INF talks, supported the long-range goalmore » of reducing the military effectiveness of NATO, and also supported the goal of reducing U.S. influence in Europe.« less

BCI Performance and Brain Metabolism Profile in Severely Brain-Injured Patients Without Response to Command at Bedside.

PubMed

Annen, Jitka; Blandiaux, Séverine; Lejeune, Nicolas; Bahri, Mohamed A; Thibaut, Aurore; Cho, Woosang; Guger, Christoph; Chatelle, Camille; Laureys, Steven

2018-01-01

Detection and interpretation of signs of "covert command following" in patients with disorders of consciousness (DOC) remains a challenge for clinicians. In this study, we used a tactile P3-based BCI in 12 patients without behavioral command following, attempting to establish "covert command following." These results were then confronted to cerebral metabolism preservation as measured with glucose PET (FDG-PET). One patient showed "covert command following" (i.e., above-threshold BCI performance) during the active tactile paradigm. This patient also showed a higher cerebral glucose metabolism within the language network (presumably required for command following) when compared with the other patients without "covert command-following" but having a cerebral glucose metabolism indicative of minimally conscious state. Our results suggest that the P3-based BCI might probe "covert command following" in patients without behavioral response to command and therefore could be a valuable addition in the clinical assessment of patients with DOC.

Passive Motion Paradigm: An Alternative to Optimal Control

PubMed Central

Mohan, Vishwanathan; Morasso, Pietro

2011-01-01

In the last years, optimal control theory (OCT) has emerged as the leading approach for investigating neural control of movement and motor cognition for two complementary research lines: behavioral neuroscience and humanoid robotics. In both cases, there are general problems that need to be addressed, such as the “degrees of freedom (DoFs) problem,” the common core of production, observation, reasoning, and learning of “actions.” OCT, directly derived from engineering design techniques of control systems quantifies task goals as “cost functions” and uses the sophisticated formal tools of optimal control to obtain desired behavior (and predictions). We propose an alternative “softer” approach passive motion paradigm (PMP) that we believe is closer to the biomechanics and cybernetics of action. The basic idea is that actions (overt as well as covert) are the consequences of an internal simulation process that “animates” the body schema with the attractor dynamics of force fields induced by the goal and task-specific constraints. This internal simulation offers the brain a way to dynamically link motor redundancy with task-oriented constraints “at runtime,” hence solving the “DoFs problem” without explicit kinematic inversion and cost function computation. We argue that the function of such computational machinery is not only restricted to shaping motor output during action execution but also to provide the self with information on the feasibility, consequence, understanding and meaning of “potential actions.” In this sense, taking into account recent developments in neuroscience (motor imagery, simulation theory of covert actions, mirror neuron system) and in embodied robotics, PMP offers a novel framework for understanding motor cognition that goes beyond the engineering control paradigm provided by OCT. Therefore, the paper is at the same time a review of the PMP rationale, as a computational theory, and a perspective presentation of how to develop it for designing better cognitive architectures. PMID:22207846

A novel onset detection technique for brain-computer interfaces using sound-production related cognitive tasks in simulated-online system

NASA Astrophysics Data System (ADS)

Song, YoungJae; Sepulveda, Francisco

2017-02-01

Objective. Self-paced EEG-based BCIs (SP-BCIs) have traditionally been avoided due to two sources of uncertainty: (1) precisely when an intentional command is sent by the brain, i.e., the command onset detection problem, and (2) how different the intentional command is when compared to non-specific (or idle) states. Performance evaluation is also a problem and there are no suitable standard metrics available. In this paper we attempted to tackle these issues. Approach. Self-paced covert sound-production cognitive tasks (i.e., high pitch and siren-like sounds) were used to distinguish between intentional commands (IC) and idle states. The IC states were chosen for their ease of execution and negligible overlap with common cognitive states. Band power and a digital wavelet transform were used for feature extraction, and the Davies-Bouldin index was used for feature selection. Classification was performed using linear discriminant analysis. Main results. Performance was evaluated under offline and simulated-online conditions. For the latter, a performance score called true-false-positive (TFP) rate, ranging from 0 (poor) to 100 (perfect), was created to take into account both classification performance and onset timing errors. Averaging the results from the best performing IC task for all seven participants, an 77.7% true-positive (TP) rate was achieved in offline testing. For simulated-online analysis the best IC average TFP score was 76.67% (87.61% TP rate, 4.05% false-positive rate). Significance. Results were promising when compared to previous IC onset detection studies using motor imagery, in which best TP rates were reported as 72.0% and 79.7%, and which, crucially, did not take timing errors into account. Moreover, based on our literature review, there is no previous covert sound-production onset detection system for spBCIs. Results showed that the proposed onset detection technique and TFP performance metric have good potential for use in SP-BCIs.

Investigative Operations: Use of Covert Testing to Identify Security Vulnerabilities and Fraud, Waste, and Abuse

DTIC Science & Technology

2007-11-14

including evaluations of controls over radioactive materials and security at America’s borders, airport security , sales of sensitive and surplus...officers. The details of this March 2006 report are classified; however, TSA has authorized this limited discussion. Airport Security Testing Sale of...of covert security vulnerability testing of numerous airports across the country. During these covert tests, our investigators passed through airport

Covert Action Lead -- Central Intelligence Agency or Special Forces

DTIC Science & Technology

2007-05-01

to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...place as an elevated threat to the U.S., combined with the decline in the CIA’s ability to perform Covert Action, is it now time for Special Forces to... time for Special Forces to assume the lead role in Covert Action? iii TABLE OF CONTENTS INTRODUCTION

Updating the premotor theory: the allocation of attention is not always accompanied by saccade preparation.

PubMed

Belopolsky, Artem V; Theeuwes, Jan

2012-08-01

There is an ongoing controversy regarding the relationship between covert attention and saccadic eye movements. While there is quite some evidence that the preparation of a saccade is obligatory preceded by a shift of covert attention, the reverse is not clear: Is allocation of attention always accompanied by saccade preparation? Recently, a shifting and maintenance account was proposed suggesting that shifting and maintenance components of covert attention differ in their relation to the oculomotor system. Specifically, it was argued that a shift of covert attention is always accompanied by activation of the oculomotor program, while maintaining covert attention at a location can be accompanied either by activation or suppression of oculomotor program, depending on the probability of executing an eye movement to the attended location. In the present study we tested whether there is such an obligatory coupling between shifting of attention and saccade preparation and how quickly saccade preparation gets suppressed. The results showed that attention shifting was always accompanied by saccade preparation whenever covert attention had to be shifted during visual search, as well as in response to exogenous or endogenous cues. However, for the endogenous cues the saccade program to the attended location was suppressed very soon after the attention shift was completed. The current findings support the shifting and maintenance account and indicate that the premotor theory needs to be updated to include a shifting and maintenance component for the cases in which covert shifts of attention are made without the intention to execute a saccade. (c) 2012 APA, all rights reserved.

Is conflict monitoring supramodal? Spatiotemporal dynamics of cognitive control processes in an auditory Stroop task

PubMed Central

Donohue, Sarah E.; Liotti, Mario; Perez, Rick; Woldorff, Marty G.

2011-01-01

The electrophysiological correlates of conflict processing and cognitive control have been well characterized for the visual modality in paradigms such as the Stroop task. Much less is known about corresponding processes in the auditory modality. Here, electroencephalographic recordings of brain activity were measured during an auditory Stroop task, using three different forms of behavioral response (Overt verbal, Covert verbal, and Manual), that closely paralleled our previous visual-Stroop study. As expected, behavioral responses were slower and less accurate for incongruent compared to congruent trials. Neurally, incongruent trials showed an enhanced fronto-central negative-polarity wave (Ninc), similar to the N450 in visual-Stroop tasks, with similar variations as a function of behavioral response mode, but peaking ~150 ms earlier, followed by an enhanced positive posterior wave. In addition, sequential behavioral and neural effects were observed that supported the conflict-monitoring and cognitive-adjustment hypothesis. Thus, while some aspects of the conflict detection processes, such as timing, may be modality-dependent, the general mechanisms would appear to be supramodal. PMID:21964643

Cortisol and Anti-social Behavior in Early Adolescence: The Role of Gender in an Economically Disadvantaged Sample

PubMed Central

Kobak, Roger; Zajac, Kristyn; Levine, Seymour

2014-01-01

This study examines the relation between adolescents’ anti-social behaviors and adrenocortical activity during a laboratory visit in a sample of economically disadvantaged families (N = 116, ages 12 – 14, 51% female). Pre-task cortisol levels indexed adolescents’ pre-challenge response to the lab visit, while adolescents’ response to a conflict discussion with their caregivers was indexed with residualized change in pre- to post- conflict cortisol levels. A trait measure of anti-social behavior (derived from parent, teacher, and self-reports) was associated with lower pre-task cortisol levels but greater cortisol response to the conflict discussion. Gender moderated anti-social adolescents’ cortisol response to the conflict discussion with girls who reported more covert risky problem behaviors showing an increased cortisol response. The findings suggest that, while anti-social adolescents had lower pre-task cortisol levels, conflict discussions with caregivers present a unique challenge to anti-social girls compared with anti-social boys. PMID:19338699

Coherence across consciousness levels: Symmetric visual displays spare working memory resources.

PubMed

Dumitru, Magda L

2015-12-15

Two studies demonstrate that the need for coherence could nudge individuals to use structural similarities between binary visual displays and two concurrent cognitive tasks to unduly solve the latter in similar fashion. In an overt truth-judgement task, participants decided whether symmetric colourful displays matched conjunction or disjunction descriptions (e.g., "the black and/or the orange"). In the simultaneous covert categorisation task, they decided whether a colour name (e.g., "black") described a two-colour object or half of a single-colour object. Two response patterns emerged as follows. Participants either acknowledged or rejected matches between disjunction descriptions and two visual stimuli and, similarly, either acknowledged or rejected matches between single colour names and two-colour objects or between single colour names and half of single-colour objects. These findings confirm the coherence hypothesis, highlight the role of coherence in preserving working-memory resources, and demonstrate an interaction between high-level and low-level consciousness. Copyright © 2015 Elsevier Inc. All rights reserved.

The inhibitory spillover effect: Controlling the bladder makes better liars *

PubMed Central

Fenn, Elise; Blandón-Gitlin, Iris; Coons, Jennifer; Pineda, Catherine; Echon, Reinalyn

2015-01-01

The Inhibitory-Spillover-Effect (ISE) on a deception task was investigated. The ISE occurs when performance in one self-control task facilitates performance in another (simultaneously conducted) self-control task. Deceiving requires increased access to inhibitory control. We hypothesized that inducing liars to control urination urgency (physical inhibition) would facilitate control during deceptive interviews (cognitive inhibition). Participants drank small (low-control) or large (high-control) amounts of water. Next, they lied or told the truth to an interviewer. Third-party observers assessed the presence of behavioral cues and made true/lie judgments. In the high-control, but not the low-control condition, liars displayed significantly fewer behavioral cues to deception, more behavioral cues signaling truth, and provided longer and more complex accounts than truth-tellers. Accuracy detecting liars in the high-control condition was significantly impaired; observers revealed bias toward perceiving liars as truth-tellers. The ISE can operate in complex behaviors. Acts of deception can be facilitated by covert manipulations of self-control. PMID:26366466

Neuroimaging self-esteem: a fMRI study of individual differences in women

PubMed Central

Lundberg, Erica; Brimson-Théberge, Melanie; Théberge, Jean

2013-01-01

Although neuroimaging studies strongly implicate the medial prefrontal cortex (ventral and dorsal), cingulate gyrus (anterior and posterior), precuneus and temporoparietal cortex in mediating self-referential processing (SRP), little is known about the neural bases mediating individual differences in valenced SRP, that is, processes intrinsic to self-esteem. This study investigated the neural correlates of experimentally engendered valenced SRP via the Visual–Verbal Self-Other Referential Processing Task in 20 women with fMRI. Participants viewed pictures of themselves or unknown other women during separate trials while covertly rehearsing ‘I am’ or ‘She is’, followed by reading valenced trait adjectives, thus variably associating the self/other with positivity/negativity. Response within dorsal and ventral medial prefrontal cortex, cingulate cortex and left temporoparietal cortex varied with individual differences in both pre-task rated self-descriptiveness of the words, as well as task-induced affective responses. Results are discussed as they relate to a social cognitive and affective neuroscience view of self-esteem. PMID:22403154

Reducing covert self-injurious behavior maintained by automatic reinforcement through a variable momentary DRO procedure.

PubMed

Toussaint, Karen A; Tiger, Jeffrey H

2012-01-01

Covert self-injurious behavior (i.e., behavior that occurs in the absence of other people) can be difficult to treat. Traditional treatments typically have involved sophisticated methods of observation and often have employed positive punishment procedures. The current study evaluated the effectiveness of a variable momentary differential reinforcement contingency in the treatment of covert self-injury. Neither positive punishment nor extinction was required to produce decreased skin picking.

Do physicians clean their hands? Insights from a covert observational study.

PubMed

Kovacs-Litman, Adam; Wong, Kimberly; Shojania, Kaveh G; Callery, Sandra; Vearncombe, Mary; Leis, Jerome A

2016-12-01

Physicians are notorious for poor hand hygiene (HH) compliance. We wondered if lower performance by physicians compared with other health professionals might reflect differences in the Hawthorne effect. We introduced covert HH observers to see if performance differences between physicians and nurses decreased and to gain further insights into physician HH behaviors. Following training and validation with a hospital HH auditor, 2 students covertly measured HH during clinical rotations. Students rotated off clinical services every week to increase exposure to different providers and minimize risk of exposing the covert observation. We compared covertly measured HH compliance with data from overt observation by hospital auditors during the same time period. Covert observation produced much lower HH compliance than recorded by hospital auditors during the same time period: 50.0% (799/1597) versus 83.7% (2769/3309) (P < 0.0002). The difference in physician compliance between hospital auditors and covert observers was 19.0% (73.2% vs 54.2%); for nurses this difference was much higher at 40.7% (85.8% vs 45.1%) (P < 0.0001). Physician trainees showed markedly better compliance when attending staff cleaned their hands compared with encounters when attending did not (79.5% vs 18.9%; P < 0.0002). Our study suggests that traditional HH audits not only overstate HH performance overall, but can lead to inaccurate inferences about performance by professional groupings due to relative differences in the Hawthorne effect. We suggest that future improvement efforts will rely on more accurate HH monitoring systems and strong attending physician leadership to set an example for trainees. Journal of Hospital Medicine 2015;11:862-864. © 2015 Society of Hospital Medicine. © 2016 Society of Hospital Medicine.

The Noncompliant Patient in Psychiatry: The Case For and Against Covert/Surreptitious Medication

PubMed Central

Latha, K. S.

2010-01-01

Nonadherence to treatment continues to be one of psychiatry’s greatest challenges. To improve adherence and thus improve the care of patients, clinicians and patients’ family members sometimes resort to hiding medication in food or drink, a practice referred to as covert/ surreptitious medication. The practice of covert drug administration in food and beverages is well known in the treatment of psychiatrically ill world-wide but no prevalence rates exist. Covert medication may seem like a minor matter, but it touches on legal and ethical issues of a patient’s competence, autonomy, and insight. Medicating patients without their knowledge is not justifiable solely as a shortcut for institutions or families wishing to calm a troublesome patient and thus alleviate some of the burdens of care giving. The paramount principle is ensuring the well-being of a patient who lacks the competence to give informed consent. Ethically, covert/surreptitious administration can be seen as a breach of trust by the doctor or by family members who administer the drugs. Covert medication contravenes contemporary ethical practice. Legally, treatment without consent is permissible only where common law or statute provides such authority. The practice of covert administration of medication is not specifically covered in the mental health legislation in developing countries. Many of the current dilemmas in this area have come to public attention because of two important developments in medical ethics and the law - the increasing importance accorded to respect for autonomy and loss of the parens patriae jurisdiction of the courts [parens patriae means ‘parent of the country’; it permitted a court to consent or refuse treatment on behalf of an ‘incapacity’, or alternatively to appoint a guardian with such powers]. PMID:21327173

Bandwidth and Detection of Packet Length Covert Channels

DTIC Science & Technology

2011-03-01

Shared Resource Matrix ( SRM ): Develop a matrix of all resources on one side and on the other all the processes. Then, determine which process uses which...system calls. This method is similar to that of the SRM . Covert channels have also been created by modulating packet timing, data and headers of net- work...analysis, noninterference analysis, SRM method, and the covert flow tree method [4]. These methods can be used during the design phase of a system. Less

Assessing Boundary Conditions of the Testing Effect: On the Relative Efficacy of Covert vs. Overt Retrieval

PubMed Central

Sundqvist, Max L.; Mäntylä, Timo; Jönsson, Fredrik U.

2017-01-01

Repeated testing during learning often improves later memory, which is often referred to as the testing effect. To clarify its boundary conditions, we examined whether the testing effect was selectively affected by covert (retrieved but not articulated) or overt (retrieved and articulated) response format. In Experiments 1 and 2, we compared immediate (5 min) and delayed (1 week) cued recall for paired associates following study-only, covert, and overt conditions, including two types of overt articulation (typing and writing). A clear testing effect was observed in both experiments, but with no selective effects of response format. In Experiments 3 and 4, we compared covert and overt retrieval under blocked and random list orders. The effect sizes were small in both experiments, but there was a significant effect of response format, with overt retrieval showing better final recall performance than covert retrieval. There were no significant effects of blocked vs. random list orders with respect to the testing effect produced. Taken together, these findings suggest that, under specific circumstances, overt retrieval may lead to a greater testing effect than that of covert retrieval, but because of small effect sizes, it appears that the testing effect is mainly the result of retrieval processes and that articulation has fairly little to add to its magnitude in a paired-associates learning paradigm. PMID:28680411

Assessing Boundary Conditions of the Testing Effect: On the Relative Efficacy of Covert vs. Overt Retrieval.

PubMed

Sundqvist, Max L; Mäntylä, Timo; Jönsson, Fredrik U

2017-01-01

Repeated testing during learning often improves later memory, which is often referred to as the testing effect. To clarify its boundary conditions, we examined whether the testing effect was selectively affected by covert (retrieved but not articulated) or overt (retrieved and articulated) response format. In Experiments 1 and 2, we compared immediate (5 min) and delayed (1 week) cued recall for paired associates following study-only, covert, and overt conditions, including two types of overt articulation (typing and writing). A clear testing effect was observed in both experiments, but with no selective effects of response format. In Experiments 3 and 4, we compared covert and overt retrieval under blocked and random list orders. The effect sizes were small in both experiments, but there was a significant effect of response format, with overt retrieval showing better final recall performance than covert retrieval. There were no significant effects of blocked vs. random list orders with respect to the testing effect produced. Taken together, these findings suggest that, under specific circumstances, overt retrieval may lead to a greater testing effect than that of covert retrieval, but because of small effect sizes, it appears that the testing effect is mainly the result of retrieval processes and that articulation has fairly little to add to its magnitude in a paired-associates learning paradigm.

Latent Class Analysis of Antisocial Behavior: Interaction of Serotonin Transporter Genotype and Maltreatment

PubMed Central

Li, James J.

2010-01-01

To improve understanding about genetic and environmental influences on antisocial behavior (ASB), we tested the association of the 44-base pair polymorphism of the serotonin transporter gene (5-HTTLPR) and maltreatment using latent class analysis in 2,488 boys and girls from Wave 1 of the National Longitudinal Study of Adolescent Health. In boys, ASB was defined by three classes (Exclusive Covert, Mixed Covert and Overt, and No Problems) whereas in girls, ASB was defined by two classes (Exclusive Covert, No Problems). In boys, 5-HTTLPR and maltreatment were not significantly related to ASB. However, in girls, maltreatment, but not 5-HTTLPR, was significantly associated with ASB. A significant interaction between 5-HTTLPR and maltreatment was also observed, where maltreated girls homozygous for the short allele were 12 times more likely to be classified in the Exclusive Covert group than in the No Problems group. Structural differences in the latent structure of ASB at Wave 2 and Wave 3 prevented repeat LCA modeling. However, using counts of ASB, 5-HTTLPR, maltreatment, and its interaction were unrelated to overt and covert ASB at Wave 2 and only maltreatment was related to covert ASB at Wave 3. We discuss these findings within the context of sex differences in ASB and relevant models of gene-environment interplay across developmental periods. PMID:20405199

Narcissism and boredom revisited: an exploration of correlates of overt and covert narcissism among Dutch university students.

PubMed

Zondag, Hessel J

2013-04-01

This article presents a study of the relationship between narcissism, overt and covert, and seven aspects of boredom, defined as listlessness, drawn out experience of time, depletion, lack of concentration, restlessness, experience seeking, and lack of interest. The survey was conducted using questionnaires administered to 32 men and 177 women. The mean age of male respondents was 30.9 yr. (SD = 11.9), that of female respondents 30.2 yr. (SD = 12.2). In general terms, covert narcissism was found to be positively, and overt narcissism negatively, associated with boredom. The results showed a more complex pattern than was found in previous research into the relationship between narcissism and boredom and suggest that overt and covert narcissism are at opposite ends of the adjustment continuum.

1. Historic American Buildings Survey V. Covert Martin Collection, Stockton, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Historic American Buildings Survey V. Covert Martin Collection, Stockton, Calif. Original: 1925 Re- photo: April, 1940 GENERAL VIEW - Gravestones, North Branch Cemetery, Altaville, Calaveras County, CA

Parietal blood oxygenation level-dependent response evoked by covert visual search reflects set-size effect in monkeys.

PubMed

Atabaki, A; Marciniak, K; Dicke, P W; Karnath, H-O; Thier, P

2014-03-01

Distinguishing a target from distractors during visual search is crucial for goal-directed behaviour. The more distractors that are presented with the target, the larger is the subject's error rate. This observation defines the set-size effect in visual search. Neurons in areas related to attention and eye movements, like the lateral intraparietal area (LIP) and frontal eye field (FEF), diminish their firing rates when the number of distractors increases, in line with the behavioural set-size effect. Furthermore, human imaging studies that have tried to delineate cortical areas modulating their blood oxygenation level-dependent (BOLD) response with set size have yielded contradictory results. In order to test whether BOLD imaging of the rhesus monkey cortex yields results consistent with the electrophysiological findings and, moreover, to clarify if additional other cortical regions beyond the two hitherto implicated are involved in this process, we studied monkeys while performing a covert visual search task. When varying the number of distractors in the search task, we observed a monotonic increase in error rates when search time was kept constant as was expected if monkeys resorted to a serial search strategy. Visual search consistently evoked robust BOLD activity in the monkey FEF and a region in the intraparietal sulcus in its lateral and middle part, probably involving area LIP. Whereas the BOLD response in the FEF did not depend on set size, the LIP signal increased in parallel with set size. These results demonstrate the virtue of BOLD imaging in monkeys when trying to delineate cortical areas underlying a cognitive process like visual search. However, they also demonstrate the caution needed when inferring neural activity from BOLD activity. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Frontal eye fields control attentional modulation of alpha and gamma oscillations in contralateral occipitoparietal cortex.

PubMed

Marshall, Tom R; O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O

2015-01-28

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8-12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. Copyright © 2015 the authors 0270-6474/15/351638-10$15.00/0.

How microsaccades relate to lateralized ERP components of spatial attention: A co-registration study.

PubMed

Meyberg, Susann; Sommer, Werner; Dimigen, Olaf

2017-05-01

Covert shifts of attention that follow the presentation of a cue are associated with lateralized components in the event-related potential (ERP): the "early directing attention negativity" (EDAN) and the "anterior directing attention negativity" (ADAN). Traditionally, these shifts are thought to take place while gaze is fixated and, thus, in the absence of saccades. However, microsaccades of small amplitude (<1°) occur frequently and involuntarily also during fixation and are closely correlated with spatial attention. To investigate potential links between microsaccades and lateralized ERP components, we simultaneously recorded eye movements and ERPs in a spatial cueing task. As a first major result, we show that both the posterior EDAN and the orientation of microsaccades align more strongly with the location of the task-relevant part of the cue stimulus than with the direction of the attention shift indicated by that cue. A coupling between microsaccades and EDAN was also present on the single-trial level: The EDAN was largest when microsaccades were oriented toward the relevant cue, but absent when microsaccades were oriented away from it, suggesting that EDAN and microsaccades are generated by the same neural network, which selects relevant stimuli and orients behavior toward them. As a second major result, we show that small corneoretinal artifacts from microsaccades, which fall below conventional EOG rejection thresholds, contaminate the measurement of the ADAN. After correcting the EEG for microsaccade-related artifacts with an optimized variant of independent component analysis, ADAN was abolished at frontal sites, but a genuine ADAN was still present at central sites. Thus, the combined measurement of microsaccades and lateralized ERPs sheds new light onto cue-elicited shifts of covert attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Punctuation and Implicit Prosody in Silent Reading: An ERP Study Investigating English Garden-Path Sentences.

PubMed

Drury, John E; Baum, Shari R; Valeriote, Hope; Steinhauer, Karsten

2016-01-01

This study presents the first two ERP reading studies of comma-induced effects of covert (implicit) prosody on syntactic parsing decisions in English. The first experiment used a balanced 2 × 2 design in which the presence/absence of commas determined plausibility (e.g., John, said Mary, was the nicest boy at the party vs. John said Mary was the nicest boy at the party ). The second reading experiment replicated a previous auditory study investigating the role of overt prosodic boundaries in closure ambiguities (Pauker et al., 2011). In both experiments, commas reliably elicited CPS components and generally played a dominant role in determining parsing decisions in the face of input ambiguity. The combined set of findings provides further evidence supporting the claim that mechanisms subserving speech processing play an active role during silent reading.

Assessment of parental overt and covert control of child's food intake: a population-based validation study with mothers of preschoolers.

PubMed

Nowicka, Paulina; Flodmark, Carl-Erik; Hales, Derek; Faith, Myles S

2014-12-01

Overt and covert control are novel constructs representing two different parental feeding practices with regard to the child's ability to detect them. Preliminary research indicates that covert control is linked to a healthier diet and lower child weight status. In this study, we report the first psychometric validation of the original measures of overt and covert control outside the UK in a large sample of parents of preschoolers. Based on records from the population register, all mothers of 4-year-olds (n = 3007) from the third largest city in Sweden, Malmö, were contacted by mail. Out of those, 876 returned the measures of overt and covert control together with a background questionnaire and the Child Feeding Questionnaire (CFQ). Test-retest data were obtained from 64% (n = 563) of these mothers. The mean age of the mothers was 35.6 years; their mean BMI was 24.1, 31.5% were overweight or obese. The children were on average 4.5 years old; 48% were girls, 12.8% were overweight or obese. While the fit for the original 9-item 2-factor model was poor, shorter 8- and 6-item versions were supported by confirmatory factor analysis (CFI > 0.95, RMSEA < 0.05). Internal and test–retest reliability of the shorter version was good (ICC= 0.65-0.71). Results also suggest that the factor structure and loadings were invariant(i.e., did not significantly differ) over time and between child sexes. Both overt and covert control factors were moderately correlated with CFQ monitoring. Overt control was also moderately related to CFQ pressure and weakly correlated with CFQ restriction. Covert control, on the other hand, was moderately related to restriction and not related with pressure. Correlations of both factors with child and parent BMI were very small. We found good psychometric properties of the revised versions of the overt and control behaviors ina multiethnic sample of mothers from Sweden. Future studies need to establish causal associations between overt and covert control and the obesity related outcomes.

Downward delegation of implantable cardioverter defibrillator decision-making in a restricted-resource environment: the pitfalls of bedside rationing.

PubMed

Simpson, Christopher S; Hoffmaster, Barry; Dorian, Paul

2005-05-15

Implantable cardioverter defibrillators have been shown to reduce all-cause mortality in some patient populations at risk of sudden death. New Canadian guidelines recommend implantable cardioverter defibrillator therapy for these patients. However, the need for these devices exceeds the funded volumes in many Canadian jurisdictions. As a result, rationing of this resource has been necessary. While rationing at the macro (Ministry of Health) and meso (hospital) levels has achieved some level of acceptance by society, the responsibility for the decisions taken at the micro (individual) patient level actually rests with the physician at the bedside. This 'bedside rationing' creates a moral dilemma for physicians, who are torn between their traditional fiduciary role as 'patient advocate' and the competing role of 'gatekeeper'. This 'downward delegation' of rationing decision-making obscures the reality that rationing occurs, and encourages covert, opaque and inconsistent approaches. The remedy is the development of fair, legitimate procedures for making rationing decisions that include guidelines that structure and constrain those decisions. Macro- and meso-level stakeholders must also recognize and take responsibility for their part in restricting resources in a broadly inclusive and transparent process.

CFCC: A Covert Flows Confinement Mechanism for Virtual Machine Coalitions

NASA Astrophysics Data System (ADS)

Cheng, Ge; Jin, Hai; Zou, Deqing; Shi, Lei; Ohoussou, Alex K.

Normally, virtualization technology is adopted to construct the infrastructure of cloud computing environment. Resources are managed and organized dynamically through virtual machine (VM) coalitions in accordance with the requirements of applications. Enforcing mandatory access control (MAC) on the VM coalitions will greatly improve the security of VM-based cloud computing. However, the existing MAC models lack the mechanism to confine the covert flows and are hard to eliminate the convert channels. In this paper, we propose a covert flows confinement mechanism for virtual machine coalitions (CFCC), which introduces dynamic conflicts of interest based on the activity history of VMs, each of which is attached with a label. The proposed mechanism can be used to confine the covert flows between VMs in different coalitions. We implement a prototype system, evaluate its performance, and show that our mechanism is practical.

Protocol for the design of an instrument to measure preadolescent children's self-report of covert aggression and bullying

PubMed Central

Nelson, Helen Jean; Kendall, Garth Edward; Burns, Sharyn; Schonert-Reichl, Kimberly

2015-01-01

Introduction Covert bullying in schools is associated with a range of academic, social, emotional and physical health problems. Much research has focused on bullying, but there remains a gap in understanding about covert aggression and how to most accurately and reliably measure children's own reports of this behaviour. This paper reviews relevant literature and outlines a research project that aims to develop a self-report instrument that effectively measures covert aggression and bullying. It is anticipated that this research will result in a standardised instrument that is suitable for exploring preadolescent children's experiences of covert aggressive behaviour. The data collected by the instrument will enhance health and education professionals understanding of covert bullying behaviours and will inform the design and evaluation of interventions. Methods and analysis Relational developmental systems theory will guide the design of an online self-report instrument. The first phase of the project will include a critical review of the research literature, focus groups with children aged 8–12 years (grades 4–6) in Perth, Western Australia, and expert review. The instrument will be explored for content and face validity prior to the assessment of convergent and discriminant validity, internal consistency and test-retest reliability. Ethics and dissemination The study has been approved by the Curtin University of Human Research Ethics Committee (RDHS-38-15) and by the Executive Principal of the participating school. PMID:26553834

Combining computer game-based behavioural experiments with high-density EEG and infrared gaze tracking.

PubMed

Yoder, Keith J; Belmonte, Matthew K

2010-12-16

Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they yield data relevant to the cognitive processing that occurs under ecologically valid conditions. These two goals often are at odds, since well controlled stimuli often are too repetitive to sustain subjects' motivation. Studies employing electroencephalography (EEG) are often especially sensitive to this dilemma between ecological validity and experimental control: attaining sufficient signal-to-noise in physiological averages demands large numbers of repeated trials within lengthy recording sessions, limiting the subject pool to individuals with the ability and patience to perform a set task over and over again. This constraint severely limits researchers' ability to investigate younger populations as well as clinical populations associated with heightened anxiety or attentional abnormalities. Even adult, non-clinical subjects may not be able to achieve their typical levels of performance or cognitive engagement: an unmotivated subject for whom an experimental task is little more than a chore is not the same, behaviourally, cognitively, or neurally, as a subject who is intrinsically motivated and engaged with the task. A growing body of literature demonstrates that embedding experiments within video games may provide a way between the horns of this dilemma between experimental control and ecological validity. The narrative of a game provides a more realistic context in which tasks occur, enhancing their ecological validity (Chaytor & Schmitter-Edgecombe, 2003). Moreover, this context provides motivation to complete tasks. In our game, subjects perform various missions to collect resources, fend off pirates, intercept communications or facilitate diplomatic relations. In so doing, they also perform an array of cognitive tasks, including a Posner attention-shifting paradigm (Posner, 1980), a go/no-go test of motor inhibition, a psychophysical motion coherence threshold task, the Embedded Figures Test (Witkin, 1950, 1954) and a theory-of-mind (Wimmer & Perner, 1983) task. The game software automatically registers game stimuli and subjects' actions and responses in a log file, and sends event codes to synchronise with physiological data recorders. Thus the game can be combined with physiological measures such as EEG or fMRI, and with moment-to-moment tracking of gaze. Gaze tracking can verify subjects' compliance with behavioural tasks (e.g. fixation) and overt attention to experimental stimuli, and also physiological arousal as reflected in pupil dilation (Bradley et al., 2008). At great enough sampling frequencies, gaze tracking may also help assess covert attention as reflected in microsaccades - eye movements that are too small to foveate a new object, but are as rapid in onset and have the same relationship between angular distance and peak velocity as do saccades that traverse greater distances. The distribution of directions of microsaccades correlates with the (otherwise) covert direction of attention (Hafed & Clark, 2002).

Building the "fable hospital"--the CEO's perspective: an interview with Michael H. Covert, president and chief executive officer, Palomar Pomerado Health. Interview by David A Tam.

PubMed

Covert, Michael

2012-01-01

Hospital construction is a significant event in any health system. The financial implications are great, especially at a time of shrinking capital resources. Personnel are affected, as are the processes to perform their tasks. Often, new facilities are catalysts that change organizational culture; it has been clearly shown that new facilities have a positive impact on patient satisfaction scores. The members of the C-suite of a hospital/health system play important roles in construction projects. However, no one is more critical to the success of such major endeavors than the chief executive officer (CEO). The CEO sets the tone for the project, giving direction to the design and construction process that may have implications for the rest of the organization. Palomar Pomerado Health (PPH) is the largest public health district in California. In 2002, the PPH governing board authorized the creation of a new facility master plan for the district, which included the construction of a replacement facility for its tertiary care trauma center. The new Palomar Medical Center is slated to open in August 2012. HERD had the opportunity to speak with PPH CEO Michael H. Covert on the role of the CEO in the building of this "fable hospital".

Fixation not required: characterizing oculomotor attention capture for looming stimuli.

PubMed

Lewis, Joanna E; Neider, Mark B

2015-10-01

A stimulus moving toward us, such as a ball being thrown in our direction or a vehicle braking suddenly in front of ours, often represents a stimulus that requires a rapid response. Using a visual search task in which target and distractor items were systematically associated with a looming object, we explored whether this sort of looming motion captures attention, the nature of such capture using eye movement measures (overt/covert), and the extent to which such capture effects are more closely tied to motion onset or the motion itself. We replicated previous findings indicating that looming motion induces response time benefits and costs during visual search Lin, Franconeri, & Enns(Psychological Science 19(7): 686-693, 2008). These differences in response times were independent of fixation, indicating that these capture effects did not necessitate overt attentional shifts to a looming object for search benefits or costs to occur. Interestingly, we found no differences in capture benefits and costs associated with differences in looming motion type. Combined, our results suggest that capture effects associated with looming motion are more likely subserved by covert attentional mechanisms rather than overt mechanisms, and attention capture for looming motion is likely related to motion itself rather than the onset of motion.

Verbal Processing Speed and Executive Functioning in Long-Term Cochlear Implant Users

PubMed Central

Pisoni, David B.; Kronenberger, William G.

2015-01-01

Purpose The purpose of this study was to report how verbal rehearsal speed (VRS), a form of covert speech used to maintain verbal information in working memory, and another verbal processing speed measure, perceptual encoding speed, are related to 3 domains of executive function (EF) at risk in cochlear implant (CI) users: verbal working memory, fluency-speed, and inhibition-concentration. Method EF, speech perception, and language outcome measures were obtained from 55 prelingually deaf, long-term CI users and matched controls with normal hearing (NH controls). Correlational analyses were used to assess relations between VRS (articulation rate), perceptual encoding speed (digit and color naming), and the outcomes in each sample. Results CI users displayed slower verbal processing speeds than NH controls. Verbal rehearsal speed was related to 2 EF domains in the NH sample but was unrelated to EF outcomes in CI users. Perceptual encoding speed was related to all EF domains in both groups. Conclusions Verbal rehearsal speed may be less influential for EF quality in CI users than for NH controls, whereas rapid automatized labeling skills and EF are closely related in both groups. CI users may develop processing strategies in EF tasks that differ from the covert speech strategies routinely employed by NH individuals. PMID:25320961

Inhibition of return in static but not necessarily in dynamic search.

PubMed

Wang, Zhiguo; Zhang, Kan; Klein, Raymond M

2010-01-01

If and when search involves the serial inspection of items by covert or overt attention, its efficiency would be enhanced by a mechanism that would discourage re-inspections of items or regions of the display that had already been examined. Klein (1988, 2000; Klein & Dukewich, 2006) proposed that inhibition of return (IOR) might be such a mechanism. The present experiments explored this proposal by combining a dynamic search task (Horowitz & Wolfe, 1998, 2003) with a probe-detection task. IOR was observed when search was most efficient (static and slower dynamic search). IOR was not observed when search performance was less efficient (fast dynamic search).These findings are consistent with the "foraging facilitator" proposal of IOR and are unpredicted by theories of search that assume parallel accumulation of information across the array (plus noise) as a general explanation for the effect of set size upon search performance.

A control-theory model for human decision-making

NASA Technical Reports Server (NTRS)

Levison, W. H.; Tanner, R. B.

1971-01-01

A model for human decision making is an adaptation of an optimal control model for pilot/vehicle systems. The models for decision and control both contain concepts of time delay, observation noise, optimal prediction, and optimal estimation. The decision making model was intended for situations in which the human bases his decision on his estimate of the state of a linear plant. Experiments are described for the following task situations: (a) single decision tasks, (b) two-decision tasks, and (c) simultaneous manual control and decision making. Using fixed values for model parameters, single-task and two-task decision performance can be predicted to within an accuracy of 10 percent. Agreement is less good for the simultaneous decision and control situation.

The covert channel over HTTP protocol

NASA Astrophysics Data System (ADS)

Graniszewski, Waldemar; Krupski, Jacek; Szczypiorski, Krzysztof

2016-09-01

The paper presents a new steganographic method - the covert channel is created over HTTP protocol header, i.e. trailer field. HTTP protocol is one of the most frequently used in the Internet. The popularity of the Web servers and network traffic from, and to them, is one of the requirements for undetectable message exchange. To study this kind of the information hiding technique an application in Javascript language based on the Node.js framework was written. The results of the experiment that was performed to send a message in the covert channel are also presented.

Social Alienation in Schizophrenia Patients: Association with Insula Responsiveness to Facial Expressions of Disgust

PubMed Central

Lindner, Christian; Dannlowski, Udo; Walhöfer, Kirsten; Rödiger, Maike; Maisch, Birgit; Bauer, Jochen; Ohrmann, Patricia; Lencer, Rebekka; Zwitserlood, Pienie; Kersting, Anette; Heindel, Walter; Arolt, Volker

2014-01-01

Introduction Among the functional neuroimaging studies on emotional face processing in schizophrenia, few have used paradigms with facial expressions of disgust. In this study, we investigated whether schizophrenia patients show less insula activation to macro-expressions (overt, clearly visible expressions) and micro-expressions (covert, very brief expressions) of disgust than healthy controls. Furthermore, departing from the assumption that disgust faces signal social rejection, we examined whether perceptual sensitivity to disgust is related to social alienation in patients and controls. We hypothesized that high insula responsiveness to facial disgust predicts social alienation. Methods We used functional magnetic resonance imaging to measure insula activation in 36 schizophrenia patients and 40 healthy controls. During scanning, subjects passively viewed covert and overt presentations of disgust and neutral faces. To measure social alienation, a social loneliness scale and an agreeableness scale were administered. Results Schizophrenia patients exhibited reduced insula activation in response to covert facial expressions of disgust. With respect to macro-expressions of disgust, no between-group differences emerged. In patients, insula responsiveness to covert faces of disgust was positively correlated with social loneliness. Furthermore, patients' insula responsiveness to covert and overt faces of disgust was negatively correlated with agreeableness. In controls, insula responsiveness to covert expressions of disgust correlated negatively with agreeableness. Discussion Schizophrenia patients show reduced insula responsiveness to micro-expressions but not macro-expressions of disgust compared to healthy controls. In patients, low agreeableness was associated with stronger insula response to micro- and macro-expressions of disgust. Patients with a strong tendency to feel uncomfortable with social interactions appear to be characterized by a high sensitivity for facial expression signaling social rejection. Given the associations of insula responsiveness to covert disgust expression with low agreeableness in healthy individuals, insula responsiveness to expressions of disgust might be in general a neural marker of the personality trait of agreeableness. PMID:24465469

Social alienation in schizophrenia patients: association with insula responsiveness to facial expressions of disgust.

PubMed

Lindner, Christian; Dannlowski, Udo; Walhöfer, Kirsten; Rödiger, Maike; Maisch, Birgit; Bauer, Jochen; Ohrmann, Patricia; Lencer, Rebekka; Zwitserlood, Pienie; Kersting, Anette; Heindel, Walter; Arolt, Volker; Kugel, Harald; Suslow, Thomas

2014-01-01

Among the functional neuroimaging studies on emotional face processing in schizophrenia, few have used paradigms with facial expressions of disgust. In this study, we investigated whether schizophrenia patients show less insula activation to macro-expressions (overt, clearly visible expressions) and micro-expressions (covert, very brief expressions) of disgust than healthy controls. Furthermore, departing from the assumption that disgust faces signal social rejection, we examined whether perceptual sensitivity to disgust is related to social alienation in patients and controls. We hypothesized that high insula responsiveness to facial disgust predicts social alienation. We used functional magnetic resonance imaging to measure insula activation in 36 schizophrenia patients and 40 healthy controls. During scanning, subjects passively viewed covert and overt presentations of disgust and neutral faces. To measure social alienation, a social loneliness scale and an agreeableness scale were administered. Schizophrenia patients exhibited reduced insula activation in response to covert facial expressions of disgust. With respect to macro-expressions of disgust, no between-group differences emerged. In patients, insula responsiveness to covert faces of disgust was positively correlated with social loneliness. Furthermore, patients' insula responsiveness to covert and overt faces of disgust was negatively correlated with agreeableness. In controls, insula responsiveness to covert expressions of disgust correlated negatively with agreeableness. Schizophrenia patients show reduced insula responsiveness to micro-expressions but not macro-expressions of disgust compared to healthy controls. In patients, low agreeableness was associated with stronger insula response to micro- and macro-expressions of disgust. Patients with a strong tendency to feel uncomfortable with social interactions appear to be characterized by a high sensitivity for facial expression signaling social rejection. Given the associations of insula responsiveness to covert disgust expression with low agreeableness in healthy individuals, insula responsiveness to expressions of disgust might be in general a neural marker of the personality trait of agreeableness.

Effects of covert and overt paradigms in clinical language fMRI.

PubMed

Partovi, Sasan; Konrad, Florian; Karimi, Sasan; Rengier, Fabian; Lyo, John K; Zipp, Lisa; Nennig, Ernst; Stippich, Christoph

2012-05-01

The aim of this study was to assess the intrasubject and intersubject reproducibility of functional magnetic resonance imaging (fMRI) language paradigms on language localization and lateralization. Fourteen healthy volunteers were enrolled prospectively and underwent language fMRI using visually triggered covert and overt sentence generation (SG) and word generation (WG) paradigms. Semiautomated analysis of all functional data was performed using Brain Voyager on an individual basis. Regions of interest for Broca's area, Wernicke's area, and their contralateral homologues were drawn. The Euclidean coordinates of the center of gravidity (x, y, and z) of the respective blood oxygenation level-dependent (BOLD) activation cluster, and the correlation of the measured hemodynamic response to the applied reference function (r), relative BOLD signal change as BOLD signal characteristics were measured in each region of interest. Regional lateralization indexes were calculated for Broca's area, Wernicke's area, and their contralateral homologues separately. Wilcoxon's signed-rank test was applied for statistical comparisons (P values < .05 were considered significant). Ten of the 14 volunteers had three repeated measurements to test intrasession reproducibility and intersession reproducibility. Overall activation rates for the four paradigms were 89% for covert SG, 82% for overt SG, 89% for covert WG, and 100% for overt WG. When comparing covert and overt paradigms, language localization was significantly different in 17% (Euclidean coordinates) and 19% (BOLD signal characteristics), respectively. Language lateralization was significantly different in 75%. Intrasubject and intersubject reproducibility was excellent, with 3.3% significant differences among all five parameters for language localization and 0% significant differences for language lateralization using covert paradigms. Covert language paradigms (SG and WG) provided highly robust and reproducible localization and lateralization of essential language centers for scans performed on the same and different days. Their overt counterparts achieved confirmatory localization but lower lateralization capabilities. Reference data for presurgical application are provided. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

Overt vs. covert speed cameras in combination with delayed vs. immediate feedback to the offender.

PubMed

Marciano, Hadas; Setter, Pe'erly; Norman, Joel

2015-06-01

Speeding is a major problem in road safety because it increases both the probability of accidents and the severity of injuries if an accident occurs. Speed cameras are one of the most common speed enforcement tools. Most of the speed cameras around the world are overt, but there is evidence that this can cause a "kangaroo effect" in driving patterns. One suggested alternative to prevent this kangaroo effect is the use of covert cameras. Another issue relevant to the effect of enforcement countermeasures on speeding is the timing of the fine. There is general agreement on the importance of the immediacy of the punishment, however, in the context of speed limit enforcement, implementing such immediate punishment is difficult. An immediate feedback that mediates the delay between the speed violation and getting a ticket is one possible solution. This study examines combinations of concealment and the timing of the fine in operating speed cameras in order to evaluate the most effective one in terms of enforcing speed limits. Using a driving simulator, the driving performance of the following four experimental groups was tested: (1) overt cameras with delayed feedback, (2) overt cameras with immediate feedback, (3) covert cameras with delayed feedback, and (4) covert cameras with immediate feedback. Each of the 58 participants drove in the same scenario on three different days. The results showed that both median speed and speed variance were higher with overt than with covert cameras. Moreover, implementing a covert camera system along with immediate feedback was more conducive to drivers maintaining steady speeds at the permitted levels from the very beginning. Finally, both 'overt cameras' groups exhibit a kangaroo effect throughout the entire experiment. It can be concluded that an implementation strategy consisting of covert speed cameras combined with immediate feedback to the offender is potentially an optimal way to motivate drivers to maintain speeds at the speed limit. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mental fatigue impairs soccer-specific decision-making skill.

PubMed

Smith, Mitchell R; Zeuwts, Linus; Lenoir, Matthieu; Hens, Nathalie; De Jong, Laura M S; Coutts, Aaron J

2016-07-01

This study aimed to investigate the impact of mental fatigue on soccer-specific decision-making. Twelve well-trained male soccer players performed a soccer-specific decision-making task on two occasions, separated by at least 72 h. The decision-making task was preceded in a randomised order by 30 min of the Stroop task (mental fatigue) or 30 min of reading from magazines (control). Subjective ratings of mental fatigue were measured before and after treatment, and mental effort (referring to treatment) and motivation (referring to the decision-making task) were measured after treatment. Performance on the soccer-specific decision-making task was assessed using response accuracy and time. Visual search behaviour was also assessed throughout the decision-making task. Subjective ratings of mental fatigue and effort were almost certainly higher following the Stroop task compared to the magazines. Motivation for the upcoming decision-making task was possibly higher following the Stroop task. Decision-making accuracy was very likely lower and response time likely higher in the mental fatigue condition. Mental fatigue had unclear effects on most visual search behaviour variables. The results suggest that mental fatigue impairs accuracy and speed of soccer-specific decision-making. These impairments are not likely related to changes in visual search behaviour.

Quantum-secure covert communication on bosonic channels.

PubMed

Bash, Boulat A; Gheorghe, Andrei H; Patel, Monika; Habif, Jonathan L; Goeckel, Dennis; Towsley, Don; Guha, Saikat

2015-10-19

Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth--that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and covertly communicated over the lossy thermal-noise bosonic channel (which models various practical communication channels). We show that whenever there is some channel noise that cannot in principle be controlled by an otherwise arbitrarily powerful adversary--for example, thermal noise from blackbody radiation--the number of reliably transmissible covert bits is at most proportional to the square root of the number of orthogonal modes (the time-bandwidth product) available in the transmission interval. We demonstrate this in a proof-of-principle experiment. Our result paves the way to realizing communications that are kept covert from an all-powerful quantum adversary.

Covert video monitoring in the assessment of medically unexplained symptoms in children.

PubMed

Wallace, Dustin P; Sim, Leslie A; Harrison, Tracy E; Bruce, Barbara K; Harbeck-Weber, Cynthia

2012-04-01

Diagnosis of medically unexplained symptoms (MUS) occurs after thorough evaluations have failed to identify a physiological cause for symptoms. However, families and providers may wonder if something has been missed, leading to reduced confidence in behavioral treatment. Confidence may be improved through the use of technology such as covert video monitoring to better assess functioning across settings. A 12-year-old male presented with progressive neurological decline, precipitated by chronic pain. After thorough evaluation and the failure of standard treatments (medical, rehabilitative, and psychological) covert video monitoring revealed that the patient demonstrated greater abilities when alone in his room. Negative reinforcement was used to initiate recovery, accompanied by positive reinforcement and a rehabilitative approach. Covert video monitoring assisted in three subsequent cases over the following 3 years. In certain complex cases, video monitoring can inform the assessment and treatment of MUS. Discussion includes ethical and practical considerations.

Gradient perception of children's productions of /s/ and /θ/: A comparative study of rating methods.

PubMed

Schellinger, Sarah K; Munson, Benjamin; Edwards, Jan

2017-01-01

Past studies have shown incontrovertible evidence for the existence of covert contrasts in children's speech, i.e. differences between target productions that are nonetheless transcribed with the same phonetic symbol. Moreover, there is evidence that these are relevant to forming prognoses and tracking progress in children with speech sound disorder. A challenge remains to determine the most efficient and reliable methods for assessing covert contrasts. This study investigates how readily listeners can identify covert contrasts in children's speech when using a continuous rating scale in the form of a visual analogue scale (VAS) to denote children's productions. Individual listeners' VAS responses were found to correlate statistically significantly with a variety of continuous measures of children's production accuracy, including judgements of binary accuracy pooled over a large set of listeners. These findings reinforce the growing body of evidence that VAS judgements are potentially useful clinical measures of covert contrast.

More to ADHD than meets the eye: observable abnormalities in search behaviour do not account for performance deficits on a discrimination task.

PubMed

Sonuga-Barke, Edmund J S; Elgie, Sarah; Hall, Martin

2005-07-20

Children with Attention Deficit/Hyperactivity Disorder (ADHD) often perform poorly on tasks requiring sustained and systematic attention to stimuli for extended periods of time. The current paper tested the hypothesis that such deficits are the result of observable abnormalities in search behaviour (e.g., attention-onset, -duration and -sequencing), and therefore can be explained without reference to deficits in non-observable (i.e., cognitive) processes. Forty boys (20 ADHD and 20 controls) performed a computer-based complex discrimination task adapted from the Matching Familiar Figures Task with four different fixed search interval lengths (5-, 10-, 15- and 20-s). Children with ADHD identified fewer targets than controls (p < 0.001), initiated searches later, spent less time attending to stimuli, and searched in a less intensive and less systematic way (p's < 0.05). There were significant univariate associations between ADHD, task performance and search behaviour. However, there was no support for the hypothesis that abnormalities in search carried the effect of ADHD on performance. The pattern of results in fact suggested that abnormal attending during testing is a statistical marker, rather than a mediator, of ADHD performance deficits. The results confirm the importance of examining covert processes, as well as behavioural abnormalities when trying to understand the psychopathophyiology of ADHD.

Staring reality in the face: A comparison of social attention across laboratory and real world measures suggests little common ground.

PubMed

Hayward, Dana A; Voorhies, Willa; Morris, Jenna L; Capozzi, Francesca; Ristic, Jelena

2017-09-01

The ability to attend to someone else's gaze is thought to represent one of the essential building blocks of the human sociocognitive system. This behavior, termed social attention, has traditionally been assessed using laboratory procedures in which participants' response time and/or accuracy performance indexes attentional function. Recently, a parallel body of emerging research has started to examine social attention during real life social interactions using naturalistic and observational methodologies. The main goal of the present work was to begin connecting these two lines of inquiry. To do so, here we operationalized, indexed, and measured the engagement and shifting components of social attention using covert and overt measures. These measures were obtained during an unconstrained real-world social interaction and during a typical laboratory social cuing task. Our results indicated reliable and overall similar indices of social attention engagement and shifting within each task. However, these measures did not relate across the two tasks. We discuss these results as potentially reflecting the differences in social attention mechanisms, the specificity of the cuing task's measurement, as well as possible general dissimilarities with respect to context, task goals, and/or social presence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

26. Photocopy of photograph (from V. Covert Martin Collection, c. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Photocopy of photograph (from V. Covert Martin Collection, c. 1925) EXTERIOR, GENERAL VIEW OF MISSION AND CONVENTO AFTER COMPLETED RESTORATION, C. 1925 - Mission San Francisco Solano de Sonoma, First & Spain Streets, Sonoma, Sonoma County, CA

Electronic tracking for people with dementia: an exploratory study of the ethical issues experienced by carers in making decisions about usage.

PubMed

White, Eleanor Bantry; Montgomery, Paul

2014-03-01

Electronic tracking through GPS (global positioning system) is being used to monitor and locate people with dementia who are vulnerable to becoming lost. Through a review of the literature and an original study, this article examined ethical issues associated with use in a domestic setting. The qualitative study consisted of in-depth interviews with 10 carers who were using electronic tracking. The study explored the values, beliefs and contextual factors that motivated carers to use electronic tracking. It examined the extent of involvement of the person with dementia in decision-making and it explored the various ethical dilemmas encountered by carers when introducing the tracking system. As an issue that emerged from the interviews, specific attention was paid to exploring covert usage. From the study findings, recommendations have been made for research and practice about the use of electronic tracking in dementia care.

Punctuation and Implicit Prosody in Silent Reading: An ERP Study Investigating English Garden-Path Sentences

PubMed Central

Drury, John E.; Baum, Shari R.; Valeriote, Hope; Steinhauer, Karsten

2016-01-01

This study presents the first two ERP reading studies of comma-induced effects of covert (implicit) prosody on syntactic parsing decisions in English. The first experiment used a balanced 2 × 2 design in which the presence/absence of commas determined plausibility (e.g., John, said Mary, was the nicest boy at the party vs. John said Mary was the nicest boy at the party). The second reading experiment replicated a previous auditory study investigating the role of overt prosodic boundaries in closure ambiguities (Pauker et al., 2011). In both experiments, commas reliably elicited CPS components and generally played a dominant role in determining parsing decisions in the face of input ambiguity. The combined set of findings provides further evidence supporting the claim that mechanisms subserving speech processing play an active role during silent reading. PMID:27695428

The Dynamical Balance of the Brain at Rest

PubMed Central

Deco, Gustavo; Corbetta, Maurizio

2014-01-01

We review evidence that spontaneous, i.e. not stimulus- or task-driven, activity in the brain is not noise, but orderly organized at the level of large scale systems in a series of functional networks that maintain at all times a high level of coherence. These networks of spontaneous activity correlation or resting state networks (RSN) are closely related to the underlying anatomical connectivity, but their topography is also gated by the history of prior task activation. Network coherence does not depend on covert cognitive activity, but its strength and integrity relates to behavioral performance. Some RSN are functionally organized as dynamically competing systems both at rest and during tasks. Computational studies show that one of such dynamics, the anti-correlation between networks, depends on noise driven transitions between different multi-stable cluster synchronization states. These multi-stable states emerge because of transmission delays between regions that are modeled as coupled oscillators systems. Large-scale systems dynamics are useful for keeping different functional sub-networks in a state of heightened competition, which can be stabilized and fired by even small modulations of either sensory or internal signals. PMID:21196530

Impaired decision-making under risk in individuals with alcohol dependence

PubMed Central

Brevers, Damien; Bechara, Antoine; Cleeremans, Axel; Kornreich, Charles; Verbanck, Paul; Noël, Xavier

2014-01-01

Background Alcohol dependence is associated with poor decision-making under ambiguity, that is, when decisions are to be made in the absence of known probabilities of reward and loss. However, little is known regarding decisions made by individuals with alcohol dependence in the context of known probabilities (decision under risk). In this study, we investigated the relative contribution of these distinct aspects of decision making to alcohol dependence. Methods Thirty recently detoxified and sober asymptomatic alcohol-dependent individuals, and thirty healthy control participants were tested for decision-making under ambiguity (using the Iowa Gambling Task), and decision-making under-risk (using the Cups Task and Coin Flipping Task). We also tested their capacities for working memory storage (Digit-span Forward), and dual-tasking (Operation-span Task). Results Compared to healthy control participants, alcohol-dependent individuals made disadvantageous decisions on the Iowa Gambling Task, reflecting poor decisions under ambiguity. They also made more risky choices on the Cups and Coin Flipping Tasks reflecting poor decision-making under risk. In addition, alcohol-dependent participants showed some working memory impairments, as measured by the dual tasking, and the degree of this impairment correlated with high-risk decision-making, thus suggesting a relationship between processes sub-serving working memory and risky decisions. Conclusion These results suggest that alcohol dependent individuals are impaired in their ability to decide optimally in multiple facets of uncertainty (i.e., both risk and ambiguity), and that at least some aspects of these deficits are linked to poor working memory processes. PMID:24948198

Heuristics in Managing Complex Clinical Decision Tasks in Experts’ Decision Making

PubMed Central

Islam, Roosan; Weir, Charlene; Del Fiol, Guilherme

2016-01-01

Background Clinical decision support is a tool to help experts make optimal and efficient decisions. However, little is known about the high level of abstractions in the thinking process for the experts. Objective The objective of the study is to understand how clinicians manage complexity while dealing with complex clinical decision tasks. Method After approval from the Institutional Review Board (IRB), three clinical experts were interviewed the transcripts from these interviews were analyzed. Results We found five broad categories of strategies by experts for managing complex clinical decision tasks: decision conflict, mental projection, decision trade-offs, managing uncertainty and generating rule of thumb. Conclusion Complexity is created by decision conflicts, mental projection, limited options and treatment uncertainty. Experts cope with complexity in a variety of ways, including using efficient and fast decision strategies to simplify complex decision tasks, mentally simulating outcomes and focusing on only the most relevant information. Application Understanding complex decision making processes can help design allocation based on the complexity of task for clinical decision support design. PMID:27275019

Heuristics in Managing Complex Clinical Decision Tasks in Experts' Decision Making.

PubMed

Islam, Roosan; Weir, Charlene; Del Fiol, Guilherme

2014-09-01

Clinical decision support is a tool to help experts make optimal and efficient decisions. However, little is known about the high level of abstractions in the thinking process for the experts. The objective of the study is to understand how clinicians manage complexity while dealing with complex clinical decision tasks. After approval from the Institutional Review Board (IRB), three clinical experts were interviewed the transcripts from these interviews were analyzed. We found five broad categories of strategies by experts for managing complex clinical decision tasks: decision conflict, mental projection, decision trade-offs, managing uncertainty and generating rule of thumb. Complexity is created by decision conflicts, mental projection, limited options and treatment uncertainty. Experts cope with complexity in a variety of ways, including using efficient and fast decision strategies to simplify complex decision tasks, mentally simulating outcomes and focusing on only the most relevant information. Understanding complex decision making processes can help design allocation based on the complexity of task for clinical decision support design.

8. SIDE VIEW OF NORTHEASTERN ROCKFACED DRESSED AND MORTARED STONE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. SIDE VIEW OF NORTHEASTERN ROCKFACED DRESSED AND MORTARED STONE BRIDGE ABUTMENT (LEFT) AND DRESSED, DRY-LAID RETAINING WALL (RIGHT). FACING WEST. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

9. VIEW OF SOUTHERN ROCKFACED DRESSED AND MORTARED STONE ABUTMENT, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. VIEW OF SOUTHERN ROCKFACED DRESSED AND MORTARED STONE ABUTMENT, SHOWING STEEL CROSSBEAMS, TORSIONAL DIAGONAL STRUTS, AND WOODEN STRINGERS. FACING SOUTHWEST. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

10. SIDE VIEW OF SOUTHEASTERN ROCKFACED DRESSED AND MORTARED STONE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. SIDE VIEW OF SOUTHEASTERN ROCKFACED DRESSED AND MORTARED STONE BRIDGE ABUTMENT (RIGHT) AND DRESSED, DRY-LAID RETAINING WALL (LEFT). FACING NORTHWEST. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

Transferring cognitive tasks between brain imaging modalities: implications for task design and results interpretation in FMRI studies.

PubMed

Warbrick, Tracy; Reske, Martina; Shah, N Jon

2014-09-22

As cognitive neuroscience methods develop, established experimental tasks are used with emerging brain imaging modalities. Here transferring a paradigm (the visual oddball task) with a long history of behavioral and electroencephalography (EEG) experiments to a functional magnetic resonance imaging (fMRI) experiment is considered. The aims of this paper are to briefly describe fMRI and when its use is appropriate in cognitive neuroscience; illustrate how task design can influence the results of an fMRI experiment, particularly when that task is borrowed from another imaging modality; explain the practical aspects of performing an fMRI experiment. It is demonstrated that manipulating the task demands in the visual oddball task results in different patterns of blood oxygen level dependent (BOLD) activation. The nature of the fMRI BOLD measure means that many brain regions are found to be active in a particular task. Determining the functions of these areas of activation is very much dependent on task design and analysis. The complex nature of many fMRI tasks means that the details of the task and its requirements need careful consideration when interpreting data. The data show that this is particularly important in those tasks relying on a motor response as well as cognitive elements and that covert and overt responses should be considered where possible. Furthermore, the data show that transferring an EEG paradigm to an fMRI experiment needs careful consideration and it cannot be assumed that the same paradigm will work equally well across imaging modalities. It is therefore recommended that the design of an fMRI study is pilot tested behaviorally to establish the effects of interest and then pilot tested in the fMRI environment to ensure appropriate design, implementation and analysis for the effects of interest.

Working-Memory Load and Temporal Myopia in Dynamic Decision Making

ERIC Educational Resources Information Center

Worthy, Darrell A.; Otto, A. Ross; Maddox, W. Todd

2012-01-01

We examined the role of working memory (WM) in dynamic decision making by having participants perform decision-making tasks under single-task or dual-task conditions. In 2 experiments participants performed dynamic decision-making tasks in which they chose 1 of 2 options on each trial. The decreasing option always gave a larger immediate reward…

Effects of Practice on Task Architecture: Combined Evidence from Interference Experiments and Random-Walk Models of Decision Making

ERIC Educational Resources Information Center

Kamienkowski, Juan E.; Pashler, Harold; Dehaene, Stanislas; Sigman, Mariano

2011-01-01

Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay…

Developmental trajectories of physical aggression: prediction of overt and covert antisocial behaviors from self- and mothers' reports

PubMed Central

Di Giunta, Laura; Pastorelli, Concetta; Eisenberg, Nancy; Gerbino, Maria; Castellani, Valeria; Bombi, Anna Silvia

2010-01-01

Physical aggression declines for the majority of children from preschool to elementary school. Although this desistance generally continues during adolescence and early adulthood, a small group of children maintain a high level of physical aggression over time and develop other serious overt and covert antisocial behaviors. Typically, researchers have examined relations of developmental changes in physical aggression to later violence with teachers' or mothers' reports on surveys. Little is known about the degree to which children's self-reported physical aggression predicts later antisocial behavior. The longitudinal study in this article had a staggered, multiple cohort design. Measures of physical aggression were collected through self- and mother reports from age 11–14 years, which were used to construct trajectory groups (attrition was 6 and 14% from age 11–14, respectively, for self- and mother reports). Overt and covert antisocial behaviors were self-reported at age 18–19 years (attrition was 36% from age 11 to 18–19). Four trajectory groups (low stable, 11%; moderate-low declining, 34%; moderate declining, 39%; high stable, 16%) were identified from self-reports, whereas three trajectories (low declining, 33%; moderate declining, 49%; high stable, 18%) were identified from mothers' ratings. We examined the prediction of overt and covert antisocial behaviors in early adulthood from the high stable and the moderate declining trajectories. According to both informants, higher probability of belonging to the high stable group was associated with higher overt and covert antisocial behavior, whereas higher probability of belonging to the moderate declining group was associated with higher covert antisocial behavior. Our results support the value of children's as well as mothers' reports of children's aggression for predicting different types of serious antisocial behavior in adulthood. PMID:20878197

Developmental trajectories of physical aggression: prediction of overt and covert antisocial behaviors from self- and mothers' reports.

PubMed

Di Giunta, Laura; Pastorelli, Concetta; Eisenberg, Nancy; Gerbino, Maria; Castellani, Valeria; Bombi, Anna Silvia

2010-12-01

Physical aggression declines for the majority of children from preschool to elementary school. Although this desistance generally continues during adolescence and early adulthood, a small group of children maintain a high level of physical aggression over time and develop other serious overt and covert antisocial behaviors. Typically, researchers have examined relations of developmental changes in physical aggression to later violence with teachers' or mothers' reports on surveys. Little is known about the degree to which children's self-reported physical aggression predicts later antisocial behavior. The longitudinal study in this article had a staggered, multiple cohort design. Measures of physical aggression were collected through self- and mother reports from age 11-14 years, which were used to construct trajectory groups (attrition was 6 and 14% from age 11-14, respectively, for self- and mother reports). Overt and covert antisocial behaviors were self-reported at age 18-19 years (attrition was 36% from age 11 to 18-19). Four trajectory groups (low stable, 11%; moderate-low declining, 34%; moderate declining, 39%; high stable, 16%) were identified from self-reports, whereas three trajectories (low declining, 33%; moderate declining, 49%; high stable, 18%) were identified from mothers' ratings. We examined the prediction of overt and covert antisocial behaviors in early adulthood from the high stable and the moderate declining trajectories. According to both informants, higher probability of belonging to the high stable group was associated with higher overt and covert antisocial behavior, whereas higher probability of belonging to the moderate declining group was associated with higher covert antisocial behavior. Our results support the value of children's as well as mothers' reports of children's aggression for predicting different types of serious antisocial behavior in adulthood.

A Novel Saccadic Strategy Revealed by Suppression Head Impulse Testing of Patients with Bilateral Vestibular Loss.

PubMed

de Waele, Catherine; Shen, Qiwen; Magnani, Christophe; Curthoys, Ian S

2017-01-01

We examined the eye movement response patterns of a group of patients with bilateral vestibular loss (BVL) during suppression head impulse testing. Some showed a new saccadic strategy that may have potential for explaining how patients use saccades to recover from vestibular loss. Eight patients with severe BVL [vestibulo-ocular reflex (VOR) gains less than 0.35 and absent otolithic function] were tested. All patients were given the Dizziness Handicap Inventory and questioned about oscillopsia during abrupt head movements. Two paradigms of video head impulse testing of the horizontal VOR were used: (1) the classical head impulse paradigm [called head impulse test (HIMPs)]-fixating an earth-fixed target during the head impulse and (2) the new complementary test paradigm-fixating a head-fixed target during the head impulse (called SHIMPs). The VOR gain of HIMPs was quantified by two algorithms. During SHIMPs testing, some BVL patients consistently generated an inappropriate covert compensatory saccade during the head impulse that required a corresponding large anti-compensatory saccade at the end of the head impulse in order to obey the instructions to maintain gaze on the head-fixed target. By contrast, other BVL patients did not generate this inappropriate covert saccade and did not exhibit a corresponding anti-compensatory saccade. The latencies of the covert saccade in SHIMPs and HIMPs were similar. The pattern of covert saccades during SHIMPs appears to be related to the reduction of oscillopsia during abrupt head movements. BVL patients who did not report oscillopsia showed this unusual saccadic pattern, whereas BVL patients who reported oscillopsia did not show this pattern. This inappropriate covert SHIMPs saccade may be an objective indicator of how some patients with vestibular loss have learned to trigger covert saccades during head movements in everyday life.

Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

PubMed

Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

2014-05-01

Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

Affective and cognitive decision-making in adolescents.

PubMed

van Duijvenvoorde, Anna C K; Jansen, Brenda R J; Visser, Ingmar; Huizenga, Hilde M

2010-01-01

Adolescents demonstrate impaired decision-making in emotionally arousing situations, yet they appear to exhibit relatively mature decision-making skills in predominantly cognitive, low-arousal situations. In this study we compared adolescents' (13-15 years) performance on matched affective and cognitive decision-making tasks, in order to determine (1) their performance level on each task and (2) whether performance on the cognitive task was associated with performance on the affective task. Both tasks required a comparison of choice dimensions characterized by frequency of loss, amount of loss, and constant gain. Results indicated that in the affective task, adolescents performed sub-optimally by considering only the frequency of loss, whereas in the cognitive task adolescents used relatively mature decision rules by considering two or all three choice dimensions. Performance on the affective task was not related to performance on the cognitive task. These results are discussed in light of neural developmental trajectories observed in adolescence.

The costs and benefits of temporal predictability: impaired inhibition of prepotent responses accompanies increased activation of task-relevant responses.

PubMed

Korolczuk, Inga; Burle, Boris; Coull, Jennifer T

2018-06-20

While the benefit of temporal predictability on sensorimotor processing is well established, it is still unknown whether this is due to efficient execution of an appropriate response and/or inhibition of an inappropriate one. To answer this question, we examined the effects of temporal predictability in tasks that required selective (Simon task) or global (Stop-signal task) inhibitory control of prepotent responses. We manipulated temporal expectation by presenting cues that either predicted (temporal cues) or not (neutral cues) when the target would appear. In the Simon task, performance was better when target location (left/right) was compatible with the hand of response and performance was improved further still if targets were temporally cued. However, Conditional Accuracy Functions revealed that temporal predictability selectively increased the number of fast, impulsive errors. Temporal cueing had no effect on selective response inhibition, as measured by the dynamics of the interference effect (delta plots) in the Simon task. By contrast, in the Stop-signal task, Stop-signal reaction time, a covert measure of a more global form of response inhibition, was significantly longer in temporally predictive trials. Therefore, when the time of target onset could be predicted in advance, it was harder to stop the impulse to respond to the target. Collectively, our results indicate that temporal cueing compounded the interfering effects of a prepotent response on task performance. We suggest that although temporal predictability enhances activation of task-relevant responses, it impairs inhibition of prepotent responses. Copyright © 2018 Elsevier B.V. All rights reserved.

Secret Intelligence and Covert Action: Consensus in an Open Society

DTIC Science & Technology

1993-03-19

Drexel Godfrey characterizes clandestine human collection in terms of the moral damage to its participants, describing the process of developing a...both moral damage to the participants and limited effectiveness of the results, Drexel Godfrey argued in 1978 that political operations (covert action

College Adjustment Difficulties and the Overt and Covert Forms of Narcissism

ERIC Educational Resources Information Center

Weikel, Kim A.; Avara, Renee Mowery; Hanson, Chad A.; Kater, Hope

2010-01-01

Overt narcissism correlated negatively with emotional distress and interpersonal difficulties among female, but not male, students. After controlling for self-esteem, overt narcissism correlated positively with depression among female students and with emotional distress and interpersonal difficulties among male students. Covert narcissism…

Relaxation Training and Covert Positive Reinforcement with Elementary School Children.

ERIC Educational Resources Information Center

Vacc, Nicholas A.; Greenleaf, Susan M.

1980-01-01

Variations of systematic desensitization that include deep muscle relaxation (DMR) seem useful in remediating some behavior problems of children. Studied the effects of DMR and DMR with Covert Positive Reinforcement (CPR) in reducing maladaptive behavior of children, ages 6 to 12. (Author)

Covert Conditioning: Case Studies in Self-Management.

ERIC Educational Resources Information Center

Yager, Geoffrey G.

The self-management of thoughts and mental images was used in a series of empirical case studies to influence behavior changes. The target behaviors in the cases reported were smoking, overeating, fingernail biting, thinking self-depreciative thoughts, and responding assertively. Self-monitoring, covert positive reinforcement, covert…

Ethical use of covert videoing techniques in detecting Munchausen syndrome by proxy.

PubMed Central

Foreman, D M; Farsides, C

1993-01-01

Munchausen syndrome by proxy is an especially malignant form of child abuse in which the carer (usually the mother) fabricates or exacerbates illness in the child to obtain medical attention. It can result in serious illness and even death of the child and it is difficult to detect. Some investigators have used video to monitor the carer's interaction with the child without obtaining consent--covert videoing. The technique presents several ethical problems, including exposure of the child to further abuse and a breach of trust between carer, child, and the professionals. Although covert videoing can be justified in restricted circumstances, new abuse procedures under the Children Act now seem to make its use unethical in most cases. Sufficient evidence should mostly be obtained from separation of the child and carer or videoing with consent to enable action to be taken to protect the child under an assessment order. If the new statutory instruments prove ineffective in Munchausen syndrome by proxy covert videoing may need to be re-evaluated. PMID:8401021

Serial, Covert, Shifts of Attention during Visual Search are Reflected by the Frontal Eye Fields and Correlated with Population Oscillations

PubMed Central

Buschman, Timothy J.; Miller, Earl K.

2009-01-01

Attention regulates the flood of sensory information into a manageable stream, and so understanding how attention is controlled is central to understanding cognition. Competing theories suggest visual search involves serial and/or parallel allocation of attention, but there is little direct, neural, evidence for either mechanism. Two monkeys were trained to covertly search an array for a target stimulus under visual search (endogenous) and pop-out (exogenous) conditions. Here we present neural evidence in the frontal eye fields (FEF) for serial, covert shifts of attention during search but not pop-out. Furthermore, attention shifts reflected in FEF spiking activity were correlated with 18–34 Hz oscillations in the local field potential, suggesting a ‘clocking’ signal. This provides direct neural evidence that primates can spontaneously adopt a serial search strategy and that these serial covert shifts of attention are directed by the FEF. It also suggests that neuron population oscillations may regulate the timing of cognitive processing. PMID:19679077

Lateralized responses during covert attention are modulated by target eccentricity.

PubMed

Bahramisharif, Ali; Heskes, Tom; Jensen, Ole; van Gerven, Marcel A J

2011-03-10

Various studies have demonstrated that covert attention to different locations in the visual field can be used as a control signal for brain computer interfacing. It is well known that when covert attention is directed to the left visual hemifield, posterior alpha activity decreases in the right hemisphere while simultaneously increasing in the left hemisphere and vice versa. However, it remains unknown if and how the classical lateralization pattern depends on the eccentricity of the locations to which one attends. In this paper we study the effect of target eccentricity on the performance of a brain computer interface system that is driven by covert attention. Results show that the lateralization pattern becomes more pronounced as target eccentricity increases and suggest that in the current design the minimum eccentricity for having an acceptable classification performance for two targets at equal distance from fixation in opposite hemifields is about 6° of visual angle. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Marital Conflict in the Context of Parental Depressive Symptoms: Implications for the Development of Children’s Adjustment Problems

PubMed Central

Keller, Peggy S.; Cummings, E. Mark; Peterson, Kristina M.; Davies, Patrick T.

2008-01-01

Relations among parental depressive symptoms, overt and covert marital conflict, and child internalizing and externalizing symptoms were examined in a community sample of 235 couples and their children. Families were assessed once yearly for three years, starting when children were in kindergarten. Parents completed measures of depressive symptoms and children’s internalizing and externalizing symptoms. Behavioral observations of marital conflict behaviors (insult, threat, pursuit, and defensiveness) and self-report of covert negativity (feeling worry, sorry, worthless, and helpless) were assessed based on problem solving interactions. Results indicated that fathers’ greater covert negativity and mothers’ overt destructive conflict behaviors served as intervening variables in the link between fathers’ depressive symptoms and child internalizing symptoms, with modest support for the pathway through fathers’ covert negativity found even after controlling for earlier levels of constructs. These findings support the role of marital conflict in the impact of fathers’ depressive symptoms on child internalizing symptoms. PMID:20161202

The effect of vestibulo-ocular reflex deficits and covert saccades on dynamic vision in opioid-induced vestibular dysfunction.

PubMed

Ramaioli, Cecilia; Colagiorgio, Paolo; Sağlam, Murat; Heuser, Fabian; Schneider, Erich; Ramat, Stefano; Lehnen, Nadine

2014-01-01

Patients with bilateral vestibular dysfunction cannot fully compensate passive head rotations with eye movements, and experience disturbing oscillopsia. To compensate for the deficient vestibulo-ocular reflex (VOR), they have to rely on re-fixation saccades. Some can trigger "covert" saccades while the head still moves; others only initiate saccades afterwards. Due to their shorter latency, it has been hypothesized that covert saccades are particularly beneficial to improve dynamic visual acuity, reducing oscillopsia. Here, we investigate the combined effect of covert saccades and the VOR on clear vision, using the Head Impulse Testing Device-Functional Test (HITD-FT), which quantifies reading ability during passive high-acceleration head movements. To reversibly decrease VOR function, fourteen healthy men (median age 26 years, range 21-31) were continuously administrated the opioid remifentanil intravenously (0.15 µg/kg/min). VOR gain was assessed with the video head-impulse test, functional performance (i.e. reading) with the HITD-FT. Before opioid application, VOR and dynamic reading were intact (head-impulse gain: 0.87±0.08, mean±SD; HITD-FT rate of correct answers: 90±9%). Remifentanil induced impairment in dynamic reading (HITD-FT 26±15%) in 12/14 subjects, with transient bilateral vestibular dysfunction (head-impulse gain 0.63±0.19). HITD-FT score correlated with head-impulse gain (R = 0.63, p = 0.03) and with gain difference (before/with remifentanil, R = -0.64, p = 0.02). One subject had a non-pathological head-impulse gain (0.82±0.03) and a high HITD-FT score (92%). One subject triggered covert saccades in 60% of the head movements and could read during passive head movements (HITD-FT 93%) despite a pathological head-impulse gain (0.59±0.03) whereas none of the 12 subjects without covert saccades reached such high performance. In summary, early catch-up saccades may improve dynamic visual function. HITD-FT is an appropriate method to assess the combined gaze stabilization effect of both VOR and covert saccades (overall dynamic vision), e.g., to document performance and progress during vestibular rehabilitation.

Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

PubMed Central

Gathmann, Bettina; Schiebener, Johannes; Wolf, Oliver T.; Brand, Matthias

2015-01-01

Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring—an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task). This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST) and the newly developed Balanced Switching Task (BST), measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task. PMID:25741308

Neuroscientific Measures of Covert Behavior

ERIC Educational Resources Information Center

Ortu, Daniele

2012-01-01

In radical behaviorism, the difference between overt and covert responses does not depend on properties of the behavior but on the sensitivity of the measurement tools employed by the experimenter. Current neuroscientific research utilizes technologies that allow measurement of variables that are undetected by the tools typically used by behavior…

Covert Censorship in Libraries: A Discussion Paper

ERIC Educational Resources Information Center

Moody, Kim

2005-01-01

Librarians, through their professional associations, have long been committed to the social justice principle embedded in the concept of "free access to information". External censorship challenges to library collections threaten this principle overtly. However, censorship can also occur in libraries in various covert and often unconscious ways.…

5. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL CUT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL CUT AND MORTARED STONE PIER AND ASSOCIATED STEEL SUPERSTRUCTURE (CENTER), AND CANTILEVERED NORTHERN TRUSS SECTION (RIGHT). FACING NORTHWEST. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

Antenna array geometry optimization for a passive coherent localisation system

NASA Astrophysics Data System (ADS)

Knott, Peter; Kuschel, Heiner; O'Hagan, Daniel

2012-11-01

Passive Coherent Localisation (PCL), also known as Passive Radar, making use of RF sources of opportunity such as Radio or TV Broadcasting Stations, Cellular Phone Network Base Stations, etc. is an advancing technology for covert operation because no active radar transmitter is required. It is also an attractive addition to existing active radar stations because it has the potential to discover low-flying and low-observable targets. The CORA (Covert Radar) experimental passive radar system currently developed at Fraunhofer-FHR features a multi-channel digital radar receiver and a circular antenna array with separate elements for the VHF- and the UHF-range and is used to exploit alternatively Digital Audio (DAB) or Video Broadcasting (DVB-T) signals. For an extension of the system, a wideband antenna array is being designed for which a new discone antenna element has been developed covering the full DVB-T frequency range. The present paper describes the outline of the system and the numerical modelling and optimisation methods applied to solve the complex task of antenna array design: Electromagnetic full wave analysis is required for the parametric design of the antenna elements while combinatorial optimization methods are applied to find the best array positions and excitation coefficients for a regular omni-directional antenna performance. The different steps are combined in an iterative loop until the optimum array layout is found. Simulation and experimental results for the current system will be shown.

Aiming routines and their electrocortical concomitants among competitive rifle shooters.

PubMed

Konttinen, N; Landers, D M; Lyytinen, H

2000-06-01

The present study focused on an examination of competitive shooters' aiming process during a rifle shooting task. The barrel movements of the rifle, as detected by a laser system during the last 1000-ms time period preceding the triggering, were recorded from six elite and six pre-elite shooters. Electrocortical slow potentials (SPs) from frontal (Fz), centro-lateral (C3, C4), and occipital (Oz) brain areas were recorded to get an additional insight into the underlying covert processing. The results suggested that the elite shooters did not pull the trigger until they reached a sustained rifle position. In the pre-elite shooters the rifle appeared to be in a less stable position, and their strategy was to take advantage of the first appropriate moment of steadiness without a sustained rifle position so they could pull the trigger. The observed pre-trigger readiness potential (RP) shifts at Fz and Oz were more positive among the elite shooters relative to the pre-elite shooters, reflecting their more pronounced covert effort, rather than increasing preparedness for the trigger pull. The present study lends support for the view that a successful aiming strategy is mainly based on sustained rifle balancing. With regards to the brain slow potentials, it can be concluded that the RP shift does not specifically reflect the preparation for the trigger pull.

The eccentricity effect: target eccentricity affects performance on conjunction searches.

PubMed

Carrasco, M; Evert, D L; Chang, I; Katz, S M

1995-11-01

The serial pattern found for conjunction visual-search tasks has been attributed to covert attentional shifts, even though the possible contributions of target location have not been considered. To investigate the effect of target location on orientation x color conjunction searches, the target's duration and its position in the display were manipulated. The display was present either until observers responded (Experiment 1), for 104 msec (Experiment 2), or for 62 msec (Experiment 3). Target eccentricity critically affected performance: A pronounced eccentricity effect was very similar for all three experiments; as eccentricity increased, reaction times and errors increased gradually. Furthermore, the set-size effect became more pronounced as target eccentricity increased, and the extent of the eccentricity effect increased for larger set sizes. In addition, according to stepwise regressions, target eccentricity as well as its interaction with set size were good predictors of performance. We suggest that these findings could be explained by spatial-resolution and lateral-inhibition factors. The serial self-terminating hypothesis for orientation x color conjunction searches was evaluated and rejected. We compared the eccentricity effect as well as the extent of the orientation asymmetry in these three conjunction experiments with those found in feature experiments (Carrasco & Katz, 1992). The roles of eye movements, spatial resolution, and covert attention in the eccentricity effect, as well as their implications, are discussed.

What is a missing link among wireless persistent surveillance?

NASA Astrophysics Data System (ADS)

Hsu, Charles; Szu, Harold

2011-06-01

The next generation surveillance system will equip with versatile sensor devices and information focus capable of conducting regular and irregular surveillance and security environments worldwide. The community of the persistent surveillance must invest the limited energy and money effectively into researching enabling technologies such as nanotechnology, wireless networks, and micro-electromechanical systems (MEMS) to develop persistent surveillance applications for the future. Wireless sensor networks can be used by the military for a number of purposes such as monitoring militant activity in remote areas and force protection. Being equipped with appropriate sensors these networks can enable detection of enemy movement, identification of enemy force and analysis of their movement and progress. Among these sensor network technologies, covert communication is one of the challenging tasks in the persistent surveillance because it is highly demanded to provide secured sensor nodes and linkage for fear of deliberate sabotage. Due to the matured VLSI/DSP technologies, affordable COTS of UWB technology with noise-like direct sequence (DS) time-domain pulses is a potential solution to support low probability of intercept and low probability of detection (LPI/LPD) data communication and transmission. This paper will describe a number of technical challenges in wireless persistent surveillance development include covert communication, network control and routing, collaborating signal and information processing, and etc. The paper concludes by presenting Hermitian Wavelets to enhance SNR in support of secured communication.

Are Narcissists More Likely to Be Involved in Cyberbullying? Examining the Mediating Role of Self-Esteem.

PubMed

Fan, Cui-Ying; Chu, Xiao-Wei; Zhang, Meng; Zhou, Zong-Kui

2016-08-01

Although cyberbullying, a new type of aggressive behavior via electronic means, has been found to be strongly linked with individuals' personality characteristics, few studies to date have investigated its relationship with narcissism, especially overt and covert narcissism. The current study tested the associations between overt and covert narcissism on one hand and cyberbullying perpetration and victimization on the other. To explain these differences further, self-esteem was tested as a mediator through which the two types of narcissism may exert their influences on cyberbullying. An anonymous questionnaire was completed by 814 Chinese adolescents aged 11 to 18. Results of multiple regression analyses indicated that after controlling for gender and student status (middle or high school students), covert narcissism positively predicted both cyberbullying perpetration and victimization, whereas overt narcissism had no association with either perpetration or victimization. Furthermore, when gender and student status were controlled, self-esteem mediated the relationships between overt/covert narcissism and cyberbullying perpetration and victimization, highlighting the possibility that self-esteem is an explanatory mechanism for the associations between the two types of narcissism and cyberbullying. These findings suggest that interventions aimed at reducing engagement in cyberbullying may be more urgent and important for individuals with high levels of covert narcissism. Boosting self-esteem needs to be particularly highlighted in developing anti-bullying measures and policies.

[Validity of the Spanish version of the Hypersensitive Narcissism Scale (HSNS) in subjects attended at an Addiction Treatment Unit].

PubMed

Ripoll, Carmen; Salazar, José; Bobes, Julio

2010-01-01

Narcissistic personality is an important component of personality disorders which are prevalent in those presenting drug abuse or dependence. Assessment instruments usually consider self-esteem, narcissism and covert narcissism, but although Spanish versions of instruments for self-esteem and narcissism are available, there is no available test for covert narcissism. OBJECTIVE. To test the validity of the Spanish version of the Hypersensitive Narcissism Scale (HSNS) in individuals presenting drug abuse or dependence. In a sample of 79 outpatients, we assessed reliability by means of Cronbach's alpha and the intraclass correlation coefficient (ICC), construct validity through factor analysis, and concurrent validity by means of the correlation between the HSNS and measures of severity, disability, self-esteem, grandiose narcissism and personality disorders. Reliability of the HSNS total scale score was satisfactory (Cronbach's alpha = 0,73, ICC = 0,67), though some items would require further consideration. Factor analysis showed good construct validity with three factors compatible with the theory of covert narcissism. With regard to concurrent validity, covert narcissism (HSNS) correlated positively with open narcissism, severity and disability due to drug use, and negatively with self-esteem. Highest scores on the HSNS corresponded to borderline, narcissistic and passive-aggressive personality disorders. The Spanish version of the HSNS could be a valid instrument for the assessment of covert narcissism in those treated for drug abuse or dependence.

Relaxation/Covert Rehearsal for Problematic Children.

ERIC Educational Resources Information Center

Fling, Sheila; McKenzie, Patricia

A study was conducted to determine whether group relaxation training combined with guided fantasy as a method of covert cognitive rehearsal would be more effective than story-listening or no special treatment in enabling "problematic" children to decrease muscle tension, activity level, and behavior problems and to increase academic performance…

40 CFR 51.363 - Quality assurance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... per year per number of inspectors using covert vehicles set to fail (this requirement sets a minimum... stations that conduct both testing and repairs, at least one covert vehicle visit per station per year including the purchase of repairs and subsequent retesting if the vehicle is initially failed for tailpipe...

A Comparison of Three Covert Assertion Training Procedures.

ERIC Educational Resources Information Center

Twentyman, Craig T.; And Others

1980-01-01

Assessed the effectiveness of covert modification procedures in an assertion training program. All treatment groups were superior to the control in behavioral ratings of assertiveness during the posttest in those situations that had been employed previously in treatment; two were superior in those that had not been used, providing evidence of…

Predicting Overt and Covert Antisocial Behaviors: Parents, Peers, and Homelessness

ERIC Educational Resources Information Center

Tompsett, Carolyn J.; Toro, Paul A.

2010-01-01

Parental deviance, parental monitoring, and deviant peers were examined as predictors of overt and covert antisocial behaviors. Homeless (N=231) and housed (N=143) adolescents were assessed in adolescence and again in early adulthood. Homelessness predicted both types of antisocial behaviors, and effects persisted in young adulthood. Parental…

The Multifold Relationship Between Memory and Decision Making: An Individual-differences Study

PubMed Central

Del Missier, Fabio; Mäntylä, Timo; Hansson, Patrik; Bruine de Bruin, Wändi; Parker, Andrew M.; Nilsson, Lars-Göran

2014-01-01

Several judgment and decision-making tasks are assumed to involve memory functions, but significant knowledge gaps on the memory processes underlying these tasks remain. In a study on 568 adults between 25 to 80 years, hypotheses were tested on the specific relationships between individual differences in working memory, episodic memory, and semantic memory, respectively, and six main components of decision-making competence. In line with the hypotheses, working memory was positively related with the more cognitively-demanding tasks (Resistance to Framing, Applying Decision Rules, and Under/Overconfidence), whereas episodic memory was positively associated with a more experience-based judgment task (Recognizing Social Norms). Furthermore, semantic memory was positively related with two more knowledge-based decision-making tasks (Consistency in Risk Perception and Resistance to Sunk Costs). Finally, the age-related decline observed in some of the decision-making tasks was (partially or totally) mediated by the age-related decline in working memory or episodic memory. These findings are discussed in relation to the functional roles fulfilled by different memory processes in judgment and decision-making tasks. PMID:23565790

Decision-making under risk conditions is susceptible to interference by a secondary executive task.

PubMed

Starcke, Katrin; Pawlikowski, Mirko; Wolf, Oliver T; Altstötter-Gleich, Christine; Brand, Matthias

2011-05-01

Recent research suggests two ways of making decisions: an intuitive and an analytical one. The current study examines whether a secondary executive task interferes with advantageous decision-making in the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps executive functioning. One group of participants performed the original GDT solely, two groups performed either the GDT and a 1-back or a 2-back working memory task as a secondary task simultaneously. Results show that the group which performed the GDT and the secondary task with high executive load (2-back) decided less advantageously than the group which did not perform a secondary executive task. These findings give further evidence for the view that decision-making under risky conditions taps into the rational-analytical system which acts in a serial and not parallel way as performance on the GDT is disturbed by a parallel task that also requires executive resources.

Cognitive strategies in the mental rotation task revealed by EEG spectral power.

PubMed

Gardony, Aaron L; Eddy, Marianna D; Brunyé, Tad T; Taylor, Holly A

2017-11-01

The classic mental rotation task (MRT; Shepard & Metzler, 1971) is commonly thought to measure mental rotation, a cognitive process involving covert simulation of motor rotation. Yet much research suggests that the MRT recruits both motor simulation and other analytic cognitive strategies that depend on visuospatial representation and visual working memory (WM). In the present study, we investigated cognitive strategies in the MRT using time-frequency analysis of EEG and independent component analysis. We scrutinized sensorimotor mu (µ) power reduction, associated with motor simulation, parietal alpha (pα) power reduction, associated with visuospatial representation, and frontal midline theta (fmθ) power enhancement, associated with WM maintenance and manipulation. µ power increased concomitant with increasing task difficulty, suggesting reduced use of motor simulation, while pα decreased and fmθ power increased, suggesting heightened use of visuospatial representation processing and WM, respectively. These findings suggest that MRT performance involves flexibly trading off between cognitive strategies, namely a motor simulation-based mental rotation strategy and WM-intensive analytic strategies based on task difficulty. Flexible cognitive strategy use may be a domain-general cognitive principle that underlies aptitude and spatial intelligence in a variety of cognitive domains. We close with discussion of the present study's implications as well as future directions. Published by Elsevier Inc.

Effect of distracting faces on visual selective attention in the monkey.

PubMed

Landman, Rogier; Sharma, Jitendra; Sur, Mriganka; Desimone, Robert

2014-12-16

In primates, visual stimuli with social and emotional content tend to attract attention. Attention might be captured through rapid, automatic, subcortical processing or guided by slower, more voluntary cortical processing. Here we examined whether irrelevant faces with varied emotional expressions interfere with a covert attention task in macaque monkeys. In the task, the monkeys monitored a target grating in the periphery for a subtle color change while ignoring distracters that included faces appearing elsewhere on the screen. The onset time of distracter faces before the target change, as well as their spatial proximity to the target, was varied from trial to trial. The presence of faces, especially faces with emotional expressions interfered with the task, indicating a competition for attentional resources between the task and the face stimuli. However, this interference was significant only when faces were presented for greater than 200 ms. Emotional faces also affected saccade velocity and reduced pupillary reflex. Our results indicate that the attraction of attention by emotional faces in the monkey takes a considerable amount of processing time, possibly involving cortical-subcortical interactions. Intranasal application of the hormone oxytocin ameliorated the interfering effects of faces. Together these results provide evidence for slow modulation of attention by emotional distracters, which likely involves oxytocinergic brain circuits.

Covert effects of "one drink" of alcohol on brain processes related to car driving: an event-related potential study.

PubMed

Ebe, Kazutoshi; Itoh, Kosuke; Kwee, Ingrid L; Nakada, Tsutomu

2015-04-23

The effects of a low dose of alcohol on car driving remain controversial. To address this issue, event-related potentials were recorded while subjects performed a simple car-following task in a driving simulator before and after consuming either "one drink" of beer (representing one standard alcoholic beverage containing 14 g of alcohol) or mineral water (control condition). Subjects who had consumed the determined amount of alcohol demonstrated no detectable outward behavioral signs of intoxication while performing the driving task, an observation in agreement with previous findings. However, the parietal P3 elicited by the brake lights of the preceding car was significantly reduced in amplitude, approximately 50% that observed under the control condition, likely indicating alteration of the neural processing of visual information critical for safe driving. The finding suggests that alcohol begins to affect neural processes for driving even at quantities too low to modify behavior. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Grin and bear it: the influence of manipulated facial expression on the stress response.

PubMed

Kraft, Tara L; Pressman, Sarah D

2012-01-01

In the study reported here, we investigated whether covertly manipulating positive facial expressions would influence cardiovascular and affective responses to stress. Participants (N = 170) naive to the purpose of the study completed two different stressful tasks while holding chopsticks in their mouths in a manner that produced a Duchenne smile, a standard smile, or a neutral expression. Awareness was manipulated by explicitly asking half of all participants in the smiling groups to smile (and giving the other half no instructions related to smiling). Findings revealed that all smiling participants, regardless of whether they were aware of smiling, had lower heart rates during stress recovery than the neutral group did, with a slight advantage for those with Duchenne smiles. Participants in the smiling groups who were not explicitly asked to smile reported less of a decrease in positive affect during a stressful task than did the neutral group. These findings show that there are both physiological and psychological benefits from maintaining positive facial expressions during stress.

Increased activation in Broca's area after cognitive remediation in schizophrenia.

PubMed

Vianin, Pascal; Urben, Sébastien; Magistretti, Pierre; Marquet, Pierre; Fornari, Eleonora; Jaugey, Laure

2014-03-30

Functional magnetic resonance imaging (fMRI) was used to measure changes in cerebral activity in patients with schizophrenia after participation in the Cognitive Remediation Program for Schizophrenia and other related disorders (RECOS). As RECOS therapists make use of problem-solving and verbal mediation techniques, known to be beneficial in the rehabilitation of dysexecutive syndromes, we expected an increased activation of frontal areas after remediation. Executive functioning and cerebral activation during a covert verbal fluency task were measured in eight patients with schizophrenia before (T1) and after (T2) 14 weeks of RECOS therapy. The same measures were recorded in eight patients with schizophrenia who did not participate in RECOS at the same intervals of time (TAU group). Increased activation in Broca's area, as well as improvements in performance of executive/frontal tasks, was observed after cognitive training. Metacognitive techniques of verbalization are hypothesized to be the main factor underlying the brain changes observed in the present study. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Directed Communication between Nucleus Accumbens and Neocortex in Humans Is Differentially Supported by Synchronization in the Theta and Alpha Band.

PubMed

Horschig, Jörn M; Smolders, Ruud; Bonnefond, Mathilde; Schoffelen, Jan-Mathijs; van den Munckhof, Pepijn; Schuurman, P Richard; Cools, Roshan; Denys, Damiaan; Jensen, Ole

2015-01-01

Here, we report evidence for oscillatory bi-directional interactions between the nucleus accumbens and the neocortex in humans. Six patients performed a demanding covert visual attention task while we simultaneously recorded brain activity from deep-brain electrodes implanted in the nucleus accumbens and the surface electroencephalogram (EEG). Both theta and alpha oscillations were strongly coherent with the frontal and parietal EEG during the task. Theta-band coherence increased during processing of the visual stimuli. Granger causality analysis revealed that the nucleus accumbens was communicating with the neocortex primarily in the theta-band, while the cortex was communicating the nucleus accumbens in the alpha-band. These data are consistent with a model, in which theta- and alpha-band oscillations serve dissociable roles: Prior to stimulus processing, the cortex might suppress ongoing processing in the nucleus accumbens by modulating alpha-band activity. Subsequently, upon stimulus presentation, theta oscillations might facilitate the active exchange of stimulus information from the nucleus accumbens to the cortex.

Using the Networked Fire Chief for ego-depletion research: measuring dynamic decision-making effort and performance.

PubMed

Barber, Larissa K; Smit, Brandon W

2014-01-01

This study replicated ego-depletion predictions from the self-control literature in a computer simulation task that requires ongoing decision-making in relation to constantly changing environmental information: the Network Fire Chief (NFC). Ego-depletion led to decreased self-regulatory effort, but not performance, on the NFC task. These effects were also buffered by task enjoyment so that individuals who enjoyed the dynamic decision-making task did not experience ego-depletion effects. These findings confirm that past ego-depletion effects on decision-making are not limited to static or isolated decision-making tasks and can be extended to dynamic, naturalistic decision-making processes more common to naturalistic settings. Furthermore, the NFC simulation provides a methodological mechanism for independently measuring effort and performance when studying ego-depletion.

Brain activation for lexical decision and reading aloud: two sides of the same coin?

PubMed

Carreiras, Manuel; Mechelli, Andrea; Estévez, Adelina; Price, Cathy J

2007-03-01

This functional magnetic resonance imaging study compared the neuronal implementation of word and pseudoword processing during two commonly used word recognition tasks: lexical decision and reading aloud. In the lexical decision task, participants made a finger-press response to indicate whether a visually presented letter string is a word or a pseudoword (e.g., "paple"). In the reading-aloud task, participants read aloud visually presented words and pseudowords. The same sets of words and pseudowords were used for both tasks. This enabled us to look for the effects of task (lexical decision vs. reading aloud), lexicality (words vs. nonwords), and the interaction of lexicality with task. We found very similar patterns of activation for lexical decision and reading aloud in areas associated with word recognition and lexical retrieval (e.g., left fusiform gyrus, posterior temporal cortex, pars opercularis, and bilateral insulae), but task differences were observed bilaterally in sensorimotor areas. Lexical decision increased activation in areas associated with decision making and finger tapping (bilateral postcentral gyri, supplementary motor area, and right cerebellum), whereas reading aloud increased activation in areas associated with articulation and hearing the sound of the spoken response (bilateral precentral gyri, superior temporal gyri, and posterior cerebellum). The effect of lexicality (pseudoword vs. words) was also remarkably consistent across tasks. Nevertheless, increased activation for pseudowords relative to words was greater in the left precentral cortex for reading than lexical decision, and greater in the right inferior frontal cortex for lexical decision than reading. We attribute these effects to differences in the demands on speech production and decision-making processes, respectively.

The Effects of Covert Audio Coaching on the Job Performance of Supported Employees

ERIC Educational Resources Information Center

Bennett, Kyle; Brady, Michael P.; Scott, Jack; Dukes, Charles; Frain, Michael

2010-01-01

The importance of employment in society is unmistakable, but for many people sustained employment remains elusive. The unemployment rate for individuals with disabilities is staggering, and the consequences of being unemployed affects those individuals, their families, and society. The effects of performance feedback delivered via covert audio…

The Syntax-Pragmatics Interface in Language Loss: Covert Restructuring of Aspect in Heritage Russian

ERIC Educational Resources Information Center

Laleko, Oksana Vladislavovna

2010-01-01

Heritage grammars, linguistic varieties emerging in the context of intergenerational language loss, are known to diverge from the corresponding full-fledged baseline varieties in principled and systematic ways, as typically illustrated by errors made by heritage speakers in production. This dissertation examines "covert" restructuring of aspect in…

Dissociated Overt and Covert Recognition as an Emergent Property of Lesioned Attractor Networks

DTIC Science & Technology

1992-01-01

1989). Prosopagnosia and object agnosia without covert recognition. Neuropsychologia, 27, 179-191. Rafal, R., Smith, J., Krantz, J., Cohen, A., Brennan...recognition in patients with face agnosia . RphaiorA2 Brain Research, 30, 235-249. 55 Volpe, B. T., LeDoux, J. A., and Gazzaniga, M. S. (1979). Information

The Treatment of Covert Self-Injury through Contingencies on Response Products.

ERIC Educational Resources Information Center

Grace, Nancy C.; And Others

1996-01-01

Covert self-injurious behavior in a 21-year old with mild mental retardation and cerebral palsy was treated by first identifying tangible and social reinforcers and then providing reinforcers contingent on absence of tissue damage identified during physical examination. Almost complete success was achieved and maintained over 10 months. (DB)

Navigating the Complexities at an LGTTQQI-Identified Charter School: An Ethnography of C/Overt Narratives

ERIC Educational Resources Information Center

Goodrich, Kristopher M.; Luke, Melissa

2016-01-01

The authors describe ethnographic research exploring the experiences of school stakeholders at a lesbian, gay, bisexual, transgender, queer, questioning, and intersex (LGBTQQI)-identified charter school. Participants evidenced use of an overt and covert narrative that appeared to reflect how they navigated the complexities at the…

Reducing Covert Self-Injurious Behavior Maintained by Automatic Reinforcement through a Variable Momentary DRO Procedure

ERIC Educational Resources Information Center

Toussaint, Karen A.; Tiger, Jeffrey H.

2012-01-01

Covert self-injurious behavior (i.e., behavior that occurs in the absence of other people) can be difficult to treat. Traditional treatments typically have involved sophisticated methods of observation and often have employed positive punishment procedures. The current study evaluated the effectiveness of a variable momentary differential…

Is there still a glass ceiling for women in academic surgery?

PubMed

Zhuge, Ying; Kaufman, Joyce; Simeone, Diane M; Chen, Herbert; Velazquez, Omaida C

2011-04-01

Despite the dramatically increased entry of women into general surgery and surgical subspecialties, traditionally male-dominated fields, there remains a gross under-representation of women in the leadership positions of these departments. Women begin their careers with fewer academic resources and tend to progress through the ranks slower than men. Female surgeons also receive significantly lower salaries than their male counterparts and are more vulnerable to discrimination, both obvious and covert. Although some argue that female surgeons tend to choose their families over careers, studies have actually shown that women are as eager as men to assume leadership positions, are equally qualified for these positions as men, and are as good as men at leadership tasks.Three major constraints contribute to the glass-ceiling phenomenon: traditional gender roles, manifestations of sexism in the medical environment, and lack of effective mentors. Gender roles contribute to unconscious assumptions that have little to do with actual knowledge and abilities of an individuals and they negatively influence decision-making when it comes to promotions. Sexism has many forms, from subtle to explicit forms, and some studies show that far more women report being discriminately against than do men. There is a lack of same-sex mentors and role models for women in academic surgery, thereby isolating female academicians further. This review summarizes the manifestation of the glass-ceiling phenomenon, identifies some causes of these inequalities, and proposes different strategies for continuing the advancement of women in academic surgery and to shatter the glass ceiling.

Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance.

PubMed

Adam, Kirsten C S; Robison, Matthew K; Vogel, Edward K

2018-01-08

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

Stimulus- and goal-driven control of eye movements: action videogame players are faster but not better.

PubMed

Heimler, Benedetta; Pavani, Francesco; Donk, Mieke; van Zoest, Wieske

2014-11-01

Action videogame players (AVGPs) have been shown to outperform nongamers (NVGPs) in covert visual attention tasks. These advantages have been attributed to improved top-down control in this population. The time course of visual selection, which permits researchers to highlight when top-down strategies start to control performance, has rarely been investigated in AVGPs. Here, we addressed specifically this issue through an oculomotor additional-singleton paradigm. Participants were instructed to make a saccadic eye movement to a unique orientation singleton. The target was presented among homogeneous nontargets and one additional orientation singleton that was more, equally, or less salient than the target. Saliency was manipulated in the color dimension. Our results showed similar patterns of performance for both AVGPs and NVGPs: Fast-initiated saccades were saliency-driven, whereas later-initiated saccades were more goal-driven. However, although AVGPs were faster than NVGPs, they were also less accurate. Importantly, a multinomial model applied to the data revealed comparable underlying saliency-driven and goal-driven functions for the two groups. Taken together, the observed differences in performance are compatible with the presence of a lower decision bound for releasing saccades in AVGPs than in NVGPs, in the context of comparable temporal interplay between the underlying attentional mechanisms. In sum, the present findings show that in both AVGPs and NVGPs, the implementation of top-down control in visual selection takes time to come about, and they argue against the idea of a general enhancement of top-down control in AVGPs.

Exogenous orienting of attention depends upon the ability to execute eye movements.

PubMed

Smith, Daniel T; Rorden, Chris; Jackson, Stephen R

2004-05-04

Shifts of attention can be made overtly by moving the eyes or covertly with attention being allocated to a region of space that does not correspond to the current direction of gaze. However, the precise relationship between eye movements and the covert orienting of attention remains controversial. The influential premotor theory proposes that the covert orienting of attention is produced by the programming of (unexecuted) eye movements and thus predicts a strong relationship between the ability to execute eye movements and the operation of spatial attention. Here, we demonstrate for the first time that impaired spatial attention is observed in an individual (AI) who is neurologically healthy but who cannot execute eye movements as a result of a congenital impairment in the elasticity of her eye muscles. This finding provides direct support for the role of the eye-movement system in the covert orienting of attention and suggests that whereas intact cortical structures may be necessary for normal attentional reflexes, they are not sufficient. The ability to move our eyes is essential for the development of normal patterns of spatial attention.

Dolphin Sounds-Inspired Covert Underwater Acoustic Communication and Micro-Modem

PubMed Central

Qiao, Gang; Liu, Songzuo; Bilal, Muhammad

2017-01-01

A novel portable underwater acoustic modem is proposed in this paper for covert communication between divers or underwater unmanned vehicles (UUVs) and divers at a short distance. For the first time, real dolphin calls are used in the modem to realize biologically inspired Covert Underwater Acoustic Communication (CUAC). A variety of dolphin whistles and clicks stored in an SD card inside the modem helps to realize different biomimetic CUAC algorithms based on the specified covert scenario. In this paper, the information is conveyed during the time interval between dolphin clicks. TMS320C6748 and TLV320AIC3106 are the core processors used in our unique modem for fast digital processing and interconnection with other terminals or sensors. Simulation results show that the bit error rate (BER) of the CUAC algorithm is less than 10−5 when the signal to noise ratio is over ‒5 dB. The modem was tested in an underwater pool, and a data rate of 27.1 bits per second at a distance of 10 m was achieved. PMID:29068363

Early detection of consciousness in patients with acute severe traumatic brain injury.

PubMed

Edlow, Brian L; Chatelle, Camille; Spencer, Camille A; Chu, Catherine J; Bodien, Yelena G; O'Connor, Kathryn L; Hirschberg, Ronald E; Hochberg, Leigh R; Giacino, Joseph T; Rosenthal, Eric S; Wu, Ona

2017-09-01

See Schiff (doi:10.1093/awx209) for a scientific commentary on this article. Patients with acute severe traumatic brain injury may recover consciousness before self-expression. Without behavioural evidence of consciousness at the bedside, clinicians may render an inaccurate prognosis, increasing the likelihood of withholding life-sustaining therapies or denying rehabilitative services. Task-based functional magnetic resonance imaging and electroencephalography techniques have revealed covert consciousness in the chronic setting, but these techniques have not been tested in the intensive care unit. We prospectively enrolled 16 patients admitted to the intensive care unit for acute severe traumatic brain injury to test two hypotheses: (i) in patients who lack behavioural evidence of language expression and comprehension, functional magnetic resonance imaging and electroencephalography detect command-following during a motor imagery task (i.e. cognitive motor dissociation) and association cortex responses during language and music stimuli (i.e. higher-order cortex motor dissociation); and (ii) early responses to these paradigms are associated with better 6-month outcomes on the Glasgow Outcome Scale-Extended. Patients underwent functional magnetic resonance imaging on post-injury Day 9.2 ± 5.0 and electroencephalography on Day 9.8 ± 4.6. At the time of imaging, behavioural evaluation with the Coma Recovery Scale-Revised indicated coma (n = 2), vegetative state (n = 3), minimally conscious state without language (n = 3), minimally conscious state with language (n = 4) or post-traumatic confusional state (n = 4). Cognitive motor dissociation was identified in four patients, including three whose behavioural diagnosis suggested a vegetative state. Higher-order cortex motor dissociation was identified in two additional patients. Complete absence of responses to language, music and motor imagery was only observed in coma patients. In patients with behavioural evidence of language function, responses to language and music were more frequently observed than responses to motor imagery (62.5-80% versus 33.3-42.9%). Similarly, in 16 matched healthy subjects, responses to language and music were more frequently observed than responses to motor imagery (87.5-100% versus 68.8-75.0%). Except for one patient who died in the intensive care unit, all patients with cognitive motor dissociation and higher-order cortex motor dissociation recovered beyond a confusional state by 6 months. However, 6-month outcomes were not associated with early functional magnetic resonance imaging and electroencephalography responses for the entire cohort. These observations suggest that functional magnetic resonance imaging and electroencephalography can detect command-following and higher-order cortical function in patients with acute severe traumatic brain injury. Early detection of covert consciousness and cortical responses in the intensive care unit could alter time-sensitive decisions about withholding life-sustaining therapies. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effect of feedback mode and task difficulty on quality of timing decisions in a zero-sum game.

PubMed

Tikuisis, Peter; Vartanian, Oshin; Mandel, David R

2014-09-01

The objective was to investigate the interaction between the mode of performance outcome feedback and task difficulty on timing decisions (i.e., when to act). Feedback is widely acknowledged to affect task performance. However, the extent to which feedback display mode and its impact on timing decisions is moderated by task difficulty remains largely unknown. Participants repeatedly engaged a zero-sum game involving silent duels with a computerized opponent and were given visual performance feedback after each engagement. They were sequentially tested on three different levels of task difficulty (low, intermediate, and high) in counterbalanced order. Half received relatively simple "inside view" binary outcome feedback, and the other half received complex "outside view" hit rate probability feedback. The key dependent variables were response time (i.e., time taken to make a decision) and survival outcome. When task difficulty was low to moderate, participants were more likely to learn and perform better from hit rate probability feedback than binary outcome feedback. However, better performance with hit rate feedback exacted a higher cognitive cost manifested by higher decision response time. The beneficial effect of hit rate probability feedback on timing decisions is partially moderated by task difficulty. Performance feedback mode should be judiciously chosen in relation to task difficulty for optimal performance in tasks involving timing decisions.

Methods for Conducting Cognitive Task Analysis for a Decision Making Task.

DTIC Science & Technology

1996-01-01

Cognitive task analysis (CTA) improves traditional task analysis procedures by analyzing the thought processes of performers while they complete a...for using these methods to conduct a CTA for domains which involve critical decision making tasks in naturalistic settings. The cognitive task analysis methods

Beyond the initial 140 ms, lexical decision and reading aloud are different tasks: An ERP study with topographic analysis.

PubMed

Mahé, Gwendoline; Zesiger, Pascal; Laganaro, Marina

2015-11-15

Most of our knowledge on the time-course of the mechanisms involved in reading derived from electrophysiological studies is based on lexical decision tasks. By contrast, very few ERP studies investigated the processes involved in reading aloud. It has been suggested that the lexical decision task provides a good index of the processes occurring during reading aloud, with only late processing differences related to task response modalities. However, some behavioral studies reported different sensitivity to psycholinguistic factors between the two tasks, suggesting that print processing could differ at earlier processing stages. The aim of the present study was thus to carry out an ERP comparison between lexical decision and reading aloud in order to determine when print processing differs between these two tasks. Twenty native French speakers performed a lexical decision task and a reading aloud task with the same written stimuli. Results revealed different electrophysiological patterns on both waveform amplitudes and global topography between lexical decision and reading aloud from about 140 ms after stimulus presentation for both words and pseudowords, i.e., as early as the N170 component. These results suggest that only very early, low-level visual processes are common to the two tasks which differ in core processes. Taken together, our main finding questions the use of the lexical decision task as an appropriate paradigm to investigate reading processes and warns against generalizing its results to word reading. Copyright © 2015 Elsevier Inc. All rights reserved.

Associations of parental feeding styles with child snacking behaviour and weight in the context of general parenting.

PubMed

Rodenburg, Gerda; Kremers, Stef P J; Oenema, Anke; van de Mheen, Dike

2014-05-01

To examine cross-sectional and longitudinal (one-year follow-up) associations of parental feeding styles with child snacking behaviour and weight in the context of general parenting, taking into account the multidimensionality of the controlling feeding style. Linear regression analyses were performed. Parents completed a questionnaire to measure five feeding style dimensions (Instrumental Feeding, Emotional Feeding, Encouragement, Overt Control and Covert Control) and children's fruit, energy-dense snack and sugar-sweetened beverage (SSB) intakes. Children's height and weight were measured to calculate their BMI Z-scores. Moderation by parenting style was tested by adding interaction terms to the regression analyses. Observational study in the Netherlands. Parent-child dyads (n 1275) participating in the INPACT (IVO Nutrition and Physical Activity Child cohorT) study; children were (on average) 9 years of age. Instrumental Feeding and Emotional Feeding were negatively related to child fruit intake one year later and positively to (changes in) child energy-dense snack intake. Encouragement was negatively related to child energy-dense snacking and SSB intake one year later. Overt Control was cross-sectionally and prospectively related to (changes in) child energy-dense snacking and SSB intake in a negative direction. Covert Control showed similar associations with child energy-dense snacking and SSB intake as Overt Control. Although Covert Control was also positively related to child fruit intake and (changes in) child BMI Z-score, bootstrapping analyses revealed only a differential effect of Overt Control and Covert Control on child BMI Z-score one year later, with Covert Control displaying a stronger, positive association. Moderation analyses showed that some significant associations between parental feeding styles and outcome measures were dependent on the degree of psychological control and behavioural control. Instrumental Feeding and Emotional Feeding may have a detrimental impact on children's snacking behaviour, while Encouragement, Overt Control and Covert Control may lead to less energy-dense snacking and less SSB intake. Overt Control and Covert Control have differential effects on child BMI Z-score one year later, which supports the idea that they should be treated as separate constructs. Prospective studies with a longer follow-up may elucidate the causal pathways between the various feeding styles and children's snacking behaviour and weight, as well as the moderating influences of psychological and behavioural control.

Linking Theoretical Decision-making Mechanisms in the Simon Task with Electrophysiological Data: A Model-based Neuroscience Study in Humans.

PubMed

Servant, Mathieu; White, Corey; Montagnini, Anna; Burle, Borís

2016-10-01

A current challenge for decision-making research is in extending models of simple decisions to more complex and ecological choice situations. Conflict tasks (e.g., Simon, Stroop, Eriksen flanker) have been the focus of much interest, because they provide a decision-making context representative of everyday life experiences. Modeling efforts have led to an elaborated drift diffusion model for conflict tasks (DMC), which implements a superimposition of automatic and controlled decision activations. The DMC has proven to capture the diversity of behavioral conflict effects across various task contexts. This study combined DMC predictions with EEG and EMG measurements to test a set of linking propositions that specify the relationship between theoretical decision-making mechanisms involved in the Simon task and brain activity. Our results are consistent with a representation of the superimposed decision variable in the primary motor cortices. The decision variable was also observed in the EMG activity of response agonist muscles. These findings provide new insight into the neurophysiology of human decision-making. In return, they provide support for the DMC model framework.

Naturalistic Decision Making: Implications for Design

DTIC Science & Technology

1993-04-01

Cognitive Task Analysis Decision Making Design Engineer Design System Human-Computer Interface System Development 15. NUMBER OF PAGES 182 16...people use to select a course of action. The SOAR explains how stress affects the decision making of both individuals and teams. COGNITIVE TASK ANALYSIS : This...procedures for Cognitive Task Analysis , contrasting the strengths and weaknesses of each, and showing how a Cognitive Task Analysis

Decision Making and Ratio Processing in Patients with Mild Cognitive Impairment.

PubMed

Pertl, Marie-Theres; Benke, Thomas; Zamarian, Laura; Delazer, Margarete

2015-01-01

Making advantageous decisions is important in everyday life. This study aimed at assessing how patients with mild cognitive impairment (MCI) make decisions under risk. Additionally, it investigated the relationship between decision making, ratio processing, basic numerical abilities, and executive functions. Patients with MCI (n = 22) were compared with healthy controls (n = 29) on a complex task of decision making under risk (Game of Dice Task-Double, GDT-D), on two tasks evaluating basic decision making under risk, on a task of ratio processing, and on several neuropsychological background tests. Patients performed significantly lower than controls on the GDT-D and on ratio processing, whereas groups performed comparably on basic decision tasks. Specifically, in the GDT-D, patients obtained lower net scores and lower mean expected values, which indicate a less advantageous performance relative to that of controls. Performance on the GDT-D correlated significantly with performance in basic decision tasks, ratio processing, and executive-function measures when the analysis was performed on the whole sample. Patients with MCI make sub-optimal decisions in complex risk situations, whereas they perform at the same level as healthy adults in simple decision situations. Ratio processing and executive functions have an impact on the decision-making performance of both patients and healthy older adults. In order to facilitate advantageous decisions in complex everyday situations, information should be presented in an easily comprehensible form and cognitive training programs for patients with MCI should focus--among other abilities--on executive functions and ratio processing.

Effects of Information Availability on Command-and-Control Decision Making: Performance, Trust, and Situation Awareness.

PubMed

Marusich, Laura R; Bakdash, Jonathan Z; Onal, Emrah; Yu, Michael S; Schaffer, James; O'Donovan, John; Höllerer, Tobias; Buchler, Norbou; Gonzalez, Cleotilde

2016-03-01

We investigated how increases in task-relevant information affect human decision-making performance, situation awareness (SA), and trust in a simulated command-and-control (C2) environment. Increased information is often associated with an improvement of SA and decision-making performance in networked organizations. However, previous research suggests that increasing information without considering the task relevance and the presentation can impair performance. We used a simulated C2 task across two experiments. Experiment 1 varied the information volume provided to individual participants and measured the speed and accuracy of decision making for task performance. Experiment 2 varied information volume and information reliability provided to two participants acting in different roles and assessed decision-making performance, SA, and trust between the paired participants. In both experiments, increased task-relevant information volume did not improve task performance. In Experiment 2, increased task-relevant information volume reduced self-reported SA and trust, and incorrect source reliability information led to poorer task performance and SA. These results indicate that increasing the volume of information, even when it is accurate and task relevant, is not necessarily beneficial to decision-making performance. Moreover, it may even be detrimental to SA and trust among team members. Given the high volume of available and shared information and the safety-critical and time-sensitive nature of many decisions, these results have implications for training and system design in C2 domains. To avoid decrements to SA, interpersonal trust, and decision-making performance, information presentation within C2 systems must reflect human cognitive processing limits and capabilities. © 2016, Human Factors and Ergonomics Society.

Powerlessness, Normalization, and Resistance: A Foucauldian Discourse Analysis of Women's Narratives On Obstetric Fistula in Eastern Sudan.

PubMed

Hamed, Sarah; Ahlberg, Beth-Maina; Trenholm, Jill

2017-10-01

Eastern Sudan has high prevalence of female circumcision and child marriage constituting a risk for developing obstetric fistula. Few studies have examined gender roles' relation with obstetric fistula in Sudan. To explore the associated power-relations that may put women at increased risk for developing obstetric fistula, we conducted nine interviews with women living with obstetric fistula in Kassala in eastern Sudan. Using a Foucauldian discourse analysis, we identified three discourses: powerlessness, normalization, and covert resistance. Existing power-relations between the women and other societal members revealed their internalization of social norms as absolute truth, and influenced their status and decision-making power in regard to circumcision, early marriage, and other transformative decisions as well as women's general behaviors. The women showed subtle resistance to these norms and the harassment they encountered because of their fistula. These findings suggest that a more in-depth contextual assessment could benefit future maternal health interventions.

Theory of mind and decision-making processes are impaired in Parkinson's disease.

PubMed

Xi, Chunhua; Zhu, Youling; Mu, Yanfang; Chen, Bing; Dong, Bin; Cheng, Huaidong; Hu, Panpan; Zhu, Chunyan; Wang, Kai

2015-02-15

Prefrontal cortex plays a vital role in the theory of mind (ToM) and decision making, as shown in functional brain imaging and lesion studies. Considering the primary neuropathology of Parkinson's disease (PD) involving the frontal lobe system, patients with PD are expected to exhibit deficits in ToM and social decision making. The aim of this study was to investigate affective ToM and decision making in patients with PD and healthy controls (HC) in a task assessing affective ToM (Reading the Mind in the Eyes, RME) and two decision-making tasks (Iowa Gambling Task, IGT; Game of Dice Task, GDT). Consistent with previous findings, patients with PD were impaired in the affective ToM task, and when making decisions under ambiguity and in risk situations. The score of emotion recognition in the RME task was negatively correlated with the severity of the disease and positively correlated with the total number of advantageous cards chosen in the IGT. However, the final capital in the GDT was correlated with memory impairment. The present study implies that affective ToM and decision making under ambiguity may share similar neural mechanisms, while decision making under ambiguity and decision making under risk may involve processing within different neural networks. Copyright © 2014 Elsevier B.V. All rights reserved.

Online Identity: Guidelines for Discerning Covert Racism in Blogs

ERIC Educational Resources Information Center

Kurubacak, Gulsun

2008-01-01

Blogs are web sites, which have the specific themes and are updated with the latest news, views, and trends including philosophical reflections, opinions, and social and/or political issues. Due to representing the personality of the author or the web site, the main purpose of this article is to discuss the guidelines of discerning covert racism…

Covert Modeling vs. Behavior Rehearsal in the Training and Generalization of Assertive Behaviors: A Crossover Design.

ERIC Educational Resources Information Center

Zielinski, Joseph J.; Williams, Leslie J.

1979-01-01

Twenty-four underassertive adults were randomly assigned to two treatment orders that included covert modeling and behavior rehearsal. No measurable difference in treatments was found, but participants preferred and had greater expectations of behavior rehearsal. Skill generalization to untrained situations occurred on 8 of 11 behavioral measures.…

Virtual Red Light Districts: Detecting Covert Networks and Sex Trafficking Circuits in the U.S.

ERIC Educational Resources Information Center

Ibanez, Michelle

2015-01-01

The United States is the second leading destination country for sex trafficking in the world. Increased effort to understand patterns of sex trafficking within the U.S. is imperative to combatting this issue. Covert networks are increasingly using information and communication technologies (ICTs) to extend their operations. Due to the increase in…

6. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL PIER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL PIER AND ASSOCIATED SUPERSTRUCTURE, AND CANTILEVERED NORTHERN TRUSS SECTION. NOTE THE JOIN BETWEEN EYE-BAR (LEFT) AND RIVETED CHANNEL (RIGHT) LOWER BRIDGE CHORDS AT CENTER LEFT OF PHOTOGRAPH. FACING NORTH. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

An fMRI Investigation of Covertly and Overtly Produced Mono- And Multisyllabic Words

ERIC Educational Resources Information Center

Shuster, Linda I.; Lemieux, Susan K.

2005-01-01

Studies suggest that the left insula may play an important role in speech motor programming. We used functional magnetic resonance imaging to investigate the role of the left insula in the production of monosyllabic or multisyllabic words during overt and covert speech conditions. The left insula did not show a BOLD response for multisyllabic…

Updating the Premotor Theory: The Allocation of Attention Is Not Always Accompanied by Saccade Preparation

ERIC Educational Resources Information Center

Belopolsky, Artem V.; Theeuwes, Jan

2012-01-01

There is an ongoing controversy regarding the relationship between covert attention and saccadic eye movements. While there is quite some evidence that the preparation of a saccade is obligatory preceded by a shift of covert attention, the reverse is not clear: Is allocation of attention always accompanied by saccade preparation? Recently, a…

Levels of Death Anxiety in Terminally Ill Men: A Pilot Study.

ERIC Educational Resources Information Center

Hayslip, Bert, Jr.; And Others

1992-01-01

Administered measures of overt and covert fear of death to 20 healthy men and 13 men diagnosed with Acquired Immune Deficiency Syndrome (AIDS). Groups did not differ significantly on overt measure; AIDS group had higher total scores on covert measure. Findings suggest that one's life trajectory is redefined when the diagnosis of terminal illness…

Deficits in the Covert Orienting of Attention in Children with Developmental Coordination Disorder: Does Severity of DCD Count?

ERIC Educational Resources Information Center

Chen, Wei-Ying; Wilson, Peter H.; Wu, Sheng K.

2012-01-01

Children with Developmental Coordination Disorder (DCD) show deficits in the covert orienting of visuospatial attention, suggesting an underlying issue in attentional disengagement and/or inhibitory control. However, an important theoretical issue that remains unclear is whether the pattern of deficits varies with DCD severity. Fifty-one children…

Dramatising the Hidden Hurt: Acting against Covert Bullying by Adolescent Girls

ERIC Educational Resources Information Center

Burton, Bruce

2010-01-01

This paper, delivered at the International Drama in Education Research Institute (IDIERI) conference in Sydney in July 2009, explores the outcomes of a project designed to apply the applied theatre techniques developed for the Acting Against Bullying programme to the specific problem of covert or hidden bullying by adolescent girls. Conducted in a…

Deconstructing Phonetic Transcription: Covert Contrast, Perceptual Bias, and an Extraterrestrial View of "Vox Humana"

ERIC Educational Resources Information Center

Munson, Benjamin; Edwards, Jan; Schellinger, Sarah K.; Beckman, Mary E.; Meyer, Marie K.

2010-01-01

This article honours Adele Miccio's life work by reflecting on the utility of phonetic transcription. The first section reviews the literature on cases where children whose speech appears to neutralize a contrast in the adult language are found on closer examination to produce a contrast ("covert contrast"). This study presents evidence…

Digital video steganalysis exploiting collusion sensitivity

NASA Astrophysics Data System (ADS)

Budhia, Udit; Kundur, Deepa

2004-09-01

In this paper we present an effective steganalyis technique for digital video sequences based on the collusion attack. Steganalysis is the process of detecting with a high probability and low complexity the presence of covert data in multimedia. Existing algorithms for steganalysis target detecting covert information in still images. When applied directly to video sequences these approaches are suboptimal. In this paper, we present a method that overcomes this limitation by using redundant information present in the temporal domain to detect covert messages in the form of Gaussian watermarks. Our gains are achieved by exploiting the collusion attack that has recently been studied in the field of digital video watermarking, and more sophisticated pattern recognition tools. Applications of our scheme include cybersecurity and cyberforensics.

Individual differences in emotion processing: how similar are diffusion model parameters across tasks?

PubMed

Mueller, Christina J; White, Corey N; Kuchinke, Lars

2017-11-27

The goal of this study was to replicate findings of diffusion model parameters capturing emotion effects in a lexical decision task and investigating whether these findings extend to other tasks of implicit emotion processing. Additionally, we were interested in the stability of diffusion model parameters across emotional stimuli and tasks for individual subjects. Responses to words in a lexical decision task were compared with responses to faces in a gender categorization task for stimuli of the emotion categories: happy, neutral and fear. Main effects of emotion as well as stability of emerging response style patterns as evident in diffusion model parameters across these tasks were analyzed. Based on earlier findings, drift rates were assumed to be more similar in response to stimuli of the same emotion category compared to stimuli of a different emotion category. Results showed that emotion effects of the tasks differed with a processing advantage for happy followed by neutral and fear-related words in the lexical decision task and a processing advantage for neutral followed by happy and fearful faces in the gender categorization task. Both emotion effects were captured in estimated drift rate parameters-and in case of the lexical decision task also in the non-decision time parameters. A principal component analysis showed that contrary to our hypothesis drift rates were more similar within a specific task context than within a specific emotion category. Individual response patterns of subjects across tasks were evident in significant correlations regarding diffusion model parameters including response styles, non-decision times and information accumulation.

The role of spatial selective attention in working memory for locations: evidence from event-related potentials.

PubMed

Awh, E; Anllo-Vento, L; Hillyard, S A

2000-09-01

We investigated the hypothesis that the covert focusing of spatial attention mediates the on-line maintenance of location information in spatial working memory. During the delay period of a spatial working-memory task, behaviorally irrelevant probe stimuli were flashed at both memorized and nonmemorized locations. Multichannel recordings of event-related potentials (ERPs) were used to assess visual processing of the probes at the different locations. Consistent with the hypothesis of attention-based rehearsal, early ERP components were enlarged in response to probes that appeared at memorized locations. These visual modulations were similar in latency and topography to those observed after explicit manipulations of spatial selective attention in a parallel experimental condition that employed an identical stimulus display.

Stress and decision making: neural correlates of the interaction between stress, executive functions, and decision making under risk.

PubMed

Gathmann, Bettina; Schulte, Frank P; Maderwald, Stefan; Pawlikowski, Mirko; Starcke, Katrin; Schäfer, Lena C; Schöler, Tobias; Wolf, Oliver T; Brand, Matthias

2014-03-01

Stress and additional load on the executive system, produced by a parallel working memory task, impair decision making under risk. However, the combination of stress and a parallel task seems to preserve the decision-making performance [e.g., operationalized by the Game of Dice Task (GDT)] from decreasing, probably by a switch from serial to parallel processing. The question remains how the brain manages such demanding decision-making situations. The current study used a 7-tesla magnetic resonance imaging (MRI) system in order to investigate the underlying neural correlates of the interaction between stress (induced by the Trier Social Stress Test), risky decision making (GDT), and a parallel executive task (2-back task) to get a better understanding of those behavioral findings. The results show that on a behavioral level, stressed participants did not show significant differences in task performance. Interestingly, when comparing the stress group (SG) with the control group, the SG showed a greater increase in neural activation in the anterior prefrontal cortex when performing the 2-back task simultaneously with the GDT than when performing each task alone. This brain area is associated with parallel processing. Thus, the results may suggest that in stressful dual-tasking situations, where a decision has to be made when in parallel working memory is demanded, a stronger activation of a brain area associated with parallel processing takes place. The findings are in line with the idea that stress seems to trigger a switch from serial to parallel processing in demanding dual-tasking situations.

A queueing model of pilot decision making in a multi-task flight management situation

NASA Technical Reports Server (NTRS)

Walden, R. S.; Rouse, W. B.

1977-01-01

Allocation of decision making responsibility between pilot and computer is considered and a flight management task, designed for the study of pilot-computer interaction, is discussed. A queueing theory model of pilot decision making in this multi-task, control and monitoring situation is presented. An experimental investigation of pilot decision making and the resulting model parameters are discussed.

On the status of cue independence as a criterion for memory inhibition: evidence against the covert blocking hypothesis.

PubMed

Weller, Peter D; Anderson, Michael C; Gómez-Ariza, Carlos J; Bajo, M Teresa

2013-07-01

Retrieving memories can impair recall of other related traces. Items affected by this retrieval-induced forgetting (RIF) are often less accessible when tested with independent probes, a characteristic known as cue independence. Cue independence has been interpreted as evidence for inhibitory mechanisms that suppress competing items during retrieval (M. C. Anderson & Spellman, 1995). Several authors, however, have proposed that apparent cue independence might instead reflect noninhibitory cue-dependent blocking mechanisms. In this view, when participants receive an independent probe test, they do not limit themselves to those probes but instead recall study cues covertly to aid performance. This strategy is thought to be self-defeating, because it reintroduces cues that instigate blocking, lending the appearance of generalized inhibition. M. C. Anderson (2003), in contrast, proposed that covert cuing masks cue-independent forgetting by providing a compound cuing advantage. Here, we replicated cue-independent RIF and documented how access to the original study cues influences this effect. In Experiments 1-2, we found that overtly providing category cues on independent probe tests never increased RIF. Indeed, when we provided categories selectively for items that should suffer the most blocking, a sizable reversal of RIF occurred, consistent with the masking hypothesis. Simply asking participants to covertly retrieve categories eliminated cue-independent RIF, contradicting predictions of the self-inflicted blocking account. Far from causing cue-independent forgetting, covert cuing masks it. These findings strongly support the inhibition account of RIF and, importantly, may explain why cue-independent forgetting is not always found. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Patients Covertly Recording Clinical Encounters: Threat or Opportunity? A Qualitative Analysis of Online Texts

PubMed Central

Tsulukidze, Maka; Grande, Stuart W.; Thompson, Rachel; Rudd, Kenneth; Elwyn, Glyn

2015-01-01

Background The phenomenon of patients covertly recording clinical encounters has generated controversial media reports. This study aims to examine the phenomenon and analyze the underlying issues. Methods and Findings We conducted a qualitative analysis of online posts, articles, blogs, and forums (texts) discussing patients covertly recording clinical encounters. Using Google and Google Blog search engines, we identified and analyzed 62 eligible texts published in multiple countries between 2006 and 2013. Thematic analysis revealed four key themes: 1) a new behavior that elicits strong reactions, both positive and negative, 2) an erosion of trust, 3) shifting patient-clinician roles and relationships, and 4) the existence of confused and conflicting responses. When patients covertly record clinical encounters – a behavior made possible by various digital recording technologies – strong reactions are evoked among a range of stakeholders. The behavior represents one consequence of an erosion of trust between patients and clinicians, and when discovered, leads to further deterioration of trust. Confused and conflicting responses to the phenomenon by patients and clinicians highlight the need for policy guidance. Conclusions This study describes strong reactions, both positive and negative, to the phenomenon of patients covertly recording clinical encounters. The availability of smartphones capable of digital recording, and shifting attitudes to patient-clinician relationships, seems to have led to this behavior, mostly viewed as a threat by clinicians but as a welcome and helpful innovation by some patients, possibly indicating a perception of subordination and a lack of empowerment. Further examination of this tension and its implications is needed. PMID:25933002

Metaphors we think with: the role of metaphor in reasoning.

PubMed

Thibodeau, Paul H; Boroditsky, Lera

2011-02-23

The way we talk about complex and abstract ideas is suffused with metaphor. In five experiments, we explore how these metaphors influence the way that we reason about complex issues and forage for further information about them. We find that even the subtlest instantiation of a metaphor (via a single word) can have a powerful influence over how people attempt to solve social problems like crime and how they gather information to make "well-informed" decisions. Interestingly, we find that the influence of the metaphorical framing effect is covert: people do not recognize metaphors as influential in their decisions; instead they point to more "substantive" (often numerical) information as the motivation for their problem-solving decision. Metaphors in language appear to instantiate frame-consistent knowledge structures and invite structurally consistent inferences. Far from being mere rhetorical flourishes, metaphors have profound influences on how we conceptualize and act with respect to important societal issues. We find that exposure to even a single metaphor can induce substantial differences in opinion about how to solve social problems: differences that are larger, for example, than pre-existing differences in opinion between Democrats and Republicans.

Impact of managed care on physicians' decisions to manipulate reimbursement rules: an explanatory model.

PubMed

VanGeest, Jonathan; Weiner, Saul; Johnson, Timothy; Cummins, Deborah

2007-07-01

To develop and test an explanatory model of the impact of managed care on physicians' decisions to manipulate reimbursement rules for patients. A self-administered mailed questionnaire of a national random sample of 1124 practicing physicians in the USA. Structural equation modelling was used. The main outcome measure assessed whether or not physicians had manipulated reimbursement rules (such as exaggerated the severity of patients conditions, changed billing diagnoses, or reported signs or symptoms that the patients did not have) to help patients secure coverage for needed treatment or services. The response rate was 64% (n = 720). Physicians' decisions to manipulate reimbursement rules for patients are directly driven not only by ethical beliefs about gaming the system but also by requests from patients, the perception of insufficient time to deliver care, and the proportion of Medicaid patients. Covert advocacy is also the indirect result of utilization review hassles, primary care specialty, and practice environment. Managed care is not just a set of rules that physicians choose to follow or disobey, but an environment of competing pressures from patients, purchasers, and high workload. Reimbursement manipulation is a response to that environment, rather than simply a reflection of individual physicians' values.

Gaze-based rehearsal in children under 7: a developmental investigation of eye movements during a serial spatial memory task.

PubMed

Morey, Candice C; Mareva, Silvana; Lelonkiewicz, Jaroslaw R; Chevalier, Nicolas

2018-05-01

The emergence of strategic verbal rehearsal at around 7 years of age is widely considered a major milestone in descriptions of the development of short-term memory across childhood. Likewise, rehearsal is believed by many to be a crucial factor in explaining why memory improves with age. This apparent qualitative shift in mnemonic processes has also been characterized as a shift from passive visual to more active verbal mnemonic strategy use, but no investigation of the development of overt spatial rehearsal has informed this explanation. We measured serial spatial order reconstruction in adults and groups of children 5-7 years old and 8-11 years old, while recording their eye movements. Children, particularly the youngest children, overtly fixated late-list spatial positions longer than adults, suggesting that younger children are less likely to engage in covert rehearsal during stimulus presentation than older children and adults. However, during retention the youngest children overtly fixated more of the to-be-remembered sequences than any other group, which is inconsistent with the idea that children do nothing to try to remember. Altogether, these data are inconsistent with the notion that children under 7 do not engage in any attempts to remember. They are most consistent with proposals that children's style of remembering shifts around age 7 from reactive cue-driven methods to proactive, covert methods, which may include cumulative rehearsal. © 2017 John Wiley & Sons Ltd.

Two distinct auditory-motor circuits for monitoring speech production as revealed by content-specific suppression of auditory cortex.

PubMed

Ylinen, Sari; Nora, Anni; Leminen, Alina; Hakala, Tero; Huotilainen, Minna; Shtyrov, Yury; Mäkelä, Jyrki P; Service, Elisabet

2015-06-01

Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehearsal compared with control, but only when they matched the rehearsed items. This critical specificity to speech content enables accurate speech monitoring by forward prediction, as proposed by current models of speech production. The one-to-one phonological motor-to-auditory mappings also appear to serve the maintenance of information in phonological working memory. Further findings of right-hemispheric suppression in the case of whole-item matches and left-hemispheric enhancement for last-syllable mismatches suggest that speech production is monitored by 2 auditory-motor circuits operating on different timescales: Finer grain in the left versus coarser grain in the right hemisphere. Taken together, our findings provide hemisphere-specific evidence of the interface between inner and heard speech. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Lifelong Transfer Learning for Heterogeneous Teams of Agents in Sequential Decision Processes

DTIC Science & Technology

2016-06-01

making (SDM) tasks in dynamic environments with simulated and physical robots . 15. SUBJECT TERMS Sequential decision making, lifelong learning, transfer...sequential decision-making (SDM) tasks in dynamic environments with both simple benchmark tasks and more complex aerial and ground robot tasks. Our work...and ground robots in the presence of disturbances: We applied our methods to the problem of learning controllers for robots with novel disturbances in

Knowledge Representations Underlying Covert Metalinguistic Activity: A Working Hypothesis

ERIC Educational Resources Information Center

Gutierrez, Xavier

2011-01-01

Covert metalinguistic activity has received little attention in the field of second language (L2) education, even though the few studies that have examined this type of attention to language note that it plays a role in L2 learning and use. However, little is known about this phenomenon. The study reported in this article focuses on the knowledge…

Covert Action: A Systems Approach

DTIC Science & Technology

2014-12-01

consider a covert action to support rebels within the Colombian province of Panama. The objective was relatively simple: support the creation of an...prevented Colombian reinforcements from either landing ashore or transiting from Colon to Panama City. The junta declared...154 He also exerted a significant level of control over the event by immediately deploying gunboats to the port which ensured that Colombian forces

Investigating the Inner Speech of People Who Stutter: Evidence for (and against) the Covert Repair Hypothesis

ERIC Educational Resources Information Center

Brocklehurst, Paul H.; Corley, Martin

2011-01-01

In their Covert Repair Hypothesis, Postma and Kolk (1993) suggest that people who stutter make greater numbers of phonological encoding errors, which are detected during the monitoring of inner speech and repaired, with stuttering-like disfluencies as a consequence. Here, we report an experiment that documents the frequency with which such errors…

A Uniform Approach to National Suicide Bomber Incident Response and Recovery

DTIC Science & Technology

2008-03-01

33 D. ELEMENTS OF MOTIVATION.................................................................35 E. THE TAMIL TIGER INFLUENCE...34 Ibid., 11. 35 Ibid., 8-12. 12 support of common objectives. Use of the Incident Command System (ICS) is an important element across multi... elements : • Initial strategic focus: to drive overt and covert United States forces from Muslim lands in the Near and Middle East. Covert American

Covert Channels in SIP for VoIP Signalling

NASA Astrophysics Data System (ADS)

Mazurczyk, Wojciech; Szczypiorski, Krzysztof

In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.

Audio steganography by amplitude or phase modification

NASA Astrophysics Data System (ADS)

Gopalan, Kaliappan; Wenndt, Stanley J.; Adams, Scott F.; Haddad, Darren M.

2003-06-01

This paper presents the results of embedding short covert message utterances on a host, or cover, utterance by modifying the phase or amplitude of perceptually masked or significant regions of the host. In the first method, the absolute phase at selected, perceptually masked frequency indices was changed to fixed, covert data-dependent values. Embedded bits were retrieved at the receiver from the phase at the selected frequency indices. Tests on embedding a GSM-coded covert utterance on clean and noisy host utterances showed no noticeable difference in the stego compared to the hosts in speech quality or spectrogram. A bit error rate of 2 out of 2800 was observed for a clean host utterance while no error occurred for a noisy host. In the second method, the absolute phase of 10 or fewer perceptually significant points in the host was set in accordance with covert data. This resulted in a stego with successful data retrieval and a slightly noticeable degradation in speech quality. Modifying the amplitude of perceptually significant points caused perceptible differences in the stego even with small changes of amplitude made at five points per frame. Finally, the stego obtained by altering the amplitude at perceptually masked points showed barely noticeable differences and excellent data recovery.

Decision Making in Adults with ADHD

ERIC Educational Resources Information Center

Montyla, Timo; Still, Johanna; Gullberg, Stina; Del Missier, Fabio

2012-01-01

Objectives: This study examined decision-making competence in ADHD by using multiple decision tasks with varying demands on analytic versus affective processes. Methods: Adults with ADHD and healthy controls completed two tasks of analytic decision making, as measured by the Adult Decision-Making Competence (A-DMC) battery, and two affective…

Path Analysis Examining Self-Efficacy and Decision-Making Performance on a Simulated Baseball Task

ERIC Educational Resources Information Center

Hepler, Teri J.; Feltz, Deborah L.

2012-01-01

The purpose of this study was to examine the relationship between decision-making self-efficacy and decision-making performance in sport. Undergraduate students (N = 78) performed 10 trials of a decision-making task in baseball. Self-efficacy was measured before performing each trial. Decision-making performance was assessed by decision speed and…

Put your hands up! Gesturing improves preschoolers' executive function.

PubMed

Rhoads, Candace L; Miller, Patricia H; Jaeger, Gina O

2018-09-01

This study addressed the causal direction of a previously reported relation between preschoolers' gesturing and their executive functioning on the Dimensional Change Card Sort (DCCS) sorting-switch task. Gesturing the relevant dimension for sorting was induced in a Gesture group through instructions, imitation, and prompts. In contrast, the Control group was instructed to "think hard" when sorting. Preschoolers (N = 50) performed two DCCS tasks: (a) sort by size and then spatial orientation of two objects and (b) sort by shape and then proximity of the two objects. An examination of performance over trials permitted a fine-grained depiction of patterns of younger and older children in the Gesture and Control conditions. After the relevant dimension was switched, the Gesture group had more accurate sorts than the Control group, particularly among younger children on the second task. Moreover, the amount of gesturing predicted the number of correct sorts among younger children on the second task. The overall association between gesturing and sorting was not reflected at the level of individual trials, perhaps indicating covert gestural representation on some trials or the triggering of a relevant verbal representation by the gesturing. The delayed benefit of gesturing, until the second task, in the younger children may indicate a utilization deficiency. Results are discussed in terms of theories of gesturing and thought. The findings open up a new avenue of research and theorizing about the possible role of gesturing in emerging executive function. Copyright © 2018 Elsevier Inc. All rights reserved.

The factor structure of generalized workplace harassment.

PubMed

Rospenda, Kathleen M; Richman, Judith A

2004-04-01

We describe the development and psychometric characteristics of the Generalized Workplace Harassment Questionnaire (GWHQ), a 29-item instrument developed to assess harassing experiences at work in five conceptual domains: verbal aggression, disrespect, isolation/exclusion, threats/bribes, and physical aggression. Over 1700 current and former university employees completed the GWHQ at three time points. Factor analytic results at each wave of data suggested a five-factor solution that did not correspond to the original five conceptual factors. We suggest a revised scoring scheme for the GWHQ utilizing four of the empirically extracted factors: covert hostility, verbal hostility, manipulation, and physical hostility. Covert hostility was the most frequently experienced type of harassment, followed by verbal hostility, manipulation, and physical hostility. Verbal hostility, covert hostility, and manipulation were found to be significant predictors of psychological distress.

Assessing the Influence of Farm Women's Self-Identity on Task Allocation and Decision Making.

ERIC Educational Resources Information Center

Bokemeier, Janet; Garkovich, Lorraine

1987-01-01

Uses data from survey of 880 Kentucky farm women to present theoretical framework integrating microsocial, household economy, and farm structural perspectives to explain gender allocation of farm-specific tasks and decision making. Finds self-identity validated by participation in farm tasks/decision making, but, overall, women indicate low levels…

Framing matters: Effects of framing on older adults’ exploratory decision-making

PubMed Central

Cooper, Jessica A.; Blanco, Nathaniel; Maddox, W. Todd

2016-01-01

We examined framing effects on exploratory decision-making. In Experiment 1 we tested older and younger adults in two decision-making tasks separated by one week, finding that older adults’ decision-making performance was preserved when maximizing gains, but declined when minimizing losses. Computational modeling indicates that younger adults in both conditions, and older adults in gains-maximization, utilized a decreasing threshold strategy (which is optimal), but older adults in losses were better fit by a fixed-probability model of exploration. In Experiment 2 we examined within-subjects behavior in older and younger adults in the same exploratory decision-making task, but without a time separation between tasks. We replicated the older adult disadvantage in loss-minimization from Experiment 1, and found that the older adult deficit was significantly reduced when the loss-minimization task immediately followed the gains-maximization task. We conclude that older adults’ performance in exploratory decision-making is hindered when framed as loss-minimization, but that this deficit is attenuated when older adults can first develop a strategy in a gains-framed task. PMID:27977218

Framing matters: Effects of framing on older adults' exploratory decision-making.

PubMed

Cooper, Jessica A; Blanco, Nathaniel J; Maddox, W Todd

2017-02-01

We examined framing effects on exploratory decision-making. In Experiment 1 we tested older and younger adults in two decision-making tasks separated by one week, finding that older adults' decision-making performance was preserved when maximizing gains, but it declined when minimizing losses. Computational modeling indicates that younger adults in both conditions, and older adults in gains maximization, utilized a decreasing threshold strategy (which is optimal), but older adults in losses were better fit by a fixed-probability model of exploration. In Experiment 2 we examined within-subject behavior in older and younger adults in the same exploratory decision-making task, but without a time separation between tasks. We replicated the older adult disadvantage in loss minimization from Experiment 1 and found that the older adult deficit was significantly reduced when the loss-minimization task immediately followed the gains-maximization task. We conclude that older adults' performance in exploratory decision-making is hindered when framed as loss minimization, but that this deficit is attenuated when older adults can first develop a strategy in a gains-framed task. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Reduction of influence of task difficulty on perceptual decision making by STN deep brain stimulation.

PubMed

Green, Nikos; Bogacz, Rafal; Huebl, Julius; Beyer, Ann-Kristin; Kühn, Andrea A; Heekeren, Hauke R

2013-09-09

Neurocomputational models of optimal decision making ascribe a crucial role-the computation of conflict between choice alternatives-to the subthalamic nucleus (STN). Specifically, these models predict that deep brain stimulation (DBS) of the STN will diminish the influence of decision conflict on decision making. In this work, patients with Parkinson's disease judged the direction of motion in random dot stimuli while ON and OFF DBS. To induce decision conflict, we varied the task difficulty (motion coherence), leading to increased reaction time (RT) in trials with greater task difficulty in healthy subjects. Results indicate that DBS significantly influences performance for perceptual decisions under high decision conflict. RT increased substantially OFF DBS as the task became more difficult, and a diffusion model best accounted for behavioral data. In contrast, ON DBS, the influence of task difficulty on RT was significantly reduced and a race model best accounted for the observed data. Individual data fits of evidence accumulation models demonstrate different information processing under distinct DBS states. Furthermore, ON DBS, speed-accuracy tradeoffs affected the magnitude of decision criterion adjustment significantly less compared to OFF DBS. Together, these findings suggest a crucial role for the STN in adjusting decision making during high-conflict trials in perceptual decision making. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pitting intuitive and analytical thinking against each other: the case of transitivity.

PubMed

Rusou, Zohar; Zakay, Dan; Usher, Marius

2013-06-01

Identifying which thinking mode, intuitive or analytical, yields better decisions has been a major subject of inquiry by decision-making researchers. Yet studies show contradictory results. One possibility is that the ambiguity is due to the variability in experimental conditions across studies. Our hypothesis is that decision quality depends critically on the level of compatibility between the thinking mode employed in the decision and the nature of the decision-making task. In two experiments, we pitted intuition and analytical thinking against each other on tasks that were either mainly intuitive or mainly analytical. Thinking modes, as well as task characteristics, were manipulated in a factorial design, with choice transitivity as the dependent measure. Results showed higher choice consistency (transitivity) when thinking mode and the characteristics of the decision task were compatible.

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.

Word Frequency Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger W.; McCann, Robert S.; VanSelst, Mark; Shafto, Michael G. (Technical Monitor)

1997-01-01

Word frequency effects in dual-task lexical decision are variously reported to be additive or underadditive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again, we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

Word Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger; McCann, Robert S.; VanSelst, Mark; Shafto, Michael (Technical Monitor)

1997-01-01

Word frequency effects in dual-task, lexical decision are variously reported to be additive or under-additive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

Improved Volitional Recall of Motor-Imagery-Related Brain Activation Patterns Using Real-Time Functional MRI-Based Neurofeedback.

PubMed

Bagarinao, Epifanio; Yoshida, Akihiro; Ueno, Mika; Terabe, Kazunori; Kato, Shohei; Isoda, Haruo; Nakai, Toshiharu

2018-01-01

Motor imagery (MI), a covert cognitive process where an action is mentally simulated but not actually performed, could be used as an effective neurorehabilitation tool for motor function improvement or recovery. Recent approaches employing brain-computer/brain-machine interfaces to provide online feedback of the MI during rehabilitation training have promising rehabilitation outcomes. In this study, we examined whether participants could volitionally recall MI-related brain activation patterns when guided using neurofeedback (NF) during training. The participants' performance was compared to that without NF. We hypothesized that participants would be able to consistently generate the relevant activation pattern associated with the MI task during training with NF compared to that without NF. To assess activation consistency, we used the performance of classifiers trained to discriminate MI-related brain activation patterns. Our results showed significantly higher predictive values of MI-related activation patterns during training with NF. Additionally, this improvement in the classification performance tends to be associated with the activation of middle temporal gyrus/inferior occipital gyrus, a region associated with visual motion processing, suggesting the importance of performance monitoring during MI task training. Taken together, these findings suggest that the efficacy of MI training, in terms of generating consistent brain activation patterns relevant to the task, can be enhanced by using NF as a mechanism to enable participants to volitionally recall task-related brain activation patterns.

Changes in P3b Latency and Amplitude Reflect Expertise Acquisition in a Football Visuomotor Learning Task.

PubMed

Morgan, Kyle K; Luu, Phan; Tucker, Don M

2016-01-01

Learning is not a unitary phenomenon. Rather, learning progresses through stages, with the stages reflecting different challenges that require the support of specific cognitive processes that reflect the functions of different brain networks. A theory of general learning proposes that learning can be divided into early and late stages controlled by corticolimbic networks located in frontal and posterior brain regions, respectively. Recent human studies using dense-array EEG (dEEG) support these results by showing progressive increases in P3b amplitude (an Event Related Potential with estimated sources in posterior cingulate cortex and hippocampus) as participants acquire a new visuomotor skill. In the present study, the P3b was used to track the learning and performance of participants as they identify defensive football formations and make an appropriate response. Participants acquired the task over three days, and P3b latency and amplitude significantly changed when participants learned the task. As participants demonstrated further proficiency with extensive training, amplitude and latency changes in the P3b continued to closely mirror performance improvements. Source localization results across all days suggest that an important source generator of the P3b is located in the posterior cingulate cortex. Results from the study support prior findings and further suggest that the careful analysis of covert learning mechanisms and their underlying electrical signatures are a robust index of task competency.

Theta-Modulated Gamma-Band Synchronization Among Activated Regions During a Verb Generation Task

PubMed Central

Doesburg, Sam M.; Vinette, Sarah A.; Cheung, Michael J.; Pang, Elizabeth W.

2012-01-01

Expressive language is complex and involves processing within a distributed network of cortical regions. Functional MRI and magnetoencephalography (MEG) have identified brain areas critical for expressive language, but how these regions communicate across the network remains poorly understood. It is thought that synchronization of oscillations between neural populations, particularly at a gamma rate (>30 Hz), underlies functional integration within cortical networks. Modulation of gamma rhythms by theta-band oscillations (4–8 Hz) has been proposed as a mechanism for the integration of local cell coalitions into large-scale networks underlying cognition and perception. The present study tested the hypothesis that these oscillatory mechanisms of functional integration were present within the expressive language network. We recorded MEG while subjects performed a covert verb generation task. We localized activated cortical regions using beamformer analysis, calculated inter-regional phase locking between activated areas, and measured modulation of inter-regional gamma synchronization by theta phase. The results show task-dependent gamma-band synchronization among regions activated during the performance of the verb generation task, and we provide evidence that these transient and periodic instances of high-frequency connectivity were modulated by the phase of cortical theta oscillations. These findings suggest that oscillatory synchronization and cross-frequency interactions are mechanisms for functional integration among distributed brain areas supporting expressive language processing. PMID:22707946

Individual differences in intrinsic brain connectivity predict decision strategy.

PubMed

Barnes, Kelly Anne; Anderson, Kevin M; Plitt, Mark; Martin, Alex

2014-10-15

When humans are provided with ample time to make a decision, individual differences in strategy emerge. Using an adaptation of a well-studied decision making paradigm, motion direction discrimination, we probed the neural basis of individual differences in strategy. We tested whether strategies emerged from moment-to-moment reconfiguration of functional brain networks involved in decision making with task-evoked functional MRI (fMRI) and whether intrinsic properties of functional brain networks, measured at rest with functional connectivity MRI (fcMRI), were associated with strategy use. We found that human participants reliably selected one of two strategies across 2 days of task performance, either continuously accumulating evidence or waiting for task difficulty to decrease. Individual differences in decision strategy were predicted both by the degree of task-evoked activation of decision-related brain regions and by the strength of pretask correlated spontaneous brain activity. These results suggest that spontaneous brain activity constrains strategy selection on perceptual decisions.

Additive and Interactive Effects in Semantic Priming: Isolating Lexical and Decision Processes in the Lexical Decision Task

ERIC Educational Resources Information Center

Yap, Melvin J.; Balota, David A.; Tan, Sarah E.

2013-01-01

The present study sheds light on the interplay between lexical and decision processes in the lexical decision task by exploring the effects of lexical decision difficulty on semantic priming effects. In 2 experiments, we increased lexical decision difficulty by either using transposed letter wordlike nonword distracters (e.g., JUGDE; Experiment 1)…

From guideline modeling to guideline execution: defining guideline-based decision-support services.

PubMed Central

Tu, S. W.; Musen, M. A.

2000-01-01

We describe our task-based approach to defining the guideline-based decision-support services that the EON system provides. We categorize uses of guidelines in patient-specific decision support into a set of generic tasks--making of decisions, specification of work to be performed, interpretation of data, setting of goals, and issuance of alert and reminders--that can be solved using various techniques. Our model includes constructs required for representing the knowledge used by these techniques. These constructs form a toolkit from which developers can select modeling solutions for guideline task. Based on the tasks and the guideline model, we define a guideline-execution architecture and a model of interactions between a decision-support server and clients that invoke services provided by the server. These services use generic interfaces derived from guideline tasks and their associated modeling constructs. We describe two implementations of these decision-support services and discuss how this work can be generalized. We argue that a well-defined specification of guideline-based decision-support services will facilitate sharing of tools that implement computable clinical guidelines. PMID:11080007

The optimum decision rules for the oddity task.

PubMed

Versfeld, N J; Dai, H; Green, D M

1996-01-01

This paper presents the optimum decision rule for an m-interval oddity task in which m-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur with "roved" or "fixed" experiments (Macmillan & Creelman, 1991, p. 147). It is shown that the commonly used decision rule for an m-interval oddity task corresponds to the special case of highly correlated observations. However, as is also true for the same-different paradigm, there exists a different optimum decision rule when the observations are independent. The relation between the probability of a correct response and d' is derived for the three-interval oddity task. Tables are presented of this relation for the three-, four-, and five-interval oddity task. Finally, an experimental method is proposed that allows one to determine the decision rule used by the observer in an oddity experiment.

Understanding self-reported difficulties in decision-making by people with autism spectrum disorders.

PubMed

Vella, Lydia; Ring, Howard A; Aitken, Mike Rf; Watson, Peter C; Presland, Alexander; Clare, Isabel Ch

2017-04-01

Autobiographical accounts and a limited research literature suggest that adults with autism spectrum disorders can experience difficulties with decision-making. We examined whether some of the difficulties they describe correspond to quantifiable differences in decision-making when compared to adults in the general population. The participants (38 intellectually able adults with autism spectrum disorders and 40 neurotypical adults) were assessed on three tasks of decision-making (Iowa Gambling Task, Cambridge Gamble Task and Information Sampling Task), which quantified, respectively, decision-making performance and relative attention to negative and positive outcomes, speed and flexibility, and information sampling. As a caution, all analyses were repeated with a subset of participants ( n ASD  = 29 and n neurotypical  = 39) who were not taking antidepressant or anxiolytic medication. Compared to the neurotypical participants, participants with autism spectrum disorders demonstrated slower decision-making on the Cambridge Gamble Task, and superior performance on the Iowa Gambling Task. When those taking the medications were excluded, participants with autism spectrum disorders also sampled more information. There were no other differences between the groups. These processing tendencies may contribute to the difficulties self-reported in some contexts; however, the results also highlight strengths in autism spectrum disorders, such as a more logical approach to, and care in, decision-making. The findings lead to recommendations for how adults with autism spectrum disorders may be better supported with decision-making.

Instructional Cues Modify Performance on the Iowa Gambling Task

ERIC Educational Resources Information Center

Balodis, Iris M.; MacDonald, Tara K.; Olmstead, Mary C.

2006-01-01

The current study investigated whether acute alcohol intoxication produces impaired decision-making on tasks assessing ventromedial prefrontal (VMF) cortex functioning and impulsive responding. Participants completed the Iowa Gambling Task (IGT), a decision-making test targeting the VMF, and the Newman Perseveration Task (NT), a measure of…

Modularly Constructed Synthetic Granzyme B Molecule Enables Interrogation of Intracellular Proteases for Targeted Cytotoxicity.

PubMed

Ho, Patrick; Ede, Christopher; Chen, Yvonne Y

2017-08-18

Targeted therapies promise to increase the safety and efficacy of treatments against diseases ranging from cancer to viral infections. However, the vast majority of targeted therapeutics relies on the recognition of extracellular biomarkers, which are rarely restricted to diseased cells and are thus prone to severe and sometimes-fatal off-target toxicities. In contrast, intracellular antigens present a diverse yet underutilized repertoire of disease markers. Here, we report a protein-based therapeutic platform-termed Cytoplasmic Oncoprotein VErifier and Response Trigger (COVERT)-which enables the interrogation of intracellular proteases to trigger targeted cytotoxicity. COVERT molecules consist of the cytotoxic protein granzyme B (GrB) fused to an inhibitory N-terminal peptide, which can be removed by researcher-specified proteases to activate GrB function. We demonstrate that fusion of a small ubiquitin-like modifier 1 (SUMO1) protein to GrB yields a SUMO-GrB molecule that is specifically activated by the cancer-associated sentrin-specific protease 1 (SENP1). SUMO-GrB selectively triggers apoptotic phenotypes in HEK293T cells that overexpress SENP1, and it is highly sensitive to different SENP1 levels across cell lines. We further demonstrate the rational design of additional COVERT molecules responsive to enterokinase (EK) and tobacco etch virus protease (TEVp), highlighting the COVERT platform's modularity and adaptability to diverse protease targets. As an initial step toward engineering COVERT-T cells for adoptive T-cell therapy, we verified that primary human T cells can express, package, traffic, and deliver engineered GrB molecules in response to antigen stimulation. Our findings set the foundation for future intracellular-antigen-responsive therapeutics that can complement surface-targeted therapies.

Concerns about covert HIV testing are associated with delayed presentation of suspected malaria in Ethiopian children: a cross-sectional study

PubMed Central

2014-01-01

Background Early diagnosis is important in preventing mortality from malaria. The hypothesis that guardians’ fear of covert human immunodeficiency virus (HIV) testing delays presentation of children with suspected malaria was tested. Methods The study design is a cross-sectional survey. The study population consisted of guardians of children with suspected malaria who presented to health centres in Oromia Region, Ethiopia. Data were collected on attitudes to HIV testing and the duration of children’s symptoms using interview administered questionnaires. Results Some 830 individuals provided data representing a response rate of 99% of eligible participants. Of these, 423 (51%) guardians perceived that HIV testing was routinely done on blood donated for malaria diagnosis, and 353 (43%) were aware of community members who delayed seeking medical advice because of these concerns. Children whose guardians suspected that blood was covertly tested for HIV had longer median delay to presentation for evaluation at health centres compared to those children whose guardians did not hold this belief (three days compared to two days, p < 0.001). Children whose guardians were concerned about covert HIV testing were at a higher odds of a prolonged delay before being seen at a health centre (odds ratio 1.73, 95% confidence intervals: 1.10 to 270 for a delay of ≥3 days compared to those seen in ≤2 days). Conclusion Children whose guardians believed that covert testing for HIV was routine clinical practice presented later for investigation of suspected malaria. This may account for up to 14% of the delay in presentation and represents a reversible risk factor for suboptimal management of malaria. PMID:25098338

Sublethal effects of iridovirus disease in a mosquito.

PubMed

Marina, Carlos F; Arredondo-Jiménez, Juan I; Castillo, Alfredo; Williams, Trevor

1999-05-01

Recognition of the importance of debilitating effects of insect virus diseases is currently growing. Commonly observed effects of sublethal infection at the individual level include extended development times, reduced pupal and adult weights, and lowered fecundity. However, for the most part, sublethal infections are assumed to be present in survivors of an inoculum challenge, rather than demonstrated to be present by microscopy or molecular techniques. Invertebrate iridescent viruses are dsDNA viruses capable of causing disease with symptoms obvious to the naked eye, a "patent" infection, that is lethal. Furthermore, inapparent "covert" infections may occur that are non-lethal and which can only be detected using bioassay or molecular techniques. In this study, replication of Invertebrate iridescent virus 6 in Aedes aegypti larvae was demonstrated in the absence of patent disease. A sensitive insect bioassay (using Galleria mellonella) allowed the detection of covert infections, which were more common than patent infections. A concentration-response relationship was detected for the incidence of patent infections. Covert infections were up to 2 orders of magnitude commoner than patent infections, but the prevalence of covert infections did not appear to be related to virus inoculum concentration. Exposure of larvae to virus inoculum resulted in extended juvenile development times. A reduction in the mean and an increase in the variability of fecundity and adult progeny production was observed in females exposed to an inoculum challenge, although formal analysis was not possible. Males appeared capable of passing virus to uninfected females during the mating process. Covertly infected females were smaller and had shorter lifespans than control or virus-challenged females. A conservative estimate for the reduction in the net reproductive rate (R 0 ) of such insects was calculated at slightly more than 20% relative to controls.

Effects of covert subject actions on percent body fat by air-displacement plethsymography.

PubMed

Tegenkamp, Michelle H; Clark, R Randall; Schoeller, Dale A; Landry, Greg L

2011-07-01

Air-displacement plethysmography (ADP) is used for estimation of body composition, however, some individuals, such as athletes in weight classification sports, may use covert methods during ADP testing to alter their apparent percent body fat. The purpose of this study was to examine the effect of covert subject actions on percent body fat measured by ADP. Subjects underwent body composition analysis in the Bod Pod following the standard procedure using the manufacturer's guidelines. The subjects then underwent 8 more measurements while performing the following intentional manipulations: 4 breathing patterns altering lung volume, foot movement to disrupt air, hand cupping to trap air, and heat and cold exposure before entering the chamber. Increasing and decreasing lung volume during thoracic volume measurement and during body density measurement altered the percent body fat assessment (p < 0.001). High lung volume during thoracic gas measures overestimated fat by 3.7 ± 2.1 percentage points. Lowered lung volume during body volume measures overestimated body fat by an additional 2.2 ± 2.1 percentage points. The heat and cold exposure, tapping, and cupping treatments provided similar estimates of percent body fat when compared with the standard condition. These results demonstrate the subjects were able to covertly change their estimated ADP body composition value by altering breathing when compared with the standard condition. We recommend that sports conditioning coaches, athletic trainers, and technicians administering ADP should be aware of the potential effects of these covert actions. The individual responsible for administering ADP should remain vigilant during testing to detect deliberate altered breathing patterns by athletes in an effort to gain a competitive advantage by manipulating their body composition assessment.

Automated hand hygiene auditing with and without an intervention.

PubMed

Kwok, Yen Lee Angela; Juergens, Craig P; McLaws, Mary-Louise

2016-12-01

Daily feedback from continuous automated auditing with a peer reminder intervention was used to improve compliance. Compliance rates from covert and overt automated auditing phases with and without intervention were compared with human mandatory audits. An automated system was installed to covertly detect hand hygiene events with each depression of the alcohol-based handrub dispenser for 5 months. The overt phase included key clinicians trained to share daily rates with clinicians, set compliance goals, and nudge each other to comply for 6 months. During a further 6 months, the intervention continued without being refreshed. Hand Hygiene Australia (HHA) human audits were performed quarterly during the intervention in accordance with the World Health Organization guidelines. Percentage point (PP) differences between compliance rates were used to determine change. HHA rates for June 2014 were 85% and 87% on the medical and surgical wards, respectively. These rates were 55 PPs and 38 PPs higher than covert automation rates for June 2014 on the medical and surgical ward at 30% and 49%, respectively. During the intervention phase, average compliance did not change on the medical ward from their covert rate, whereas the surgical ward improved compared with the covert phase by 11 PPs to 60%. On average, compliance during the intervention without being refreshed did not change on the medical ward, whereas the average rate on the surgical ward declined by 9 PPs. Automation provided a unique opportunity to respond to daily rates, but compliance will return to preintervention levels once active intervention ceases or human auditors leave the ward, unless clinicians are committed to change. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

The influence of method-related partner violence on covert pill use and pill discontinuation among women living in La Paz, El Alto and Santa Cruz, Bolivia.

PubMed

McCarraher, Donna R; Martin, Sandra L; Bailey, Patricia E

2006-03-01

Intimate partner violence is widespread worldwide. While assumed to impact women's ability to use contraceptive methods, few data are available to support this claim. In this study, eight focus group discussions were conducted to guide questionnaire development and to provide contextual information. Participants were women who were currently using the pill and women who had used the pill previously. In addition, 300 women were interviewed who initiated oral contraceptive pill use between December 1995 and April 1996. Participants were interviewed 3-6 months later to investigate the role intimate partner violence played in covert pill use and pill discontinuation. Special study procedures for asking women questions about violence were employed. Nineteen per cent of the women interviewed were using the pill covertly. The odds of covert pill use were four times higher in El Alto and La Paz than in Santa Cruz. Women who used the pill covertly were more likely to have experienced method-related partner violence (OR = 21.27) than women whose partners knew of their pill use. One-third of the women had discontinued pill use at the time of the interview. In the final multivariate analysis, having experienced side-effects (OR = 2.37) was a significant predictor of pill discontinuation and method-related partner violence was marginally predictive (OR = 1.91; 95% CI 1.0-3.66). While efforts are ongoing to incorporate men into family planning programmes, some male partners oppose, and in some situations violently oppose, contraceptive use. The needs of women with these types of partners must not be overlooked.

Dissociation between decision-making under risk and decision-making under ambiguity in premanifest and manifest Huntington's disease.

PubMed

Adjeroud, Najia; Besnard, Jeremy; Verny, Christophe; Prundean, Adriana; Scherer, Clarisse; Gohier, Bénédicte; Bonneau, Dominique; Massioui, Nicole El; Allain, Philippe

2017-08-01

We investigated decision-making under ambiguity (DM-UA) and decision making under risk (DM-UR) in individuals with premanifest and manifest Huntington's disease (HD). Twenty individuals with premanifest HD and 23 individuals with manifest HD, on one hand, and 39 healthy individuals divided into two control groups, on the other, undertook a modified version of the Iowa Gambling Task (IGT), an adaptation of a DM-UA task, and a modified version of the Game of Dice Task (GDT), an adaptation of a DM-UR task. Participants also filled in a questionnaire of impulsivity and responded to cognitive tests specifically designed to assess executive functions. Compared to controls, individuals with premanifest HD were unimpaired in performing executive tests as well as in decision-making tasks, except for the Stroop task. In contrast, individuals with manifest HD were impaired in both the IGT and executive tasks, but not in the GDT. No sign of impulsivity was observed in individuals with premanifest or manifest HD. Our results suggest that the progression of HD impairs DM-UA without affecting DM-UR, and indicate that decision-making abilities are preserved during the premanifest stage of HD. Copyright © 2017 Elsevier Ltd. All rights reserved.

The neural system of metacognition accompanying decision-making in the prefrontal cortex

PubMed Central

Qiu, Lirong; Su, Jie; Ni, Yinmei; Bai, Yang; Zhang, Xuesong; Li, Xiaoli

2018-01-01

Decision-making is usually accompanied by metacognition, through which a decision maker monitors uncertainty regarding a decision and may then consequently revise the decision. These metacognitive processes can occur prior to or in the absence of feedback. However, the neural mechanisms of metacognition remain controversial. One theory proposes an independent neural system for metacognition in the prefrontal cortex (PFC); the other, that metacognitive processes coincide and overlap with the systems used for the decision-making process per se. In this study, we devised a novel “decision–redecision” paradigm to investigate the neural metacognitive processes involved in redecision as compared to the initial decision-making process. The participants underwent a perceptual decision-making task and a rule-based decision-making task during functional magnetic resonance imaging (fMRI). We found that the anterior PFC, including the dorsal anterior cingulate cortex (dACC) and lateral frontopolar cortex (lFPC), were more extensively activated after the initial decision. The dACC activity in redecision positively scaled with decision uncertainty and correlated with individual metacognitive uncertainty monitoring abilities—commonly occurring in both tasks—indicating that the dACC was specifically involved in decision uncertainty monitoring. In contrast, the lFPC activity seen in redecision processing was scaled with decision uncertainty reduction and correlated with individual accuracy changes—positively in the rule-based decision-making task and negatively in the perceptual decision-making task. Our results show that the lFPC was specifically involved in metacognitive control of decision adjustment and was subject to different control demands of the tasks. Therefore, our findings support that a separate neural system in the PFC is essentially involved in metacognition and further, that functions of the PFC in metacognition are dissociable. PMID:29684004

Age determination of mallards

USGS Publications Warehouse

Krapu, G.L.; Johnson, D.H.; Dane, C.W.

1979-01-01

A technique for distinguishing adult from yearling wild mallards (Anas platyrhynchos), from late winter through the nesting season, was developed by applying discriminant analysis procedures to selected wing feather characters of 126 yearlings and 76 adults (2-year-olds) hand-reared from wild eggs during 1974, 1975, and 1977. Average values for feather characters generally increased as the birds advanced from yearlings to adults. Black-white surface area of greater secondary covert 2 was the single most reliable aging character identified during the study. The error rate was lowest in females (3%) when discriminant functions were used with measurements of primary 1 weight and black-white area of greater secondary covert 2 and in males (9%) when the functions were used with black-white area of greater secondary coverts 1, 2, and 3. Methodology precludes aging of birds in the field during capture operations.

Human perceptual decision making: disentangling task onset and stimulus onset.

PubMed

Cardoso-Leite, Pedro; Waszak, Florian; Lepsien, Jöran

2014-07-01

The left dorsolateral prefrontal cortex (ldlPFC) has been highlighted as a key actor in human perceptual decision-making (PDM): It is theorized to support decision-formation independently of stimulus type or motor response. PDM studies however generally confound stimulus onset and task onset: when the to-be-recognized stimulus is presented, subjects know that a stimulus is shown and can set up processing resources-even when they do not know which stimulus is shown. We hypothesized that the ldlPFC might be involved in task preparation rather than decision-formation. To test this, we asked participants to report whether sequences of noisy images contained a face or a house within an experimental design that decorrelates stimulus and task onset. Decision-related processes should yield a sustained response during the task, whereas preparation-related areas should yield transient responses at its beginning. The results show that the brain activation pattern at task onset is strikingly similar to that observed in previous PDM studies. In particular, they contradict the idea that ldlPFC forms an abstract decision and suggest instead that its activation reflects preparation for the upcoming task. We further investigated the role of the fusiform face areas and parahippocampal place areas which are thought to be face and house detectors, respectively, that feed their signals to higher level decision areas. The response patterns within these areas suggest that this interpretation is unlikely and that the decisions about the presence of a face or a house in a noisy image might instead already be computed within these areas without requiring higher-order areas. Copyright © 2013 Wiley Periodicals, Inc.

Broader autism phenotype in parents of autistic children: reality or myth?

PubMed

Scheeren, Anke M; Stauder, Johannes E A

2008-02-01

The finding that relatives of individuals with autism show mild autistic traits is referred to as the broader autism phenotype (BAP). In the current study, 25 parents with a child with high-functioning autism and 25 parents with typically developed children were compared on: (1) the Block Design Test, (2) the Autism-Spectrum Quotient (AQ), and (3) a reaction time task to examine reflexive covert visual orienting to social (eyes) and non-social (arrows) cues. The parent groups were scored similar on the Block Design Test and the AQ. However, fathers with an autistic child demonstrated a different reaction time pattern and responded slower on the social cues than control fathers. These results partly support and further elaborate on the BAP in parents with an autistic child.

Maintenance of tactile short-term memory for locations is mediated by spatial attention.

PubMed

Katus, Tobias; Andersen, Søren K; Müller, Matthias M

2012-01-01

According to the attention-based rehearsal hypothesis, maintenance of spatial information is mediated by covert orienting towards memorized locations. In a somatosensory memory task, participants simultaneously received bilateral pairs of mechanical sample pulses. For each hand, sample stimuli were randomly assigned to one of three locations (fingers). A subsequent visual retro-cue determined whether the left or right hand sample was to be memorized. The retro-cue elicited lateralized activity reflecting the location of the relevant sample stimulus. Sensory processing during the retention period was probed by task-irrelevant pulses randomized to locations at the cued and uncued hand. The somatosensory N140 was enhanced for probes delivered to the cued hand, relative to uncued. Probes presented shortly after the retro-cue showed greatest attentional modulations. This suggests that transient contributions from retrospective selection overlapped with the sustained effect of attention-based rehearsal. In conclusion, focal attention shifts within tactile mnemonic content occurred after retro-cues and guided sensory processing during retention. Copyright © 2011 Elsevier B.V. All rights reserved.

Why do lesions in the rodent anterior thalamic nuclei cause such severe spatial deficits?

PubMed Central

Aggleton, John P.; Nelson, Andrew J.D.

2015-01-01

Lesions of the rodent anterior thalamic nuclei cause severe deficits to multiple spatial learning tasks. Possible explanations for these effects are examined, with particular reference to T-maze alternation. Anterior thalamic lesions not only impair allocentric place learning but also disrupt other spatial processes, including direction learning, path integration, and relative length discriminations, as well as aspects of nonspatial learning, e.g., temporal discriminations. Working memory tasks, such as T-maze alternation, appear particularly sensitive as they combine an array of these spatial and nonspatial demands. This sensitivity partly reflects the different functions supported by individual anterior thalamic nuclei, though it is argued that anterior thalamic lesion effects also arise from covert pathology in sites distal to the thalamus, most critically in the retrosplenial cortex and hippocampus. This two-level account, involving both local and distal lesion effects, explains the range and severity of the spatial deficits following anterior thalamic lesions. These findings highlight how the anterior thalamic nuclei form a key component in a series of interdependent systems that support multiple spatial functions. PMID:25195980

Effects of Peripheral Eccentricity and Head Orientation on Gaze Discrimination.

PubMed

Palanica, Adam; Itier, Roxane J

2014-01-01

Visual search tasks support a special role for direct gaze in human cognition, while classic gaze judgment tasks suggest the congruency between head orientation and gaze direction plays a central role in gaze perception. Moreover, whether gaze direction can be accurately discriminated in the periphery using covert attention is unknown. In the present study, individual faces in frontal and in deviated head orientations with a direct or an averted gaze were flashed for 150 ms across the visual field; participants focused on a centred fixation while judging the gaze direction. Gaze discrimination speed and accuracy varied with head orientation and eccentricity. The limit of accurate gaze discrimination was less than ±6° eccentricity. Response times suggested a processing facilitation for direct gaze in fovea, irrespective of head orientation, however, by ±3° eccentricity, head orientation started biasing gaze judgments, and this bias increased with eccentricity. Results also suggested a special processing of frontal heads with direct gaze in central vision, rather than a general congruency effect between eye and head cues. Thus, while both head and eye cues contribute to gaze discrimination, their role differs with eccentricity.

Visual-Spatial Attention Aids the Maintenance of Object Representations in Visual Working Memory

PubMed Central

Williams, Melonie; Pouget, Pierre; Boucher, Leanne; Woodman, Geoffrey F.

2013-01-01

Theories have proposed that the maintenance of object representations in visual working memory is aided by a spatial rehearsal mechanism. In this study, we used two different approaches to test the hypothesis that overt and covert visual-spatial attention mechanisms contribute to the maintenance of object representations in visual working memory. First, we tracked observers’ eye movements while remembering a variable number of objects during change-detection tasks. We observed that during the blank retention interval, participants spontaneously shifted gaze to the locations that the objects had occupied in the memory array. Next, we hypothesized that if attention mechanisms contribute to the maintenance of object representations, then drawing attention away from the object locations during the retention interval would impair object memory during these change-detection tasks. Supporting this prediction, we found that attending to the fixation point in anticipation of a brief probe stimulus during the retention interval reduced change-detection accuracy even on the trials in which no probe occurred. These findings support models of working memory in which visual-spatial selection mechanisms contribute to the maintenance of object representations. PMID:23371773

The wandering mind of men: ERP evidence for gender differences in attention bias towards attractive opposite sex faces

PubMed Central

Crawford, Helen; van Vugt, Mark

2011-01-01

To examine the time course and automaticity of our attention bias towards attractive opposite sex faces, event-related potentials (ERPs) were recorded from 20 males and 20 females while they carried out a covert orienting task. Faces that were high, low or average in attractiveness, were presented in focus of attention, but were unrelated to task goals. Across the entire sample larger P2 amplitudes were found in response to both attractive and unattractive opposite sex faces, presumably reflecting early implicit selective attention to distinctive faces. In male but not female participants this was followed by an increased late slow wave for the attractive faces, signifying heightened processing linked to motivated attention. This latter finding is consistent with sexual strategy theory, which suggests that men and women have evolved to pursue different mating strategies with men being more attentive to cues such as facial beauty. In general, our ERP results suggest that, in addition to threat-related stimuli, other evolutionary-relevant information is also prioritized by our attention systems. PMID:20601424

The wandering mind of men: ERP evidence for gender differences in attention bias towards attractive opposite sex faces.

PubMed

van Hooff, Johanna C; Crawford, Helen; van Vugt, Mark

2011-09-01

To examine the time course and automaticity of our attention bias towards attractive opposite sex faces, event-related potentials (ERPs) were recorded from 20 males and 20 females while they carried out a covert orienting task. Faces that were high, low or average in attractiveness, were presented in focus of attention, but were unrelated to task goals. Across the entire sample larger P2 amplitudes were found in response to both attractive and unattractive opposite sex faces, presumably reflecting early implicit selective attention to distinctive faces. In male but not female participants this was followed by an increased late slow wave for the attractive faces, signifying heightened processing linked to motivated attention. This latter finding is consistent with sexual strategy theory, which suggests that men and women have evolved to pursue different mating strategies with men being more attentive to cues such as facial beauty. In general, our ERP results suggest that, in addition to threat-related stimuli, other evolutionary-relevant information is also prioritized by our attention systems.

Eye vergence responses during a visual memory task.

PubMed

Solé Puig, Maria; Romeo, August; Cañete Crespillo, Jose; Supèr, Hans

2017-02-08

In a previous report it was shown that covertly attending visual stimuli produce small convergence of the eyes, and that visual stimuli can give rise to different modulations of the angle of eye vergence, depending on their power to capture attention. Working memory is highly dependent on attention. Therefore, in this study we assessed vergence responses in a memory task. Participants scanned a set of 8 or 12 images for 10 s, and thereafter were presented with a series of single images. One half were repeat images - that is, they belonged to the initial set - and the other half were novel images. Participants were asked to indicate whether or not the images were included in the initial image set. We observed that eyes converge during scanning the set of images and during the presentation of the single images. The convergence was stronger for remembered images compared with the vergence for nonremembered images. Modulation in pupil size did not correspond to behavioural responses. The correspondence between vergence and coding/retrieval processes of memory strengthen the idea of a role for vergence in attention processing of visual information.

How about Lunch? Consequences of the Meal Context on Cognition and Emotion

PubMed Central

Sommer, Werner; Stürmer, Birgit; Shmuilovich, Olga; Martin-Loeches, Manuel; Schacht, Annekathrin

2013-01-01

Although research addresses the effects of a meal’s context on food preference, the psychological consequences of meal situations are largely unexplored. We compared the cognitive and emotional effects of a restaurant meal eaten in the company of others to a solitary meal consumed in a plain office using pre- and post-tests analysis and controlling for the kind and amount of food consumed. Three tasks were conducted, measuring: (1) semantic memory (2) cognitive control and error monitoring, and (3) processing of emotional facial expressions. Covert processes in these tasks were assessed with event-related brain potentials. A mood rating questionnaire indicated a relaxation effect of the restaurant as compared to the plain meal situation. The restaurant meal increased sensitivity to threatening facial expressions and diminished cognitive control and error monitoring. No effects were observed for semantic memory. These findings provide the first experimental evidence that a restaurant meal with a social component may be more relaxing than a meal eaten alone in a plain setting and may reduce cognitive control. PMID:23936184

Cognitive control modulates attention to food cues: Support for the control readiness model of self-control.

PubMed

Kleiman, Tali; Trope, Yaacov; Amodio, David M

2016-12-01

Self-control in one's food choices often depends on the regulation of attention toward healthy choices and away from temptations. We tested whether selective attention to food cues can be modulated by a newly developed proactive self-control mechanism-control readiness-whereby control activated in one domain can facilitate control in another domain. In two studies, we elicited the activation of control using a color-naming Stroop task and tested its effect on attention to food cues in a subsequent, unrelated task. We found that control readiness modulates both overt attention, which involves shifts in eye gaze (Study 1), and covert attention, which involves shift in mental attention without shifting in eye gaze (Study 2). We further demonstrated that individuals for whom tempting food cues signal a self-control problem (operationalized by relatively higher BMI) were especially likely to benefit from control readiness. We discuss the theoretical contributions of the control readiness model and the implications of our findings for enhancing proactive self-control to overcome temptation in food choices. Copyright © 2016 Elsevier Inc. All rights reserved.

Conflict and user involvement in drug misuse treatment decision-making: a qualitative study

PubMed Central

Fischer, Jan; Neale, Joanne; Bloor, Michael; Jenkins, Nicholas

2008-01-01

Background This paper examines client/staff conflict and user involvement in drug misuse treatment decision-making. Methods Seventy-nine in-depth interviews were conducted with new treatment clients in two residential and two community drug treatment agencies. Fifty-nine of these clients were interviewed again after twelve weeks. Twenty-seven interviews were also conducted with staff, who were the keyworkers for the interviewed clients. Results Drug users did not expect, desire or prepare for conflict at treatment entry. They reported few actual conflicts within the treatment setting, but routinely discussed latent conflicts – that is, negative experiences and problematic aspects of current or previous treatment that could potentially escalate into overt disputes. Conflict resulted in a number of possible outcomes, including the premature termination of treatment; staff deciding on the appropriate outcome; the client appealing to the governance structure of the agency; brokered compromise; and staff skilfully eliciting client consent for staff decisions. Conclusion Although the implementation of user involvement in drug treatment decision-making has the potential to trigger high levels of staff-client conflict, latent conflict is more common than overt conflict and not all conflict is negative. Drug users generally want to be co-operative at treatment entry and often adopt non-confrontational forms of covert resistance to decisions about which they disagree. Staff sometimes deploy user involvement as a strategy for managing conflict and soliciting client compliance to treatment protocols. Suggestions for minimising and avoiding harmful conflict in treatment settings are given. PMID:18837989

Is the Go/No-Go Lexical Decision Task Preferable to the Yes/No Task with Developing Readers?

ERIC Educational Resources Information Center

Moret-Tatay, Carmen; Perea, Manuel

2011-01-01

The lexical decision task is probably the most common laboratory visual word identification task together with the naming task. In the usual setup, participants need to press the "yes" button when the stimulus is a word and the "no" button when the stimulus is not a word. A number of studies have employed this task with developing readers;…

Review of Department Identified Contracts and Grants for Public Relations Services. Final Inspection Report. ED-OIG/I13-F0012

ERIC Educational Resources Information Center

US Department of Education, 2005

2005-01-01

The objective of this inspection was to review the materials produced under 20 contracts and 15 grants issued by the Department of Education (Department) to determine whether any of the contracts and grants resulted in covert propaganda. It has been concluded that none of the grants resulted in covert propaganda under the existing guidance of the…

Goal-Directed Decision Making with Spiking Neurons.

PubMed

Friedrich, Johannes; Lengyel, Máté

2016-02-03

Behavioral and neuroscientific data on reward-based decision making point to a fundamental distinction between habitual and goal-directed action selection. The formation of habits, which requires simple updating of cached values, has been studied in great detail, and the reward prediction error theory of dopamine function has enjoyed prominent success in accounting for its neural bases. In contrast, the neural circuit mechanisms of goal-directed decision making, requiring extended iterative computations to estimate values online, are still unknown. Here we present a spiking neural network that provably solves the difficult online value estimation problem underlying goal-directed decision making in a near-optimal way and reproduces behavioral as well as neurophysiological experimental data on tasks ranging from simple binary choice to sequential decision making. Our model uses local plasticity rules to learn the synaptic weights of a simple neural network to achieve optimal performance and solves one-step decision-making tasks, commonly considered in neuroeconomics, as well as more challenging sequential decision-making tasks within 1 s. These decision times, and their parametric dependence on task parameters, as well as the final choice probabilities match behavioral data, whereas the evolution of neural activities in the network closely mimics neural responses recorded in frontal cortices during the execution of such tasks. Our theory provides a principled framework to understand the neural underpinning of goal-directed decision making and makes novel predictions for sequential decision-making tasks with multiple rewards. Goal-directed actions requiring prospective planning pervade decision making, but their circuit-level mechanisms remain elusive. We show how a model circuit of biologically realistic spiking neurons can solve this computationally challenging problem in a novel way. The synaptic weights of our network can be learned using local plasticity rules such that its dynamics devise a near-optimal plan of action. By systematically comparing our model results to experimental data, we show that it reproduces behavioral decision times and choice probabilities as well as neural responses in a rich set of tasks. Our results thus offer the first biologically realistic account for complex goal-directed decision making at a computational, algorithmic, and implementational level. Copyright © 2016 the authors 0270-6474/16/361529-18$15.00/0.

Goal-Directed Decision Making with Spiking Neurons

PubMed Central

Lengyel, Máté

2016-01-01

Behavioral and neuroscientific data on reward-based decision making point to a fundamental distinction between habitual and goal-directed action selection. The formation of habits, which requires simple updating of cached values, has been studied in great detail, and the reward prediction error theory of dopamine function has enjoyed prominent success in accounting for its neural bases. In contrast, the neural circuit mechanisms of goal-directed decision making, requiring extended iterative computations to estimate values online, are still unknown. Here we present a spiking neural network that provably solves the difficult online value estimation problem underlying goal-directed decision making in a near-optimal way and reproduces behavioral as well as neurophysiological experimental data on tasks ranging from simple binary choice to sequential decision making. Our model uses local plasticity rules to learn the synaptic weights of a simple neural network to achieve optimal performance and solves one-step decision-making tasks, commonly considered in neuroeconomics, as well as more challenging sequential decision-making tasks within 1 s. These decision times, and their parametric dependence on task parameters, as well as the final choice probabilities match behavioral data, whereas the evolution of neural activities in the network closely mimics neural responses recorded in frontal cortices during the execution of such tasks. Our theory provides a principled framework to understand the neural underpinning of goal-directed decision making and makes novel predictions for sequential decision-making tasks with multiple rewards. SIGNIFICANCE STATEMENT Goal-directed actions requiring prospective planning pervade decision making, but their circuit-level mechanisms remain elusive. We show how a model circuit of biologically realistic spiking neurons can solve this computationally challenging problem in a novel way. The synaptic weights of our network can be learned using local plasticity rules such that its dynamics devise a near-optimal plan of action. By systematically comparing our model results to experimental data, we show that it reproduces behavioral decision times and choice probabilities as well as neural responses in a rich set of tasks. Our results thus offer the first biologically realistic account for complex goal-directed decision making at a computational, algorithmic, and implementational level. PMID:26843636

Effects of environmental support on overt and covert visuospatial rehearsal.

PubMed

Lilienthal, Lindsey; Myerson, Joel; Abrams, Richard A; Hale, Sandra

2018-09-01

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants' eye movements revealed that the presence of support increased participants' fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.

Overt versus covert conduct disorder symptoms and the prospective prediction of antisocial personality disorder.

PubMed

Le Corff, Yann; Toupin, Jean

2014-12-01

Studies have shown strong continuity between conduct disorder (CD) in adolescence and antisocial personality disorder (APD) in adulthood. Researchers have been trying to explain why some adolescents with CD persist into adult APD and others do not. A few studies reported that overt and covert CD symptoms have a differential predictive power for APD, with mixed results. The present study aimed to evaluate the prospective association of overt and covert CD symptoms with APD in a sample of male adolescents with CD (N = 128, mean age = 15.6, SD = 1.6). Participants were recruited at intake in Quebec Youth Centers and reassessed 3 years later (n = 73). CD and ADHD symptoms were assessed at intake with the DISC-R while APD was assessed 3 years later with the SCID-II. Logistic regression results showed that, contrary to previous prospective studies (Lahey, Loeber, Burke, & Applegate, 2005; Washburn et al., 2007), overt (OR = 2.12, 95% CI [1.29, 3.50]) but not covert (OR = 1.04, 95% CI [0.69, 1.56]) symptoms predicted later APD, controlling for ADHD symptoms and socioeconomic status. It is hypothesized that the divergence with previous studies may be explained by the higher mean number and wider range of overt CD symptoms in our sample.

Revisiting the body-schema concept in the context of whole-body postural-focal dynamics.

PubMed

Morasso, Pietro; Casadio, Maura; Mohan, Vishwanathan; Rea, Francesco; Zenzeri, Jacopo

2015-01-01

The body-schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert) but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the equilibrium-point hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory-motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability.

Deficient attention modulation of lateralized alpha power in schizophrenia.

PubMed

Kustermann, Thomas; Rockstroh, Brigitte; Kienle, Johanna; Miller, Gregory A; Popov, Tzvetan

2016-06-01

Modulation of 8-14 Hz (alpha) activity in posterior brain regions is associated with covert attention deployment in visuospatial tasks. Alpha power decrease contralateral to to-be-attended stimuli is believed to foster subsequent processing, such as retention of task-relevant input. Degradation of this alpha-regulation mechanism may reflect an early stage of disturbed attention regulation contributing to impaired attention and working memory commonly found in schizophrenia. The present study tested this hypothesis of early disturbed attention regulation by examining alpha power modulation in a lateralized cued delayed response task in 14 schizophrenia patients (SZ) and 25 healthy controls (HC). Participants were instructed to remember the location of a 100-ms saccade-target cue in the left or right visual hemifield in order to perform a delayed saccade to that location after a retention interval. As expected, alpha power decrease during the retention interval was larger in contralateral than ipsilateral posterior regions, and SZ showed less of this lateralization than did HC. In particular, SZ failed to show hemifield-specific alpha modulation in posterior right hemisphere. Results suggest less efficient modulation of alpha oscillations that are considered critical for attention deployment and item encoding and, hence, may affect subsequent spatial working memory performance. © 2016 Society for Psychophysiological Research.

Revisiting the Body-Schema Concept in the Context of Whole-Body Postural-Focal Dynamics

PubMed Central

Morasso, Pietro; Casadio, Maura; Mohan, Vishwanathan; Rea, Francesco; Zenzeri, Jacopo

2015-01-01

The body-schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert) but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the equilibrium-point hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory–motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability. PMID:25741274

Spatial Attention and Temporal Expectation Under Timed Uncertainty Predictably Modulate Neuronal Responses in Monkey V1

PubMed Central

Sharma, Jitendra; Sugihara, Hiroki; Katz, Yarden; Schummers, James; Tenenbaum, Joshua; Sur, Mriganka

2015-01-01

The brain uses attention and expectation as flexible devices for optimizing behavioral responses associated with expected but unpredictably timed events. The neural bases of attention and expectation are thought to engage higher cognitive loci; however, their influence at the level of primary visual cortex (V1) remains unknown. Here, we asked whether single-neuron responses in monkey V1 were influenced by an attention task of unpredictable duration. Monkeys covertly attended to a spot that remained unchanged for a fixed period and then abruptly disappeared at variable times, prompting a lever release for reward. We show that monkeys responded progressively faster and performed better as the trial duration increased. Neural responses also followed monkey's task engagement—there was an early, but short duration, response facilitation, followed by a late but sustained increase during the time monkeys expected the attention spot to disappear. This late attentional modulation was significantly and negatively correlated with the reaction time and was well explained by a modified hazard function. Such bimodal, time-dependent changes were, however, absent in a task that did not require explicit attentional engagement. Thus, V1 neurons carry reliable signals of attention and temporal expectation that correlate with predictable influences on monkeys' behavioral responses. PMID:24836689

Exposure to Unsolvable Anagrams Impairs Performance on the Iowa Gambling Task

PubMed Central

Starcke, Katrin; Agorku, Janet D.; Brand, Matthias

2017-01-01

Recent research indicates that external manipulations, such as stress or mood induction, can affect decision-making abilities. In the current study, we investigated whether the exposure to an unsolvable task affected subsequent performance on the Iowa Gambling Task. Participants were randomly assigned to a condition in which they were exposed to unsolvable anagrams (n = 20), or a condition in which they worked on solvable anagrams (n = 22). Afterwards, all participants played the Iowa Gambling Task, a prominent task that measures decision making under uncertain conditions with no explicit rules for gains and losses. In this task, it is essential to process feedback from previous decisions. The results demonstrated that participants who worked on unsolvable anagrams made more disadvantageous decisions on the Iowa Gambling Task than the other participants. In addition, a significant gender effect was observed: Males who worked on unsolvable anagrams made a more disadvantageous decisions than the other male participants. Females who worked on unsolvable anagrams also made more disadvantageous decision than the other female participants, but differences were small and not significant. We conclude that the exposure to unsolvable anagrams induced the experience of uncontrollability which can elicit stress and learned helplessness. Stress and learned helplessness might have reduced the ability to learn from the given feedback, particularly in male participants. We assume that in real life, uncontrollable challenges that last longer than a single experimental manipulation can affect decision making severely, at least in males. PMID:28642693

[Decision making and executive function in severe traumatic brain injured patients: validation of a decision-making task and correlated features].

PubMed

Wiederkehr, S; Barat, M; Dehail, P; de Sèze, M; Lozes-Boudillon, S; Giroire, J-M

2005-02-01

At the chronic stage, severe traumatic brain injured (TBI) patients experience difficulty in making decisions. Several studies have demonstrated the involvement of the prefrontal cortex, in particular the orbitofrontal region, in decision-making. The aim of the present study was to validate a decision-making task in this population and to ascertain whether the components of their dysexecutive syndrome may affect their decision-making and lead to difficulties for social rehabilitation. Fifteen TBI patients and 15 controlled subjects matched for age, sex and years of education were assessed by a battery of executive tests (GREFEX) and by the gambling task (GT). The TBI subjects performed significantly worse than the controlled group in five out of six GREFEX tests. The TBI choices are significantly more disadvantageous than the choices of the control group when considering the three last blocks of 20 cards of the GT. The GT total score correlated significantly with execution time of the Stroop interference condition and the Trail Making Task B, as well as with the two measures (correct sequence span and number of crossed boxes) of the double condition of Baddeley's task. We postulate that executive functioning (supervisory attentional system) influence performance in the gambling task through mechanisms of inhibitory control, divided attention and working memory. Thus, this task seems to be determined by multiple factors; the process of decision-making may depend on frontal integrity.

Theory of choice in bandit, information sampling and foraging tasks.

PubMed

Averbeck, Bruno B

2015-03-01

Decision making has been studied with a wide array of tasks. Here we examine the theoretical structure of bandit, information sampling and foraging tasks. These tasks move beyond tasks where the choice in the current trial does not affect future expected rewards. We have modeled these tasks using Markov decision processes (MDPs). MDPs provide a general framework for modeling tasks in which decisions affect the information on which future choices will be made. Under the assumption that agents are maximizing expected rewards, MDPs provide normative solutions. We find that all three classes of tasks pose choices among actions which trade-off immediate and future expected rewards. The tasks drive these trade-offs in unique ways, however. For bandit and information sampling tasks, increasing uncertainty or the time horizon shifts value to actions that pay-off in the future. Correspondingly, decreasing uncertainty increases the relative value of actions that pay-off immediately. For foraging tasks the time-horizon plays the dominant role, as choices do not affect future uncertainty in these tasks.

Age differences in experiential and deliberative processes in unambiguous and ambiguous decision making.

PubMed

Huang, Yumi H; Wood, Stacey; Berger, Dale E; Hanoch, Yaniv

2015-09-01

Older adults experience declines in deliberative decisional capacities, while their affective or experiential abilities tend to remain intact (Peters & Bruine de Bruin, 2012). The current study used this framework to investigate age differences in description-based and experience-based decision-making tasks. Description-based tasks emphasize deliberative processing by allowing decision makers to analyze explicit descriptions of choice-reward information. Experience-based tasks emphasize affective or experiential processing because they lack the explicit choice-reward information, forcing decision makers to rely on feelings and information derived from past experiences. This study used the Columbia Card Task (CCT) as a description-based task where probability information is provided and the Iowa Gambling Task (IGT) as an experience-based task, where it is not. As predicted, compared to younger adults (N = 65), older adults (N = 65) performed more poorly on the CCT but performed similarly on the IGT. Deliberative capacities (i.e., executive control and numeracy abilities) explained the relationship between age and performance on the CCT, suggesting that age-related differences in description-based decision-making tasks are related to declines in deliberative capacities. However, deliberative capacities were not associated with performance on the IGT for either older or younger adults. Nevertheless, on the IGT, older adults reported more use of affect-based strategies versus deliberative strategies, whereas younger adults reported similar use of these strategies. This finding offers partial support for the idea that decision-making tasks that rely on deliberate processing are more likely to demonstrate age effects than those that are more experiential. (c) 2015 APA, all rights reserved).

Reasoning and mathematical skills contribute to normatively superior decision making under risk: evidence from the game of dice task.

PubMed

Pertl, Marie-Theres; Zamarian, Laura; Delazer, Margarete

2017-08-01

In this study, we assessed to what extent reasoning improves performance in decision making under risk in a laboratory gambling task (Game of Dice Task-Double, GDT-D). We also investigated to what degree individuals with above average mathematical competence decide better than those with average mathematical competence. Eighty-five participants performed the GDT-D and several numerical tasks. Forty-two individuals were asked to calculate the probabilities and the outcomes associated with the different options of the GDT-D before performing it. The other 43 individuals performed the GDT-D at the beginning of the test session. Both reasoning and mathematical competence had a positive effect on decision making. Different measures of mathematical competence correlated with advantageous performance in decision making. Results suggest that decision making under explicit risk conditions improves when individuals are encouraged to reflect about the contingencies of a decision situation. Interventions based on numerical reasoning may also be useful for patients with difficulties in decision making.

"Decisions, decisions, decisions": transfer and specificity of decision-making skill between sports.

PubMed

Causer, Joe; Ford, Paul R

2014-08-01

The concept of transfer of learning holds that previous practice or experience in one task or domain will enable successful performance in another related task or domain. In contrast, specificity of learning holds that previous practice or experience in one task or domain does not transfer to other related tasks or domains. The aim of the current study is to examine whether decision-making skill transfers between sports that share similar elements, or whether it is specific to a sport. Participants (n = 205) completed a video-based temporal occlusion decision-making test in which they were required to decide on which action to execute across a series of 4 versus 4 soccer game situations. A sport engagement questionnaire was used to identify 106 soccer players, 43 other invasion sport players and 58 other sport players. Positive transfer of decision-making skill occurred between soccer and other invasion sports, which are related and have similar elements, but not from volleyball, supporting the concept of transfer of learning.

Acquisition and production of skilled behavior in dynamic decision-making tasks

NASA Technical Reports Server (NTRS)

Kirlik, Alex

1990-01-01

Ongoing research investigating perceptual and contextual influences on skilled human performance in dynamic decision making environments is discussed. The research is motivated by two general classes of findings in recent decision making research. First, many studies suggest that the concrete context in which a task is presented has strong influences on the psychological processes used to perform the task and on subsequent performance. Second, studies of skilled behavior in a wide variety of task environments typically implicate the perceptual system as an important contributor to decision-making performance, either in its role as a mediator between the current decision context and stored knowledge, or as a mechanism capable of directly initiating activity through the development of a 'trained eye.' Both contextual and perceptual influences place limits on the ability of traditional utility-theoretic accounts of decision-making to guide display design, as variance in behavior due to contextual factors or the development of a perceptual skill is left unexplained. The author outlines a framework in which to view questions of perceptual and contextual influences on behavior and describe an experimental task and analysis technique which will be used to diagnose the possible role of perception in skilled decision making performance.

Predicting explorative motor learning using decision-making and motor noise.

PubMed

Chen, Xiuli; Mohr, Kieran; Galea, Joseph M

2017-04-01

A fundamental problem faced by humans is learning to select motor actions based on noisy sensory information and incomplete knowledge of the world. Recently, a number of authors have asked whether this type of motor learning problem might be very similar to a range of higher-level decision-making problems. If so, participant behaviour on a high-level decision-making task could be predictive of their performance during a motor learning task. To investigate this question, we studied performance during an explorative motor learning task and a decision-making task which had a similar underlying structure with the exception that it was not subject to motor (execution) noise. We also collected an independent measurement of each participant's level of motor noise. Our analysis showed that explorative motor learning and decision-making could be modelled as the (approximately) optimal solution to a Partially Observable Markov Decision Process bounded by noisy neural information processing. The model was able to predict participant performance in motor learning by using parameters estimated from the decision-making task and the separate motor noise measurement. This suggests that explorative motor learning can be formalised as a sequential decision-making process that is adjusted for motor noise, and raises interesting questions regarding the neural origin of explorative motor learning.

Predicting explorative motor learning using decision-making and motor noise

PubMed Central

Galea, Joseph M.

2017-01-01

A fundamental problem faced by humans is learning to select motor actions based on noisy sensory information and incomplete knowledge of the world. Recently, a number of authors have asked whether this type of motor learning problem might be very similar to a range of higher-level decision-making problems. If so, participant behaviour on a high-level decision-making task could be predictive of their performance during a motor learning task. To investigate this question, we studied performance during an explorative motor learning task and a decision-making task which had a similar underlying structure with the exception that it was not subject to motor (execution) noise. We also collected an independent measurement of each participant’s level of motor noise. Our analysis showed that explorative motor learning and decision-making could be modelled as the (approximately) optimal solution to a Partially Observable Markov Decision Process bounded by noisy neural information processing. The model was able to predict participant performance in motor learning by using parameters estimated from the decision-making task and the separate motor noise measurement. This suggests that explorative motor learning can be formalised as a sequential decision-making process that is adjusted for motor noise, and raises interesting questions regarding the neural origin of explorative motor learning. PMID:28437451

Decision-Making under Ambiguity Is Modulated by Visual Framing, but Not by Motor vs. Non-Motor Context. Experiments and an Information-Theoretic Ambiguity Model

PubMed Central

Grau-Moya, Jordi; Ortega, Pedro A.; Braun, Daniel A.

2016-01-01

A number of recent studies have investigated differences in human choice behavior depending on task framing, especially comparing economic decision-making to choice behavior in equivalent sensorimotor tasks. Here we test whether decision-making under ambiguity exhibits effects of task framing in motor vs. non-motor context. In a first experiment, we designed an experience-based urn task with varying degrees of ambiguity and an equivalent motor task where subjects chose between hitting partially occluded targets. In a second experiment, we controlled for the different stimulus design in the two tasks by introducing an urn task with bar stimuli matching those in the motor task. We found ambiguity attitudes to be mainly influenced by stimulus design. In particular, we found that the same subjects tended to be ambiguity-preferring when choosing between ambiguous bar stimuli, but ambiguity-avoiding when choosing between ambiguous urn sample stimuli. In contrast, subjects’ choice pattern was not affected by changing from a target hitting task to a non-motor context when keeping the stimulus design unchanged. In both tasks subjects’ choice behavior was continuously modulated by the degree of ambiguity. We show that this modulation of behavior can be explained by an information-theoretic model of ambiguity that generalizes Bayes-optimal decision-making by combining Bayesian inference with robust decision-making under model uncertainty. Our results demonstrate the benefits of information-theoretic models of decision-making under varying degrees of ambiguity for a given context, but also demonstrate the sensitivity of ambiguity attitudes across contexts that theoretical models struggle to explain. PMID:27124723

Decision-Making under Ambiguity Is Modulated by Visual Framing, but Not by Motor vs. Non-Motor Context. Experiments and an Information-Theoretic Ambiguity Model.

PubMed

Grau-Moya, Jordi; Ortega, Pedro A; Braun, Daniel A

2016-01-01

A number of recent studies have investigated differences in human choice behavior depending on task framing, especially comparing economic decision-making to choice behavior in equivalent sensorimotor tasks. Here we test whether decision-making under ambiguity exhibits effects of task framing in motor vs. non-motor context. In a first experiment, we designed an experience-based urn task with varying degrees of ambiguity and an equivalent motor task where subjects chose between hitting partially occluded targets. In a second experiment, we controlled for the different stimulus design in the two tasks by introducing an urn task with bar stimuli matching those in the motor task. We found ambiguity attitudes to be mainly influenced by stimulus design. In particular, we found that the same subjects tended to be ambiguity-preferring when choosing between ambiguous bar stimuli, but ambiguity-avoiding when choosing between ambiguous urn sample stimuli. In contrast, subjects' choice pattern was not affected by changing from a target hitting task to a non-motor context when keeping the stimulus design unchanged. In both tasks subjects' choice behavior was continuously modulated by the degree of ambiguity. We show that this modulation of behavior can be explained by an information-theoretic model of ambiguity that generalizes Bayes-optimal decision-making by combining Bayesian inference with robust decision-making under model uncertainty. Our results demonstrate the benefits of information-theoretic models of decision-making under varying degrees of ambiguity for a given context, but also demonstrate the sensitivity of ambiguity attitudes across contexts that theoretical models struggle to explain.

Opening the Black Box: Cognitive Strategies in Family Practice

PubMed Central

Christensen, Robert E.; Fetters, Michael D.; Green, Lee A.

2005-01-01

PURPOSE We wanted to describe the cognitive strategies used by family physicians when structuring the decision-making tasks of an outpatient visit. METHODS This qualitative study used cognitive task analysis, a structured interview method in which a trained interviewer works individually with expert decision makers to capture their stages and elements of information processing. RESULTS Eighteen family physicians of varying levels of experience participated. Three dominant themes emerged: time pressure, a high degree of variation in task structuring, and varying degrees of task automatization. Based on these data and previous research from the cognitive sciences, we developed a model of novice and expert approaches to decision making in primary care. The model illustrates differences in responses to unexpected opportunity in practice, particularly the expert’s use of attentional surplus (reserve capacity to handle problems) vs the novice’s choice between taking more time or displacing another task. CONCLUSIONS Family physicians have specific, highly individualized cognitive task-structuring approaches and show the decision behavior features typical of expert decision makers in other fields. This finding places constraints on and suggests useful approaches for improving practice. PMID:15798041

Strategic and non-strategic problem gamblers differ on decision-making under risk and ambiguity.

PubMed

Lorains, Felicity K; Dowling, Nicki A; Enticott, Peter G; Bradshaw, John L; Trueblood, Jennifer S; Stout, Julie C

2014-07-01

To analyse problem gamblers' decision-making under conditions of risk and ambiguity, investigate underlying psychological factors associated with their choice behaviour and examine whether decision-making differed in strategic (e.g., sports betting) and non-strategic (e.g., electronic gaming machine) problem gamblers. Cross-sectional study. Out-patient treatment centres and university testing facilities in Victoria, Australia. Thirty-nine problem gamblers and 41 age, gender and estimated IQ-matched controls. Decision-making tasks included the Iowa Gambling Task (IGT) and a loss aversion task. The Prospect Valence Learning (PVL) model was used to provide an explanation of cognitive, motivational and response style factors involved in IGT performance. Overall, problem gamblers performed more poorly than controls on both the IGT (P = 0.04) and the loss aversion task (P = 0.01), and their IGT decisions were associated with heightened attention to gains (P = 0.003) and less consistency (P = 0.002). Strategic problem gamblers did not differ from matched controls on either decision-making task, but non-strategic problem gamblers performed worse on both the IGT (P = 0.006) and the loss aversion task (P = 0.02). Furthermore, we found differences in the PVL model parameters underlying strategic and non-strategic problem gamblers' choices on the IGT. Problem gamblers demonstrated poor decision-making under conditions of risk and ambiguity. Strategic (e.g. sports betting, poker) and non-strategic (e.g. electronic gaming machines) problem gamblers differed in decision-making and the underlying psychological processes associated with their decisions. © 2014 Society for the Study of Addiction.

Critical Issues in Telecollaborative Task Design

ERIC Educational Resources Information Center

O'Dowd, R.; Waire, P.

2009-01-01

In this article we examine how instructors make decisions about task design in telecollaboration and the factors that influence these decisions during the actual implementation of the tasks. We begin with a review of the recent literature of online intercultural exchanges to identify and describe a typology of 12 different types of tasks and task…

Rodent models of adaptive decision making.

PubMed

Izquierdo, Alicia; Belcher, Annabelle M

2012-01-01

Adaptive decision making affords the animal the ability to respond quickly to changes in a dynamic environment: one in which attentional demands, cost or effort to procure the reward, and reward contingencies change frequently. The more flexible the organism is in adapting choice behavior, the more command and success the organism has in navigating its environment. Maladaptive decision making is at the heart of much neuropsychiatric disease, including addiction. Thus, a better understanding of the mechanisms that underlie normal, adaptive decision making helps achieve a better understanding of certain diseases that incorporate maladaptive decision making as a core feature. This chapter presents three general domains of methods that the experimenter can manipulate in animal decision-making tasks: attention, effort, and reward contingency. Here, we present detailed methods of rodent tasks frequently employed within these domains: the Attentional Set-Shift Task, Effortful T-maze Task, and Visual Discrimination Reversal Learning. These tasks all recruit regions within the frontal cortex and the striatum, and performance is heavily modulated by the neurotransmitter dopamine, making these assays highly valid measures in the study of psychostimulant addiction.

Erroneous knowledge of results affects decision and memory processes on timing tasks.

PubMed

Ryan, Lawrence J; Fritz, Matthew S

2007-12-01

On mental timing tasks, erroneous knowledge of results (KR) leads to incorrect performance accompanied by the subjective judgment of accurate performance. Using the start-stop technique (an analogue of the peak interval procedure) with both reproduction and production timing tasks, the authors analyze what processes erroneous KR alters. KR provides guidance (performance error information) that lowers decision thresholds. Erroneous KR also provides targeting information that alters response durations proportionately to the magnitude of the feedback error. On the production task, this shift results from changes in the reference memory, whereas on the reproduction task this shift results from changes in the decision threshold for responding. The idea that erroneous KR can alter different cognitive processes on related tasks is supported by the authors' demonstration that the learned strategies can transfer from the reproduction task to the production task but not visa versa. Thus effects of KR are both task and context dependent.

Transferring control demands across incidental learning tasks – stronger sequence usage in serial reaction task after shortcut option in letter string checking

PubMed Central

Gaschler, Robert; Marewski, Julian N.; Wenke, Dorit; Frensch, Peter A.

2014-01-01

After incidentally learning about a hidden regularity, participants can either continue to solve the task as instructed or, alternatively, apply a shortcut. Past research suggests that the amount of conflict implied by adopting a shortcut seems to bias the decision for vs. against continuing instruction-coherent task processing. We explored whether this decision might transfer from one incidental learning task to the next. Theories that conceptualize strategy change in incidental learning as a learning-plus-decision phenomenon suggest that high demands to adhere to instruction-coherent task processing in Task 1 will impede shortcut usage in Task 2, whereas low control demands will foster it. We sequentially applied two established incidental learning tasks differing in stimuli, responses and hidden regularity (the alphabet verification task followed by the serial reaction task, SRT). While some participants experienced a complete redundancy in the task material of the alphabet verification task (low demands to adhere to instructions), for others the redundancy was only partial. Thus, shortcut application would have led to errors (high demands to follow instructions). The low control demand condition showed the strongest usage of the fixed and repeating sequence of responses in the SRT. The transfer results are in line with the learning-plus-decision view of strategy change in incidental learning, rather than with resource theories of self-control. PMID:25506336

Examining Preservice Teachers' Decision Behaviors and Individual Differences in Three Online Case-Based Approaches

ERIC Educational Resources Information Center

Cevik, Yasemin Demiraslan; Andre, Thomas

2013-01-01

This study compared the impact of three types of case-based methods (case-based reasoning, worked example, and faded worked example) on preservice teachers' (n = 71) interaction with decision tasks and whether decision related measures (task difficulty, mental effort, decision making performance) were associated with the differences in student…

Subthalamic Neural Activity Patterns Anticipate Economic Risk Decisions in Gambling

PubMed Central

Rosa, M.; Carpaneto, J.; Priori, A.

2018-01-01

Abstract Economic decision-making is disrupted in individuals with gambling disorder, an addictive behavior observed in Parkinson’s disease (PD) patients receiving dopaminergic therapy. The subthalamic nucleus (STN) is involved in the inhibition of impulsive behaviors; however, its role in impulse control disorders and addiction is still unclear. Here, we recorded STN local field potentials (LFPs) in PD patients with and without gambling disorder during an economic decision-making task. Reaction times analysis showed that for all patients, the decision whether to risk preceded task onset. We compared then for both groups the STN LFP preceding high- and low-risk economic decisions. We found that risk avoidance in gamblers correlated with larger STN LFP low-frequency (<12-Hz) fluctuations preceding task onset. In particular, the amplitude of low-frequency LFP fluctuations carried significant information about future decisions. Decisions of patients not affected by gambling disorder were instead not correlated with pretask STN LFP. Our results suggest that STN activity preceding task onset affects risk decisions by preemptively inhibiting attraction to high but unlikely rewards in favor of a long-term payoff. PMID:29445770

Development of a novel task for investigating decision making in a social context following traumatic brain injury.

PubMed

Kelly, Michelle; McDonald, Skye; Kellett, David

2014-01-01

Examination of social cognition as a target for assessment and intervention is beginning to gain momentum in a number of illnesses and acquired disorders. One facet of social cognition is decision making within interpersonal situations. This skill forms an important part of our everyday lives and is commonly impaired in those with neurological and mental health conditions. A novel task was developed to allow the assessment of decision making specifically within a social context and was examined within a group known to experience this difficulty. Participants with severe traumatic brain injury (TBI) were compared to healthy control participants on the Social Decision Making Task (SDMT), which required the participant to learn who the "friendly" players were in a game of toss. Participants also completed a nonsocial decision-making task, the Iowa Gambling Task (IGT) as well as a battery of neuropsychological tests and social cognition tasks. Current social functioning was also examined. Consistent with predictions, the TBI group made poorer decisions on the SDMT than the control group; however, group differences were not evident on the IGT. No significant relationships were observed between the SDMT and either measures of executive functioning (including working memory and reversal learning) or social cognition (including emotion recognition and theory of mind). Performance on the SDMT and the IGT were not associated, suggesting that the two tasks measure different constructs. The SDMT offers a novel way of examining decision making within a social context following TBI and may also be useful in other populations known to have specific social cognition impairment. Future research should aim to provide further clarification of the mechanisms of action and neuroanatomical correlates of poor performance on this task.

Covert Android Rootkit Detection: Evaluating Linux Kernel Level Rootkits on the Android Operating System

DTIC Science & Technology

2012-06-14

the attacker . Thus, this race condition causes a privilege escalation . 2.2.5 Summary This section reviewed software exploitation of a Linux kernel...has led to increased targeting by malware writers. Android attacks have naturally sparked interest in researching protections for Android . This...release, Android 4.0 Ice Cream Sandwich. These rootkits focused on covert techniques to hide the presence of data used by an attacker to infect a

Selective attention within the foveola.

PubMed

Poletti, Martina; Rucci, Michele; Carrasco, Marisa

2017-10-01

Efficient control of attentional resources and high-acuity vision are both fundamental for survival. Shifts in visual attention are known to covertly enhance processing at locations away from the center of gaze, where visual resolution is low. It is unknown, however, whether selective spatial attention operates where the observer is already looking-that is, within the high-acuity foveola, the small yet disproportionally important rod-free region of the retina. Using new methods for precisely controlling retinal stimulation, here we show that covert attention flexibly improves and speeds up both detection and discrimination at loci only a fraction of a degree apart within the foveola. These findings reveal a surprisingly precise control of attention and its involvement in fine spatial vision. They show that the commonly studied covert shifts of attention away from the fovea are the expression of a global mechanism that exerts its action across the entire visual field.

Age determination of female redhead ducks

USGS Publications Warehouse

Dane, C.W.; Johnson, D.H.

1975-01-01

Eighty-seven fall-collected wings from female redhead ducks (Aythya americana) were assigned to the adult or juvenile group based on 'tertial' and 'tertial covert' shape and wear. To obtain spring age-related characters from these fall-collected groupings, we considered parameters of flight feathers retained until after the first breeding season. Parameters measured included: markings on and width of greater secondary coverts, and length, weight, and diameter of primary feathers. The best age categorization was obtained with discriminant analysis based on a combination of the most accurately measured parameters. This analysis, applied to 81 wings with complete measurements, resulted in only 1 being incorrectly aged and 3 placed in a questionable category. Discriminant functions used with covert markings and the three 5th primary parameters were applied to 30 known-age juvenile, hand-reared redhead females, 28 were correctly aged, none was incorrectly aged, and only 2 were placed in the questionable category.

Peer Status in Boys With and Without Attention-Deficit Hyperactivity Disorder: Predictions from Overt and Covert Antisocial Behavior, Social Isolation, and Authoritative Parenting Beliefs.

PubMed

Hinshaw, Stephen P; Zupan, Brian A; Simmel, Cassandra; Nigg, Joel T; Melnick, Sharon

1997-10-01

Because of the centrality of peer relationship difficulties for children with attentiondeficit hyperactivity disorder (ADHD), we investigated behavioral (overt and covert antisocial activity), internalizing (self-reports and observed social isolation), and familial (authoritative, authoritarian, and permissive parenting beliefs) predictors of peer sociometric nominations among previously unfamiliar, ethnically diverse ADHD (N=73) and comparison (N=60) boys, aged 6-12 years. Authoritative maternal parenting beliefs and negatively weighted social isolation explained significant variance in positive peer regard; aggression, covert behavior, and authoritative parenting beliefs were the independent predictors of both negative peer status and peer social preference. We extended such predictions with statistical control of (1) child cognitive variables, (2) maternal psychopathology, and (3) ADHD boys, but authoritative parenting beliefs were stronger predictors in ADHD than in comparison youth. We discuss family-peer linkages regarding peer competence.

Selective attention within the foveola

PubMed Central

Poletti, Martina; Rucci, Michele; Carrasco, Marisa

2018-01-01

Efficient control of attentional resources and high-acuity vision are both fundamental for survival. Shifts in visual attention are known to covertly enhance processing at locations away from the center of gaze, where visual resolution is low. It is unknown, however, whether selective spatial attention operates where the observer already looks, i.e., within the high-acuity foveola, the small, yet disproportionally important rod-free region of the retina. Using new methods for precisely controlling retinal stimulation, here we show that covert attention flexibly improves and speeds-up both detection and discrimination at loci only a fraction of a degree apart within the foveola. These findings reveal a surprisingly precise control of attention and its involvement in fine spatial vision. They show that the commonly studied covert shifts of attention away from the fovea are the expression of a global mechanism that exerts its action across the entire visual field. PMID:28805816

Relations of Proactive and Reactive Dimensions of Aggression to Overt and Covert Narcissism in Nonclinical Adolescents

PubMed Central

Fossati, Andrea; Borroni, Serena; Eisenberg, Nancy; Maffei, Cesare

2009-01-01

In recent years, there has been increasing acknowledgement of the multidimensionality of narcissism and that different types of narcissism may relate differently to other domains of functioning. Similarly, aggression—a frequently discussed correlate of narcissism--is a heterogeneous construct. In the present study, the relations of proactive and reactive aggression with overt and covert manifestations of narcissism were examined in a sample of 674 Italian high school students (mean age = 15.5 years, SD = 2.1 years). Overt narcissism was positively related to both proactive and reactive subtypes of aggression, whereas covert narcissism related only to reactive aggression. Vanity, Authority, Exhibitionism, and Exploitativeness were the components of overt narcissism related to Proactive Aggression (all remained unique correlates when controlling for Reactive Aggression), whereas Reactive Aggression was associated with the Exhibitionism, Superiority, and Entitlement subscales (only the latter was uniquely related when controlling for Proactive Aggression). PMID:19918915

The stigma of obesity in customer service: a mechanism for remediation and bottom-line consequences of interpersonal discrimination.

PubMed

King, Eden B; Shapiro, Jenessa R; Hebl, Michelle R; Singletary, Sarah L; Turner, Stacey

2006-05-01

Using a customer service paradigm, the authors extended the justification-suppression model (JSM) of prejudice (C. S. Crandall & A. Eshleman, 2003) to include contemporary, covert forms of discrimination and to identify a discrimination remediation mechanism. Overall, the results of 3 studies revealed that actual and confederate obese shoppers in high-prejudice justification conditions faced more interpersonal discrimination than average-weight shoppers. Furthermore, Studies 1 and 2 demonstrate that adopting strategies that remove perceivers' justifications for discriminating against obese individuals (i.e., the controllability of weight) decreases the incidence of interpersonal discrimination. Additionally, Study 3 demonstrates negative bottom-line consequences of interpersonal discrimination for organizations (e.g., customer loyalty, purchasing behavior). Together, these studies confirm that the JSM applies to covert forms of discrimination, show the importance of examining subtle discrimination, and offer a mechanism for theory-driven strategies for the reduction of covert forms of discrimination.

A pill in the sandwich: covert medication in food and drink.

PubMed Central

Treloar, A; Beats, B; Philpot, M

2000-01-01

The covert administration of medicines in food and drink has been condemned by some and condoned by others. We used questionnaires to ascertain the views of people caring for patients with dementia in institutions and in the community. In 24 (71%) of 34 residential, nursing and inpatient units in south-east England, the respondent said that medicines were sometimes given in this way. It was often done secretly and without discussion, probably for fear of professional retribution. Few institutions had a formal policy on the matter. Of 50 people caring for demented patients in the community, 48 (96%) thought the practice sometimes justifiable, but 47 believed that doctors should consult with carers before deciding. Even if, as most carers and some authorities believe, covert medication can be justified, the poor recording and secrecy surrounding the practice in institutions are cause for concern. PMID:10983501

[Mild head injury in children and adults: Diagnostic challenges in the emergency department].

PubMed

Leidel, B A; Lindner, T; Wolf, S; Bogner, V; Steinbeck, A; Börner, N; Peiser, C; Audebert, H J; Biberthaler, P; Kanz, K-G

2015-06-01

Mild head injuries are one of the most frequent reasons for attending emergency departments and are particularly challenging in different ways. While clinically important injuries are infrequent, delayed or missed injuries may lead to fatal consequences. The initial mostly inconspicuous appearance may not reflect the degree of intracranial injury and computed tomography (CT) is necessary to rule out covert injuries. Furthermore, infants and young children with a lack of or rudimentary cognitive and language development are challenging, especially for those examiners not familiar with pediatric care. Established check lists of clinical risk factors for children and adults regarding traumatic brain injuries allow specific and rational decision-making for cranial CT imaging. Clinically important intracranial injuries can be reliably detected and unnecessary radiation exposure avoided at the same time.

[Mild head injury in children and adults. Diagnostic challenges in the emergency department].

PubMed

Leidel, B A; Lindner, T; Wolf, S; Bogner, V; Steinbeck, A; Börner, N; Peiser, C; Audebert, H J; Biberthaler, P; Kanz, K-G

2015-01-01

Mild head injuries are one of the most frequent reasons for attending emergency departments and are particularly challenging in different ways. While clinically important injuries are infrequent, delayed or missed injuries may lead to fatal consequences. The initial mostly inconspicuous appearance may not reflect the degree of intracranial injury and computed tomography (CT) is necessary to rule out covert injuries. Furthermore, infants and young children with a lack of or rudimentary cognitive and language development are challenging, especially for those examiners not familiar with pediatric care. Established check lists of clinical risk factors for children and adults regarding traumatic brain injuries allow specific and rational decision-making for cranial CT imaging. Clinically important intracranial injuries can be reliably detected and unnecessary radiation exposure avoided at the same time.

Flight feather attachment in rock pigeons (Columba livia): covert feathers and smooth muscle coordinate a morphing wing.

PubMed

Hieronymus, Tobin L

2016-11-01

Mechanisms for passively coordinating forelimb movements and flight feather abduction and adduction have been described separately from both in vivo and ex vivo studies. Skeletal coordination has been identified as a way for birds to simplify the neuromotor task of controlling flight stroke, but an understanding of the relationship between skeletal coordination and the coordination of the aerodynamic control surface (the flight feathers) has been slow to materialize. This break between the biomechanical and aerodynamic approaches - between skeletal kinematics and airfoil shape - has hindered the study of dynamic flight behaviors. Here I use dissection and histology to identify previously overlooked interconnections between musculoskeletal elements and flight feathers. Many of these structures are well-placed to directly link elements of the passive musculoskeletal coordination system with flight feather movements. Small bundles of smooth muscle form prominent connections between upper forearm coverts (deck feathers) and the ulna, as well as the majority of interconnections between major flight feathers of the hand. Abundant smooth muscle may play a role in efficient maintenance of folded wing posture, and may also provide an autonomically regulated means of tuning wing shape and aeroelastic behavior in flight. The pattern of muscular and ligamentous linkages of flight feathers to underlying muscle and bone may provide predictable passive guidance for the shape of the airfoil during flight stroke. The structures described here provide an anatomical touchstone for in vivo experimental tests of wing surface coordination in an extensively researched avian model species. © 2016 Anatomical Society.

Neural foundations of overt and covert actions.

PubMed

Simos, Panagiotis G; Kavroulakis, Eleftherios; Maris, Thomas; Papadaki, Efrosini; Boursianis, Themistoklis; Kalaitzakis, Giorgos; Savaki, Helen E

2017-05-15

We used fMRI to assess the human brain areas activated for execution, observation and 1st person motor imagery of a visually guided tracing task with the index finger. Voxel-level conjunction analysis revealed several cortical areas activated in common across all three motor conditions, namely, the upper limb representation of the primary motor and somatosensory cortices, the dorsal and ventral premotor, the superior and inferior parietal cortices as well as the posterior part of the superior and middle temporal gyrus including the temporo-parietal junction (TPj) and the extrastriate body area (EBA). Functional connectivity analyses corroborated the notion that a common sensory-motor fronto-parieto-temporal cortical network is engaged for execution, observation, and imagination of the very same action. Taken together these findings are consistent with the more parsimonious account of motor cognition provided by the mental simulation theory rather than the recently revised mirror neuron view Action imagination and observation were each associated with several additional functional connections, which may serve the distinction between overt action and its covert counterparts, and the attribution of action to the correct agent. For example, the central position of the right middle and inferior frontal gyrus in functional connectivity during motor imagery may reflect the suppression of movements during mere imagination of action, and may contribute to the distinction between 'imagined' and 'real' action. Also, the central role of the right EBA in observation, assessed by functional connectivity analysis, may be related to the attribution of action to the 'external agent' as opposed to the 'self'. Copyright © 2017 Elsevier Inc. All rights reserved.

Classification images reveal decision variables and strategies in forced choice tasks

PubMed Central

Pritchett, Lisa M.; Murray, Richard F.

2015-01-01

Despite decades of research, there is still uncertainty about how people make simple decisions about perceptual stimuli. Most theories assume that perceptual decisions are based on decision variables, which are internal variables that encode task-relevant information. However, decision variables are usually considered to be theoretical constructs that cannot be measured directly, and this often makes it difficult to test theories of perceptual decision making. Here we show how to measure decision variables on individual trials, and we use these measurements to test theories of perceptual decision making more directly than has previously been possible. We measure classification images, which are estimates of templates that observers use to extract information from stimuli. We then calculate the dot product of these classification images with the stimuli to estimate observers' decision variables. Finally, we reconstruct each observer's “decision space,” a map that shows the probability of the observer’s responses for all values of the decision variables. We use this method to examine decision strategies in two-alternative forced choice (2AFC) tasks, for which there are several competing models. In one experiment, the resulting decision spaces support the difference model, a classic theory of 2AFC decisions. In a second experiment, we find unexpected decision spaces that are not predicted by standard models of 2AFC decisions, and that suggest intrinsic uncertainty or soft thresholding. These experiments give new evidence regarding observers’ strategies in 2AFC tasks, and they show how measuring decision variables can answer long-standing questions about perceptual decision making. PMID:26015584

Attention and implicit memory in the category-verification and lexical decision tasks.

PubMed

Mulligan, Neil W; Peterson, Daniel

2008-05-01

Prior research on implicit memory appeared to support 3 generalizations: Conceptual tests are affected by divided attention, perceptual tasks are affected by certain divided-attention manipulations, and all types of priming are affected by selective attention. These generalizations are challenged in experiments using the implicit tests of category verification and lexical decision. First, both tasks were unaffected by divided-attention tasks known to impact other priming tasks. Second, both tasks were unaffected by a manipulation of selective attention in which colored words were either named or their colors identified. Thus, category verification, unlike other conceptual tasks, appears unaffected by divided attention, and some selective-attention tasks, and lexical decision, unlike other perceptual tasks, appears unaffected by a difficult divided-attention task and some selective-attention tasks. Finally, both tasks were affected by a selective-attention task in which attention was manipulated across objects (rather than within objects), indicating some susceptibility to selective attention. The results contradict an analysis on the basis of the conceptual-perceptual distinction and other more specific hypotheses but are consistent with the distinction between production and identification priming.

How Expert Pilots Think Cognitive Processes in Expert Decision Making

DTIC Science & Technology

1993-02-01

Management (CRM) This document is available to the public Advanced Qualification Program (AQP) through the National Technical Information Cognitive Task Analysis (CTA...8217 Selecting realistic EDM scenarios with critical events and performing a cognitive task analysis of novice vs. expert decision making for these events...scenarios with critical events and performing a cognitive task analysis of novice vs. expert decision making for these events is a basic requirement for

Different effects of dopaminergic medication on perceptual decision-making in Parkinson's disease as a function of task difficulty and speed-accuracy instructions.

PubMed

Huang, Yu-Ting; Georgiev, Dejan; Foltynie, Tom; Limousin, Patricia; Speekenbrink, Maarten; Jahanshahi, Marjan

2015-08-01

When choosing between two options, sufficient accumulation of information is required to favor one of the options over the other, before a decision is finally reached. To establish the effect of dopaminergic medication on the rate of accumulation of information, decision thresholds and speed-accuracy trade-offs, we tested 14 patients with Parkinson's disease (PD) on and off dopaminergic medication and 14 age-matched healthy controls on two versions of the moving-dots task. One version manipulated the level of task difficulty and hence effort required for decision-making and the other the urgency, requiring decision-making under speed vs. accuracy instructions. The drift diffusion model was fitted to the behavioral data. As expected, the reaction time data revealed an effect of task difficulty, such that the easier the perceptual decision-making task was, the faster the participants responded. PD patients not only made significantly more errors compared to healthy controls, but interestingly they also made significantly more errors ON than OFF medication. The drift diffusion model indicated that PD patients had lower drift rates when tested ON compared to OFF medication, indicating that dopamine levels influenced the quality of information derived from sensory information. On the speed-accuracy task, dopaminergic medication did not directly influence reaction times or error rates. PD patients OFF medication had slower RTs and made more errors with speed than accuracy instructions compared to the controls, whereas such differences were not observed ON medication. PD patients had lower drift rates and higher response thresholds than the healthy controls both with speed and accuracy instructions and ON and OFF medication. For the patients, only non-decision time was higher OFF than ON medication and higher with accuracy than speed instructions. The present results demonstrate that when task difficulty is manipulated, dopaminergic medication impairs perceptual decision-making and renders it more errorful in PD relative to when patients are tested OFF medication. In contrast, for the speed/accuracy task, being ON medication improved performance by eliminating the significantly higher errors and slower RTs observed for patients OFF medication compared to the HC group. There was no evidence of dopaminergic medication inducing impulsive decisions when patients were acting under speed pressure. For the speed-accuracy instructions, the sole effect of dopaminergic medication was on non-decision time, which suggests that medication primarily affected processes tightly coupled with the motor symptoms of PD. Interestingly, the current results suggest opposite effects of dopaminergic medication on the levels of difficulty and speed-accuracy versions of the moving dots task, possibly reflecting the differential effect of dopamine on modulating drift rate (levels of difficulty task) and non-decision time (speed-accuracy task) in the process of perceptual decision making. Copyright © 2015 Elsevier Ltd. All rights reserved.

Land Ahoy! Understanding Submarine Command and Control During the Completion of Inshore Operations.

PubMed

Roberts, Aaron P J; Stanton, Neville A; Fay, Daniel

2017-12-01

The aim of this study was to use multiple command teams to provide empirical evidence for understanding communication flow, information pertinence, and tasks undertaken in a submarine control room when completing higher- and lower-demand inshore operation (INSO) scenarios. The focus of submarine operations has changed, and submarines are increasingly required to operate in costal littoral zones. However, submarine command team performance during INSO is not well understood, particularly from a sociotechnical systems perspective. A submarine control-room simulator was built. The creation of networked workstations allowed a team of nine operators to perform tasks completed by submarine command teams during INSO. The Event Analysis of Systematic Teamwork method was used to model the social, task, and information networks and to describe command team performance. Ten teams were recruited for the study, affording statistical comparisons of how command-team roles and level of demand affected performance. Results indicated that the submarine command-team members are required to rapidly integrate sonar and visual data as the periscope is used, periodically, in a "duck-and-run" fashion, to maintain covertness. The fusion of such information is primarily completed by the operations officer (OPSO), with this operator experiencing significantly greater demand than any other operator. The OPSO was a bottleneck in the command team when completing INSO, experiencing similar load in both scenarios, suggesting that the command team may benefit from data synthesis tasks being more evenly distributed within the command team. The work can inform future control-room design and command-team ways of working by identifying bottlenecks in terms of information and task flow between operators.

On the relation between feeling of knowing and lexical decision: persistent subthreshold activation or topic familiarity?

PubMed

Connor, L T; Balota, D A; Neely, J H

1992-05-01

Experiment 1 replicated Yaniv and Meyer's (1987) finding that lexical decision and episodic recognition performance was better for words previously yielding high-accessibility levels (a combination of feeling-of-knowing and tip-of-the-tongue ratings) in comparison with those yielding low-accessibility levels in a rare word definition task. Experiment 2 yielded the same pattern even though lexical decisions preceded accessibility estimates by a full week. Experiment 3 dismissed the possibility that the Experiment 2 results may have been due to a long-term influence from the lexical decision task to the rare word judgment task. These results support a model in which Ss (a) retrieve topic familiarity information in making accessibility estimates in the rare word definition task and (b) use this information to modulate lexical decision performance.

Cognitive programs: software for attention's executive

PubMed Central

Tsotsos, John K.; Kruijne, Wouter

2014-01-01

What are the computational tasks that an executive controller for visual attention must solve? This question is posed in the context of the Selective Tuning model of attention. The range of required computations go beyond top-down bias signals or region-of-interest determinations, and must deal with overt and covert fixations, process timing and synchronization, information routing, memory, matching control to task, spatial localization, priming, and coordination of bottom-up with top-down information. During task execution, results must be monitored to ensure the expected results. This description includes the kinds of elements that are common in the control of any kind of complex machine or system. We seek a mechanistic integration of the above, in other words, algorithms that accomplish control. Such algorithms operate on representations, transforming a representation of one kind into another, which then forms the input to yet another algorithm. Cognitive Programs (CPs) are hypothesized to capture exactly such representational transformations via stepwise sequences of operations. CPs, an updated and modernized offspring of Ullman's Visual Routines, impose an algorithmic structure to the set of attentional functions and play a role in the overall shaping of attentional modulation of the visual system so that it provides its best performance. This requires that we consider the visual system as a dynamic, yet general-purpose processor tuned to the task and input of the moment. This differs dramatically from the almost universal cognitive and computational views, which regard vision as a passively observing module to which simple questions about percepts can be posed, regardless of task. Differing from Visual Routines, CPs explicitly involve the critical elements of Visual Task Executive (vTE), Visual Attention Executive (vAE), and Visual Working Memory (vWM). Cognitive Programs provide the software that directs the actions of the Selective Tuning model of visual attention. PMID:25505430

Conversation Effects on Neural Mechanisms Underlying Reaction Time to Visual Events while Viewing a Driving Scene using MEG

PubMed Central

Bowyer, Susan M.; Hsieh, Li; Moran, John E.; Young, Richard A.; Manoharan, Arun; Liao, Chia-cheng Jason; Malladi, Kiran; Yu, Ya-Ju; Chiang, Yow-Ren; Tepley, Norman

2009-01-01

Magnetoencephalography (MEG) imaging examined the neural mechanisms that modulate reaction times to visual events while viewing a driving video, with and without a conversation. Twenty-four subjects ages 18–65 were monitored by whole-head MEG. The primary tasks were to monitor a driving video and to depress a foot pedal in response to a small red light presented to the left or below the driving scene at unpredictable times. The behavioral reaction time (RT) to the lights was recorded. The secondary task was a hands-free conversation. The subject pressed a button to answer a ring tone, and then covertly answered pre-recorded non-emotional questions such as “What is your birth date?” RTs for the conversation task (1043ms, SE=65ms) were slightly longer than for the primary task (baseline no conversation (944ms, SE=48ms). During the primary task RTs were inversely related to the amount of brain activity detected by MEG in the right superior parietal lobe (Brodmann’s Area 7). Brain activity was seen in the 200 to 300 ms range after the onset of the red light and in the visual cortex (BA 19) about 85 ms after the red light. Conversation reduced the strengths of these regression relationships and increased mean RT. Conversation may contribute to increased reaction times by (1) damping brain activation in specific regions during specific time windows, or (2) reducing facilitation from attention inputs into those areas. These laboratory findings should not be interpreted as indicative of real-world driving, without on-road validation, and comparison to other in-vehicle tasks. PMID:18992728

Effects of task complexity on activation of language areas in a semantic decision fMRI protocol.

PubMed

Lopes, Tátila Martins; Yasuda, Clarissa Lin; de Campos, Brunno Machado; Balthazar, Marcio L F; Binder, Jeffrey R; Cendes, Fernando

2016-01-29

Language tasks used for clinical fMRI studies may be too complex for some patients with cognitive impairments, and "easier" versions are sometimes substituted, though the effects on brain activity of such changes in task complexity are largely unknown. To investigate these differences, we compared two versions of an fMRI language comprehension protocol, with different levels of difficulty, in 24 healthy right-handed adults. The protocol contrasted an auditory word comprehension task (semantic decision) with a nonspeech control task using tone sequences (tone decision). In the "complex" version (CV), the semantic decision task required two complex semantic decisions for each word, and the tone decision task required the participant to count the number of target tones in each sequence. In the "easy" version (EV), the semantic task required only a single easier decision, and the tone task required only detection of the presence or absence of a target tone in each sequence. The protocols were adapted for a Brazilian population. Typical left hemisphere language lateralization was observed in 92% of participants for both CV and EV using the whole-brain lateralization index, and typical language lateralization was also observed for others regions of interest. Task performance was superior on the EV compared to the CV (p=0.014). There were many common areas of activation across the two version; however, the CV produced greater activation in the left superior and middle frontal giri, angular gyrus, and left posterior cingulate gyrus compared to the EV, the majority of which are areas previously identified with language and semantic processing. The EV produced stronger activation only in a small area in the posterior middle temporal gyrus. These results reveal differences between two versions of the protocol and provide evidence that both are useful for language lateralization and worked well for Brazilian population. The complex version produces stronger activation in several nodes of the semantic network and therefore is elected for participants who can perform well these tasks. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of Information Visualization on Older Adults' Decision-Making Performance in a Medicare Plan Selection Task: A Comparative Usability Study.

PubMed

Price, Margaux M; Crumley-Branyon, Jessica J; Leidheiser, William R; Pak, Richard

2016-06-01

Technology gains have improved tools for evaluating complex tasks by providing environmental supports (ES) that increase ease of use and improve performance outcomes through the use of information visualizations (info-vis). Complex info-vis emphasize the need to understand individual differences in abilities of target users, the key cognitive abilities needed to execute a decision task, and the graphical elements that can serve as the most effective ES. Older adults may be one such target user group that would benefit from increased ES to mitigate specific declines in cognitive abilities. For example, choosing a prescription drug plan is a necessary and complex task that can impact quality of life if the wrong choice is made. The decision to enroll in one plan over another can involve comparing over 15 plans across many categories. Within this context, the large amount of complex information and reduced working memory capacity puts older adults' decision making at a disadvantage. An intentionally designed ES, such as an info-vis that reduces working memory demand, may assist older adults in making the most effective decision among many options. The objective of this study is to examine whether the use of an info-vis can lower working memory demands and positively affect complex decision-making performance of older adults in the context of choosing a Medicare prescription drug plan. Participants performed a computerized decision-making task in the context of finding the best health care plan. Data included quantitative decision-making performance indicators and surveys examining previous history with purchasing insurance. Participants used a colored info-vis ES or a table (no ES) to perform the decision task. Task difficulty was manipulated by increasing the number of selection criteria used to make an accurate decision. A repeated measures analysis was performed to examine differences between the two table designs. Twenty-three older adults between the ages of 66 and 80 completed the study. There was a main effect for accuracy such that older adults made more accurate decisions in the color info-vis condition than the table condition. In the low difficulty condition, participants were more successful at choosing the correct answer when the question was about the gap coverage attribute in the info-vis condition. Participants also made significantly faster decisions in the info-vis condition than in the table condition. Reducing the working memory demand of the task through the use of an ES can improve decision accuracy, especially when selection criteria is only focused on a single attribute of the insurance plan.

Good decision-making is associated with an adaptive cardiovascular response to social competitive stress.

PubMed

Alacreu-Crespo, Adrián; Costa, Raquel; Abad-Tortosa, Diana; Salvador, Alicia; Serrano, Miguel Ángel

2018-06-22

Competition elicits different psychological and cardiovascular responses depending on a person's skills. Decision-making has been considered a distal factor that influences competition, but there are no studies analyzing this relationship. Our objective was to analyze whether decision-making affects the response to competition. Specifically, we aimed to test whether good performers on a decision-making test, the Iowa Gambling Task (IGT), showed an adaptive cardiovascular response to competition. In all, 116 participants (44 women) performed the IGT and were classified into Good or Poor decision-makers. Subsequently, they were exposed to a stress task in two different conditions: a face-to-face competition (winners/losers) or a control condition, while an electrocardiogram was recorded. In the competition group, good decision-makers increased their high-frequency respect to the total heart rate variability (HF/HRV) levels during the task, compared to Poor decision-makers. Again, competition group good decision-makers, showed lower LF and higher HF/HRV reactivity than the control group, which represents lower HRV stress pattern. Moreover, in the group of losers, good decision-makers had a decline in low frequency (LF) during the task and faster recovery than poor decision-makers. In conclusion, good decision-makers have a more adaptive stress response and higher levels of mental effort, based on total HRV interpretation. Decision-making skills could be a factor in a more adaptive cardiovascular response to competition.

Economic decision-making compared with an equivalent motor task.

PubMed

Wu, Shih-Wei; Delgado, Mauricio R; Maloney, Laurence T

2009-04-14

There is considerable evidence that human economic decision-making deviates from the predictions of expected utility theory (EUT) and that human performance conforms to EUT in many perceptual and motor decision tasks. It is possible that these results reflect a real difference in decision-making in the 2 domains but it is also possible that the observed discrepancy simply reflects typical differences in experimental design. We developed a motor task that is mathematically equivalent to choosing between lotteries and used it to compare how the same subject chose between classical economic lotteries and the same lotteries presented in equivalent motor form. In experiment 1, we found that subjects are more risk seeking in deciding between motor lotteries. In experiment 2, we used cumulative prospect theory to model choice and separately estimated the probability weighting functions and the value functions for each subject carrying out each task. We found no patterned differences in how subjects represented outcome value in the motor and the classical tasks. However, the probability weighting functions for motor and classical tasks were markedly and significantly different. Those for the classical task showed a typical tendency to overweight small probabilities and underweight large probabilities, and those for the motor task showed the opposite pattern of probability distortion. This outcome also accounts for the increased risk-seeking observed in the motor tasks of experiment 1. We conclude that the same subject distorts probability, but not value, differently in making identical decisions in motor and classical form.

Effort-Based Decision Making: A Novel Approach for Assessing Motivation in Schizophrenia

PubMed Central

Green, Michael F.; Horan, William P.; Barch, Deanna M.; Gold, James M.

2015-01-01

Because negative symptoms, including motivational deficits, are a critical unmet need in schizophrenia, there are many ongoing efforts to develop new pharmacological and psychosocial interventions for these impairments. A common challenge of these studies involves how to evaluate and select optimal endpoints. Currently, all studies of negative symptoms in schizophrenia depend on ratings from clinician-conducted interviews. Effort-based decision-making tasks may provide a more objective, and perhaps more sensitive, endpoint for trials of motivational negative symptoms. These tasks assess how much effort a person is willing to exert for a given level of reward. This area has been well-studied with animal models of effort and motivation, and effort-based decision-making tasks have been adapted for use in humans. Very recently, several studies have examined physical and cognitive types of effort-based decision-making tasks in cross-sectional studies of schizophrenia, providing evidence for effort-related impairment in this illness. This article covers the theoretical background on effort-based decision-making tasks to provide a context for the subsequent articles in this theme section. In addition, we review the existing literature of studies using these tasks in schizophrenia, consider some practical challenges in adapting them for use in clinical trials in schizophrenia, and discuss interpretive challenges that are central to these types of tasks. PMID:26089350

Perceptual and Motor Performance of Combat-Sport Athletes Differs According to Specific Demands of the Discipline.

PubMed

Chen, Wei-Ying; Wu, Sheng K; Song, Tai-Fen; Chou, Kuei-Ming; Wang, Kuei-Yuan; Chang, Yao-Ching; Goodbourn, Patrick T

2016-12-07

The specific demands of a combat-sport discipline may be reflected in the perceptual-motor performance of its athletes. Taekwondo, which emphasizes kicking, might require faster perceptual processing to compensate for longer latencies to initiate lower-limb movements and to give rapid visual feedback for dynamic postural control, while Karate, which emphasizes both striking with the hands and kicking, might require exceptional eye-hand coordination and fast perceptual processing. In samples of 38 Taekwondo athletes (16 females, 22 males; mean age = 19.9 years, SD = 1.2), 24 Karate athletes (9 females, 15 males; mean age = 18.9 years, SD = 0.9), and 35 Nonathletes (20 females, 15 males; mean age = 20.6 years, SD = 1.5), we measured eye-hand coordination with the Finger-Nose-Finger task, and both perceptual-processing speed and attentional control with the Covert Orienting of Visual Attention (COVAT) task. Eye-hand coordination was significantly better for Karate athletes than for Taekwondo athletes and Nonathletes, but reaction times for the upper extremities in the COVAT task-indicative of perceptual-processing speed-were faster for Taekwondo athletes than for Karate athletes and Nonathletes. In addition, we found no significant difference among groups in attentional control, as indexed by the reaction-time cost of an invalid cue in the COVAT task. The results suggest that athletes in different combat sports exhibit distinct profiles of perceptual-motor performance. © The Author(s) 2016.

Functional imaging of decision conflict.

PubMed

Pochon, Jean-Baptiste; Riis, Jason; Sanfey, Alan G; Nystrom, Leigh E; Cohen, Jonathan D

2008-03-26

Decision conflict occurs when people feel uncertain as to which option to choose from a set of similarly attractive (or unattractive) options, with many studies demonstrating that this conflict can lead to suboptimal decision making. In this article, we investigate the neurobiological underpinnings of decision conflict, in particular, the involvement of the anterior cingulate cortex (ACC). Previous studies have implicated the ACC in conflict monitoring during perceptual tasks, but there is considerable controversy as to whether the ACC actually indexes conflict related to choice, or merely conflict related to selection of competing motor responses. In a functional magnetic resonance imaging study, we dissociate the decision and response phases of a decision task, and show that the ACC does indeed index conflict at the decision stage. Furthermore, we show that it does so for a complex decision task, one that requires the integration of beliefs and preferences and not just perceptual judgments.

The Influence of Math Anxiety, Math Performance, Worry, and Test Anxiety on the Iowa Gambling Task and Balloon Analogue Risk Task.

PubMed

Buelow, Melissa T; Barnhart, Wesley R

2017-01-01

Multiple studies have shown that performance on behavioral decision-making tasks, such as the Iowa Gambling Task (IGT) and Balloon Analogue Risk Task (BART), is influenced by external factors, such as mood. However, the research regarding the influence of worry is mixed, and no research has examined the effect of math or test anxiety on these tasks. The present study investigated the effects of anxiety (including math anxiety) and math performance on the IGT and BART in a sample of 137 undergraduate students. Math performance and worry were not correlated with performance on the IGT, and no variables were correlated with BART performance. Linear regressions indicated math anxiety, physiological anxiety, social concerns/stress, and test anxiety significantly predicted disadvantageous selections on the IGT during the transition from decision making under ambiguity to decision making under risk. Implications for clinical evaluation of decision making are discussed. © The Author(s) 2015.

Heuristic-based information acquisition and decision making among pilots.

PubMed

Wiggins, Mark W; Bollwerk, Sandra

2006-01-01

This research was designed to examine the impact of heuristic-based approaches to the acquisition of task-related information on the selection of an optimal alternative during simulated in-flight decision making. The work integrated features of naturalistic and normative decision making and strategies of information acquisition within a computer-based, decision support framework. The study comprised two phases, the first of which involved familiarizing pilots with three different heuristic-based strategies of information acquisition: frequency, elimination by aspects, and majority of confirming decisions. The second stage enabled participants to choose one of the three strategies of information acquisition to resolve a fourth (choice) scenario. The results indicated that task-oriented experience, rather than the information acquisition strategies, predicted the selection of the optimal alternative. It was also evident that of the three strategies available, the elimination by aspects information acquisition strategy was preferred by most participants. It was concluded that task-oriented experience, rather than the process of information acquisition, predicted task accuracy during the decision-making task. It was also concluded that pilots have a preference for one particular approach to information acquisition. Applications of outcomes of this research include the development of decision support systems that adapt to the information-processing capabilities and preferences of users.

Risky Decision Making Assessed With the Gambling Task in Adults with HIV

PubMed Central

Hardy, David J.; Hinkin, Charles H.; Castellon, Steven A.; Levine, Andrew J.; Lam, Mona N.

2010-01-01

Decision making was assessed using a laboratory gambling task in 67 adults with the Human Immunodeficiency Virus (HIV+) and in 19 HIV-seronegative (HIV−) control participants. Neurocognitive test performance across several domains was also analyzed to examine potential cognitive mechanisms of gambling task performance. As predicted, the HIV+ group performed worse on the gambling task, indicating greater risky decision making. Specifically, the HIV+ group selected more cards from the “risky” or disadvantageous deck that included relatively large payoffs but infrequent large penalties. The control group also selected such risky cards but quickly learned to avoid them. Exploratory analyses also indicated that in the HIV+ group, but not in the control group, gambling task performance was correlated with Stroop Interference performance and long delay free recall on the California Verbal Learning Test, suggesting the role of inhibitory processes and verbal memory in the poorer gambling task performance in HIV. These findings indicate the usefulness of the gambling task as a laboratory tool to examine risky decision making and cognition in the HIV population. PMID:16719628

Probabilistic learning and inference in schizophrenia

PubMed Central

Averbeck, Bruno B.; Evans, Simon; Chouhan, Viraj; Bristow, Eleanor; Shergill, Sukhwinder S.

2010-01-01

Patients with schizophrenia make decisions on the basis of less evidence when required to collect information to make an inference, a behavior often called jumping to conclusions. The underlying basis for this behaviour remains controversial. We examined the cognitive processes underpinning this finding by testing subjects on the beads task, which has been used previously to elicit jumping to conclusions behaviour, and a stochastic sequence learning task, with a similar decision theoretic structure. During the sequence learning task, subjects had to learn a sequence of button presses, while receiving noisy feedback on their choices. We fit a Bayesian decision making model to the sequence task and compared model parameters to the choice behavior in the beads task in both patients and healthy subjects. We found that patients did show a jumping to conclusions style; and those who picked early in the beads task tended to learn less from positive feedback in the sequence task. This favours the likelihood of patients selecting early because they have a low threshold for making decisions, and that they make choices on the basis of relatively little evidence. PMID:20810252

Probabilistic learning and inference in schizophrenia.

PubMed

Averbeck, Bruno B; Evans, Simon; Chouhan, Viraj; Bristow, Eleanor; Shergill, Sukhwinder S

2011-04-01

Patients with schizophrenia make decisions on the basis of less evidence when required to collect information to make an inference, a behavior often called jumping to conclusions. The underlying basis for this behavior remains controversial. We examined the cognitive processes underpinning this finding by testing subjects on the beads task, which has been used previously to elicit jumping to conclusions behavior, and a stochastic sequence learning task, with a similar decision theoretic structure. During the sequence learning task, subjects had to learn a sequence of button presses, while receiving a noisy feedback on their choices. We fit a Bayesian decision making model to the sequence task and compared model parameters to the choice behavior in the beads task in both patients and healthy subjects. We found that patients did show a jumping to conclusions style; and those who picked early in the beads task tended to learn less from positive feedback in the sequence task. This favours the likelihood of patients selecting early because they have a low threshold for making decisions, and that they make choices on the basis of relatively little evidence. Published by Elsevier B.V.

Sexual Harassment in Medical Schools: The Challenge of Covert Retaliation as a Barrier to Reporting.

PubMed

Binder, Renee; Garcia, Paul; Johnson, Bonnie; Fuentes-Afflick, Elena

2018-05-22

Although Title IX, the federal law prohibiting sexual harassment in educational institutions, was enacted in 1972, sexual harassment continues to be distressingly common in medical training. In addition, many women who experience sexual harassment do not report their experiences to authorities within the medical school.In this article, the authors review the literature on the prevalence of sexual harassment in medical schools since Title IX was enacted and on the cultural and legal changes that have occurred during that period that have affected behaviors. These changes include decreased tolerance for harassing behavior, increased legal responsibility assigned to institutions, and a significant increase in the number of female medical students, residents, and faculty. The authors then discuss persisting barriers to reporting sexual harassment, including fears of reprisals and retaliation, especially covert retaliation. They define covert retaliation as vindictive comments made by a person accused of sexual harassment about his or her accuser in a confidential setting, such as a grant review, award selection, or search committee.The authors concluding by highlighting institutional and organizational approaches to decreasing sexual harassment and overt retaliation, and they propose other approaches to decreasing covert retaliation. These initiatives include encouraging senior faculty members to intervene and file bystander complaints when they witness inappropriate comments or behaviors as well as group reporting when multiple women are harassed by the same person.

"Scientific roots" of dualism in neuroscience.

PubMed

Arshavsky, Yuri I

2006-07-01

Although the dualistic concept is unpopular among neuroscientists involved in experimental studies of the brain, neurophysiological literature is full of covert dualistic statements on the possibility of understanding neural mechanisms of human consciousness. Particularly, the covert dualistic attitude is exhibited in the unwillingness to discuss neural mechanisms of consciousness, leaving the problem of consciousness to psychologists and philosophers. This covert dualism seems to be rooted in the main paradigm of neuroscience that suggests that cognitive functions, such as language production and comprehension, face recognition, declarative memory, emotions, etc., are performed by neural networks consisting of simple elements. I argue that neural networks of any complexity consisting of neurons whose function is limited to the generation of electrical potentials and the transmission of signals to other neurons are hardly capable of producing human mental activity, including consciousness. Based on results obtained in physiological, morphological, clinical, and genetic studies of cognitive functions (mainly linguistic ones), I advocate the hypothesis that the performance of cognitive functions is based on complex cooperative activity of "complex" neurons that are carriers of "elementary cognition." The uniqueness of human cognitive functions, which has a genetic basis, is determined by the specificity of genes expressed by these "complex" neurons. The main goal of the review is to show that the identification of the genes implicated in cognitive functions and the understanding of a functional role of their products is a possible way to overcome covert dualism in neuroscience.

Transfer of Decision Making and Farm Tasks from Father to Son in Father-and-Son Farming Arrangements. RS-51, August 1976.

ERIC Educational Resources Information Center

Coughenour, C. Milton; And Others

The study examined the division of decision-making and farm tasks in a joint father and son enterprise, the extent to which the decisions tended to be shared equally, and the extent to which the principal operator had responsibility for those tasks not shared. Data were collected in 1974 from fathers and sons who were joint operators of 145 farms…

Do (un)certainty appraisal tendencies reverse the influence of emotions on risk taking in sequential tasks?

PubMed

Bagneux, Virginie; Bollon, Thierry; Dantzer, Cécile

2012-01-01

According to the Appraisal-Tendency Framework (Han, Lerner, & Keltner, 2007), certainty-associated emotions increase risk taking compared with uncertainty-associated emotions. To date, this general effect has only been shown in static judgement and decision-making paradigms; therefore, the present study tested the effect of certainty on risk taking in a sequential decision-making task. We hypothesised that the effect would be reversed due to the kind of processing involved, as certainty is considered to encourage heuristic processing that takes into account the emotional cues arising from previous decisions, whereas uncertainty leads to more systematic processing. One hundred and one female participants were induced to feel one of three emotions (film clips) before performing a decision-making task involving risk (Game of Dice Task; Brand et al., 2005). As expected, the angry and happy participants (certainty-associated emotions) were more likely than the fearful participants (uncertainty-associated emotion) to make safe decisions (vs. risky decisions).

An fMRI Study of Risky Decision Making: The Role of Mental Preparation and Conflict.

PubMed

Sohrabi, Ahmad; Smith, Andra M; West, Robert L; Cameron, Ian

2015-10-01

The current study aimed to elucidate the role of preparatory cognitive control in decision making and its neural correlates using functional Magnetic Resonance Imaging (fMRI). To this effect, by employing a series of new cognitive tasks, we assessed the role of preparatory cognitive control in monetary (risky) decision making. The participants had to decide between a risky and a safe gamble based on their chance of winning (high or low). In the 2-phase gambling task (similar to Cambridge gambling task), the chance and the gamble were presented at the same time (i.e. in a single phase), but in a new 3-phase gambling task, the chance is presented before the gamble. The tasks ended with a feedback phase. In the 3-phase task, holding the chance in memory to guide their decision enabled the participants to have more control on their risk taking behaviors as shown by activation in a network of brain areas involved in the control and conflict, including dorsal Anterior Cingulate Cortex (dACC), indexed by faster reaction times and better performance in the gambling task, and the temporal lobe, which has a role in holding contextual information. Holding information in memory to guide decision presumably enables the participants to have more control on their risk taking behaviors. The conflict and uncertainty resulting from this risky decision was indexed by the activation of dACC, known to be activated in conflict and cognitive control.

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

Stopping decisions: information order effects on nonfocal evaluations.

PubMed

Yu, Michael; Gonzalez, Cleotilde

2013-08-01

We investigated how the order in which information is presented affects when a person decides to stop performing a task. A stopping decision is a decision to stop performing a task on the basis of a sequence of cues. Previous order-effects models do not account for how these contexts limit available working memory for making such decisions. Participants decided how long to perform a task known as the Work Hazard Game that began by rewarding points but later cost points if work continued after an unannounced "emergency." An additive sequence of cues indicated the probability of an emergency. Study I involved a three-group design with cue sequences that indicated the same risk at each decision point but whose final cue presented a high, medium, or low probability. Study 2 had a 2 x 2 design with high or low final cues and an easy or a challenging task. In Study I, participants stopped sooner when the most recent cue presented a high rather than low probability (p = .09), despite the same emergency risk. In Study 2, participants stopped sooner when the most recent cue presented a high rather than low probability for the challenging task but not for the easy task (p = .08). Stopping decisions appear sensitive to the most recent cue observed while experiencing task load. Participants responded to the same risks differently only on the basis of a change in presentation. Findings may be relevant for research and training for hazardous jobs, such as subsurface coal mining, fishing, and trucking.

Not just for consumers: context effects are fundamental to decision making.

PubMed

Trueblood, Jennifer S; Brown, Scott D; Heathcote, Andrew; Busemeyer, Jerome R

2013-06-01

Context effects--preference changes that depend on the availability of other options--have attracted a great deal of attention among consumer researchers studying high-level decision tasks. In the experiments reported here, we showed that these effects also arise in simple perceptual-decision-making tasks. This finding casts doubt on explanations limited to consumer choice and high-level decisions, and it indicates that context effects may be amenable to a general explanation at the level of the basic decision process. We demonstrated for the first time that three important context effects from the preferential-choice literature--similarity, attraction, and compromise effects--all occurred within a single perceptual-decision task. Not only do our results challenge previous explanations for context effects proposed by consumer researchers, but they also challenge the choice rules assumed in theories of perceptual decision making.

Group benefits in joint perceptual tasks-a review.

PubMed

Wahn, Basil; Kingstone, Alan; König, Peter

2018-05-12

In daily life, humans often perform perceptual tasks together to reach a shared goal. In these situations, individuals may collaborate (e.g., by distributing task demands) to perform the task better than when the task is performed alone (i.e., attain a group benefit). In this review, we identify the factors influencing if, and to what extent, a group benefit is attained and provide a framework of measures to assess group benefits in perceptual tasks. In particular, we integrate findings from two frequently investigated joint perceptual tasks: visuospatial tasks and decision-making tasks. For both task types, we find that an exchange of information between coactors is critical to improve joint performance. Yet, the type of exchanged information and how coactors collaborate differs between tasks. In visuospatial tasks, coactors exchange information about the performed actions to distribute task demands. In perceptual decision-making tasks, coactors exchange their confidence on their individual perceptual judgments to negotiate a joint decision. We argue that these differences can be explained by the task structure: coactors distribute task demands if a joint task allows for a spatial division and stimuli can be accurately processed by one individual. Otherwise, they perform the task individually and then integrate their individual judgments. © 2018 New York Academy of Sciences.

Do individual differences in Iowa Gambling Task performance predict adaptive decision making for risky gains and losses?

PubMed

Weller, Joshua A; Levin, Irwin P; Bechara, Antoine

2010-02-01

We relate performance on the Iowa Gambling Task (IGT), a widely used, but complex, neuropsychological task of executive function in which mixed outcomes (gains and losses) are experienced together, to performance on a relatively simpler descriptive task, the Cups task, which isolates adaptive decision making for achieving gains and avoiding losses. We found that poor IGT performance was associated with suboptimal decision making on Cups, especially for risky losses, suggesting that losses are weighted more than gains in the IGT. These findings were significant beyond several notable gender differences in which men outperformed women. Implications for the neuropsychological study of risk are discussed.

Affective decision-making and externalizing behaviors: the role of autonomic activity.

PubMed

Bubier, Jennifer L; Drabick, Deborah A G

2008-08-01

We tested a conceptual model involving the inter-relations among affective decision-making (indexed by a gambling task), autonomic nervous system (ANS) activity, and attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) symptoms in a largely impoverished, inner city sample of first through third grade children (N=63, 54% male). The present study hypothesized that impaired affective decision-making and decreased sympathetic and parasympathetic activation would be associated with higher levels of ADHD and ODD symptoms, and that low sympathetic and parasympathetic activation during an emotion-inducing task would mediate the relation between affective decision-making and child externalizing symptoms. In support of our model, disadvantageous decision-making on a gambling task was associated with ADHD hyperactivity/impulsivity symptoms among boys, and attenuated sympathetic activation during an emotion-inducing task mediated this relation. Support for the model was not found among girls.

Decision-Making in Multiple Sclerosis Patients: A Systematic Review.

PubMed

Neuhaus, Mireille; Calabrese, Pasquale; Annoni, Jean-Marie

2018-01-01

Multiple sclerosis (MS) is frequently associated with cognitive and behavioural deficits. A growing number of studies suggest an impact of MS on decision-making abilities. The aim of this systematic review was to assess if (1) performance of MS patients in decision-making tasks was consistently different from controls and (2) whether this modification was associated with cognitive dysfunction and emotional alterations. The search was conducted on Pubmed/Medline database. 12 studies evaluating the difference between MS patients and healthy controls using validated decision-making tasks were included. Outcomes considered were quantitative (net scores) and qualitative measurements (deliberation time and learning from feedback). Quantitative and qualitative decision-making impairment in MS was present in 64.7% of measurements. Patients were equally impaired in tasks for decision-making under risk and ambiguity. A correlation to other cognitive functions was present in 50% of cases, with the highest associations in the domains of processing speed and attentional capacity. In MS patients, qualitative and quantitative modifications may be present in any kind of decision-making task and can appear independently of other cognitive measures. Since decision-making abilities have a significant impact on everyday life, this cognitive aspect has an influential importance in various MS-related treatment settings.

Impact of ambiguity and risk on decision making in mild Alzheimer's disease.

PubMed

Sinz, H; Zamarian, L; Benke, T; Wenning, G K; Delazer, M

2008-01-01

Decisions under ambiguity and decisions under risk are crucial types of decision making in daily living at any age. This is the first study assessing these two types of decisions in patients with mild dementia of Alzheimer's type (DAT) by means of the Iowa Gambling Task (IGT) and a newly developed, Probability-Associated Gambling (PAG) task. While rules for gains and losses are implicit in the IGT, in the PAG task rules are explicit and winning probabilities, which change from trial to trial, can be estimated. Results of the IGT indicated that DAT patients made more disadvantageous decisions than healthy controls. Patients also shifted more frequently among decks, i.e. under ambiguity decisions were taken randomly and no advantageous strategy was established over time by DAT patients. Thus, not only actual choices but also development of advantageous strategies may be revealing about decision making in the IGT. Compared to controls, patients demonstrated less advantageous choices in the PAG task as well. They gambled more often in the low winning probabilities and less frequently in the high probabilities than healthy participants. Patients' performance on both tasks correlated with measures of executive functions. Findings of the present investigation are consistent with the early pathological cerebral changes and related (cognitive, emotional) deficits reported for DAT. As suggested by our study, decisions under ambiguity as well as decisions under risk are impaired in mild DAT. It may thus be expected that patients with mild DAT have difficulties in taking decisions in every-day life situations, both in cases of ambiguity (information on probability is missing or conflicting, and the expected utility of the different options is incalculable) and in cases of risk (outcomes can be predicted by well-defined or estimable probabilities).

Individual quality explains association between plumage colouration, arrival dates and mate acquisition in yellow warblers (Setophaga petechia).

PubMed

Jones, Teri B; Drake, Anna; Green, David J

2014-05-07

In many bird species colour traits influence social dominance and breeding success. In our study we first evaluated whether the colour of the basic plumage (tail feathers grown at the end of the breeding season), that provides an index of individual quality, influenced winter habitat use by yellow warblers. We then evaluated whether winter habitat use (inferred using δ13C and δ15N signatures of winter grown greater-coverts) influenced alternate plumage colouration, after controlling for individual quality using basic plumage colouration. Finally, we investigated whether basic and alternate plumage colouration influenced arrival dates, mate acquisition, breeding phenology and reproductive success of yellow warblers breeding in southern (Revelstoke, B.C.) and arctic (Inuvik, N.W.T.) Canada. The colour (chroma and hue) of tail feathers, grown on the breeding grounds, was not related to subsequent winter habitat use. Greater covert and tail feather colour (chroma and hue) were correlated, suggesting genetics and/or individual quality played a role in pigment deposition. After controlling for individual difference in tail colour, δ13C values did not explain any variation in greater covert colour, but birds with high δ15N signatures had greater coverts with higher chroma. Male arrival dates varied with tail chroma in Revelstoke and tail hue in Inuvik. Males that arrived early paired with older and/or more colourful mates that initiated clutches earlier, and at one site (Revelstoke) were more likely to fledge young. In addition, in Revelstoke (but not Inuvik) males with high tail hue also acquired more colourful mates. In contrast, after controlling for individual differences in tail colour, greater covert colour did not affect male arrival date, the quality of the mate obtained or reproductive success in either population. Our results suggest that plumage colour effects on breeding phenology and mate acquisition result from differences in the intrinsic quality of individuals rather than a carry-over effect of winter habitat use.

Individual quality explains association between plumage colouration, arrival dates and mate acquisition in yellow warblers (Setophaga petechia)

PubMed Central

2014-01-01

Background In many bird species colour traits influence social dominance and breeding success. In our study we first evaluated whether the colour of the basic plumage (tail feathers grown at the end of the breeding season), that provides an index of individual quality, influenced winter habitat use by yellow warblers. We then evaluated whether winter habitat use (inferred using δ13C and δ15N signatures of winter grown greater-coverts) influenced alternate plumage colouration, after controlling for individual quality using basic plumage colouration. Finally, we investigated whether basic and alternate plumage colouration influenced arrival dates, mate acquisition, breeding phenology and reproductive success of yellow warblers breeding in southern (Revelstoke, B.C.) and arctic (Inuvik, N.W.T.) Canada. Results The colour (chroma and hue) of tail feathers, grown on the breeding grounds, was not related to subsequent winter habitat use. Greater covert and tail feather colour (chroma and hue) were correlated, suggesting genetics and/or individual quality played a role in pigment deposition. After controlling for individual difference in tail colour, δ13C values did not explain any variation in greater covert colour, but birds with high δ15N signatures had greater coverts with higher chroma. Male arrival dates varied with tail chroma in Revelstoke and tail hue in Inuvik. Males that arrived early paired with older and/or more colourful mates that initiated clutches earlier, and at one site (Revelstoke) were more likely to fledge young. In addition, in Revelstoke (but not Inuvik) males with high tail hue also acquired more colourful mates. In contrast, after controlling for individual differences in tail colour, greater covert colour did not affect male arrival date, the quality of the mate obtained or reproductive success in either population. Conclusions Our results suggest that plumage colour effects on breeding phenology and mate acquisition result from differences in the intrinsic quality of individuals rather than a carry-over effect of winter habitat use. PMID:24886073

The cognitive demands of second order manual control: Applications of the event related brain potential

NASA Technical Reports Server (NTRS)

Wickens, C.; Gill, R.; Kramer, A.; Ross, W.; Donchin, E.

1981-01-01

Three experiments are described in which tracking difficulty is varied in the presence of a covert tone discrimination task. Event related brain potentials (ERPs) elicited by the tones are employed as an index of the resource demands of tracking. The ERP measure reflected the control order variation, and this variable was thereby assumed to compete for perceptual/central processing resources. A fine-grained analysis of the results suggested that the primary demands of second order tracking involve the central processing operations of maintaining a more complex internal model of the dynamic system, rather than the perceptual demands of higher derivative perception. Experiment 3 varied tracking bandwidth in random input tracking, and the ERP was unaffected. Bandwidth was then inferred to compete for response-related processing resources that are independent of the ERP.

Error-associated behaviors and error rates for robotic geology

NASA Technical Reports Server (NTRS)

Anderson, Robert C.; Thomas, Geb; Wagner, Jacob; Glasgow, Justin

2004-01-01

This study explores human error as a function of the decision-making process. One of many models for human decision-making is Rasmussen's decision ladder [9]. The decision ladder identifies the multiple tasks and states of knowledge involved in decision-making. The tasks and states of knowledge can be classified by the level of cognitive effort required to make the decision, leading to the skill, rule, and knowledge taxonomy (Rasmussen, 1987). Skill based decisions require the least cognitive effort and knowledge based decisions require the greatest cognitive effort. Errors can occur at any of the cognitive levels.

Overlapping Risky Decision-Making and Olfactory Processing Ability in HIV-Infected Individuals.

PubMed

Jackson, Christopher; Rai, Narayan; McLean, Charlee K; Hipolito, Maria Mananita S; Hamilton, Flora Terrell; Kapetanovic, Suad; Nwulia, Evaristus A

2017-09-01

Given neuroimaging evidences of overlap in the circuitries for decision-making and olfactory processing, we examined the hypothesis that impairment in psychophysical tasks of olfaction would independently predict poor performances on Iowa Gambling Task (IGT), a laboratory task that closely mimics real-life decision-making, in a US cohort of HIV-infected (HIV+) individuals. IGT and psychophysical tasks of olfaction were administered to a Washington DC-based cohort of largely African American HIV+ subjects (N=100), and to a small number of demographically-matched non-HIV healthy controls (N=43) from a different study. Constructs of olfactory ability and decision-making were examined through confirmatory factor analysis (CFA). Structural equation models (SEMs) were used to evaluate the validity of the path relationship between these two constructs. The 100 HIV+ participants (56% female; 96% African Americans; median age = 48 years) had median CD4 count of 576 cells/μl and median HIV RNA viral load <48 copies per milliliter. Majority of HIV+ participants performed randomly throughout the course of IGT tasks, and failed to demonstrate a learning curve. Confirmatory factor analysis provided support for a unidimensional factor underlying poor performances on IGT. Nomological validity for correlations between olfactory ability and IGT performance was confirmed through SEM. Finally, factor scores of olfactory ability and IGT performance strongly predicted 6 months history of drug use, while olfaction additionally predicted hallucinogen use. This study suggests that combination of simple, office-based tasks of olfaction and decision-making may identify those HIV+ individuals who are more prone to risky decision-making. This finding may have significant clinical, public health value if joint impairments in olfaction and IGT task correlates with more decreased activity in brain regions relevant to decision-making.

Impaired Decision-Making in Adolescent Suicide Attempters

PubMed Central

Bridge, Jeffrey A.; McBee-Strayer, Sandra M.; Cannon, Elizabeth A.; Sheftall, Arielle H.; Reynolds, Brady; Campo, John V.; Pajer, Kathleen A.; Barbe, Rémy P.; Brent, David A.

2012-01-01

Objective Decision-making deficits have been linked to suicidal behavior in adults. However, it remains unclear whether impaired decision-making plays a role in the etiopathogenesis of youth suicidal behavior. The purpose of this study was to examine decision-making processes in adolescent suicide attempters and never-suicidal comparison subjects. Method Using the Iowa Gambling Task, the authors examined decision-making in 40 adolescent suicide attempters, ages 13–18, and 40 never-suicidal, demographically-matched psychiatric comparison subjects. Results Overall, suicide attempters performed significantly worse on the Iowa Gambling Task than comparison subjects. This difference in overall task performance between the groups persisted in an exact conditional logistic regression analysis that controlled for affective disorder, current psychotropic medication use, impulsivity, and hostility (adjusted odds ratio=0.96, 95% confidence interval=0.90–0.99, p<.05). A two-way repeated-measures analysis of variance revealed a significant group-by-block interaction, demonstrating that attempters failed to learn during the task, picking approximately the same proportion of disadvantageous cards in the first and final blocks of the task. In contrast, comparison subjects picked proportionately fewer cards from the disadvantageous decks as the task progressed. Within the attempter group, overall task performance did not correlate with any characteristic of the index attempt or with the personality dimensions of impulsivity, hostility, and emotional lability. Conclusions Similar to findings in adults, impaired decision-making is associated with suicidal behavior in adolescents. Longitudinal studies are needed to elucidate the temporal relationship between decision-making processes and suicidal behavior and help frame potential targets for early identification and preventive interventions to reduce youth suicide and suicidal behavior. PMID:22449645

A diffusion decision model analysis of evidence variability in the lexical decision task.

PubMed

Tillman, Gabriel; Osth, Adam F; van Ravenzwaaij, Don; Heathcote, Andrew

2017-12-01

The lexical-decision task is among the most commonly used paradigms in psycholinguistics. In both the signal-detection theory and Diffusion Decision Model (DDM; Ratcliff, Gomez, & McKoon, Psychological Review, 111, 159-182, 2004) frameworks, lexical-decisions are based on a continuous source of word-likeness evidence for both words and non-words. The Retrieving Effectively from Memory model of Lexical-Decision (REM-LD; Wagenmakers et al., Cognitive Psychology, 48(3), 332-367, 2004) provides a comprehensive explanation of lexical-decision data and makes the prediction that word-likeness evidence is more variable for words than non-words and that higher frequency words are more variable than lower frequency words. To test these predictions, we analyzed five lexical-decision data sets with the DDM. For all data sets, drift-rate variability changed across word frequency and non-word conditions. For the most part, REM-LD's predictions about the ordering of evidence variability across stimuli in the lexical-decision task were confirmed.

Hierarchical Task Analysis and Training Decisions.

ERIC Educational Resources Information Center

Shepherd, A.

1985-01-01

Hierarchical task analysis (HTA), which requires description of a task in terms of a hierarchy of operations and plans, is reviewed and examined as a basis for making training decisions. Benefits of HTA in terms of economy of analysis and as a means of accounting for complex performance are outlined. (Author/MBR)

Age of acquisition affects the retrieval of grammatical category information.

PubMed

Bai, Lili; Ma, Tengfei; Dunlap, Susan; Chen, Baoguo

2013-01-01

This study investigated age of acquisition (AoA) effects on processing grammatical category information of Chinese single-character words. In Experiment 1, nouns and verbs that were acquired at different ages were used as materials in a grammatical category decision task. Results showed that the grammatical category information of earlier acquired nouns and verbs was easier to retrieve. In Experiment 2, AoA and predictability from orthography to grammatical category were manipulated in a grammatical category decision task. Results showed larger AoA effects under lower predictability conditions. In Experiment 3, a semantic category decision task was used with the same materials as those in Experiment 2. Different results were found from Experiment 2, suggesting that the grammatical category decision task is not merely the same as the semantic category decision task, but rather involves additional processing of grammatical category information. Therefore the conclusions of Experiments 1 and 2 were strengthened. In summary, it was found for the first time that AoA affects the retrieval of grammatical category information, thus providing new evidence in support of the arbitrary mapping hypothesis.

Cross-Lingual Neighborhood Effects in Generalized Lexical Decision and Natural Reading

ERIC Educational Resources Information Center

Dirix, Nicolas; Cop, Uschi; Drieghe, Denis; Duyck, Wouter

2017-01-01

The present study assessed intra- and cross-lingual neighborhood effects, using both a generalized lexical decision task and an analysis of a large-scale bilingual eye-tracking corpus (Cop, Dirix, Drieghe, & Duyck, 2016). Using new neighborhood density and frequency measures, the general lexical decision task yielded an inhibitory…

Preliminary Design Options for Meteor Burst Communications Systems Buoy Relays

DTIC Science & Technology

1986-12-01

FIELDS BRAYTON OTTO ELECTROSTATIC FIELDS SUPERCRITICAL Figure 5.1. Structure of current power source technology for ocean applications. 32 L / P 9 t ~A...As in the sulphur dioxide cell, a low weight, high surface area, carbon positive elec- trode acts as a catalyst for the reduction of the cathode...Operating Transmit Power No. (Relay/Service) Type Covert Covert Mode Duty Cycle (watts) 2.1 Trans Ocean Relay Shore/Ship No Yes Remote 20 Msg/hr 0.9

Core verbal working-memory capacity: the limit in words retained without covert articulation.

PubMed

Chen, Zhijian; Cowan, Nelson

2009-07-01

Verbal working memory may combine phonological and conceptual units. We disentangle their contributions by extending a prior procedure (Chen & Cowan, 2005) in which items recalled from lists of previously seen word singletons and of previously learned word pairs depended on the list length in chunks. Here we show that a constant capacity of about 3 chunks holds across list lengths and list types, provided that covert phonological rehearsal is prevented. What remains is a core verbal working-memory capacity.

Data Hiding and the Statistics of Images

NASA Astrophysics Data System (ADS)

Cox, Ingemar J.

The fields of digital watermarking, steganography and steganalysis, and content forensics are closely related. In all cases, there is a class of images that is considered “natural”, i.e. images that do not contain watermarks, images that do not contain covert messages, or images that have not been tampered with. And, conversely, there is a class of images that is considered to be “unnatural”, i.e. images that contain watermarks, images that contain covert messages, or images that have been tampered with.

The Covert Use of the Global Special Operations Network and the Militarization of Covert Action in Political Warfare and the Gray Zone

DTIC Science & Technology

2017-06-09

new as writers such as Sun Tzu described its effects: “To win a hundred victories in a hundred battles is not the highest excellence; the highest...15 Sun Wu and Samuel Griffith, Sun Tzu The Art of War, trans. Samuel B. Griffith (Oxford, England...and Samuel Griffith. Sun Tzu The Art of War. Translated by Samuel B. Griffith. Oxford, England: Oxford University Press, 1971. Government Documents

Take the first heuristic, self-efficacy, and decision-making in sport.

PubMed

Hepler, Teri J; Feltz, Deborah L

2012-06-01

Can taking the first (TTF) option in decision-making lead to the best decisions in sports contexts? And, is one's decision-making self-efficacy in that context linked to TTF decisions? The purpose of this study was to examine the role of the TTF heuristic and self-efficacy in decision-making on a simulated sports task. Undergraduate and graduate students (N = 72) participated in the study and performed 13 trials in each of two video-based basketball decision tasks. One task required participants to verbally generate options before making a final decision on what to do next, while the other task simply asked participants to make a decision regarding the next move as quickly as possible. Decision-making self-efficacy was assessed using a 10-item questionnaire comprising various aspects of decision-making in basketball. Participants also rated their confidence in the final decision. Results supported many of the tenets of the TTF heuristic, such that people used the heuristic on a majority of the trials (70%), earlier generated options were better than later ones, first options were meaningfully generated, and final options were meaningfully selected. Results did not support differences in dynamic inconsistency or decision confidence based on the number of options. Findings also supported the link between self-efficacy and the TTF heuristic. Participants with higher self-efficacy beliefs used TTF more frequently and generated fewer options than those with low self-efficacy. Thus, not only is TTF an important heuristic when making decisions in dynamic, time-pressure situations, but self-efficacy plays an influential role in TTF.

Nonword repetition priming in lexical decision reverses as a function of study task and speed stress.

PubMed

Zeelenberg, René; Wagenmakers, Eric-Jan; Shiffrin, Richard M

2004-01-01

The authors argue that nonword repetition priming in lexical decision is the net result of 2 opposing processes. First, repeating nonwords in the lexical decision task results in the storage of a memory trace containing the interpretation that the letter string is a nonword; retrieval of this trace leads to an increase in performance for repeated nonwords. Second, nonword repetition results in increased familiarity, making the nonword more "wordlike," leading to a decrease in performance. Consistent with this dual-process account, Experiment 1 showed a facilitatory effect for nonwords studied in a lexical decision task but an inhibitory effect for nonwords studied in a letter-height task. Experiment 2 showed inhibitory nonword repetition priming for participants tested under speed-stress instructions. ((c) 2004 APA, all rights reserved)

Differential performance on tasks of affective processing and decision-making in patients with Panic Disorder and Panic Disorder with comorbid Major Depressive Disorder.

PubMed

Kaplan, Johanna S; Erickson, Kristine; Luckenbaugh, David A; Weiland-Fiedler, Petra; Geraci, Marilla; Sahakian, Barbara J; Charney, Dennis; Drevets, Wayne C; Neumeister, Alexander

2006-10-01

Neuropsychological studies have provided evidence for deficits in psychiatric disorders, such as schizophrenia and mood disorders. However, neuropsychological function in Panic Disorder (PD) or PD with a comorbid diagnosis of Major Depressive Disorder (MDD) has not been comprehensively studied. The present study investigated neuropsychological functioning in patients with PD and PD + MDD by focusing on tasks that assess attention, psychomotor speed, executive function, decision-making, and affective processing. Twenty-two unmedicated patients with PD, eleven of whom had a secondary diagnosis of MDD, were compared to twenty-two healthy controls, matched for gender, age, and intelligence on tasks of attention, memory, psychomotor speed, executive function, decision-making, and affective processing from the Cambridge Neuropsychological Test Automated Battery (CANTAB), Cambridge Gamble Task, and Affective Go/No-go Task. Relative to matched healthy controls, patients with PD + MDD displayed an attentional bias toward negatively-valenced verbal stimuli (Affective Go/No-go Task) and longer decision-making latencies (Cambridge Gamble Task). Furthermore, the PD + MDD group committed more errors on a task of memory and visual discrimination compared to their controls. In contrast, no group differences were found for PD patients relative to matched control subjects. The sample size was limited, however, all patients were drug-free at the time of testing. The PD + MDD patients demonstrated deficits on a task involving visual discrimination and working memory, and an attentional bias towards negatively-valenced stimuli. In addition, patients with comorbid depression provided qualitatively different responses in the areas of affective and decision-making processes.

Team performance in networked supervisory control of unmanned air vehicles: effects of automation, working memory, and communication content.

PubMed

McKendrick, Ryan; Shaw, Tyler; de Visser, Ewart; Saqer, Haneen; Kidwell, Brian; Parasuraman, Raja

2014-05-01

Assess team performance within a net-worked supervisory control setting while manipulating automated decision aids and monitoring team communication and working memory ability. Networked systems such as multi-unmanned air vehicle (UAV) supervision have complex properties that make prediction of human-system performance difficult. Automated decision aid can provide valuable information to operators, individual abilities can limit or facilitate team performance, and team communication patterns can alter how effectively individuals work together. We hypothesized that reliable automation, higher working memory capacity, and increased communication rates of task-relevant information would offset performance decrements attributed to high task load. Two-person teams performed a simulated air defense task with two levels of task load and three levels of automated aid reliability. Teams communicated and received decision aid messages via chat window text messages. Task Load x Automation effects were significant across all performance measures. Reliable automation limited the decline in team performance with increasing task load. Average team spatial working memory was a stronger predictor than other measures of team working memory. Frequency of team rapport and enemy location communications positively related to team performance, and word count was negatively related to team performance. Reliable decision aiding mitigated team performance decline during increased task load during multi-UAV supervisory control. Team spatial working memory, communication of spatial information, and team rapport predicted team success. An automated decision aid can improve team performance under high task load. Assessment of spatial working memory and the communication of task-relevant information can help in operator and team selection in supervisory control systems.

The ethical and legal aspects of palliative sedation in severely brain-injured patients: a French perspective

PubMed Central

2011-01-01

To fulfill their crucial duty of relieving suffering in their patients, physicians may have to administer palliative sedation when they implement treatment-limitation decisions such as the withdrawal of life-supporting interventions in patients with poor prognosis chronic severe brain injury. The issue of palliative sedation deserves particular attention in adults with serious brain injuries and in neonates with severe and irreversible brain lesions, who are unable to express pain or to state their wishes. In France, treatment limitation decisions for these patients are left to the physicians. Treatment-limitation decisions are made collegially, based on the presence of irreversible brain lesions responsible for chronic severe disorders of consciousness. Before these decisions are implemented, they are communicated to the relatives. Because the presence and severity of pain cannot be assessed in these patients, palliative analgesia and/or sedation should be administered. However, palliative sedation is a complex strategy that requires safeguards to prevent a drift toward hastening death or performing covert euthanasia. In addition to the law on patients' rights at the end of life passed in France on April 22, 2005, a recent revision of Article 37 of the French code of medical ethics both acknowledges that treatment-limitation decisions and palliative sedation may be required in patients with severe brain injuries and provides legal and ethical safeguards against a shift towards euthanasia. This legislation may hold value as a model for other countries where euthanasia is illegal and for countries such as Belgium and Netherlands where euthanasia is legal but not allowed in patients incapable of asking for euthanasia but in whom a treatment limitation decision has been made. PMID:21303504

Task conflict effect in task switching.

PubMed

Braverman, Ami; Meiran, Nachshon

2010-11-01

A part of action preparation is deciding what the relevant task is. This task-decision process is conceptually separate from response selection. To show this, the authors manipulated task conflict in a spatial task-switching paradigm, using conflict stimuli that appeared during trials with univalent targets (affording 1 task). The conflict stimuli afforded task identity because they were used as task cues with bivalent targets (affording 2 tasks) that were intermixed with the univalent targets. Thus, for univalent targets, irrelevant stimuli either caused low task conflict or high task conflict. In three experiments, the authors found poorer performance in high task conflict trials than in low task conflict trials. Task conflict was introduced during target appearance (Experiment 1) or task preparation (Experiments 2 and 3). In the latter case, the task conflict effect decreased with increasing task preparation time showing that task preparation involves task decision.

Self-reported strategies in decisions under risk: role of feedback, reasoning abilities, executive functions, short-term-memory, and working memory.

PubMed

Schiebener, Johannes; Brand, Matthias

2015-11-01

In decisions under objective risk conditions information about the decision options' possible outcomes and the rules for outcomes' occurrence are provided. Thus, deciders can base decision-making strategies on probabilistic laws. In many laboratory decision-making tasks, choosing the option with the highest winning probability in all trials (=maximization strategy) is probabilistically regarded the most rational behavior. However, individuals often behave less optimal, especially in case the individuals have lower cognitive functions or in case no feedback about consequences is provided in the situation. It is still unclear which cognitive functions particularly predispose individuals for using successful strategies and which strategies profit from feedback. We investigated 195 individuals with two decision-making paradigms, the Game of Dice Task (GDT) (with and without feedback), and the Card Guessing Game. Thereafter, participants reported which strategies they had applied. Interaction effects (feedback × strategy), effect sizes, and uncorrected single group comparisons suggest that feedback in the GDT tended to be more beneficial to individuals reporting exploratory strategies (e.g., use intuition). In both tasks, the self-reported use of more principled and more rational strategies was accompanied by better decision-making performance and better performances in reasoning and executive functioning tasks. The strategy groups did not significantly differ in most short-term and working-memory tasks. Thus, particularly individual differences in reasoning and executive functions seem to predispose individuals toward particular decision-making strategies. Feedback seems to be useful for individuals who rather explore the decision-making situation instead of following a certain plan.

Effects of Information Visualization on Older Adults’ Decision-Making Performance in a Medicare Plan Selection Task: A Comparative Usability Study

PubMed Central

Price, Margaux M; Crumley-Branyon, Jessica J; Leidheiser, William R

2016-01-01

Background Technology gains have improved tools for evaluating complex tasks by providing environmental supports (ES) that increase ease of use and improve performance outcomes through the use of information visualizations (info-vis). Complex info-vis emphasize the need to understand individual differences in abilities of target users, the key cognitive abilities needed to execute a decision task, and the graphical elements that can serve as the most effective ES. Older adults may be one such target user group that would benefit from increased ES to mitigate specific declines in cognitive abilities. For example, choosing a prescription drug plan is a necessary and complex task that can impact quality of life if the wrong choice is made. The decision to enroll in one plan over another can involve comparing over 15 plans across many categories. Within this context, the large amount of complex information and reduced working memory capacity puts older adults’ decision making at a disadvantage. An intentionally designed ES, such as an info-vis that reduces working memory demand, may assist older adults in making the most effective decision among many options. Objective The objective of this study is to examine whether the use of an info-vis can lower working memory demands and positively affect complex decision-making performance of older adults in the context of choosing a Medicare prescription drug plan. Methods Participants performed a computerized decision-making task in the context of finding the best health care plan. Data included quantitative decision-making performance indicators and surveys examining previous history with purchasing insurance. Participants used a colored info-vis ES or a table (no ES) to perform the decision task. Task difficulty was manipulated by increasing the number of selection criteria used to make an accurate decision. A repeated measures analysis was performed to examine differences between the two table designs. Results Twenty-three older adults between the ages of 66 and 80 completed the study. There was a main effect for accuracy such that older adults made more accurate decisions in the color info-vis condition than the table condition. In the low difficulty condition, participants were more successful at choosing the correct answer when the question was about the gap coverage attribute in the info-vis condition. Participants also made significantly faster decisions in the info-vis condition than in the table condition. Conclusions Reducing the working memory demand of the task through the use of an ES can improve decision accuracy, especially when selection criteria is only focused on a single attribute of the insurance plan. PMID:27251110

Serotonin Transporter Gene-Linked Polymorphic Region (5-HTTLPR) Influences Decision Making under Ambiguity and Risk in a Large Chinese Sample

PubMed Central

He, Qinghua; Xue, Gui; Chen, Chuansheng; Lu, Zhonglin; Dong, Qi; Lei, Xuemei; Ding, Ni; Li, Jin; Li, He; Chen, Chunhui; Li, Jun; Moyzis, Robert K.; Bechara, Antoine

2010-01-01

Risky decision-making is a complex process that involves weighing the probabilities of alternative options that can be desirable, undesirable, or neutral. Individuals vary greatly in how they make decisions either under ambiguity and/or under risk. Such individual differences may have genetic bases. Based on previous studies on the genetic basis of decision making, two decision making tasks [i.e., Iowa Gambling Task (IGT) and Loss Aversion Task (LAT)] were used to test the effect of 5-HTTLPR polymorphism on decision making under ambiguity and under risk in a large Han Chinese sample (572 college students, 312 females). Basic intelligence and memory tests were also included to control for the influence of basic cognitive abilities on decision making. We found that 5-HTTLPR polymorphism significantly influenced performance in both IGT and LAT. After controlling for intellectual and memory abilities, subjects homozygous for s allele had lower IGT scores than l carriers in the first 40 trials of the IGT task. They also exhibited higher loss aversion than l carriers in the LAT task. Moreover, the effects of 5-HTTLPR were stronger for males than for females. These results extend the literature on the important role of emotion in decision under ambiguity and risk, and provide additional lights on how decision-making is influenced by culture as well as sex differences. Combining our results with existing literature, we propose that these effects might be mediated by a neural circuitry that comprises the amygdala, ventromedial prefrontal cortex, and insular cortex. Understanding the genetic factors affecting decision in healthy subjects may allow us better identify at-risk individuals, and target better the development of new potential treatments for specific disorders such as schizophrenia, addiction, and depression. PMID:20659488

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.

Signal detection theory and methods for evaluating human performance in decision tasks

NASA Technical Reports Server (NTRS)

Obrien, Kevin; Feldman, Evan M.

1993-01-01

Signal Detection Theory (SDT) can be used to assess decision making performance in tasks that are not commonly thought of as perceptual. SDT takes into account both the sensitivity and biases in responding when explaining the detection of external events. In the standard SDT tasks, stimuli are selected in order to reveal the sensory capabilities of the observer. SDT can also be used to describe performance when decisions must be made as to the classification of easily and reliably sensed stimuli. Numbers are stimuli that are minimally affected by sensory processing and can belong to meaningful categories that overlap. Multiple studies have shown that the task of categorizing numbers from overlapping normal distributions produces performance predictable by SDT. These findings are particularly interesting in view of the similarity between the task of the categorizing numbers and that of determining the status of a mechanical system based on numerical values that represent sensor readings. Examples of the use of SDT to evaluate performance in decision tasks are reviewed. The methods and assumptions of SDT are shown to be effective in the measurement, evaluation, and prediction of human performance in such tasks.

Factors contributing to the development of overt encephalopathy in liver cirrhosis patients.

PubMed

Iwasa, Motoh; Sugimoto, Ryosuke; Mifuji-Moroka, Rumi; Hara, Nagisa; Yoshikawa, Kyoko; Tanaka, Hideaki; Eguchi, Akiko; Yamamoto, Norihiko; Sugimoto, Kazushi; Kobayashi, Yoshinao; Hasegawa, Hiroshi; Takei, Yoshiyuki

2016-10-01

The aim of this study was to clarify the relationships among psychometric testing results, blood ammonia (NH3) levels, electrolyte abnormalities, and degree of inflammation, and their associations with the development of overt hepatic encephalopathy (HE) in liver cirrhosis (LC) patients. The relationships between covert HE and blood NH3, sodium (Na), and C-reactive protein (CRP) were examined in 40 LC patients. The effects of elevated NH3, hyponatremia, and elevated CRP on the development of overt HE were also investigated. The covert HE group had significantly lower serum Na levels and significantly higher serum CRP levels. During the median observation period of 11 months, 10 patients developed overt HE, and the results of multivariate analysis showed that covert HE and elevated blood NH3 were factors contributing to the development of overt HE. Electrolyte abnormalities and mild inflammation are involved in the pathogenesis of HE. Abnormal psychometric testing results and hyperammonemia are linked to subsequent development of overt HE.

Young children's understanding of briefly versus extremely delayed images of the self: emergence of the autobiographical stance.

PubMed

Povinelli, D J; Simon, B B

1998-01-01

Eighty-eight young 3-, 4-, and 5-year-olds were scheduled for 2 testing sessions. On Visit 1, the children were videotaped playing a game while an experimenter covertly placed a large sticker on their head and covertly removed it after the game. One week later, the children were videotaped playing a different game. A sticker was again covertly placed on their heads. Half the children in each age group then observed the video from the previous week, whereas the other half observed the tape from 3 min earlier. Less than half of the 3-year-olds in both conditions reached up for the sticker. In contrast, the majority of 4- and 5-year-olds in the briefly delayed condition reached for the sticker, but few in the extremely delayed condition did so. By 4 years of age, children may have developed a causal understanding of the self's endurance through time.

Managing young children's snack food intake. The role of parenting style and feeding strategies.

PubMed

Boots, Samantha B; Tiggemann, Marika; Corsini, Nadia; Mattiske, Julie

2015-09-01

One major contributor to the problem of childhood overweight and obesity is the over-consumption of foods high in fat, salt and sugar, such as snack foods. The current study aimed to examine young children's snack intake and the influence of feeding strategies used by parents in the context of general parenting style. Participants were 611 mothers of children aged 2-7 years who completed an online questionnaire containing measures of general parenting domains and two particular feeding strategies, restriction and covert control. It was found that greater unhealthy snack intake was associated with higher restriction and lower covert control, while greater healthy snack intake was associated with lower restriction and higher covert control. Further, the feeding strategies mediated the association between parental demandingness and responsiveness and child snack intake. These findings provide evidence for the differential impact of controlling and positive parental feeding strategies on young children's snack intake in the context of general parenting. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lax decision criteria lead to negativity bias: evidence from the emotional stroop task.

PubMed

Liu, Guofang; Xin, Ziqiang; Lin, Chongde

2014-06-01

Negativity bias means that negative information is usually given more emphasis than comparable positive information. Under signal detection theory, recent research found that people more frequently and incorrectly identify negative task-related words as having been presented originally than positive words, even when they were not presented. That is, people have lax decision criteria for negative words. However, the response biases for task-unrelated negative words and for emotionally important words are still unclear. This study investigated response bias for these two kinds of words. Study 1 examined the response bias for task-unrelated negative words using an emotional Stroop task. Proportions of correct recognition to negative and positive words were assessed by non-parametric signal detection analysis. Participants have lower (i.e., more lax) decision criteria for task-unrelated negative words than for positive words. Study 2 supported and expanded this result by investigating participants' response bias for highly emotional words. Participants have lower decision criteria for highly emotional words than for less emotional words. Finally, possible evolutionary sources of the response bias were discussed.

Knowledge inhibition and N400: a study with words that look like common words.

PubMed

Debruille, J B

1998-04-01

In addition to their own representations, low frequency words, such as BRIBE, can covertly activate the representations of higher frequency words they look like (e.g., BRIDE). Hence, look-alike words can activate knowledge that is incompatible with the knowledge corresponding to accurate representations. Comparatively, eccentric words, that is, low frequency words that do not look as much like higher frequency words, are less likely to activate incompatible knowledge. This study focuses on the hypothesis that the N400 component of the event-related potential reflects the inhibition of incompatible knowledge. This hypothesis predicts that look-alike words elicit N400s of greater amplitudes than eccentric words in conditions where incompatible knowledge is inhibited. Results from a single item lexical decision experiment are reported which support the inhibition hypothesis. Copyright 1998 Academic Press.