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The magnitude of the effect of an intervention on a quantitative outcome may be expressed as a standardized mean difference by dividing the difference in means by the standard deviation of the outcome. This is useful to compare outcomes measured using different scales, especially in meta-analysis. However, uncertainty about the standard deviation leads to complicated formulae to avoid bias and
These demonstrations stress individualdifferences, a concept becoming increasingly important in psychological research. Intended for use in undergraduate psychology courses, four demonstrations that illustrate common examples of human variation are described. The demonstrations deal with the following individualdifferences: taste blindness,…
There is increased need for efficient computerized methods to collect reliable data on a range of cognitive domains that can be linked to specific brain systems. Such need arises in functional neuroimaging studies, where individualdifferences in cognitive performance are variables of interest or serve as confounds. In genetic studies of complex behavior, which require particularly large samples, such trait measures can serve as endophenotypes. Traditional neuropsychological tests, based on clinical pathological correlations, are protracted, require extensive training in administration and scoring, and leave lengthy paper trails (double-entry for analysis). We present a computerized battery that takes an average of 1 hour and provides measures of accuracy and speed on 9 neurocognitive domains. They are cognitive neuroscience-based in that have been linked experimentally to specific brain systems with functional neuroimaging studies. We describe the process of translating tasks used in functional neuroimaging to tests for assessing individualdifferences. Data are presented on each test with samples ranging from 139 (81 female) to 536 (311 female) of carefully screened healthy individuals ranging in age from 18 to 84. Item consistency was established with acceptable to high Cronbach alpha coefficients. Inter-item correlations were moderate to high within domain and low to nil across domains, indicating construct validity. Initial criterion validity was demonstrated by sensitivity to sex differences and the effects of age, education and parental education. These results encourage the use of this battery in studies needing an efficient assessment of major neurocognitive domains such as multisite genetic studies and clinical trials.
Distance perception is among the most pervasive mental phenomena and the oldest research topics in behavioural science. However, we do not understand well the most pervasive finding of distance perception research, that of large individualdifferences. There are large individualdifferences in acrophobia (fear of heights), which we commonly assume consists of an abnormal fear of stimuli perceived normally. Evolved navigation theory (ENT) instead suggests that acrophobia consists of a more normal fear of stimuli perceived abnormally. ENT suggests that distance perception individualdifferences produce major components of acrophobia. Acrophobia tested over a broad range in the present study predicted large individualdifferences in distance estimation of surfaces that could produce falls. This fear of heights correlated positively with distance estimates of a vertical surface—even among non-acrophobic individuals at no risk of falling and without knowledge of being tested for acrophobia. Acrophobia score predicted magnitude of the descent illusion, which is thought to reflect the risk of falling. These data hold important implications in environmental navigation, clinical aetiology and the evolution of visual systems.
Although One-Stop Career Centers are mandated to promote client-centered services, patrons are ordinarily funneled through a standard procedure. Adult education principles suggest that these centers should be learner-centered and address individualdifferences. Therefore, the purpose of the this study was to describe the interaction of the…
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Reports that, even though young infants can discriminate among different facial expressions, there are individualdifferences in infants' expressivity and ability to produce and discriminate facial expressions. (PCB)
Music cognition depends on the existence and deployment of processes for detecting, storing and organizing musical materials according to underlying structural features. Common cultural experiences develop these processes to a certain degree, but specifically designed and supported learning environments are required to achieve the levels of expertise required to perform western art music. Certain motivational and social factors are therefore implicated in the maintenance of activities that promote skill-acquisition, such as practice. Expert musical performance is not just a matter of technical motor skill, it also requires the ability to generate expressively different performances of the same piece of music according to the nature of intended structural and emotional communication. This review examines these abilities and describes how some of them have been shown to have lawful relationships to objective musical and extra-musical parameters. Psychological research is thus engaged in a process of demystifying musical expertise, a process that helps to improve upon culturally prevalent, but ultimately non-explanatory, notions of inborn 'talent'. PMID:11025283
A quantitative system is presented to permit the determination of separate multidimensional perceptual spaces for individuals having different viewpoints about stimulus interrelationships. The structure of individualdifferences in the perception of stimulus relationships is also determined to provide a framework for ascertaining the varieties of consistent individual viewpoints and their relationships with other variables.
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Presents results of two studies examining individualdifferences in self-presentation style. Identifies three major groups among subjects: consistents, flexible impression managers, and rigid impression managers. Reports differences in self-evaluations among the groups with consistents rating themselves most favorably. Concludes that individuals'…
Individualdifferences in abilities to form, access, and hone phonological representations of words are implicated in the development of oral and written language. This study addressed two important gaps in the literature concerning measurement of individualdifferences in phonological representation. First, we empirically examined the…
Anthony, Jason L.; Williams, Jeffrey M.; Aghara, Rachel G.; Dunkelberger, Martha; Novak, Barbara; Mukherjee, Anuja Divatia
The literature on the effects of noise on sleep is searched for evidence on individualdifferences along the dimensions of age, sex, occupation, personality, neuroticism, and mental health. With the exception of age, little firm evidence is found. Thus there remains a need to establish at better than the anecdotal level whether or not real individualdifferences exist.
Individuals often differ in what they do. This has been recognised since antiquity. Nevertheless, the ecological and evolutionary significance of such variation is attracting widespread interest, which is burgeoning to an extent that is fragmenting the literature. As a first attempt at synthesis, we focus on individualdifferences in behaviour within populations that exceed the day-to-day variation in individual behaviour (i.e. behavioural specialisation). Indeed, the factors promoting ecologically relevant behavioural specialisation within natural populations are likely to have far-reaching ecological and evolutionary consequences. We discuss such individualdifferences from three distinct perspectives: individual niche specialisations, the division of labour within insect societies and animal personality variation. In the process, while recognising that each area has its own unique motivations, we identify a number of opportunities for productive ‘crossfertilisation’ among the (largely independent) bodies of work. We conclude that a complete understanding of evolutionarily and ecologically relevant individualdifferences must specify how ecological interactions impact the basic biological process (e.g. Darwinian selection, development and information processing) that underpin the organismal features determining behavioural specialisations. Moreover, there is likely to be covariation amongst behavioural specialisations. Thus, we sketch the key elements of a general framework for studying the evolutionary ecology of individualdifferences.
Dall, Sasha R. X.; Bell, Alison M.; Bolnick, Daniel I.; Ratnieks, Francis L. W.
This article describes a research program addressing several issues about the role of individualdifferences in working memory and reading comprehension. The studies show a strong positive relationship between measures of working memory capacity and highe...
Discussion of information visualization and computer graphics focuses on a study that contrasted performance in three dimensional (3D) and two dimensional zooming interactively (2.5D) virtual worlds for people with differing levels of spatial and structure learning ability. Suggests implications of individualdifferences for the usability and…
The influence of age and individual ability differences on event-based prospective memory was examined using an adapted version of G. O. Einstein and M. A. McDaniel's (1990) task. Two samples of younger and older adults who differed in educational attainment, occupational status, and verbal ability were compared. Results yield comparable prospective performance for the younger groups and higher ability older
We investigated individualdifferences in the neural substrates of morphosyntactic processing among monolingual English speakers using event-related potentials (ERPs). Although grand-mean analysis showed a biphasic LAN-P600 pattern to grammatical violations, analysis of individuals? ERP responses showed that brain responses varied systematically along a continuum between negativity- and positivity-dominant ERP responses across individuals. Moreover, the left hemisphere topography of the negativity resulted from component overlap between a centro-parietal N400 in some individuals and a right hemisphere-dominant P600 in others. Our results show that biphasic ERP waveforms do not always reflect separable processing stages within individuals, and moreover, that the LAN can be a variant of the N400. These results show that there are multiple neurocognitive routes to successful grammatical comprehension in language users across the proficiency spectrum. Our results underscore that understanding and quantifying individualdifferences can provide an important source of evidence about language processing in the general population. PMID:24530237
This paper presents IEC/SC 45B Radiation protection instrumentation and its standards for individual monitoring of ionising radiation: IEC 61526 Ed. 3 for active personal dosemeters and IEC 62387-1 for passive integrating dosimetry systems. The transposition of these standards as CENELEC (European) standards is also discussed together with the collaboration between IEC/SC 45B and ISO/TC 85/SC 2.
Voytchev, Miroslav [IRSN; Ambrosi, P. [Physikalisch-Technische Bundesanstalt (PTB); Behrens, R. [Physikalisch-Technische Bundesanstalt (PTB); Chiaro Jr, Peter John [ORNL
Previous research has documented individualdifferences in a range of constructs relating to social stereotyping, prejudice, and intergroup attitudes. However, research has not sought specifically to measure a general acceptance of social stereotyping. In the present research, we explored attitudinal, cognitive, emotional, and personality correlates of a person’s self-reported willingness to rely on stereotypical information when interacting with people of
Jason D. Carter; Judith A. Hall; Dana R. Carney; Janelle C. Rosip
Explored origins of individualdifferences in infant shyness by studying its relationship to parental shyness, sociability, and introversion-extraversion. Full adoption design examined role of both genetic and family environmental influences as possible etiological factors in development of infant shyness. Results indicate genetic influences and…
Individualdifferences such as personality and demographic factors have effects on how people react to Electronic Performance Monitoring (EPM), yet the literature on this aspect of electronic monitoring has been scattered. The present paper summarizes this body of empirical research and presents a framework for organizing current research findings based on two dimensions: the probability of successful work under the
Understanders appear to routinely and immediately evaluate the congruence of discourse at many levels of analysis, processes often labeled "validation." This study was an initial exploration of individualdifferences in discourse validation. Text "reading-time" profiles were examined as a function of two negligibly correlated…
In an extension of previous studies on deception and deception detection, the present study investigated the relations among individualdifferences, behavioral cues displayed when deceiving and telling the truth, and the perceptions of naive observers. 63 undergraduates were measured on the Self-Monitoring Scale, the Affective Communication Test, the Personality Research Form, the Eysenck Personality Inventory, their acting ability, and their
Current research and though regarding the relationship of individualdifference (ID) factors to achievement in the basic skills is reviewed. Four major categories and nine subcategories of ID factors are defined and serve as the framework for the review: status factors (age, sex, and race, ethnic group, and socioeconomic status); intelligence…
Several different theories exist about the origin of kinetosis and the space adaptation syndrome, with individual sensitivities differing significantly. One explanation involves the hypothesis of a different otolith mass between the right and left statolith organ and especially a difference in the utricles. A difference in mass results in a different sensitivity to acceleration. For this reason we measured interindividual variances in saccular and utricular otolith mass. Since the anatomy of the vestibular organ in vertebrates is based as similar principles, we selected fish (salmon and trout) as our study model to facilitation preparations. The maximum difference in mass in the saccule was 17% and was generally smaller in the utricle, although in individual cases was much higher. We assume that a misbalanced sensitivity of the statolith organs occurs but is totally compensated for by the vestibular system as long as physiological motion patterns take place. Decompensation leads to kinetosis under non-physiological motion patterns. When the vestibular system is better balanced and has an equally distributed otolith mass to both sides, the possibility for developing kinetosis or space adaptation syndrome is much less likely. PMID:9221260
Conflict-monitoring theory argues for a general cognitive mechanism that monitors for conflicts in information-processing. If that mechanism detects conflict, it engages cognitive control to resolve it. A slow-down in response to incongruent trials (conflict effect), and a modulation of the conflict effect by the congruence of the preceding trial (Gratton or context effect) have been taken as indicators of such a monitoring system. The present study (N = 157) investigated individualdifferences in the conflict and the context effect in a horizontal and a vertical Simon task, and their correlation with working memory capacity (WMC). Strength of conflict was varied by proportion of congruent trials. Coherent factors could be formed representing individualdifferences in speeded performance, conflict adaptation, and context adaptation. Conflict and context factors were not associated with each other. Contrary to theories assuming a close relation between working memory and cognitive control, WMC showed no relation with any factors representing adaptation to conflict. PMID:24385971
A study was conducted to investigate individualdifferences in perceived esteem (perceptions of how positively one is viewed by others) and the relationship between perceived esteem, self-esteem, self-monitoring, and life satisfaction across cultures. A study with Japanese and American college students (and a pilot study with Caucasian and Asian American participants), indicated that a 10-item measure of perceived esteem, assessing
Anthony D. Hermann; Gale M. Lucas; James Friedrich
This study investigated individualdifferences in different aspects of early number concepts in preschoolers. Eighty 4-year-olds from Oxford nursery classes took part. They were tested on accuracy of counting sets of objects; the cardinal word principle; the order irrelevance principle; and predicting the results of repeated addition and subtraction by 1 from a set of objects. There were marked individualdifferences for most tasks. Most children were reasonably proficient at counting and 70% understood the cardinal word principle. Based on the results of a repeated addition and subtraction by 1 task, the children were divided into three approximately equal groups: those who were already able to use an internalized counting sequence for the simplest forms of addition and subtraction; those who relied on a repeated 'counting-all' procedure for such tasks; and those who were as yet unable to cope with such tasks. In each group, significant relationships between some, but not all, of the numerical tasks were found. However, for almost any two tasks, it was possible to find individuals who could carry out either one of the tasks but not the other. Thus, even before formal instruction, arithmetical cognition is not unitary but is made up of many components. PMID:18801119
A number of studies investigating the relationship between personality and prospective memory (ProM) have appeared during the last decade. However, a review of these studies reveals little consistency in their findings and conclusions. To clarify the relationship between ProM and personality, we conducted two studies: a meta-analysis of prior research investigating the relationships between ProM and personality, and a study with 378 participants examining the relationships between ProM, personality, verbal intelligence, and retrospective memory. Our review of prior research revealed great variability in the measures used to assess ProM, and in the methodological quality of prior research; these two factors may partially explain inconsistent findings in the literature. Overall, the meta-analysis revealed very weak correlations (rs ranging from 0.09 to 0.10) between ProM and three of the Big Five factors: Openness, Conscientiousness, and Agreeableness. Our experimental study showed that ProM performance was related to individualdifferences such as verbal intelligence as well as to personality factors and that the relationship between ProM and personality factors depends on the ProM subdomain. In combination, the two studies suggest that ProM performance is relatively weakly related to personality factors and more strongly related to individualdifferences in cognitive factors.
Uttl, Bob; White, Carmela A.; Wong Gonzalez, Daniela; McDouall, Joanna; Leonard, Carrie A.
The study of individualdifferences encompasses broad constructs including intelligence, creativity, and personality. However, substantially less research is devoted to the study of specific aptitudes in spite of their importance to educational, occupational, and avocational success. We sought to determine subcortical brain structural correlates of several broad aptitudes including Math, Vocabulary, Foresight, Paper Folding, and Inductive Reasoning in a large (N = 107), healthy, young (age range ?= 16-29) cohort. Subcortical volumes were measured using an automated technique (FreeSurfer) across structures including bilateral caudate, putamen, globus pallidus, thalamus, nucleus accumbens, hippocampus, amygdala, and five equal regions of the corpus callosum. We found that performance on measures of each aptitude was predicted by different subcortical structures: Math--higher right nucleus accumbens volume; Vocabulary--higher left hippocampus volume; Paper Folding--higher right thalamus volume; Foresight--lower right thalamus and higher mid anterior corpus callosum volume; Inductive Reasoning--higher mid anterior corpus callosum volume. Our results support general findings, within the cognitive neurosciences, showing lateralization of structure-function relationships, as well as more specific relationships between individual structures (e.g., left hippocampus) and functions relevant to particular aptitudes (e.g., Vocabulary). PMID:24586770
Jung, Rex E; Ryman, Sephira G; Vakhtin, Andrei A; Carrasco, Jessica; Wertz, Chris; Flores, Ranee A
In cognitive modeling, data are often categorical observations taken over participants and items. Usually subsets of these observations are pooled and analyzed by a cognitive model assuming the category counts come from a multinomial distribution with the same model parameters underlying all observations. It is well known that if there are individualdifferences in participants and/or items, a model analysis of the pooled data may be quite misleading, and in such cases it may be appropriate to augment the cognitive model with parametric random effects assumptions. On the other hand, if random effects are incorporated into a cognitive model that is not needed, the resulting model may be more flexible than the multinomial model that assumes no heterogeneity, and this may lead to overfitting. This article presents Monte Carlo statistical tests for directly detecting individual participant and/or item heterogeneity that depend only on the data structure itself. These tests are based on the fact that heterogeneity in participants and/or items results in overdispersion of certain category count statistics. It is argued that the methods developed in the article should be applied to any set of participant x item categorical data prior to cognitive model-based analyses. PMID:18792498
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There are marked individualdifferences in the formation of cognitive maps both in the real world and in virtual environments (VE; e.g., Blajenkova, Motes, & Kozhevnikov, 2005; Chai & Jacobs, 2010; Ishikawa & Montello, 2006; Wen, Ishikawa, & Sato, 2011). These differences, however, are poorly understood and can be difficult to assess except by self-report methods. VEs offer an opportunity to collect objective data in environments that can be controlled and standardized. In this study, we designed a VE consisting of buildings arrayed along 2 separated routes, allowing for differentiation of between-route and within-route representation. Performance on a pointing task and a model-building task correlated with self-reported navigation ability. However, for participants with lower levels of between-route pointing, the Santa Barbara Sense of Direction scale (Hegarty, Richardson, Montello, Lovelace, & Subbiah, 2002) did not predict individualdifferences in accuracy when pointing to buildings within the same route. Thus, we confirm the existence of individualdifferences in the ability to construct a cognitive map of an environment, identify both the strengths and the potential weaknesses of self-report measures, and isolate a dimension that may help to characterize individualdifferences more completely. The VE designed for this study provides an objective behavioral measure of navigation ability that can be widely used as a research tool. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24364725
Weisberg, Steven M; Schinazi, Victor R; Newcombe, Nora S; Shipley, Thomas F; Epstein, Russell A
Previous research suggests that members of East Asian cultures show a greater preference for dialectical thinking than do Westerners. This paper attempts to account for these differences in cognition using individualdifference variables that may explain variation in performance both within and across cultures. Especially, we propose that the abovementioned cultural differences are rooted in a greater fear of isolation (FOI) in East Asians than in Westerners. To support this hypothesis, in Experiment 1, we manipulated FOI in American participants before having them resolve two conflicts: an interpersonal conflict and a conflict between an individual and an institution. We found that the Americans among whom a high level of FOI had been induced were more likely to look for a dialectical resolution than those among whom a low level had been prompted. The relationship between conflict resolution and FOI was further investigated in Experiment 2, in which FOI was not manipulated. The results indicated that Koreans had higher chronic FOI on average than did the Americans. Compared to the Americans, the Koreans were more likely to resolve the interpersonal conflict dialectically, but did not show the same bias in resolving the person-institution conflict. The differences in the preference for dialectical resolution between FOI conditions in Experiment 1 and cultural groups in Experiment 2 were mediated by FOI. These findings bolster previous research on FOI in showing that chronic levels of FOI are positively related to both preference for dialectical sentences and sensitivity to context. They provide clearer insight into how differences in FOI affect attention and thereby higher-level reasoning such as dialectic description and conflict resolution. PMID:22871043
Modeling of individual or group differences, believed to be a powerful test for computational models, is still rare in current cognitive science. In this paper, we discuss alternative approaches to the computational modeling of both qualitative and quantitative differences among individuals as well as groups of individuals. Then, an example is presented of how accounting for individualdifferences in short
Adam Chuderski; Zbigniew Stettner; Jaroslaw Orzechowski
Two hundred twenty-four undergraduate students wrote about one-half of an inning of a baseball game and about one-half of a soccer game, counterbalanced, for 20 min each. Students then completed two six-item interest inventories—one each on the topics of baseball and soccer—and tests of baseball knowledge and soccer knowledge. Hierarchical regression analyses revealed that individual interest in baseball was significantly
Marsha L. Albin; Stephen L. Benton; Irina Khramtsova
Four types of training techniques were compared in the training of a perceptual concept-formation task. Adaptive training, a technique in which one parameter in the learning situation is varied so that the difficulty of a learning task remains constant for that individual, was compared to three intermediate approaches to training (self-adaptive, in which the trainees could control their own pace of learning by indicating when they felt they had mastered the problem, fixed sequence, and fixed task). The relationship between individual trainee's perceptual style and various stages of training was also investigated. Perceptual style was measured by the Hidden Figures Test, the Rod-and-frame Test, a Distracting Context Test, and a Cancellation Test. Results showed a definite (time to perform the task) advantage in favor of the adaptive training method. Fewer errors were committed under the self-adaptive approach, but the task completion time was significantly higher. Further analysis showed that for the adaptive-training group, measures of perceptual style could be used as predictors of future task success. No such relationship was found for other training techniques. In particular, field-independence appears to be important early in training but becomes increasingly less important, and for the final training criterion trials, is not predictive of performance. In contrast, the Distracting Contest Test-II, early in training, is not an important predictor but is an important predictor for the final criterion trials. PMID:327433
Barrett, G V; Greenawalt, J P; Thornton, C I; Williamson, T R
Background With the present functional magnetic resonance imaging (fMRI) study at 3 T, we investigated the neural correlates of visualization and verbalization during arithmetic word problem solving. In the domain of arithmetic, visualization might mean to visualize numbers and (intermediate) results while calculating, and verbalization might mean that numbers and (intermediate) results are verbally repeated during calculation. If the brain areas involved in number processing are domain-specific as assumed, that is, that the left angular gyrus (AG) shows an affinity to the verbal domain, and that the left and right intraparietal sulcus (IPS) shows an affinity to the visual domain, the activation of these areas should show a dependency on an individual’s cognitive style. Methods 36 healthy young adults participated in the fMRI study. The participants habitual use of visualization and verbalization during solving arithmetic word problems was assessed with a short self-report assessment. During the fMRI measurement, arithmetic word problems that had to be solved by the participants were presented in an event-related design. Results We found that visualizers showed greater brain activation in brain areas involved in visual processing, and that verbalizers showed greater brain activation within the left angular gyrus. Conclusions Our results indicate that cognitive styles or preferences play an important role in understanding brain activation. Our results confirm, that strong visualizers use mental imagery more strongly than weak visualizers during calculation. Moreover, our results suggest that the left AG shows a specific affinity to the verbal domain and subserves number processing in a modality-specific way.
This experiment investigated the relationships between speed, level, and complexity in individualdifferences in spatial ability. Thirty male high school and college students representing a wide range of individualdifferences in verbal ability and spatia...
This monograph describes the development of the Metaphoric Triads Task (MTT), an instrument designed to assess metaphoric comprehension. Validity and reliability of the instrument are discussed and data for 12 samples of subjects are reported. Sex differences were negligible, but progressive improvement in MTT score with age was noted. Pictorial…
Single case designs are a set of research methods for evaluating treatment effects by assigning different treatments to the same individual and measuring outcomes over time and are used across fields such as behavior analysis, clinical psychology, special education, and medicine. Emerging standards for single case designs have focused attention on…
Hedges, Larry V.; Pustejovsky, James E.; Shadish, William R.
This paper describes several experiments examining the source of individualdifferences in the experience of mental workload. Three sources of such differences were examined: information processing abilities, timesharing abilities, and personality traits/behavior patterns. On the whole, there was little evidence that individualdifferences in information processing abilities or timesharing abilities are related to perceived differences in mental workload. However, individuals with strong Type A coronary prone behavior patterns differed in both single- and multiple-task performance from individuals who showed little evidence of such a pattern. Additionally, individuals with a strong Type A pattern showed some dissociation between objective performance and the experience of mental workload.
Determined whether individual neonate characteristics could be detected and reliably measured in preterm infants. Results showed that preterms were highly self-consistent in their reactions to stimuli from neurobehavioral assessments. Highly reliable individualdifferences among infants were also seen. Individual consistencies and differences in…
Accuracy of participants' ratings of gender differences on 77 behaviors and traits was assessed by correlating participants' ratings with actual gender differences based on meta-analyses. Accuracy at the group level was impressively high in 5 samples of participants. Accuracy of individuals showed wide variability, suggesting that ability to accurately describe gender differences is an individualdifference. Analysis of correlations between
Dyads composed of unacquainted females (n=82) watched a cartoon while consuming salty aperitif snacks. The Affective Communication Test was used to measure nonverbal expressiveness. Computing intraclass correlation coefficients, the extent to which participants within dyads matched each other's food intake was analyzed. Food intake matched highly for dyads with two expressive individuals and moderately for dyads with one expressive participant. For dyads with two unexpressive participants, there was no evidence for matching behavior. Highly expressive people seem to be able to synchronize with others and thereby allow for close matching. This is the first study to show an influence of personality on matching consumption behavior. PMID:22182829
A phonetic confusion model and some procedural artifacts were eliminated as sources for individualdifferences in fusion rate. Results of these two experiments were consistent with the hypothesis that individualdifferences in fusion rate are due to differences in perceptual dependence on linguistic rules. (Editor/RK)
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Although recent models for the evolution of personality, using game theory and life-history theory, predict that individuals should differ consistently in their cooperative behaviour, consistent individualdifferences in cooperative behaviour have rarely been documented. In this study, we used a long-term data set on wild meerkats to quantify the repeatability of two types of cooperative care (babysitting and provisioning) within individuals and examined how repeatability varied across age, sex and status categories. Contributions to babysitting and provisioning were significantly repeatable and positively correlated within individuals, with provisioning more repeatable than babysitting. While repeatability of provisioning was relatively invariant across categories of individuals, repeatability of babysitting increased with age and was higher for subordinates than dominants. These results provide support for theoretical predictions that life-history trade-offs favour the evolution of consistent individualdifferences in cooperative behaviour and raise questions about why some individuals consistently help more than others across a suite of cooperative behaviours. PMID:20492087
The assessment of individualdifferences in facial expression recognition is normally required to address two major issues: (1) high agreement level (ceiling effect) and (2) differential difficulty levels across emotions. We propose a new assessment method designed to quantify individualdifferences in the recognition of the six basic emotions,…
Although previous studies have identified several regularities in buying behavior, no integrated view of individualdifferences related to such patterns has been yet proposed. The present research examined individualdifferences in patterns of buying behavior of fast-moving consumer goods, using panel data with information concerning purchases of…
Cavalcanti, Paulo R.; Oliveira-Castro, Jorge M.; Foxall, Gordon R.
This study assessed the reproductive performance of mice housed in 2 types of individually ventilated caging systems. Breeding pairs from 48 female and 24 male mice of 3 established transgenic mouse breeding colonies were placed in either a standard or disposable ventilated caging system. For 3 breeding cycles, the number of pups born, pup survival rate to weaning, time interval between litters, and pup weights were monitored for each breeding pair. Disposable and standard cages were maintained in the same location during breeding. Environmental parameters included intracage temperature, humidity, and ammonia and carbon dioxide levels and room light intensity and sound. Overall, 776 offspring were produced. Breeding performance did not differ significantly between the 2 cage types. By 11 wk of age, the weights of pups from both cage types were equivalent. The intracage temperature was 1.1 °F warmer and light intensity at the site of the nest was 34 lx dimmer in disposable cages than in standard caging. The difference in lighting likely was due to nest location; the nests in the disposable cages were at the back of the cages and away from the anterior air supply, whereas in standard caging, nests were at the front of the cages, with the air supply at the rear. Under these husbandry conditions, mice housed in disposable caging systems have comparable breeding performance to those housed in standardindividually ventilated cages.
The response to an exercise intervention is often described in general terms, with the assumption that the group average represents a typical response for most individuals. In reality, however, it is more common for individuals to show a wide range of responses to an intervention rather than a similar response. This phenomenon of 'high responders' and 'low responders' following a standardized training intervention may provide helpful insights into mechanisms of training adaptation and methods of training prescription. Therefore, the aim of this review was to discuss factors associated with inter-individual variation in response to standardized, endurance-type training. It is well-known that genetic influences make an important contribution to individual variation in certain training responses. The association between genotype and training response has often been supported using heritability estimates; however, recent studies have been able to link variation in some training responses to specific single nucleotide polymorphisms. It would appear that hereditary influences are often expressed through hereditary influences on the pre-training phenotype, with some parameters showing a hereditary influence in the pre-training phenotype but not in the subsequent training response. In most cases, the pre-training phenotype appears to predict only a small amount of variation in the subsequent training response of that phenotype. However, the relationship between pre-training autonomic activity and subsequent maximal oxygen uptake response appears to show relatively stronger predictive potential. Individual variation in response to standardized training that cannot be explained by genetic influences may be related to the characteristics of the training program or lifestyle factors. Although standardized programs usually involve training prescribed by relative intensity and duration, some methods of relative exercise intensity prescription may be more successful in creating an equivalent homeostatic stress between individuals than other methods. Individual variation in the homeostatic stress associated with each training session would result in individuals experiencing a different exercise 'stimulus' and contribute to individual variation in the adaptive responses incurred over the course of the training program. Furthermore, recovery between the sessions of a standardized training program may vary amongst individuals due to factors such as training status, sleep, psychological stress, and habitual physical activity. If there is an imbalance between overall stress and recovery, some individuals may develop fatigue and even maladaptation, contributing to variation in pre-post training responses. There is some evidence that training response can be modulated by the timing and composition of dietary intake, and hence nutritional factors could also potentially contribute to individual variation in training responses. Finally, a certain amount of individual variation in responses may also be attributed to measurement error, a factor that should be accounted for wherever possible in future studies. In conclusion, there are several factors that could contribute to individual variation in response to standardized training. However, more studies are required to help clarify and quantify the role of these factors. Future studies addressing such topics may aid in the early prediction of high or low training responses and provide further insight into the mechanisms of training adaptation. PMID:24807838
Mann, Theresa N; Lamberts, Robert P; Lambert, Michael I
Spatial skills are known to vary widely among normal individuals. This project was designed to address whether these individualdifferences are differentially related to large-scale environmental learning from route (ground-level) and survey (aerial) perspectives. Participants learned two virtual environments (route and survey) with limited…
Cultural differences between Arabs and Americans were investigated using Wagner's individualism-collectivism survey. Arab subjects were significantly more collectivist than U.S. subjects, and within the Arab culture, Egyptian subjects were significantly more individualistic than Gulf States subjects.
When engaged in behavioural games, animals can adjust their use of alternative tactics until groups reach stable equilibria. Recent theory on behavioural plasticity in games predicts that individuals should differ in their plasticity or responsiveness and hence in their degree of behavioural adjustment. Moreover, individuals are predicted to be consistent in their plasticity within and across biological contexts. These predictions have yet to be tested empirically and so we examine the behavioural adjustment of individual nutmeg mannikins (Lonchura punctulata), gregarious ground-feeding passerines, when playing two different social foraging games: producer–scrounger (PS) and patch-choice (PC) games. We found: (i) significant individualdifferences in plasticity and sampling behaviour in each of the two games, (ii) individualdifferences in sampling behaviour were consistent over different test conditions within a game (PC) and over a six month period (PS), (iii) but neither individual plasticity nor sampling behaviour was correlated from one social foraging game to another. The rate at which birds sampled alternative tactics was positively associated with seed intake in PS trials but negatively associated in PC trials. These results suggest that games with frequency dependence of pay-offs can maintain differences in behavioural plasticity but that an important component of this plasticity is group- and/or context-specific.
Steroid hormones play an important role in modulating social behavior in many species. Estrogens are thought to act on an interconnected network of hypothalamic and limbic brain areas to affect aggressive behavior, although the specific nuclei unknown remain unspecified. We show that individual variation in estrogen receptor alpha (ER?) immunoreactivity in the lateral septum (LS), ventral bed nucleus of the stria terminalis (vBNST), and anterior hypothalamus (AHA) of CD-1 mice is positively correlated with aggressive behavior. When males were treated with fadrozole (an aromatase inhibitor), aggressive behavior was reduced, although castration did not reduce aggression. These results suggest that estrogens modulate aggressive behavior by acting on a circuit that includes the LS, vBNST, and AHA and that the source of estrogens is nongonadal. Fadrozole also decreased c-fos expression in the lateral septum following aggressive encounters. Although the effects of estrogen on aggression appear to involve regulation of neuronal activity in the LS, additional processes are likely involved. These results suggest that estrogen acts in a specific subset of a complex network of nuclei to affect aggressive behavior.
Trainor, Brian C.; Greiwe, Kelly M.; Nelson, Randy J.
Knowledge about word and object meanings can be organized taxonomically (fruits, mammals, etc.) based on shared features, or thematically (eating breakfast, taking a dog for a walk, etc.) based on participation in events or scenarios. An eye-tracking study showed that both kinds of knowledge are activated during comprehension of a single spoken word, even when the listener is not required to perform any active task. The results further revealed that an individual’s relative activation of taxonomic relations compared to thematic relations predicts that individual’s tendency to favor taxonomic over thematic relations when asked to choose between them in a similarity judgment task. These results argue that individualsdiffer in the relative strengths of their taxonomic and thematic semantic knowledge and suggest that meaning information is organized in two parallel, complementary semantic systems.
Individual variations in annoyance and in susceptibility to noise were studied to establish a finer definition of the ingredients of the human annoyance response. The study involved interactions among a heterogeneous sample of human subjects, various noise stimuli, and different physical environments of exposure. Significant differences in annoyance ratings among the six noise stimuli, all equated for peak sound pressure level, were found.
The literature on differences between aggressive individuals exhibiting reactive and proactive aggression raises the issue whether different treatment programs should be developed for violent forensic psychiatric patients with a conduct disorder or an antisocial personality disorder. In order to study this issue, aggressive behavior of 133 inpatients and of 176 outpatients was analyzed in detail for four subgroups, composed on
Ruud H. J. Hornsveld; Clive R. Hollin; Henk L. I. Nijman; Floor W. Kraaimaat
Individualdifferences in adult human brain structure have been found to reveal a great deal of information about variability in behaviors, cognitive abilities and mental and physical health. Driven by such evidence, what contributes to individual variation in brain structure has gained accelerated attention as a research question. Findings thus far appear to support the notion that an individual’s brain architecture is determined largely by genetic and environmental influences. This review aims to evaluate the empirical literature on whether and how genes and the environment contribute to individualdifferences in brain structure. It first considers how genetic and environmental effects may separately contribute to brain morphology, by examining evidence from twin, genome-wide association, cross-sectional and longitudinal studies. Next, evidence for the influence of the complex interplay between genetic and environmental factors, characterized as gene-environment interactions and correlations, is reviewed. In evaluating the extant literature, this review will conclude that both genetic and environmental factors play critical roles in contributing to individual variability in brain structure.
Results by two groups of subjects, pilots and nonpilots, for two subjective workload assessment techniques (the SWAT and NASA-TLX tests) intended to evaluate individualdifferences in the perception and reporting of subjective workload are compared with results obtained for several traditional personality tests. The personality tests were found to discriminate between the groups while the workload tests did not. It is concluded that although the workload tests may provide useful information with respect to the interaction between tasks and personality, they are not effective as pure tests of individualdifferences.
Objective The concept of “adaptation” has been proposed to account for differences between individual and societal valuations of specific health states in patients with chronic diseases. Little is known about psychological indices of adaptational capacity, which may predict differences in individual and societal valuations of health states. We investigated whether such differences were partially explained by personality traits in chronic disease patients. Research Design Analysis of baseline data of randomized controlled trial. Subjects Three hundred seventy patients with chronic disease. Measures The NEO-five factor inventory measure of personality, EuroQoL-5D (EQ-5D) societal-based, and the EQ visual analogue scale individually-based measures of health valuation. Results Regression analyses modeled Dev, a measure of difference between the EQ-Visual Analogue Scale and EQ-5D, as a function of personality traits, sociodemographic factors, and chronic diseases. Individual valuations were significantly and clinically higher than societal valuations among patients in the second and third quartile of conscientiousness (Dev = 0.08, P = 0.01); among covariates, only depression (Dev = -0.04, P = 0.046) was also associated with Dev. Conclusion Compared with societal valuations of a given health state, persons at higher quartiles of conscientiousness report less disutility associated with poor health. The effect is roughly twice that of some estimates of minimally important clinical differences on the EQ-5D and of depression. Although useful at the aggregate level, societal preference measures may systematically undervalue the health states of more conscientious individuals. Future work should examine the impact this has on individual patient outcome evaluation in clinical studies.
Chapman, Benjamin P.; Franks, Peter; Duberstein, Paul R.; Jerant, Anthony
124 subjects were tested in a procedure designed to measure sensitivity to transient currents applied cutaneously, and to assess individual characteristics accounting for sensitivity differences. College students (one male and one female group), female office workers, and male maintenance workers (electricians, carpenters, plumber, and sheet metal workers) were tested. Perception and annoyance thresholds were determined for capacitive discharged stimuli to the fingertip and forearm. Nonsensory data were taken for each individual in an attempt to account for individual sensitivity differences (occupation, sex, age, height, weight, skin temperature, finger and forearm diameter, skin hardness, customary physical activity level, and prior degree of experience with electric shock). Of these, body size was the only significant correlate of electrical sensitivity. Apparent correlations with sex and occupation were found to be artifacts of the body size relationship. A regression equation relating sensitivity to body weight is presented.
Because early theoretical frameworks such as Piaget's stage model and social learning theory sought to explain the development and performance of imitation in terms of overall group trends, any evidence for individualdifferences in this behavior was until recently largely overlooked. Results of contemporary imitation studies have not only begun…
Bilingualism (Sanz, 2000), motivation (Pintrich, 1989), and language aptitude (Grigorenko, Sternberg, and Ehrman, 2000) are crucial individualdifferences that contribute to successful adult language learning. Since Gardner's (1985) seminal work on motivation, many studies have shown that motivation is dynamic and that it affects language…
This final report reviews a program of theoretical and empirical research focusing on the ability determinants of individualdifferences in skill acquisition. An integrative framework for information processing and cognitive ability determinants of skills is presented, along with principles for ability-skill relations. Three major patterns of…
Although statistical learning and language have been assumed to be intertwined, this theoretical presupposition has rarely been tested empirically. The present study investigates the relationship between statistical learning and language using a within-subject design embedded in an individual-differences framework. Participants were administered…
Two studies examined fifth- and sixth-grade students' perceptions of antisocial and prosocial teasing among peers and potential correlates of individualdifferences in their tendencies to engage in both forms of teasing. The children were rated as showing a greater tendency to be prosocial teasers than antisocial teasers by both teachers and…
Barnett, Mark A.; Burns, Susan R.; Sanborn, Fred W.; Bartel, Jeffrey S.; Wilds, Stacey J.
In opposition to conceptualizing working memory (WM) in terms of a general capacity, we present four experiments that favor the view that individualdifferences in WM depend on attentional control. High- and low-WM participants, as assessed by the operation span task, learned unrelated sentences for which the subject and predicate of the sentences…
Observers are more sensitive to variations in the depth of stereoscopic surfaces in a vertical than in a horizontal direction; however, there are large individualdifferences in this anisotropy. The authors measured discrimination thresholds for surfaces slanted about a vertical axis or inclined about a horizontal axis for 50 observers. Orientation and spatial frequency discrimination thresholds were also measured. For
Paul B. Hibbard; Mark F. Bradshaw; Keith Langley; Brian J. Rogers
This study examined individual and group differences in the nature and frequency of reports of past speech in the autobiographical memories of young adults. A sample of 108 participants (60 females, 48 males) responded in writing to six memory prompts. They also completed the Five Factor Inventory (Costa & McCrae, 1992) and the Personal Attributes Questionnaire (Spence & Helmreich, 1978).
In opposition to conceptualizing working memory (WM) in terms of a general capacity, we present four experiments that favor the view that individualdifferences in WM depend on attentional control. High- and low-WM participants, as assessed by the operation span task, learned unrelated sentences for which the subject and predicate of the sentences shared concepts (fan). Sentences were learned in
Michael F. Bunting; Andrew R. A. Conway; Richard P. Heitz
Investigated the effects of individualdifference variables of field dependence/independence and spatial visualization ability on the performance of college students in three modes. The extent to which four variables account for variability in retention test performance on certain tasks was also viewed. (MP)
Developmental trajectories and individualdifferences in 70 American middle-income 2.5- to 4-year olds' moral judgments were examined 3 times across 1 year using latent growth modeling. At Wave 1, children distinguished hypothetical moral from conventional transgressions on all criteria, but only older preschoolers did so when rating deserved…
Background: This paper presents results from the first wave of a longitudinal study examining the effects of various psychosocial variables on scholastic achievement and behaviour at school. Aims: The main aim is to investigate the nature and strength of the effects of major individualdifference dimensions on important outcome variables at school…
Petrides, K.V.; Chamorro-Premuzic, Tomas; Frederickson, Norah; Furnham, Adrian
In this article we explore the role of individualdifferences in the proclivity to pursue legal rights. A series of field surveys and a laboratory experiment indicated that a measure of claim propensity was consistently related to the reporting of “rights” problems, the tendency to make claims in response to these problems, and preferences for styles of conflict resolution. Although
The present study (n = 761, 58.1% female) examined whether or not individual learner variables (gender, ethnicity, SES) contribute to differences in mathematics performance as measured by test score and mathematics grade for fifth and sixth grade mathematics students in Alabama. Multiple regression analysis revealed that gender and SES show…
Shores, Melanie L.; Smith, Tommy G.; Jarrell, Sasha L.
The authors examined developmental and individualdifferences in pure numerical estimation, the type of estimation that depends solely on knowledge of numbers. Children between kindergarten and 4th grade were asked to solve 4 types of numerical estimation problems: computational, numerosity, measurement, and number line. In Experiment 1,…
In preparation for a conference on learning and individualdifferences, the invited authors prepared chapters, which were distributed in draft form. Presentations were followed by discussions, which were recorded, and then edited for this volume, so that the discussion transcript follows each paper. The chapters in part 1, General Background and…
Ackerman, Phillip L.; Kyllonen, Patrick C.; Roberts, Richard D.
Although the syntactic priming methodology is a promising tool for language acquisition researchers, using the technique with children raises issues that are not problematic in adult research. The current paper reports on an individualdifferences study that addressed some of these outstanding issues. (a) Does priming purely reflect syntactic…
This study used fMRI to examine individualdifferences in the neural basis of causal inferencing. Participants with varying language skill levels, as indexed by scores on the vocabulary portion of the Nelson-Denny Reading Test, read four types of two-sentence passages in which causal relatedness (moderate and distant) and presence or absence of…
Prat, Chantel S.; Mason, Robert A.; Just, Marcel Adam
Individualdifferences in food-related knowledge structures were explored by applying schema theory to examine the categories 42 adults used to classify foods across four eating contexts. Food card-sort labels were organized into 12 categories, category salience for each person was evaluated, and cluster analysis was used to identify clusters of participants according to the salience of their categories. Clusters were
Research Findings: Sibling teaching and learning behaviors were investigated in 2 studies of children in early and middle childhood. Study 1 addressed individualdifferences in teaching/learning and associations with dyadic age, age gap, gender, birth order, and relationship quality in 71 middle-class dyads (firstborns M age = 81.54 months;…
Cultural differences between Arabs and Americans were investigated using the individualism-collectivism survey of J. Wagner (1995). Arab subjects (n=331) were significantly more collectivist than U.S. subjects (n=102), and within the Arab group, Egyptian subjects (n=224) were significantly more individualistic than Gulf States subjects.…
Summary When visual input has conflicting interpretations, conscious perception can alternate spontaneously between competing interpretations . There is a large amount of unexplained variability between individuals in the rate of such spontaneous alternations in perception [2–5]. We hypothesized that variability in perceptual rivalry might be reflected in individualdifferences in brain structure, because brain structure can exhibit systematic relationships with an individual's cognitive experiences and skills [6–9]. To test this notion, we examined in a large group of individuals how cortical thickness, local gray-matter density, and local white-matter integrity correlate with individuals' alternation rate for a bistable, rotating structure-from-motion stimulus . All of these macroscopic measures of brain structure consistently revealed that the structure of bilateral superior parietal lobes (SPL) could account for interindividual variability in perceptual alternation rate. Furthermore, we examined whether the bilateral SPL regions play a causal role in the rate of perceptual alternations by using transcranial magnetic stimulation (TMS) and found that transient disruption of these areas indeed decreases the rate of perceptual alternations. These findings demonstrate a direct relationship between structure of SPL and individuals' perceptual switch rate.
Previous studies have shown that as a group 6-month-old infants successfully discriminate numerical changes when the values differ by at least a 1:2 ratio but fail at a 2:3 ratio (e.g. 8 vs. 16 but not 8 vs. 12). However, no studies have yet examined individualdifferences in number discrimination in infancy. Using a novel numerical change…
Transcranial electrical stimulation (TCES) is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject's head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging (MRI) data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individualdifferences were greatest near the electrodes (ten-fold differences were common), but simulated current was found in all regions of the brain. Sites that were distant from the electrodes (e.g. hypothalamus) typically showed two-fold individualdifferences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI-based modeling should be considered in place of the 10-20 system when accurate TCES is needed.
Russell, Michael J; Goodman, Theodore; Pierson, Ronald; Shepherd, Shane; Wang, Qiang; Groshong, Bennett; Wiley, David F
The optical properties of single colloidal semiconductor nanoparticles (NPs) are considerably influenced by the direct environment of the NPs. Here, the influence of different liquid and solid glycol matrices on CdSe-based NPs is investigated. Since the fluorescence of individual NPs varies from one NP to another, it is highly desirable to study the very same individual NPs in different matrices. This was accomplished by immobilizing NPs in a liquid cell sample holder or in microfluidic devices. The samples have been investigated by space-resolved wide-field fluorescence microscopy and energy- and time-resolved confocal scanning fluorescence microscopy with respect to fluorescence intensities, emission energies, blinking behavior, and fluorescence decay dynamics of individual NPs. During the measurements the NPs were exposed to air, to liquid ethylene glycols H(OCH2CH2)nOH (also called EGn) with different chain lengths (1 ? n ? 7), to liquid 2-methylpentane-2,3-diol, or to solid polyethylene oxide. It was found that EG6-7 (also known as PEG 300) is very well suited as a liquid matrix or solvent for experiments that correlate chemical and physical modifications of the surface and of the immediate environment of individual NPs to their fluorescence properties since it leads to intense and stable fluorescence emission of the NPs. PMID:24788878
Learning to distinguish subtle differences in objects or events can impact how one generalizes. In some cases, training can cause novel events to appear more familiar or attractive than those actually experienced during training: the peak shift effect. This study examined whether individualdifferences in learning led to systematic patterns of generalization. Participants were trained to identify simulated birdsongs, and then tested on their ability to identify a target song presented among several similar songs that differed in pitch. Initial analysis showed that those attaining moderate proficiency at discriminating songs during training were more likely to shift than those performing poorly or proficiently. However, a neural network trained to output individuals' gradient dynamics using only performance during training as input found an additional set of training variables that predicted shift. Specifically, one subset of shifters had highly conservative response biases accompanied by very little change to perceptual sensitivity in training. These findings suggest that discrimination learning may only lead to generalization shifts in some individuals, and that all individuals who shift may not do so for the same reason. PMID:24445021
Wisniewski, Matthew G; Church, Barbara A; Mercado, Eduardo
Social learning has allowed humans to build up extensive cultural repertoires, enabling them to adapt to a wide variety of environmental and social conditions. However, it is unclear which social learning strategies people use, especially in social contexts where their payoffs depend on the behaviour of others. Here we show experimentally that individualsdiffer in their social learning strategies and that they tend to employ the same learning strategy irrespective of the interaction context. Payoff-based learners focus on their peers' success, while decision-based learners disregard payoffs and exclusively focus on their peers' past behaviour. These individualdifferences may be of considerable importance for cultural evolution. By means of a simple model, we demonstrate that groups harbouring individuals with different learning strategies may be faster in adopting technological innovations and can be more efficient through successful role differentiation. Our study highlights the importance of individual variation for human interactions and sheds new light on the dynamics of cultural evolution. PMID:24705692
Molleman, Lucas; van den Berg, Pieter; Weissing, Franz J
In two experiments, we examined individualdifferences in metaphor processing. In Experiment 1, the subjects judged the literal truth of literal, metaphorical, and scrambled sentences. Overall, metaphors were more difficult to judge as false, in comparison with scrambled controls, suggesting that the metaphorical meaning was being processed automatically. However, there were individualdifferences in that high-IQ subjects showed more interference. These effects were reflected in ERP amplitude differences at the onset of N400 and after the response. In Experiment 2, the subjects completed IQ tests and a series of working memory tests and then rated and interpreted the same set of metaphors. The results showed that IQ was correlated with working memory capacity and that low-IQ subjects had similar ratings but poorer quality interpretations than did high-IQ subjects. The results were most consistent with a constraint satisfaction approach to metaphor comprehension. PMID:12956233
Kazmerski, Victoria A; Blasko, Dawn G; Dessalegn, Banchiamlack G
Sex differences in patterns of cognitive test performance have been attributed to factors, such as sex hormones or sexual dimorphisms in brain structure, that change with normal aging. The current study examined sex differences in patterns of cognitive test performance in healthy elderly individuals. Cognitive test scores of 957 men and women (age 67-89), matched for overall level of cognitive test performance, age, education, and depression scale score, were compared. Men and women were indistinguishable on tests of auditory divided attention, category fluency, and executive functioning. In contrast, women performed better than men on tests of psychomotor speed and verbal learning and memory, whereas men outperformed women on tests of visuoconstruction and visual perception. Our finding that the pattern of sex differences in cognition observed in young adults is observed in old age has implications for future studies of both healthy elderly individuals and of those with cognitive disorders. PMID:22670852
Munro, Cynthia A; Winicki, Jessica M; Schretlen, David J; Gower, Emily W; Turano, Kathleen A; Muñoz, Beatriz; Keay, Lisa; Bandeen-Roche, Karen; West, Sheila K
Individualdifferences in vulnerability to neurobehavioral performance impairment during sleep deprivation are considerable and represent a neurobiological trait. Genetic polymorphisms reported to be predictors have suggested the involvement of the homeostatic and circadian processes of sleep regulation in determining this trait. We applied mathematical and statistical modeling of these two processes to psychomotor vigilance performance and sleep physiological data from a laboratory study of repeated exposure to 36 h of total sleep deprivation in 9 healthy young adults. This served to quantify the respective contributions of individualdifferences in the two processes to the magnitudes of participants’ individual vulnerabilities to sleep deprivation. For the homeostatic process, the standard deviation for individualdifferences was found to be about 60% as expressed relative to its group-average contribution to neurobehavioral performance impairment. The same was found for the circadian process. Across the span of the total sleep deprivation period, the group-average effect of the homeostatic process was twice as big as that of the circadian process. In absolute terms, therefore, the impact of the individualdifferences in the homeostatic process was twice as large as the impact of the individualdifferences in the circadian process in this study. These modeling results indicated that individualized applications of mathematical models predicting performance on the basis of a homeostatic and a circadian process should account for individualdifferences in both processes.
Van Dongen, Hans P.A.; Bender, Amy M.; Dinges, David F.
The notion that some people are more vulnerable to adversity as a function of inherent risk characteristics is widely embraced in most fields of psychology. This is reflected in the popularity of the diathesis-stress framework, which has received a vast amount of empirical support over the years. Much less effort has been directed toward the investigation of endogenous factors associated with variability in response to positive influences. One reason for the failure to investigate individualdifferences in response to positive experiences as a function of endogenous factors may be the absence of adequate theoretical frameworks. According to the differential-susceptibility hypothesis, individuals generally vary in their developmental plasticity regardless of whether they are exposed to negative or positive influences--a notion derived from evolutionary reasoning. On the basis of this now well-supported proposition, we advance herein the new concept of vantage sensitivity, reflecting variation in response to exclusively positive experiences as a function of individual endogenous characteristics. After distinguishing vantage sensitivity from theoretically related concepts of differential-susceptibility and resilience, we review some recent empirical evidence for vantage sensitivity featuring behavioral, physiological, and genetic factors as moderators of a wide range of positive experiences ranging from family environment and psychotherapy to educational intervention. Thereafter, we discuss genetic and environmental factors contributing to individualdifferences in vantage sensitivity, potential mechanisms underlying vantage sensitivity, and practical implications. PMID:23025924
The authors evaluated the reliability and validity of a set of 7 behavioral decision-making tasks, measuring different aspects of the decision-making process. The tasks were administered to individuals from diverse populations. Participants showed relatively consistent performance within and across the 7 tasks, which were then aggregated into an Adult Decision-Making Competence (A-DMC) index that showed good reliability. The validity of
Wändi Bruine de Bruin; Andrew M. Parker; Baruch Fischhoff
Despite their similarity as visual patterns, we can discriminate and recognize many thousands of faces. This expertise has been linked to 2 coding mechanisms: holistic integration of information across the face and adaptive coding of face identity using norms tuned by experience. Recently, individualdifferences in face recognition ability have been discovered and linked to differences in holistic coding. Here we show that they are also linked to individualdifferences in adaptive coding of face identity, measured using face identity aftereffects. Identity aftereffects correlated significantly with several measures of face-selective recognition ability. They also correlated marginally with own-race face recognition ability, suggesting a role for adaptive coding in the well-known other-race effect. More generally, these results highlight the important functional role of adaptive face-coding mechanisms in face expertise, taking us beyond the traditional focus on holistic coding mechanisms. PMID:24684315
Rhodes, Gillian; Jeffery, Linda; Taylor, Libby; Hayward, William G; Ewing, Louise
This study used functional magnetic resonance imaging to investigate individualdifferences in the neural underpinnings of sentence comprehension, with a focus on neural adaptability (dynamic configuration of neural networks with changing task demands). Twenty-seven undergraduates, with varying working memory capacities and vocabularies, read sentences that were either syntactically simple or complex under conditions of varying extrinsic working memory demands (sentences alone or preceded by to-be-remembered words or nonwords). All readers showed greater neural adaptability when extrinsic working memory demands were low, suggesting that adaptability is related to resource availability. Higher capacity readers showed greater neural adaptability (greater increase in activation with increasing syntactic complexity) across conditions than did lower capacity readers. Higher capacity readers also showed better maintenance of or increase in synchronization of activation between brain regions as tasks became more demanding. Larger vocabulary was associated with more efficient use of cortical resources (reduced activation in frontal regions) in all conditions but was not associated with greater neural adaptability or synchronization. The distinct characterizations of verbal working memory capacity and vocabulary suggest that dynamic facets of brain function such as adaptability and synchronization may underlie individualdifferences in more general information processing abilities, whereas neural efficiency may more specifically reflect individualdifferences in language experience.
Waiting for uncertain news, such as the outcome of a job interview or medical test, is a ubiquitous and difficult but little studied experience. We conducted a longitudinal examination, guided by the predictions of the uncertainty navigation model (Sweeny & Cavanaugh, 2012), to examine broad trends and individualdifferences in experiences during a consequential waiting period. Fifty students preparing for the California bar exam completed questionnaires at 6 time points: shortly before and after the exam, at 2 intermediate time points during the 4-month waiting period, and immediately before and after learning whether they passed. We identified key individualdifferences in the overall experience of a waiting period, such that dispositional optimists reported lower levels of anxiety and rumination on average, and defensive pessimists and people uncomfortable with uncertainty reported higher levels. Longitudinal growth curve modeling analyses suggested that waiting is most difficult at the start and end of a waiting period, although people maintained hope and optimism throughout the wait. These temporal trends were generally robust, although some individualdifferences emerged. These findings provide the first evidence regarding when and for whom waiting periods are most difficult and thus can serve as the basis for future investigations of waiting experiences. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24841102
Simulation models that describe autonomous individual organisms (individual based models, IBM) or agents (agent-based models, ABM) have become a widely used tool, not only in ecology, but also in many other disciplines dealing with complex systems made up of autonomous entities. However, there is no standard protocol for describing such simulation models, which can make them difficult to understand and
Volker Grimm; Uta Berger; Finn Bastiansen; Sigrunn Eliassen; Vincent Ginot; Jarl Giske; John Goss-Custard; Tamara Grand; Simone K. Heinz; Geir Huse; Andreas Huth; Jane U. Jepsen; Christian Jørgensen; Wolf M. Mooij; Birgit Müller; Guy Pe’er; Cyril Piou; Steven F. Railsback; Andrew M. Robbins; Martha M. Robbins; Eva Rossmanith; Nadja Rüger; Espen Strand; Sami Souissi; Richard A. Stillman; Rune Vabø; Ute Visser; Donald L. DeAngelis
With the rise of network society, consumerism, individualization, globalization and contemporary change forces, students are pressured to both perform well in standardized academic assessments while at the same time constructing a non-standard, unique project of the self. I argue that this generates a particular set of place-based tensions for…
Cocaine use leads to addiction in only a subset of individuals. Understanding the mechanisms underlying these individualdifferences in the transition from cocaine use to cocaine abuse is important to develop treatment strategies. There is agreement that specific behavioural traits increase the risk for addiction. As such, both high impulsivity and high anxiety have been reported to predict (compulsive) cocaine self-administration behaviour. Here, we set out a new view explaining how these two behavioural traits may affect addictive behaviour. According to psychological and psychiatric evolutionary views, organisms flourish well when they fit (match) their environment by trait and genotype. However, under non-fit conditions, the need to compensate the failure to deal with this environment increases, and, as a consequence, the functional use of rewarding drugs like cocaine may also increase. It suggests that neither impulsivity nor anxiety are bad per se, but that the increased risk to develop cocaine addiction is dependent on whether behavioural traits are adaptive or maladaptive in the environment to which the animals are exposed. This 'behavioural (mal)adaptation view' on individualdifferences in vulnerability to cocaine addiction may help to improve therapies for addiction. PMID:24835358
Homberg, Judith R; Karel, Peter; Verheij, Michel M M
Individualdifferences in second language (L2) phoneme perception (within the normal population) have been related to speech perception abilities, also observed in the native language, in studies assessing the electrophysiological response mismatch negativity (MMN). Here, we investigate the brain oscillatory dynamics in the theta band, the spectral correlate of the MMN, that underpin success in phoneme learning. Using previous data obtained in an MMN paradigm, the dynamics of cortical oscillations while perceiving native and unknown phonemes and nonlinguistic stimuli were studied in two groups of participants classified as good and poor perceivers (GPs and PPs), according to their L2 phoneme discrimination abilities. The results showed that for GPs, as compared to PPs, processing of a native phoneme change produced a significant increase in theta power. Stimulus time-locked analysis event-related spectral perturbation (ERSP) showed differences for the theta band within the MMN time window (between 70 and 240 ms) for the native deviant phoneme. No other significant difference between the two groups was observed for the other phoneme or nonlinguistic stimuli. The dynamic patterns in the theta-band may reflect early automatic change detection for familiar speech sounds in the brain. The behavioral differences between the two groups may reflect individual variations in activating brain circuits at a perceptual level.
Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individualdifferences, but this burgeoning literature has been characterized by inconsistent results. To test the hypothesis that differences in task demands could contribute to between-study variability in brain-behavior relationships, we had participants perform 2 tasks that varied in the extent of cognitive involvement. We examined connectivity between brain regions during a low-demand vigilance task and a higher-demand digit–symbol visual search task using Granger causality analysis (GCA). Our results showed 1) Significant differences in numbers of frontoparietal connections between low- and high-demand tasks 2) that GCA can detect activity changes that correspond with task-demand changes, and 3) faster participants showed more vigilance-related activity than slower participants, but less visual-search activity. These results suggest that relatively low-demand cognitive performance depends on spontaneous bidirectionally fluctuating network activity, whereas high-demand performance depends on a limited, unidirectional network. The nature of brain-behavior relationships may vary depending on the extent of cognitive demand. High-demand network activity may reflect the extent to which individuals require top-down executive guidance of behavior for successful task performance. Low-demand network activity may reflect task- and performance monitoring that minimizes executive requirements for guidance of behavior.
Biswal, Bharat B.; Eldreth, Dana A.; Motes, Michael A.
We conducted an exploratory study to examine the resting electroencephalography (EEG) correlates of pseudoneglect, a phenomenon wherein neurologically intact individuals show greater attentional bias toward the left side compared with the right side of space. We took the resting EEG of 21 college students for 5 min and then had them complete a computerized line perception task, during which we asked them to judge the midpoint of horizontal lines on the screen. We computed EEG asymmetry measures for theta, alpha, beta, and gamma frequency bands for each of eight locations (right electrode activity-left electrode activity in the analogous location) and separately regressed these onto the degree of pseudoneglect using stepwise multiple regression analyses. We found significant effects for gamma, theta, and beta bands at location F3/4, indicating greater tonic right midfrontal activation in this location. These findings show that individuals with generally greater right midfrontal resting activation across theta, beta, and gamma bands also demonstrate pseudoneglect during a line perception task. These results lend a novel finding to the pseudoneglect literature, namely an individualdifferences corollary to current active task observations in the field. PMID:23839306
Simon-Dack, Stephanie L; Holtgraves, Thomas; Marsh, Lindsay M; Fogle, Kelly L
Recently, Rousselet et al. reported a 1 ms/year delay in visual processing speed in a sample of healthy aged 62 subjects (Frontiers in Psychology 2010, 1:19). Here, we replicate this finding in an independent sample of 59 subjects and investigate the contribution of optical factors (pupil size and luminance) to the age-related slowdown and to individualdifferences in visual processing speed. We conducted two experiments. In experiment 1 we recorded EEG from subjects aged 18–79. Subjects viewed images of faces and phase scrambled noise textures under nine luminance conditions, ranging from 0.59 to 60.8 cd/m2. We manipulated luminance using neutral density filters. In experiment 2, 10 young subjects (age < 35) viewed similar stimuli through pinholes ranging from 1 to 5 mm. In both experiments, subjects were tested twice. We found a 1 ms/year slowdown in visual processing that was independent of luminance. Aging effects became visible around 125 ms post-stimulus and did not affect the onsets of the face-texture ERP differences. Furthermore, luminance modulated the entire ERP time-course from 60 to 500 ms. Luminance effects peaked in the N170 time window and were independent of age. Importantly, senile miosis and individualdifferences in pupil size did not account for aging differences and inter-subject variability in processing speed. The pinhole manipulation also failed to match the ERPs of old subjects to those of young subjects. Overall, our results strongly suggest that early ERPs to faces (<200 ms) are delayed by aging and that these delays are of cortical, rather than optical origin. Our results also demonstrate that even late ERPs to faces are modulated by low-level factors.
Bieniek, Magdalena M.; Frei, Luisa S.; Rousselet, Guillaume A.
Recently, Rousselet et al. reported a 1 ms/year delay in visual processing speed in a sample of healthy aged 62 subjects (Frontiers in Psychology 2010, 1:19). Here, we replicate this finding in an independent sample of 59 subjects and investigate the contribution of optical factors (pupil size and luminance) to the age-related slowdown and to individualdifferences in visual processing speed. We conducted two experiments. In experiment 1 we recorded EEG from subjects aged 18-79. Subjects viewed images of faces and phase scrambled noise textures under nine luminance conditions, ranging from 0.59 to 60.8 cd/m(2). We manipulated luminance using neutral density filters. In experiment 2, 10 young subjects (age < 35) viewed similar stimuli through pinholes ranging from 1 to 5 mm. In both experiments, subjects were tested twice. We found a 1 ms/year slowdown in visual processing that was independent of luminance. Aging effects became visible around 125 ms post-stimulus and did not affect the onsets of the face-texture ERP differences. Furthermore, luminance modulated the entire ERP time-course from 60 to 500 ms. Luminance effects peaked in the N170 time window and were independent of age. Importantly, senile miosis and individualdifferences in pupil size did not account for aging differences and inter-subject variability in processing speed. The pinhole manipulation also failed to match the ERPs of old subjects to those of young subjects. Overall, our results strongly suggest that early ERPs to faces (<200 ms) are delayed by aging and that these delays are of cortical, rather than optical origin. Our results also demonstrate that even late ERPs to faces are modulated by low-level factors. PMID:23717297
Bieniek, Magdalena M; Frei, Luisa S; Rousselet, Guillaume A
Functional neuroimaging studies have revealed that parietal brain circuits subserve arithmetic problem solving and that their recruitment dynamically changes as a function of training and development. The present study investigated whether the brain activation during mental calculation is also modulated by individualdifferences in mathematical competence. Twenty-five adult students were selected from a larger pool based on their performance on standardized tests of intelligence and arithmetic and divided into groups of individuals with relatively lower and higher mathematical competence. These groups did not differ in their non-numerical intelligence or age. In an fMRI block-design, participants had to verify the correctness of single-digit and multi-digit multiplication problems. Analyses revealed that the individuals with higher mathematical competence displayed stronger activation of the left angular gyrus while solving both types of arithmetic problems. Additional correlational analyses corroborated the association between individualdifferences in mathematical competence and angular gyrus activation, even when variability in task performance was controlled for. These findings demonstrate that the recruitment of the left angular gyrus during arithmetic problem solving underlies individualdifferences in mathematical ability and suggests a stronger reliance on automatic, language-mediated processes in more competent individuals. PMID:17851092
Longitudinal associations of domain-general and numerical competencies with individualdifferences in children's understanding of fractions were investigated. Children (n = 163) were assessed at 6 years of age on domain-general (nonverbal reasoning, language, attentive behavior, executive control, visual-spatial memory) and numerical (number knowledge) competencies; at 7 years on whole-number arithmetic computations and number line estimation; and at 10 years on fraction concepts. Mediation analyses controlling for general mathematics ability and general academic ability revealed that numerical and mathematical competencies were direct predictors of fraction concepts, whereas domain-general competencies supported the acquisition of fraction concepts via whole-number arithmetic computations or number line estimation. Results indicate multiple pathways to fraction competence. PMID:24433246
Vukovic, Rose K; Fuchs, Lynn S; Geary, David C; Jordan, Nancy C; Gersten, Russell; Siegler, Robert S
The main methodological drawback to use physiological measures as indicators of arousal is, the large interindividual variability of autonomic responses hindering the direct comparability, between individuals. The present methodology has been tested in two cohorts (n1=910, n2=845) of, pilot applicants during a selection procedure. Physiological data were obtained during two mentally, demanding tasks and during a Flight Simulator Test. Five typical Autonomic Response Patterns (ARP), were identified by cluster analyses. Autonomic spaces were constructed separately for each group of, subjects having the same typical ARP, on the basis of their normalized eigenvectors. The length of the, vector sum of scores on autonomic space dimensions provided an integral index for arousal, labeled, Psychophysiological Arousal Value (PAV). The PAV still reflected the changes in mental load during the, tests, but equalized physiological differences among ARP-groups. The results obtained in the first, cohort were verified in the second cohort. PMID:24315952
Though much work has studied how external factors, such as stimulus properties, influence generalization of associative strength, there has been limited exploration of the influence that internal dispositions may contribute to stimulus processing. Here we report 2 studies using a modified negative patterning discrimination to test the relationship between global processing and generalization. Global processing was associated with stronger negative patterning discrimination, indicative of limited generalization between distinct stimulus compounds and their constituent elements. In Experiment 2, participants pretrained to adopt global processing similarly showed strong negative patterning discrimination. These results demonstrate considerable individualdifference in capacity to engage in negative patterning discrimination and suggest that the tendency toward global processing may be one factor explaining this variability. The need for models of learning to account for this variability in learning is discussed.
Why do some people recognize faces easily and others frequently make mistakes in recognizing faces? Classic behavioral work has shown that faces are processed in a distinctive holistic manner that is unlike the processing of objects. In the study reported here, we investigated whether individualdifferences in holistic face processing have a significant influence on face recognition. We found that the magnitude of face-specific recognition accuracy correlated with the extent to which participants processed faces holistically, as indexed by the composite-face effect and the whole-part effect. This association is due to face-specific processing in particular, not to a more general aspect of cognitive processing, such as general intelligence or global attention. This finding provides constraints on computational models of face recognition and may elucidate mechanisms underlying cognitive disorders, such as prosopagnosia and autism, that are associated with deficits in face recognition. PMID:22222218
This study examined individual and group differences in the nature and frequency of reports of past speech in the autobiographical memories of young adults. A sample of 108 participants (60 females, 48 males) responded in writing to six memory prompts. They also completed the Five Factor Inventory (Costa & McCrae, 1992) and the Personal Attributes Questionnaire (Spence & Helmreich, 1978). The frequency with which participants used reported speech was correlated with agreeableness, openness, and expressivity; however, regression analyses indicated that narrators' gender alone was the best predictor. Females used more reported speech than did males. The findings suggest that recollections of past speech are an under-appreciated yet important component of autobiographical memory. PMID:18432484
Using Gray and McNaughton's (2000) revised reinforcement sensitivity theory (r-RST), we examined the influence of personality on processing of words presented in gain-framed and loss-framed anti-speeding messages and how the processing biases associated with personality influenced message acceptance. The r-RST predicts that the nervous system regulates personality and that behaviour is dependent upon the activation of the behavioural activation system (BAS), activated by reward cues and the fight-flight-freeze system (FFFS), activated by punishment cues. According to r-RST, individualsdiffer in the sensitivities of their BAS and FFFS (i.e., weak to strong), which in turn leads to stable patterns of behaviour in the presence of rewards and punishments, respectively. It was hypothesised that individualdifferences in personality (i.e., strength of the BAS and the FFFS) would influence the degree of both message processing (as measured by reaction time to previously viewed message words) and message acceptance (measured three ways by perceived message effectiveness, behavioural intentions, and attitudes). Specifically, it was anticipated that, individuals with a stronger BAS would process the words presented in the gain-frame messages faster than those with a weaker BAS and individuals with a stronger FFFS would process the words presented in the loss-frame messages faster than those with a weaker FFFS. Further, it was expected that greater processing (faster reaction times) would be associated with greater acceptance for that message. Driver licence holding students (N=108) were recruited to view one of four anti-speeding messages (i.e., social gain-frame, social loss-frame, physical gain-frame, and physical loss-frame). A computerised lexical decision task assessed participants' subsequent reaction times to message words, as an indicator of the extent of processing of the previously viewed message. Self-report measures assessed personality and the three message acceptance measures. As predicted, the degree of initial processing of the content of the social gain-framed message mediated the relationship between the reward sensitive trait and message effectiveness. Initial processing of the physical loss-framed message partially mediated the relationship between the punishment sensitive trait and both message effectiveness and behavioural intention ratings. These results show that reward sensitivity and punishment sensitivity traits influence cognitive processing of gain-framed and loss-framed message content, respectively, and subsequently, message effectiveness and behavioural intention ratings. Specifically, a range of road safety messages (i.e., gain-frame and loss-frame messages) could be designed which align with the processing biases associated with personality and which would target those individuals who are sensitive to rewards and those who are sensitive to punishments. PMID:22608267
Kaye, Sherrie-Anne; White, Melanie J; Lewis, Ioni M
Background Determining the ways in which personality traits interact with contextual determinants to shape social behavior remains an important area of empirical investigation. The specific personality trait of neuroticism has been related to characteristic negative emotionality and associated with heightened attention to negative, emotionally arousing environmental signals. However, the mechanisms by which this personality trait may shape social behavior remain largely unspecified. Methodology/Principal Findings We employed eye tracking to investigate the relationship between characteristics of visual scanpaths in response to emotional facial expressions and individualdifferences in personality. We discovered that the amount of time spent looking at the eyes of fearful faces was positively related to neuroticism. Conclusions/Significance This finding is discussed in relation to previous behavioral research relating personality to selective attention for trait-congruent emotional information, neuroimaging studies relating differences in personality to amygdala reactivity to socially relevant stimuli, and genetic studies suggesting linkages between the serotonin transporter gene and neuroticism. We conclude that personality may be related to interpersonal interaction by shaping aspects of social cognition as basic as eye contact. In this way, eye gaze represents a possible behavioral link in a complex relationship between genes, brain function, and personality.
Perlman, Susan B.; Morris, James P.; Vander Wyk, Brent C.; Green, Steven R.; Doyle, Jaime L.; Pelphrey, Kevin A.
Imitation is crucial for social learning, and so it is important to identify what determines between-subject variability in imitation fidelity. This might help explain what makes some people, like those with social difficulties such as in autism spectrum disorder (ASD), significantly worse at performance on these tasks than others. A novel paradigm was developed to provide objective measures of imitation fidelity in which participants used a touchscreen to imitate videos of a model drawing different shapes. Comparisons between model and participants' kinematic data provided three measures of imitative fidelity. We hypothesized that imitative ability would predict variation in BOLD signal whilst performing a simple imitation task in the MRI-scanner. In particular, an overall measure of accuracy (correlation between model and imitator) would predict activity in the overarching imitation system, whereas bias would be subject to more general aspects of motor control. Participants lying in the MRI-scanner were instructed to imitate different grips on a handle, or to watch someone or a circle moving the handle. Our hypothesis was partly confirmed as correlation between model and imitator was mediated by somatosensory cortex but also ventromedial prefrontal cortex, and bias was mediated mainly by cerebellum but also by the medial frontal and parietal cortices and insula. We suggest that this variance differentially reflects cognitive functions such as feedback-sensitivity and reward-dependent learning, contributing significantly to variability in individuals' imitative abilities as characterized by objective kinematic measures.
Braadbaart, Lieke; Waiter, Gordon D.; Williams, Justin H. G.
Individual surface weather observations from land stations and ships are compared with individual cloud retrievals of the International Satellite Cloud Climatology Project (ISCCP), Stage C1, for an 8-year period (1983-1991) to relate cloud optical thicknesses and cloud-top pressures obtained from satellite data to the standard cloud types reported in visual observations from the surface. Each surface report is matched to the corresponding ISCCP-C1 report for the time of observation for the 280x280-km grid-box containing that observation. Classes of the surface reports are identified in which a particular cloud type was reported present, either alone or in combination with other clouds. For each class, cloud amounts from both surface and C1 data, base heights from surface data, and the frequency-distributions of cloud-top pressure (p(sub c) and optical thickness (tau) from C1 data are averaged over 15-degree latitude zones, for land and ocean separately, for 3-month seasons. The frequency distribution of p(sub c) and tau is plotted for each of the surface-defined cloud types occurring both alone and with other clouds. The average cloud-top pressures within a grid-box do not always correspond well with values expected for a reported cloud type, particularly for the higher clouds Ci, Ac, and Cb. In many cases this is because the satellites also detect clouds within the grid-box that are outside the field of view of the surface observer. The highest average cloud tops are found for the most extensive cloud type, Ns, averaging 7 km globally and reaching 9 km in the ITCZ. Ns also has the greatest average retrieved optical thickness, tau approximately equal 20. Cumulonimbus clouds may actually attain far greater heights and depths, but do not fill the grid-box. The tau-p(sub c) distributions show features that distinguish the high, middle, and low clouds reported by the surface observers. However, the distribution patterns for the individual low cloud types (Cu, Sc, St) occurring alone overlap to such an extent that it is not possible to distinguish these cloud types from each other on the basis of tau-p(sub c) values alone. Other cloud types whose tau-p(sub c) distributions are indistinguishable are Cb, Ns, and thick As. However, the tau-p(sub c) distribution patterns for the different low cloud types are nevertheless distinguishable when all occurrences of a low cloud type are included, indicating that the different low types differ in their probabilities of co-occurrence with middle and high clouds.
Hahn, Carole J.; Rossow, William B.; Warren, Stephen G.
This report introduces some of the principles and uses of non-standard finite-difference modelling. It begins with a review of the elements of finite-differences, and how continu- ous derivatives are replaced with differences, and incorporated into a 'scheme'. It shows examples of scheme selection by testing. Finally, it demonstrates some more advanced strategies of standard finite-differencing for stability or higher accuracy.
Recent findings suggest deficits in coherent motion sensitivity, an index of visual dorsal stream functioning, in children with poor mathematical skills or dyscalculia, a specific learning disability in mathematics. We extended these data using a longitudinal design to unravel whether visual dorsal stream functioning is able to predict individualdifferences in subsequent specific mathematical skills, i.e., single-digit subtraction and multiplication. We measured children's sensitivity to coherent motion in kindergarten (mean age: 5 years 8 months) and evaluated their subtraction and multiplication skills in third grade (mean age 8 years 3 months). Findings revealed an association between subtraction but not multiplication performance and coherent motion sensitivity. This association remained significant even when intellectual ability and reading ability were additionally controlled for. Subtractions are typically solved by means of quantity-based procedural strategies, which reliably recruit the intraparietal sulcus. Against the background of a neural overlap between the intraparietal sulcus and visual dorsal stream functioning, we hypothesize that low-level visuospatial mechanisms might set constraints on the development of quantity representations, which are used during calculation, particularly in subtraction. PMID:21324638
Attempts to understand why memory predicts intelligence have not fully leveraged state-of-the-art measures of recall dynamics. Using data from a multisession free recall study, we examine individualdifferences in measures of recall initiation and postinitiation transitions. We identify 4 sources of variation: a recency factor reflecting variation in the tendency to initiate recall from an item near the end of the list, a primacy factor reflecting a tendency to initiate from the beginning of the list, a temporal factor corresponding to transitions mediated by temporal associations, and a semantic factor corresponding to semantically mediated transitions. Together, these 4 factors account for 83% of the variability in overall recall accuracy, suggesting they provide a nearly complete picture of recall dynamics. We also show that these sources of variability account for over 80% of the variance shared between memory and intelligence. The temporal association factor was the most influential in predicting both recall accuracy and intelligence. We outline a theory of how controlled drift of temporal context may be critical across a range of cognitive activities. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24730719
Healey, M Karl; Crutchley, Patrick; Kahana, Michael J
The purpose of this study was to identify personal characteristics that predict individualdifferences in acute FEV1 response to ozone exposure. Response and predictor data were collected on 290 white male volunteers 18 to 32 yr of age who were each exposed to one of six concentrations of ozone between 0.0 and 0.40 part per million. The sample was divided into an exploratory sample of 96 and a confirmatory sample of 194 subjects. Exploratory analysis indicated that ozone, age, and several other variables explained a significant proportion of the variance in response. In the confirmatory sample, only age and ozone concentration predicted FEV1 decrement. For the combined sample ozone explained 31% of the variance, with age accounting for an additional 4%. The model predicted a decreasing response with increasing age for all nonzero ozone concentrations. For exposure to 0.40 ppm, the model predicts decrements in FEV1 of 1.07 and 0.47 L for 18- and 30-yr-old subjects, respectively. We concluded that for white male subjects age was a significant predictor of response, with older subjects being less responsive to ozone. Furthermore, we demonstrated that exploratory analysis without control of type I statistical error rates may result in apparent findings that cannot be replicated.
McDonnell, W.F.; Muller, K.E.; Bromberg, P.A.; Shy, C.M. (Environmental Protection Agency, Research Triangle Park, NC (United States))
The striatum is critical for the incremental learning of values associated with behavioral actions. The pre-frontal cortex (PFC) represents abstract rules and explicit contingencies to support rapid behavioral adaptation in the absence of cumulative experience. Here we test two alternative models of the interaction between these systems, and individualdifferences thereof, when human subjects are instructed with prior information about reward contingencies that may or may not be accurate. Behaviorally, subjects are overly influenced by prior instructions, at the expense of learning true reinforcement statistics. Computational analysis found that this pattern of data is best accounted for by a confirmation bias mechanism in which prior beliefs - putatively represented in PFC - influence the learning that occurs in the striatum such that reinforcement statistics are distorted. We assessed genetic variants affecting prefrontal and striatal dopaminergic neurotransmission. A polymorphism in the COMT gene (rs4680), associated with prefrontal dopaminergic function, was predictive of the degree to which participants persisted in responding in accordance with prior instructions even as evidence against their veracity accumulated. Polymorphisms in genes associated with striatal dopamine function (DARPP-32, rs907094, and DRD2, rs6277), were predictive of learning from positive and negative outcomes. Notably, these same variants were predictive of the degree to which such learning was overly inflated or neglected when outcomes are consistent or inconsistent with prior instructions. These findings indicate dissociable neurocomputational and genetic mechanisms by which initial biases are strengthened by experience.
Doll, Bradley B.; Hutchison, Kent E.; Frank, Michael J.
Mirror-image stimulation (MIS) was used to determine the individual behavioral phenotypes of 90 adult, 132 yearling, and 135 young yellow-bellied marmots (Marmota flaviventris). Linear typal analysis (LTA) was used to group individuals based on similarities in their MIS scores. Principal component analysis (PCA) was used to evaluate the patterns of variation in behaviors and discriminant function analysis (DFA) was used
The present study investigates individualdifferences in subjective sleepiness profiles during 36h of sustained wakefulness in a modified constant routine protocol. Twenty-three volunteers (11 females), aged between 18 and 47yrs (M age=30.41, SD=10.26) enrolled in the study. Subjective sleepiness ratings were collected every 2h by means of visual analogue scales. Circadian rhythmicity was assessed by means of salivary cortisol. Subjective sleepiness data were analyzed using functional principal component analysis (fPCA). Our results show that approximately 80% of the variance is accounted for by three functional components. The first component explains 50.28% of the variance and is characterized by a profile of exclusively positive loadings, representing vertical shifts from the mean sleepiness profile. Scores on this component are positively related to self-reported habitual sleep times and mean slow wave activity (SWA) during wake. Positive scores on the second component (18.40% of the variance) are characterized by a higher than average peak-to-trough amplitude in subjective sleepiness profiles. Participants with higher than average scores on this component show a significantly higher amplitude in salivary cortisol profiles as opposed to participants with lower than average scores. Participants with positive scores on the third component (10.09% of the variance) show higher than average levels of subjective sleepiness during morning hours, a buildup of wake effort occurring later and more afternoon sleepiness after sleep deprivation than negative scorers. Peak levels of salivary cortisol occur significantly later in these participants. Taken together, our results suggest that component 1 represents tonic differences in sleepiness profiles primarily related to mechanisms of sleep homeostasis, component 2 to circadian amplitude differences and component 3 to diurnal preference. However, since the components are additions to a mean profile, each of the three components is likely to correspond to a mixture of multiple physiological parameters, rather than to a single process. The approach shows interesting potential for (1) revealing unidentified physiological processes, (2) testing existing assumptions about regulatory mechanisms at the basis of interindividual variability in sleepiness profiles and (3) the specification of sleepiness phenotypes on a quantitative basis. PMID:23566886
Human mathematical competence emerges from two representational systems. Competence in some domains of mathematics, such as calculus, relies on symbolic representations that are unique to humans who have undergone explicit teaching. More basic numerical intuitions are supported by an evolutionarily ancient approximate number system that is shared by adults, infants and non-human animals-these groups can all represent the approximate number of items in visual or auditory arrays without verbally counting, and use this capacity to guide everyday behaviour such as foraging. Despite the widespread nature of the approximate number system both across species and across development, it is not known whether some individuals have a more precise non-verbal 'number sense' than others. Furthermore, the extent to which this system interfaces with the formal, symbolic maths abilities that humans acquire by explicit instruction remains unknown. Here we show that there are large individualdifferences in the non-verbal approximation abilities of 14-year-old children, and that these individualdifferences in the present correlate with children's past scores on standardized maths achievement tests, extending all the way back to kindergarten. Moreover, this correlation remains significant when controlling for individualdifferences in other cognitive and performance factors. Our results show that individualdifferences in achievement in school mathematics are related to individualdifferences in the acuity of an evolutionarily ancient, unlearned approximate number sense. Further research will determine whether early differences in number sense acuity affect later maths learning, whether maths education enhances number sense acuity, and the extent to which tertiary factors can affect both. PMID:18776888
Halberda, Justin; Mazzocco, Michèle M M; Feigenson, Lisa
The aim of this study was to evaluate the variation in facial soft tissue thickness in young north eastern Brazilian individuals according to gender and skeletal class. Measurements were obtained from digitized teleradiographs of 300 children, aged from 8 to 12 years, using the Sidexis Xg program. Data of mean, standard deviation, maximum and minimum soft tissue thickness values of the faces of Angle's Class I, II and III individuals, were evaluated. The results demonstrated that there was no difference in soft tissue thickness among the skeletal classes for most of anthropological points. For the Class I, statistical differences were found (P < 0.05) between the genders in the rhinion point, subnasal and upper lip. It was concluded that there was no difference in soft tissue thickness among the skeletal classes, except between Class II and III for the points: Stomion, Bottom lip and Pogonion, allowing definition of parameters of this population for the purpose of facial reconstruction. PMID:24485435
Pithon, Matheus Melo; Rodrigues Ribeiro, Débora Laís; Lacerda dos Santos, Rogério; Leite de Santana, Cláudio; Pedrosa Cruz, João Pedro
Recruiting is a critical staffing activity for organizations, but its impact on the job seeker is poorly understood. Much remains to be learned about individualdifferences in reactions to recruitment efforts. This paper discusses the results of a study of MBA candidates that examined (a) the relative importance of various job, organizational, diversity, and recruiter characteristics on assessments of organizational
Background: Parenteral nutrition (PN) improves the growth and outcome of very low birth weight (VLBW) infants. Optimal PN composition, standard (STD-PN) or individualized (IND-PN), is still controversial. Aim: To compare IND-PN and STD-PN as to nutritional and growth parameters, complications and cost. Patients and Methods: 140 VLBW infants were studied. Each of the 70 neonates from the IND-PN group was
Tatiana Smolkin; Giselle Diab; Irit Shohat; Huda Jubran; Shraga Blazer; Geila S. Rozen; Imad R. Makhoul
For decades educational psychologists have bemoaned the black box approach of much research on learning, that is, the focus on product rather than process, and the absence of fine-grained analysis of the learning process in the individual. One way that progress has been made on this point in the last couple of decades is through cognitive…
Examines individual variation in infants' exploratory play with objects. Distinguishes exploratory and nonexploratory manipulative play, and shows that only exploratory play relates to focused attention and learning. Discusses resistance to distraction during focused attention, relationships between exploratory play and mastery motivation, and the…
Combining adaptive hypermedia methods with strategies proposed by instructional theory and motivation models, an adaptable tutorial was designed and developed. The aim of this study was to assess whether the goals of an adaptable tutorial, which individualized instruction based on student motivation and prior knowledge, were being met (i.e.…
Objective: Determine the reliability of two different modified (MOD1 and MOD2) testing methods compared to a standard method (ST) for testing trunk flexion and extension endurance. Participants: Twenty?eight healthy individuals (age 26.4 ± 3.2 years, height 1.75 ± m, weight 71.8 ± 10.3 kg, body mass index 23.6 ± 3.4 m/kg2). Method: Trunk endurance time was measured in seconds for flexion and extension under the three different stabilization conditions. The MOD1 testing procedure utilized a female clinician (70.3 kg) and MOD2 utilized a male clinician (90.7 kg) to provide stabilization as opposed to the ST method of belt stabilization. Results: No significant differences occurred between flexion and extension times. Intraclass correlations (ICCs3,1) for the different testing conditions ranged from .79 to .95 (p <.000) and are found in Table 3. Concurrent validity using the ST flexion times as the gold standard coefficients were .95 for MOD1 and .90 for MOD2. For ST extension, coefficients were .91 and .80, for MOD1 and MOD2 respectively (p <.01). Conclusions: These methods proved to be a reliable substitute for previously accepted ST testing methods in normal college?aged individuals. These modified testing procedures can be implemented in athletic training rooms and weight rooms lacking appropriate tables for the ST testing. Level of Evidence: 3
Krier, Amber D.; Nelson, Julie A.; Rogers, Michael A.; Stuke, Zachariah O.; Smith, Barbara S.
Threespine sticklebacks (Gasterosteus aculeatus) from different habitats have been observed to differ in shoaling behavior, both in the wild and in laboratory studies. In the present study, we surveyed the shoaling behavior of sticklebacks from a variety of marine, lake, and stream habitats throughout the Pacific Northwest. We tested the shoaling tendencies of 113 wild-caught sticklebacks from 13 populations using a laboratory assay that was based on other published shoaling assays in sticklebacks. Using traditional behavioral measures for this assay, such as time spent shoaling and mean position in the tank, we were unable to find population differences in shoaling behavior. However, simple plotting techniques revealed differences in spatial distributions during the assay. When we collapsed individual trials into population-level data sets and applied information theoretic measurements, we found significant behavioral differences between populations. For example, entropy estimates confirm that populations display differences in the extent of clustering at various tank positions. Using log-likelihood analysis, we show that these population-level observations reflect consistent differences in individual behavioral patterns that can be difficult to discriminate using standard measures. The analytical techniques we describe may help improve the detection of potential behavioral differences between fish groups in future studies.
Wark, Abigail R.; Wark, Barry J.; Lageson, Tessa J.
In 3 studies, I report on the construction and validation of a multifaceted, self-report measure of an individual's tendency to experience feelings of sorrow or concern for the suffering of others. The Trait Sympathy Scales (TSS) displayed solid properties of reliability (Studies 1–3), content validity (Study 1), factorial validity (Study 1), construct-related validity (Studies 1–3), convergent and discriminant validity (Study
Objective To investigate the agreement among clinical experts in their judgments of monitoring data with respect to artifacts, and to examine the effect of reference standards that consist of individual and joint expert judgments on the performance of artifact filters. Design Individual judgments of four physicians, a majority vote judgment, and a consensus judgment were obtained for 30 time series of three monitoring variables: mean arterial blood pressure (ABPm), central venous pressure (CVP), and heart rate (HR). The individual and joint judgments were used to tune three existing automated filtering methods and to evaluate the performance of the resulting filters. Measurements The interrater agreement was calculated in terms of positive specific agreement (PSA). The performance of the artifact filters was quantified in terms of sensitivity and positive predictive value (PPV). Results PSA values between 0.33 and 0.85 were observed among clinical experts in their selection of artifacts, with relatively high values for CVP data. Artifact filters developed using judgments of individual experts were found to moderately generalize to new time series and other experts; sensitivity values ranged from 0.40 to 0.60 for ABPm and HR filters (PPV: 0.57–0.84), and from 0.63 to 0.80 for CVP filters (PPV: 0.71–0.86). A higher performance value for the filters was found for the three variable types when joint judgments were used for tuning the filtering methods. Conclusion Given the disagreement among experts in their individual judgment of monitoring data with respect to artifacts, the use of joint reference standards obtained from multiple experts is recommended for development of automatic artifact filters.
Verduijn, Marion; Peek, Niels; de Keizer, Nicolette F.; van Lieshout, Erik-Jan; de Pont, Anne-Cornelie J.M.; Schultz, Marcus J.; de Jonge, Evert; de Mol, Bas A.J.M.
The purpose of this study was twofold: (a) to profile physical characteristics and motor abilities of three age groups of soccer players – under 14 years, 14–17, and over 17, playing different positions – goalkeepers, defenders, midfielders, and forwards; and (b) to examine the inter-individual variability among the players in each age group in all physical and physiological measurements performed in the study. In addition, anthropometric, power, strength, and flexibility tests were administered. Findings showed large inter-individual variability in all three age groups and in all playing positions. Differences between playing positions were found only in the 14–17 group (body mass) and in the over-17 group (body height, body mass, fat-free mass, and mean power in the Wingate Anaerobic Test). Due to the observed large inter-individual variability, it was concluded that the findings obtained in the physical and physiological tests should be interpreted with caution when attempting to differentiate between successful and unsuccessful soccer players, as well as when trying to predict future success in soccer.
Nikolaidis, Pantelis; Ziv, Gal; Lidor, Ronnie; Arnon, Michal
Dental caries is a polymicrobial disease and complicated to treat. Understanding the microbiota responses to treatment from differentindividuals is a key factor in developing effective treatments. The aim of this study was to investigate the 24-h posttreatment effect of two oral antiseptics (chlorhexidine and Listerine) on species composition of microplate plaque biofilms that had been initiated from the saliva of five different donors and grown in both 0.15% and 0.5% sucrose. Plaque composition was analyzed using checkerboard DNA : DNA hybridization analysis, which comprised of a panel of 40 species associated with oral health and disease. The supernatant pH of the plaques grown in 0.15% sucrose ranged from 4.3 to 6 and in 0.5% sucrose, it ranged from 3.8 to 4. Plaque biomass was largely unaffected by either antiseptic. Each donor had a different salivary microbial profile, differentiating according to the prevalence of either caries or periodontal/anaerobic pathogens. Despite similar plaque microbiota compositions being elicited through the sucrose growth conditions, microbiota responses to chlorhexidine and Listerine differentiated according to the donor. These findings indicate that efficacious caries treatments would depend on the responses of an individual's microbiota, which may differ from person to person. PMID:18647353
Filoche, Sara K; Soma, Dennes; van Bekkum, Margo; Sissons, Chris H
Given that social anxiety disorder is a common, chronic, debilitating disorder and socially anxious women appear to have different experiences related to social development and social support than men, it is essential that the gender differences in social anxiety and social support be understood. The present study examined perceived social support quantity and satisfaction in 23 women and 28 men
Research on the relationship between cohabitation and mental health tends to ignore social psychological factors that help explain mental health differences between the married and the unmarried, including coping resources and perceived relationship quality. In this paper I draw on social psychological theory and research to clarify differences in…
...2013-04-01 2013-04-01 false What conflict of interest standards apply to individuals...CONTRACTING General Â§ 636.117 What conflict of interest standards apply to individuals...improper business practices and personal conflicts of interest will apply to the...
Hypotheses proposed to explain the evolution of cooperative behaviour typically require differentiation between either groups of conspecifics (e.g. kin/non-kin) or, more typically, individuals (e.g. reciprocal altruism). Despite this, the mechanisms that facilitate individual or class recognition have rarely been explored in cooperative species. This study examines the individual differentiation abilities of noisy miners (Manorina melanocephala), a species with one of the most complex avian societies known. Miners permanently occupy colonies numbering into hundreds of individuals. Within these colonies, cooperative coalitions form on a fission–fusion basis across numerous contexts, from social foraging through to mobbing predators. Birds often use individually distinctive ‘chur’ calls to recruit others to a caller's location, facilitating coalition formation. I used the habituation–discrimination paradigm to test the ability of miners to differentiate between the chur calls of two individuals that were both either: (i) familiar, or (ii) unfamiliar to the focal subject. This technique had not, to my knowledge, been used to assess vocalization differentiation in cooperative birds previously, but here demonstrated that miners could correctly use the spectral features of signals to differentiate between the vocalizations of differentindividuals, regardless of their familiarity. By attending to individualdifferences in recruitment calls, miners have a communication system that is capable of accommodating even the most complex cooperative hypotheses based upon acoustic information.
The purpose of this article was to extend the use of standard errors for equated score differences (SEEDs) to traditional equating functions. The SEEDs are described in terms of their original proposal for kernel equating functions and extended so that SEEDs for traditional linear and traditional equipercentile equating functions can be computed. These developments provide new understandings of the relationships
The purpose of this article was to extend the use of standard errors for equated score differences (SEEDs) to traditional equating functions. The SEEDs are described in terms of their original proposal for kernel equating functions and extended so that SEEDs for traditional linear and traditional equipercentile equating functions can be computed.…
In this paper, the author compares behaviors of systems which can be described by fractional differential and fractional difference equations using the fractional and fractional difference Caputo standard ?-Families of maps as examples. The author shows that properties of fractional difference maps (systems with falling factorial-law memory) are similar to the properties of fractional maps (systems with power-law memory). The similarities (types of attractors, power-law convergence of trajectories, existence of cascade of bifurcations and intermittent cascade of bifurcations type trajectories, and dependence of properties on the memory parameter ?) and differences in properties of falling factorial- and power-law memory maps are investigated. PMID:24985451
Multiple sclerosis (MS) is a neurodegenerative, inflammatory disease of the central nervous system, resulting in physical and cognitive disturbances. The goal of the current study was to examine the association between network integrity and composite measures of cognition and disease severity in individuals with relapsing-remitting MS (RRMS), relative to healthy controls. All participants underwent a neuropsychological and neuroimaging session, where resting-state data was collected. Independent component analysis and dual regression were employed to examine network integrity in individuals with MS, relative to healthy controls. The MS sample exhibited less connectivity in the motor and visual networks, relative to healthy controls, after controlling for group differences in gray matter volume. However, no alterations were observed in the frontoparietal, executive control, or default-mode networks, despite previous evidence of altered neuronal patterns during tasks of exogenous processing. Whole-brain, voxel-wise regression analyses with disease severity and processing speed composites were also performed to elucidate the brain-behavior relationship with neuronal network integrity. Individuals with higher levels of disease severity demonstrated reduced intra-network connectivity of the motor network, and the executive control network, while higher disease burden was associated with greater inter-network connectivity between the medial visual network and areas involved in visuomotor learning. Our findings underscore the importance of examining resting-state oscillations in this population, both as a biomarker of disease progression and a potential target for therapeutic intervention. PMID:23973635
A growing number of investigators explore evolutionary psychological hypotheses concerning the avoidance of rape using self-report measures of behavior. Among the most recent and most ambitious, is the work of McKibbin et al. (2011). McKibbin et al. presented evidence supporting their predictions that such behaviors would vary according to the individual's physical attractiveness, relationship status, and proximity to kin. In addition, McKibbin et al. predicted, but failed to find evidence, that age would exercise a similar influence. We question McKibbin et al.'s position on both theoretical and empirical grounds, arguing that (1) two of their predictions do not rule out alternative explanations, and (2) their key supporting findings may well be artifacts of their measurement instrument, the Rape Avoidance Inventory (RAI). Employing new empirical evidence derived from a broader sample of U.S. women, we simultaneously tested McKibbin et al.'s predictions and compared the RAI to alternative dependent measures. We found that McKibbin et al.'s substantive predictions were not supported, and suggest that there may be limits to the utility of the RAI beyond one specific demographic category. PMID:22722957
The prevalence of obesity and associated health conditions is increasing in the developed world. Obesity is related to atrophy and dysfunction of the hippocampus and hippocampal lesions may lead to increased appetite and weight gain. The hippocampus is connected via the fornix tract to the hypothalamus, orbitofrontal cortex, and the nucleus accumbens, all key structures for homeostatic and reward related control of food intake. The present study employed diffusion MRI tractography to investigate the relationship between microstructural properties of the fornix and variation in Body Mass Index (BMI), within normal and overweight ranges, in a group of community-dwelling older adults (53–93 years old). Larger BMI was associated with larger axial and mean diffusivity in the fornix (r?=?0.64 and r?=?0.55 respectively), relationships that were most pronounced in overweight individuals. Moreover, controlling for age, education, cognitive performance, blood pressure and global brain volume increased these correlations. Similar associations were not found in the parahippocampal cingulum, a comparison temporal association pathway. Thus, microstructural changes in fornix white matter were observed in older adults with increasing BMI levels from within normal to overweight ranges, so are not exclusively related to obesity. We propose that hippocampal-hypothalamic-prefrontal interactions, mediated by the fornix, contribute to the healthy functioning of networks involved in food intake control. The fornix, in turn, may display alterations in microstructure that reflect weight gain.
Metzler-Baddeley, Claudia; Baddeley, Roland J.; Jones, Derek K.; Aggleton, John P.; O'Sullivan, Michael J.
Working memory is crucial for many higher-level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization, and modeling in category learning has thus far been largely uninformed by knowledge about people's memory processes. This article reports a large study (N = 113) that related people's working memory capacity (WMC) to their category-learning performance using the 6 problem types of Shepard, Hovland, and Jenkins (1961). Structural equation modeling revealed a strong relationship between WMC and category learning, with a single latent variable accommodating performance on all 6 problems. A model of categorization (the Attention Learning COVEring map, ALCOVE; Kruschke, 1992) was fit to the individual data and a single latent variable was sufficient to capture the variation among associative learning parameters across all problems. The data and modeling suggest that working memory mediates category learning across a broad range of tasks. PMID:21417512
Assessed the generality of a tendency toward fast vs. slow response times in 2 different situations: (a) perceptual matching tests in which the number of response alternatives was fixed and objectively present for all Ss, and (b) a tachistoscopic recognition task in which the response alternatives had to be generated mentally. 60 boys and 53 girls in Grades 2 and
The relation between intrusions in several different recall tasks was examined in the current study. Intrusions from these tasks were moderately correlated and formed a unitary intrusion factor. This factor was related to other cognitive ability measures including working memory capacity, judgments of recency, and general source-monitoring…
Using H. J. Eysenck's (1957,1967) theory of temperament, this study examined the relationship between drug preference, drug use, and personality among incarcerated inmates. Analysis indicated a general preference for marijuana and alcohol over 8 other commonly used drugs across different personality types. Theoretical and clinical implications are…
Feldman, Marc; Kumar, V. K.; Angelini, Frank; Pekala, Ronald J.; Porter, Jack
Socioeconomic status (SES) is associated with childhood cognitive achievement. In previous research we found that this asso- ciation shows neural specificity; specifically we found that groups of low and middle SES children differed disproportionately in perisylvian\\/language and prefrontal\\/executive abilities relative to other neurocognitive abilities. Here we address several new questions: To what extent does this disparity between groups reflect a
Kimberly G. Noble; Bruce D. McCandliss; Martha J. Farah
The diagnostic value of the atropine test was investigated in 47 essentially healthy men of different age groups (25 to 39, 40 to 49 and 50 to 59 years). The cardiovascular responses were evaluated from ECG recorded continuously for an hour after subcutan...
Executive function has been shown to influence the performance of health behaviours. Healthy eating involves both the inhibitory behaviour of consuming low amounts of saturated fat, and the initiatory behaviour of consuming fruit and vegetables. Based on this distinction, it was hypothesised that these behaviours would have different determinants. Measures of inhibitory control and updating were administered to 115 participants across 2 days. One week later saturated fat intake and fruit and vegetable consumption were measured. Regression analyses revealed a double dissociation effect between the different executive function variables and the prediction of eating behaviours. Specifically, inhibitory control, but not updating, predict saturated fat intake, whilst updating, but not inhibitory control, was related to fruit and vegetable consumption. In both cases, better executive function capacity was associated with healthier eating behaviour. The results support the idea that behaviours that require stopping a response such as limiting saturated fat intake, have different determinants to those that require the initiation of a response such as fruit and vegetable consumption. The findings suggest that interventions aimed at improving these behaviours should address the relevant facet of executive function. PMID:24845785
Results from a two year longitudinal study of 181 children from fourth through fifth grade are reported. Levels of growth in children’s computation, word problem, and estimation skills using common fractions were predicted by working memory, attentive classroom behavior, conceptual knowledge about fractions, and simple arithmetic fluency. Comparisons of 55 participants identified as having mathematical difficulties to those without mathematical difficulties revealed that group differences in emerging fraction skills were consistently mediated by attentive classroom behavior and conceptual knowledge about fractions. Neither working memory nor arithmetic fluency mediated group differences in growth in fraction skills. It was also found that the development of basic fraction skills and conceptual knowledge are bidirectional in that conceptual knowledge exerted strong influences on all three types of basic fraction skills, and basic fraction skills exerted a more modest influence on subsequent conceptual knowledge. Results are discussed with reference to how the identification of potentially malleable student characteristics that contribute to the difficulties that some students have with fractions informs interventions and also will contribute to a future theoretical account concerning how domain general and domain specific factors influence the development of basic fraction skills.
Uncomfortable loudness levels were measured for two groups of subjects with either high or low scores on a noise annoyance questionnaire. The study was conducted in two stages. In the first stage scores of noise annoyance, general annoyance and locus of control were obtained from 122 respondents. Two groups of responders on the noise annoyance questionnaire attended the laboratory for the second stage involving a determination of the uncomfortable loudness level (ULL) by two methods (Békésy and analogue adjustment) and for two types of sound source (white noise and a 1 kHz tone). The key findings from the first stage were that (i) noise annoyance scores were not bimodal, showing no significant deviation from normality, (ii) females showed higher noise annoyance and (iii) both general annoyance and locus of control scales showed significant positive correlations with noise annoyance. Findings from the second stage showed that (i) Békésy determinations gave higher ULL's than those from the analogue adjustment method, (ii) based on annoyance scores, noise-annoyed subjects produced significantly higher ULL's than their less annoyed counterparts but only with the analogue determination with a 1 kHz tone, (iii) females produced markedly lower ULL's than males and (iv) deactivation, locus of control and extroversion were identified as mediating factors in the setting of the ULL. The results were further discussed in terms of methodological differences between this and earlier studies.
Attentional mechanisms are a crucial prerequisite to organize behavior. Most situations may be characterized by a ‘competition’ between salient, but irrelevant stimuli and less salient, relevant stimuli. In such situations top-down and bottom-up mechanisms interact with each other. In the present fMRI study, we examined how interindividual differences in resolving situations of perceptual conflict are reflected in brain networks mediating attentional selection. Doing so, we employed a change detection task in which subjects had to detect luminance changes in the presence and absence of competing distractors. The results show that good performers presented increased activation in the orbitofrontal cortex (BA 11), anterior cingulate (BA 25), inferior parietal lobule (BA 40) and visual areas V2 and V3 but decreased activation in BA 39. This suggests that areas mediating top-down attentional control are stronger activated in this group. Increased activity in visual areas reflects distinct neuronal enhancement relating to selective attentional mechanisms in order to solve the perceptual conflict. Opposed to good performers, brain areas activated by poor performers comprised the left inferior parietal lobule (BA 39) and fronto-parietal and visual regions were continuously deactivated, suggesting that poor performers perceive stronger conflict than good performers. Moreover, the suppression of neural activation in visual areas might indicate a strategy of poor performers to inhibit the processing of the irrelevant non-target feature. These results indicate that high sensitivity in perceptual areas and increased attentional control led to less conflict in stimulus processing and consequently to higher performance in competitive attentional selection.
Wascher, Edmund; Beste, Christian; Pfleiderer, Bettina
Repeatability is an important concept in evolutionary analyses because it provides information regarding the benefit of repeated measurements and, in most cases, a putative upper limit to heritability estimates. Repeatability (R) of different aspects of energy metabolism and behavior has been demonstrated in a variety of organisms over short and long time intervals. Recent research suggests that consistent individualdifferences in behavior and energy metabolism might covary. Here we present new data on the repeatability of body mass, standard metabolic rate (SMR), voluntary exploratory behavior, and feeding rate in a semiaquatic salamander and ask whether individual variation in behavioral traits is correlated with individual variation in metabolism on a whole-animal basis and after conditioning on body mass. All measured traits were repeatable, but the repeatability estimates ranged from very high for body mass (R = 0.98), to intermediate for SMR (R = 0.39) and food intake (R = 0.58), to low for exploratory behavior (R = 0.25). Moreover, repeatability estimates for all traits except body mass declined over time (i.e., from 3 to 9 wk), although this pattern could be a consequence of the relatively low sample size used in this study. Despite significant repeatability in all traits, we find little evidence that behaviors are correlated with SMR at the phenotypic and among-individual levels when conditioned on body mass. Specifically, the phenotypic correlations between SMR and exploratory behavior were negative in all trials but significantly so in one trial only. Salamanders in this study showed individual variation in how their exploratory behavior changed across trials (but not body mass, SMR, and feed intake), which might have contributed to observed changing correlations across trials. PMID:24769703
Gifford, Matthew E; Clay, Timothy A; Careau, Vincent
Human factors practitioners often are concerned with mental workload in multiple-task situations. Investigations of these situations have demonstrated repeatedly that individualsdiffer in their subjective estimates of workload. These differences may be attributed in part to individualdifferences in definitions of workload. However, after allowing for differences in the definition of workload, there are still unexplained individualdifferences in workload ratings. The relation between individualdifferences in multiple-task performance, subjective estimates of workload, information processing abilities, and the Type A personality trait were examined.
Williams syndrome (WS) is a developmental disorder associated with relatively spared verbal skills and severe visuospatial deficits. It has also been reported that individuals with WS are impaired at mathematics. We examined mathematical skills in persons with WS using the second edition of the Test of Early Mathematical Ability (TEMA-2), which measures a wide range of skills. We administered the TEMA-2 to 14 individuals with WS and 14 children matched individually for mental age on the matrices subtest of the Kaufman Brief Intelligence Test. There were no differences between groups on the overall scores on the TEMA-2. However, an item-by-item analysis revealed group differences. Participants with WS performed more poorly than controls when reporting which of two numbers was closest to a target number, a task thought to utilize a mental number line subserved by the parietal lobe, consistent with previous evidence showing parietal abnormalities in people with WS. In contrast, people with WS performed better than the control group at reading numbers, suggesting that verbal math skills may be comparatively strong in WS. These findings add to evidence that components of mathematical knowledge may be differentially damaged in developmental disorders.
This study investigated the hypothesis that similar behavior in different cultures may mask individualdifferences in the reasons for that behavior. Most previous research on culture and behavior has examined culture-based differences in overt behavior. In contrast, the present research focused on cultural variation in reasons for identical behavior (that is, individualdifferences in motivation), rather than cultural variation in
Daniel W. Barrett; Wilhelmina Wosinska; Jonathan Butner; Petia Petrova; Malgorzata Gornik-Durose; Robert B. Cialdini
Divergent thinking shows the ability to search for new ideas, which is an important factor contributing to innovation and problem solving. Current divergent thinking tests allow researchers to study children's divergent thinking from the age of 3 years on. This article presents the first measure of divergent thinking that can be used with children as young as 2 years. The Unusual Box test is a nonverbal and nonimitative test in which children play individually with a novel toy and novel objects. Divergent thinking is scored as the number of different actions performed. Study 1 shows that the Unusual Box test is a valid measure of divergent thinking as it correlates with standard measures of divergent thinking in 3- and 4-year-olds. Study 2 indicates that the test can be used with 2-year-olds, as it shows high test-retest reliability, demonstrating that 2-year-olds can think divergently. Across both studies, individualdifferences and age-related changes were found, indicating that some children are better at divergent thinking than others and that children's divergent thinking increases with age. This test will allow researchers to gain insight into the early emergence of divergent thinking. PMID:24588519
As it was recently shown, the colour singlet BFKL kernel, taken in Möbius representation in the space of impact parameters, can be written in quasi-conformal shape, which is unbelievably simple compared with the conventional form of the BFKL kernel in momentum space. It was also proved that the total kernel is completely defined by its Möbius representation. In this paper we calculated the difference between standard and quasi-conformal BFKL kernels in momentum space and discovered that it is rather simple. Therefore we come to the conclusion that the simplicity of the quasi-conformal kernel is caused mainly by using the impact parameter space.
Accurate and reliable determination of blood growth hormone level is essential in the diagnosis and treatment of short stature children. However, measured levels differed considerably among measurement kits available in Japan until 2003. Therefore, standardization of the measured values was attempted by measuring growth hormone levels in a sample of healthy adult individuals every year using the different kits. A standardization equation was developed for each kit through linear structural relationship with the mean values of the used kits and measured values in each kit as random variables. A Pearson’s correlation coefficient between the mean values of all kits and the measured values from each kit was also obtained. Sources for the marked discrepancies amongst the measured values in the different kits were also explored. The obtained values for slopes and intercepts in the equations varied considerably, but the standard values obtained from these equations after the measured values for each kit were transformed into standard values served well as the standard. The standard solutions in the respective measurement kits were found to be the source of variability in the measured values among the kits.
Visual exploration is driven by two main factors--the stimuli in our environment, and our own individual interests and intentions. Research investigating these two aspects of attentional guidance has focused almost exclusively on factors common across individuals. The present study took a different tack, and examined the role played by individual…
Risko, Evan F.; Anderson, Nicola C.; Lanthier, Sophie; Kingstone, Alan
...Standards Severable? 197.38 Section 197.38 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS PUBLIC HEALTH AND ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR YUCCA...
Individualdifferences in pain sensitivity have long remained a perplexing and challenging clinical problem. How can one individual have a sensory experience that is vastly different than that of another, even when they have received similar sensory input? Developing an understanding of such differences and the mechanisms that support them has progressed substantially as psychophysical findings are integrated with measures of brain activation provided by functional brain imaging techniques. Continued delineation of these mechanisms will contribute substantially to the development of combined psychophysical/psychological models that can be used to optimize pain treatment on an individual-by-individual basis.
Understanding the mechanisms responsible for consistent individualdifferences in behaviour is a recent challenge for behavioural ecology. Although theory is rapidly developing in this area, there are few empirical tests. There are at least two hypotheses to explain why individuals behave differently from one another in a dynamic social environment. The social niche specialization hypothesis proposes that repeated social interactions generate consistent individualdifferences in social behaviour. The behavioural type hypothesis proposes that an individual’s social behaviour reflects its behavioural type. We tested these two hypotheses by manipulating the opportunity for repeated social interactions in groups of three spine stickleback, Gasterosteus aculeatus, and by measuring the behavioural types of the same individuals in three contexts: when in a novel environment, when presented with an opportunity to associate with conspecifics and when confronted by an intruder. We found no evidence that repeated social interactions increased between-individual variation in social foraging behaviour. Instead, individuals’ social foraging behaviour was related to their behavioural type, specifically their shoaling behaviour. In addition, the behavioural types of the members of a group strongly influenced a group’s average foraging behaviour. Together, these results do not support the hypothesis that social dynamics within groups generates individualdifferences in behaviour. Instead, they suggest the reverse: individualdifferences in behaviour drive group-level dynamics.
The authors describe a series of experiments that explore 3 major ability determinants of individualdifferences in skill acquisition in the context of prior theory (e.g., P. L. Ackerman, 1988) and subsequent empirical and theoretical research. Experiment 1 assessed the predictability of individualdifferences in asymptotic skill levels on the Kanfer–Ackerman Air Traffic Controller (ATC) task. Experiment 2 provided an
Unique associations between three families of mathematical knowledge and individualdifferences in the mathematics skills of 103 seventh and eighth graders were studied. Conceptual and procedural knowledge adequately explained individualdifferences in fraction solving and problem set-up accuracy, but only conceptual knowledge adequately expressed…
Three experiments examined the nature of individualdifferences in switching the focus of attention in working memory. Participants performed 3 versions of a continuous counting task that required successive updating and switching between counts. Across all 3 experiments, individualdifferences in working memory span and fluid intelligence were…
Prospective memory--remembering to retrieve and execute future goals--is essential to daily life. Prospective remembering is often achieved through effortful monitoring; however, potential individualdifferences in monitoring patterns have not been characterized. We propose 3 candidate models to characterize the individualdifferences present in…
Savine, Adam C.; McDaniel, Mark A.; Shelton, Jill Talley; Scullin, Michael K.
In this study of the origins of individualdifferences in theory of mind (ToM), the Environmental Risk (E-Risk) Longitudinal Twin Study sample of 1,116 sixty-month-old twin pairs completed a comprehensive battery of ToM tasks. Individualdifferences in ToM were striking and strongly associated with verbal ability. Behavioral genetic models of the…
Hughes, Claire; Jaffee, Sara R.; Happ, Francesca; Taylor, Alan; Caspi, Avshalom; Moffitt, Terrie E.
In security tasks, there is much interest in individualdifferences as managers have a belief that ‘choosing the right person for the job’ can have a substantial effect on system performance. This programme was aimed at finding a common set of variables to characterise individualdifferences in performance of security inspection tasks. As part of this effort, an Access™ database
Colin G. Drury; Karen Holness; Kimberly M. Ghylin; Brian D. Green
Though once of central importance to psychologists and neurophysiologists alike, the elucidation of neural substrates for individualdifferences in learning no longer attracts a broad research effort and occupies a place of largely historical interest to the contemporary disciplines. The decline in interest in this subject ensued in part from the perception, arrived at decades ago, that individualdifferences in
Heterogeneity of variance may be more than a statistical nuisance--it may be of direct interest as a result of individualdifferences. In studies of short-term fluctuation, individualdifferences may relate to the magnitude of within-person variation as well as to level of an outcome or its covariation with other processes. Although models for…
Two studies were reported which attempted to estimate the stability and construct validity of human salivary response as a measure of individualdifferences (IDs) in physiological arousal. Twenty-second base line estimates and 20-second response levels to four drops of lemon juice were measured, with the former value being removed from the latter…
In two separate paired-associate learning experiments each employing 40 university students as subjects, the contribution of individualdifferences (IDs) in arousal to short- and long-term retention was investigated using IDs in salivary response to lemon juice stimulation as an index of arousal. Experimental subjects were pre-selected out of 184…
Background Repeated encounters over time enable general practitioners (GPs) to accumulate biomedical and biographical knowledge about their patients. A growing body of evidence documenting the medical relevance of lifetime experiences indicates that health personnel ought to appraise this type of knowledge and consider how to incorporate it into their treatment of patients. In order to explore the interdisciplinary communication of such knowledge within Norwegian health care, we conducted a research project at the interface between general practice and a nursing home. Methods In the present study, nine Norwegian GPs were each interviewed about one of their patients who had recently been admitted to a nursing home for short-term rehabilitation. A successive interview conducted with each of these patients aimed at both validating the GP's information and exploring the patient's life story. The GP's treatment opinions and the patient's biographical information and treatment preferences were condensed into a biographical record presented to the nursing home staff. The transcripts of the interviews and the institutional treatment measures were compared and analysed, applying a phenomenological–hermeneutical framework. In the present article, we compare and discuss: (1) the GPs’ specific recommendations for their patients; (2) the patients’ own wishes and perceived needs; and (3) if and how this information was integrated into the institution's interventions and priorities. Results Each GP made rehabilitation recommendations, which included statements regarding both the patient's personality and life circumstances. The nursing home staff individualized their selection of therapeutic interventions based on defined standardized treatment approaches, without personalizing them. Conclusion We found that the institutional voice of medicine consistently tends to override the voice of the patient's lifeworld. Thus, despite the institution's best intentions, their efforts to provide appropriate rehabilitation seem to have been jeopardized to some extent.
Mj?lstad, Bente Prytz; Kirkengen, Anna Luise; Getz, Linn; Hetlevik, Irene
Within the same population, individuals often differ in how they respond to changes in their environment. A recent series of models predicts that competition in a heterogeneous environment might promote between-individual variation in behavioural plasticity. We tested groups of sticklebacks in patchy foraging environments that differed in the level of competition. We also tested the same individuals across two different social groups and while alone to determine the social environment's influence on behavioural plasticity. In support of model predictions, individuals consistently differed in behavioural plasticity when the presence of conspecifics influenced the potential payoffs of a foraging opportunity. Whether individuals maintained their level of behavioural plasticity when placed in a new social group depended on the environmental heterogeneity. By explicitly testing predictions of recent theoretical models, we provide evidence for the types of ecological conditions under which we would expect, and not expect, variation in behavioural plasticity to be favoured. PMID:23489482
The current study investigated the effects of individualdifferences and workload on strategy adaptivity in a complex, dynamic task called the Space Fortress game (Donchin, 1989). Participants learned to use a strategy of flying a ship in circles around the fortress in a standard game environment. Once they mastered the strategy, they were assigned to different workload conditions and transferred to a nonstandard environment in which a strong wind was introduced that made it more difficult to achieve a circular orbit. About half of the participants continued with their prior circular strategy while the rest adopted a novel strategy that achieved comparable performance with less effort. With this novel strategy, rather than trying to complete orbits they flew into the wind and then allowed the wind to blow them back to achieve a pendulum-like path. Participants without a working-memory load were more likely to adopt the new strategy. Participants were also more likely to adopt the new strategy if their pattern of behavior exposed them more often to the potential of drifting with the wind. The results indicate that spontaneous changes in strategy occur when people are exposed to the potential of a new strategy and have the cognitive resources to understand its potential. PMID:23831665
Less than 5% of colorectal adenomas will become malignant, but we do not have sufficient knowledge about their natural course to target removal of these 5% only. Thus, 95% of polypectomies are a waste of time exposing patients to a small risk of complications. Recently, a new type of polyps, sessile serrated polyps, has attracted attention. Previously considered innocuous, they are now found to have molecular similarities to cancer and some guidelines recommend to have them removed. These lesions are often flat, covered by mucous, not easily seen and situated in the proximal colon where the bowel wall is thinner. Thus, polypectomy carries a higher risk of perforation than predominantly left-sided, stalked adenomas - and we do not know what is gained in terms of cancer prevention. Screening is a neat balance between harms and benefit for presumptively healthy participants not interested in risk exposure to obtain confirmation of being healthy. The situation is quite different for patient worried about symptom. Thus, the standards set for evidence-based practice may be higher for screening than for routine clinics - a mechanism which may benefit patients in the long run.
Oyserman, Coon, and Kemmelmeier's (2002) meta-analysis suggested problems in the measurement of individualism and collectivism. Studies using Hofstede's individualism scores show little convergent validity with more recent measures of individualism and collectivism. We propose that the lack of convergent validity is due to national differences in response styles. Whereas Hofstede statistically controlled for response styles, Oyserman et al.'s meta-analysis relied on uncorrected ratings. Data from an international student survey demonstrated convergent validity between Hofstede's individualism dimension and horizontal individualism when response styles were statistically controlled, whereas uncorrected scores correlated highly with the individualism scores in Oyserman et al.'s meta-analysis. Uncorrected horizontal individualism scores and meta-analytic individualism scores did not correlate significantly with nations' development, whereas corrected horizontal individualism scores and Hofstede's individualism dimension were significantly correlated with development. This pattern of results suggests that individualism is a valid construct for cross-cultural comparisons, but that the measurement of this construct needs improvement. PMID:15745862
Metacognition's roles in self-regulation of cognitive tactics and strategies is explored in relation to five sites where individualdifference factors are likely to be observed and affect performance: domain knowledge, knowledge of tactics and strategies, performance of tactics and strategies, regulation of tactics and strategies, and global dispositions. Though the current literature is sparse, tentative hypotheses about kinds of individual
This study explored the relationships of self-reflection and insight with individuals' performances on various language tasks. The Self-Reflection and Insight Scale (SRIS; Grant, Franklin, & Langford, 2002) assessed individualdifferences in three factors: engagement in reflection, need for reflection, and insight. A high need for reflection was…
Accuracy for a second target (T2) is reduced when it is presented within 500 ms of a first target (T1) in a rapid serial visual presentation (RSVP)--an attentional blink (AB). There are reliable individualdifferences in the magnitude of the AB. Recent evidence has shown that the attentional approach that an individual typically adopts during a…
MacLean, Mary H.; Arnell, Karen M.; Cote, Kimberly A.
Describes the procedures by which Kentucky's state assessment program synthesized results from three standard setting procedures (Contrasting Groups, Bookmark, and Jaeger-Mills) for the 2000 state assessment. Shows the value of using multiple standard-setting approaches to gather information from each. (SLD)
Green, Donald Ross; Trimble, C. Scott; Lewis, Daniel M.
Background Coeliacs require a life-long gluten-free diet supported by accurate measurement of gluten (hordein) in gluten-free food. The gluten-free food industry, with a value in excess of $6 billion in 2011, currently depends on two ELISA protocols calibrated against standards that may not be representative of the sample being assayed. Aim The factors affecting the accuracy of ELISA analysis of hordeins in beer were examined. Results A simple alcohol-dithiothreitol extraction protocol successfully extracts the majority of hordeins from barley flour and malt. Primary hordein standards were purified by FPLC. ELISA detected different classes of purified hordeins with vastly different sensitivity. The dissociation constant (Kd) for a given ELISA reaction with different hordeins varied by three orders of magnitude. The Kd of the same hordein determined by ELISA using different antibodies varied by up to two orders of magnitude. The choice of either ELISA kit or hordein standard may bias the results and confound interpretation. Conclusions Accurate determination of hordein requires that the hordein standard used to calibrate the ELISA reaction be identical in composition to the hordeins present in the test substance. In practice it is not feasible to isolate a representative hordein standard from each test food. We suggest that mass spectrometry is more reliable than ELISA, as ELISA enumerates only the concentration of particular amino-acid epitopes which may vary between different hordeins and may not be related to the absolute hordein concentration. MS quantification is undertaken using peptides that are specific and unique enabling the quantification of individual hordein isoforms.
Sexual narcissism (SN) has recently been proposed to be a specific risk factor for the perpetration of sexual coercion based on both self-reports of previous behavior and self-estimated likelihood of engaging in acts of sexual violence. To explore one of the potential underlying mechanisms of SN, we tested whether for highly sexually narcissistic males (measured with the German language version of the Sexual Narcissism Scale) the subtle priming of sexual concepts would evoke aggressive behavior in a standard measure of aggressive behavior, the Taylor Aggression Paradigm. Results showed that only for sexually narcissistic men did a subtle priming with mildly erotic words lead to an increase in shock volumes administered to the alleged competitor on this task. For women, it was postulated that physical force would not be represented as a functional behavioral script for sexually narcissistic females and, in line with this hypothesis, no effects were found for women. The results were discussed with regard to the underlying processes of SN and the importance of an individualdifference perspective in sex-aggression links. PMID:23430086
Imhoff, Roland; Bergmann, Xenia; Banse, Rainer; Schmidt, Alexander F
Demonstrated how individualdifferences in semantic differential data can be modeled and assessed using three-mode models by studying the characterization of Chopin's "Preludes" by 38 Japanese college students. (SLD)
TMFA, a FORTRAN program for three-mode factor analysis and individual-differences multidimensional scaling, is described. Program features include a variety of input options, extensive preprocessing of input data, and several alternative methods of analysis. (Author)
A new analysis of data from 15 cognitive tasks completed by 93 subjects with scores on the Cattell Culture Fair test show that differences in Cattell score systematically affected performance on some tasks more than on others. Implications for theories of local and global differences in mental ability are discussed. (SLD)
We have developed a set of upper extremity functional tasks to guide the design and test the performance of rehabilitation technologies that restore arm motion in people with high tetraplegia. Our goal was to develop a short set of tasks that would be representative of a much larger set of activities of daily living while also being feasible for a unilateral user of an implanted Functional Electrical Stimulation (FES) system. To compile this list of tasks, we reviewed existing clinical outcome measures related to arm and hand function, and were further informed by surveys of patient desires. We ultimately selected a set of five tasks that captured the most common components of movement seen in these tasks, making them highly relevant for assessing FES-restored unilateral arm function in individuals with high cervical spinal cord injury (SCI). The tasks are intended to be used when setting design specifications and for evaluation and standardization of rehabilitation technologies under development. While not unique, this set of tasks will provide a common basis for comparing different interventions (e.g., FES, powered orthoses, robotic assistants) and testing different user command interfaces (e.g., sip-and-puff, head joysticks, brain-computer interfaces).
Cornwell, Andrew S.; Liao, James Y.; Bryden, Anne M.; Kirsch, Robert F.
Objective: The long face pattern is a facial deformity with increased anterior total facial height due to vertical excess of the lower facial third. Individuals with long face may present different degrees of severity in vertical excess, as well as malocclusions that are difficult to manage. The categorization of vertical excess is useful to determine the treatment prognosis. This survey assessed the distribution of ethnically differentindividuals with vertical excess according to three levels of severity and determined the prevalence of long face pattern. Material and Methods: The survey was comprised of 5,020 individuals of Brazilian ethnicity (2,480 females and 2,540 males) enrolled in middle schools in Bauru-SP, Brazil. The criterion for inclusion of individuals with vertically impaired facial relationships was based on lip incompetence, evaluated under natural light, in standing natural head position with the lips at rest. Once identified, the individuals were classified into three subtypes according to the severity: mild, moderate, and severe. Then the pooled sample was distributed according to ethnical background as White (Caucasoid), Black (African descent), Brown (mixed descent), Yellow (Asian descent) and Brazilian Indian (Brazilian native descent). The Chi-square (?2) test was used (p<0.05) to compare the frequency ratios of individuals with vertically impaired facial relationships in the total sample and among different ethnicities, according to the three levels of severity. Results: The severe subtype was rare, except in Black individuals (7.32%), who also presented the highest relative frequency (45.53%) of moderate subtype, followed by Brown individuals (43.40%). In the mild subtype, Yellow (68.08%) and White individuals (62.21%) showed similar and higher relative frequency values. Conclusions: Black individuals had greater prevalence of long face pattern, followed by Brown, White and Yellow individuals. The prevalence of long face pattern was 14.06% in which 13.39% and 0.68% belonged to moderate and severe subtypes, respectively.
CARDOSO, Mauricio de Almeida; de CASTRO, Renata Cristina Faria Ribeiro; LI AN, Tien; NORMANDO, David; GARIB, Daniela Gamba; CAPELOZZA FILHO, Leopoldino
Hyperlipidemia or dyslipidemia is one of the most important risk factors for coronary heart disease. The purpose of the present study was to identify gene polymorphisms for assessment of the genetic risk for myocardial infarction (MI) in individuals with low or high serum concentrations of high- density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, or triglyceride (TG), thereby contributing to the personalized prevention of MI in such individuals. The study population comprised 2682 unrelated Japanese individuals (1796 men, 886 women), including 1113 subjects (869 men, 244 women) with MI and 1569 controls (927 men, 642 women). The genotypes for 164 polymorphisms of 137 candidate genes were determined by a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Multivariable logistic regression analyses and stepwise forward selection procedures revealed that seven different polymorphisms were significantly (P<0.005) associated with MI in individuals with low or high serum concentrations of HDL- or LDL-cholesterol or of TG: the 190T --> C (Trp64Arg) polymorphism of ADRB3 in individuals with low HDL-cholesterol; the 1018C --> T (Thr145Met) polymorphism of GP1BA, the A --> G (Ile646Val) polymorphism of AKAP10, and the -55C --> T polymorphism of UCP3 in individuals with high HDL-cholesterol; the -603A --> G polymorphism of F3 and the -11377C --> G polymorphism of ADIPOQ in individuals with low LDL-cholesterol; the 1018C --> T polymorphism of GP1BA in individuals with low TG; and the 4G --> 5G polymorphism of PAI1 in individuals with high TG. No polymorphism was associated with MI in individuals with high LDL-cholesterol. These results suggest that polymorphisms associated with MI may differ among individuals with different lipid profiles. Stratification of subjects according to lipid profiles may thus be important for personalized prevention of MI based on genetic information. PMID:17786291
Although different people respond differently to threatening events, animal research on the neural basis of fear tends to focus on typical responses. Yet there are substantial individualdifferences between animals exposed to identical behavioral procedures. In an effort to begin to understand the nature and causes of fear variability and resilience, we separated outbred Sprague-Dawley rats into high and low
David E. A. Bush; Francisco Sotres-Bayon; Joseph E. LeDoux
The elusive phenomenon of individual learning differences was probed via the concepts of transfer and practice at different stages of the learning process. Order of presentation of two films covering different subjects provided the transfer task. Practice was introduced by five repetitions of the films, interspersed among six repetitions of an…
Brain aging research relies mostly on cross-sectional studies, which infer true changes from age differences. We present longitudinal measures of five-year change in the regional brain volumes in healthy adults. Average and individualdifferences in volume changes and the effects of age, sex and hypertension were assessed with latent difference score modeling. The caudate, the cerebellum, the hippocampus and the
Naftali Raz; Ulman Lindenberger; Karen M. Rodrigue; Kristen M. Kennedy; Denise Head; Adrienne Williamson; Cheryl Dahle; Denis Gerstorf; James D. Acker
Recent advances in segmented gamma scanning have emphasized software corrections for gamma-ray self-absorption in particulates or lumps of special nuclear material in the sample. Another feature of this software is an attenuation correction factor formalism that explicitly accounts for differences in sample container size and composition between the calibration standards and the individual items being measured. Software without this container-size correction produces biases when the unknowns are not packaged in the same containers as the calibration standards. This new software allows the use of different size and composition containers for standards and unknowns, an enormous savings considering the expense of multiple calibration standard sets otherwise needed. This report presents calculations of the bias resulting from not using this new formalism. The calculations may be used to estimate bias corrections for segmented gamma scanners that do not incorporate these advanced concepts. This paper describes this attenuation-correction-factor formalism in more detail and illustrates the magnitude of the biases that may arise if it is not used. 5 refs., 7 figs.
Summary Investigations of individualdifferences have become increasingly important in the cognitive neuroscience of executive control. For instance, individual variation in lateral prefrontal cortex function (and that of associated regions) has recently been used to identify contributions of executive control processes to a number of domains, including working memory capacity, anxiety, reward/motivation, and emotion regulation. However, the origins of such individualdifferences remain poorly understood. Recent progress toward identifying the genetic and environmental sources of variation in neural traits, in combination with progress identifying the causal relationships between neural and cognitive processes, will be essential for developing a mechanistic understanding of executive control.
Abundant evidence across the behavioral and social sciences suggests that there are substantial individualdifferences in pro-social behavior. However, little is known about the psychological mechanisms that underlie social preferences. This paper investigates whether empathy and Theory of Mind shape individualdifferences in pro-social behavior as conventionally observed in neutrally framed social science experiments. Our results show that individualdifferences in the capacity for empathy do not shape social preferences. The results qualify the role of Theory of Mind in strategic interaction. We do not only show that fair individuals exhibit more accurate beliefs about the behavior of others but that Theory of Mind can be effectively used to pursue both self-interest and pro-social goals depending on the principle objectives of a person. PMID:24743312
Artinger, Florian; Exadaktylos, Filippos; Koppel, Hannes; Sääksvuori, Lauri
Effective behavioral management plans are tailored to unique behavioral patterns of each individual species. However, even within a species behavioral needs of individuals can vary. Factors such as age, sex, and temperament can affect behavioral needs of individuals. While some of these factors, such as age and sex, are taken into account, other factors, such as an individual’s temperament, are rarely specifically provided for in behavioral management plans. However, temperament may affect how animals respond to socialization, positive reinforcement training and other forms of enrichment. This review will examine how individualdifferences in temperament might affect, or be affected by, behavioral management practices for captive primates. Measuring temperament may help us predict outcome of social introductions. It can also predict which animals may be difficult to train using traditional methods. Further, knowledge of temperament may be able to help identify individuals at risk for development of behavioral problems. Taken together, understanding individualdifferences in temperament of captive primates can help guide behavioral management decisions.
Interacting with the environment requires the ability to flexibly direct attention to relevant features. We examined the degree to which individuals attend to visual features within and across Detection, Fine Discrimination, and Coarse Discrimination tasks. Electroencephalographic (EEG) responses were measured to an unattended peripheral flickering (4 or 6 Hz) grating while individuals (n = 33) attended to orientations that were offset by 0°, 10°, 20°, 30°, 40°, and 90° from the orientation of the unattended flicker. These unattended responses may be sensitive to attentional gain at the attended spatial location, since attention to features enhances early visual responses throughout the visual field. We found no significant differences in tuning curves across the three tasks in part due to individualdifferences in strategies. We sought to characterize individual attention strategies using hierarchical Bayesian modeling, which grouped individuals into families of curves that reflect attention to the physical target orientation ("on-channel") or away from the target orientation ("off-channel") or a uniform distribution of attention. The different curves were related to behavioral performance; individuals with "on-channel" curves had lower thresholds than individuals with uniform curves. Individuals with "off-channel" curves during Fine Discrimination additionally had lower thresholds than those assigned to uniform curves, highlighting the perceptual benefits of attending away from the physical target orientation during fine discriminations. Finally, we showed that a subset of individuals with optimal curves ("on-channel") during Detection also demonstrated optimal curves ("off-channel") during Fine Discrimination, indicating that a subset of individuals can modulate tuning optimally for detection and discrimination. PMID:23678013
Bridwell, David A; Hecker, Elizabeth A; Serences, John T; Srinivasan, Ramesh
This research examined whether distinct student profiles emerged from measures of interest, mastery goals, task value, and self-efficacy in samples of Norwegian student nurses and business administration students. Additionally, profile differences in self-reported strategy use and epistemological beliefs were examined, as well as changes in…
Do individuals with higher levels of task-relevant cognitive resources gain more from training, or do they gain less? For episodic memory, empirical evidence is mixed. Here, we revisit this issue by applying structural equation models for capturing individualdifferences in change to data from 108 participants aged 9–12, 20–25, and 65–78 years. Participants learned and practiced an imagery-based mnemonic to encode and retrieve words by location cues. Initial mnemonic instructions reduced between-person differences in memory performance, whereas further practice after instruction magnified between-person differences. We conclude that strategy instruction compensates for inefficient processing among the initially less able. In contrast, continued practice magnifies ability-based between-person differences by uncovering individualdifferences in memory plasticity.
Animals with low and high immobility in the forced swimming test (FST) differ in a number of neurobehavioral factors. A growing body of evidence suggests that the exposure to enriched environments mediates a number of changes in the brain. Therefore, we studied if animals' individuality can somehow modulate the response to environmental stimuli. Male rats were classified according to their immobility time scores in the FST test session as animals with low, medium or high immobility. Then, rats from groups with low and high immobility were randomly distributed in two groups to be reared in different housing conditions (i.e., enriched and standard conditions) during 8weeks. Animals were subjected to the open field test (OFT) before and 6weeks after the start of housing protocol. Rats with high immobility in the FST also showed high ambulation and high rearing time in the first OFT. Such findings were not observed in the second OFT. Conversely, an effect of environmental enrichment was found in the second OFT where enriched animals showed lower ambulation and higher grooming time than the standard control group. Rats were sacrificed after the housing protocol and neurochemical content and/or gene expression were studied in three different brain regions: the prefrontal cortex, the hippocampus and the nucleus accumbens. Rats with low immobility showed significantly higher accumbal 5-HT levels than animals with high immobility, whereas no neurochemical differences were observed between enriched and standard animals. Regarding expression data, however, an effect of enrichment on accumbal corticotropin-releasing factor (CRF) and its receptor 1 (CRFR1) levels was observed, and such effect depended on immobility levels. Thus, our results not only allowed us to identify a number of differences between animals with low and high immobility or animals housed in standard and enriched conditions, but also suggested that animals' individuality modulated in some way the response to environmental stimuli. PMID:24508814
Dual-process theories of the mind are ubiquitous in psychology. A central principle of these theories is that behavior is determined by the interplay of automatic and controlled processing. In this article, the authors examine individualdifferences in the capacity to control attention as a major contributor to differences in working memory capacity (WMC). The authors discuss the enormous implications of this individualdifference for a host of dual-process theories in social, personality, cognitive, and clinical psychology. In addition, the authors propose several new areas of investigation that derive directly from applying the concept of WMC to dual-process theories of the mind.
Barrett, Lisa Feldman; Tugade, Michele M.; Engle, Randall W.
The size of the tympanic membrane and ossicles and the stiffness of the middle-ear ligaments and joint are different between individuals, and the effects of these differences on middle-ear transfer function have not been clarified. In this study, using finite-element middle-ear models, the effects of individualdifferences in the size and mobility of the middle ear on its transmission characteristics were analyzed. The individualdifferences in the size of the normal middle ear were found to affect the transfer function by up to 10dB. The effects of the Young’s moduli of the stapedial annular ligaments and the incudostapedial joint on the transfer function were large compared to the effects of the Young’s moduli of the other parts of the middle ear.
Little is known about individualdifferences in integrating numeric base-rates and qualitative text in making probability judgments. Fuzzy-Trace Theory predicts a preference for fuzzy processing. We conducted six studies to develop the FPPI, a reliable and valid instrument assessing individualdifferences in this fuzzy processing preference. It consists of 19 probability estimation items plus 4 "M-Scale" items that distinguish simple pattern matching from “base rate respect.” Cronbach's Alpha was consistently above 0.90. Validity is suggested by significant correlations between FPPI scores and three other measurers: "Rule Based" Process Dissociation Procedure scores; the number of conjunction fallacies in joint probability estimation; and logic index scores on syllogistic reasoning. Replicating norms collected in a university study with a web-based study produced negligible differences in FPPI scores, indicating robustness. The predicted relationships between individualdifferences in base rate respect and both conjunction fallacies and syllogistic reasoning were partially replicated in two web-based studies.
This volume examines the ramifications of individualdifferences in therapy outcomes for a wide variety of communication disorders. In an era where evidence-based practice is the clinical profession's watchword, each chapter attacks this highly relevant issue from a somewhat different perspective. In some areas of communication disorders,…
Moral sentiment has been hypothesized to reflect evolved adaptations to social living. If so, individualdifferences in moral values may relate to regional variation in brain structure. We tested this hypothesis in a sample of 70 young, healthy adults examining whether differences on two major dimensions of moral values were significantly associated with regional gray matter volume. The two clusters
Gary J. Lewis; Ryota Kanai; Timothy C. Bates; Geraint Rees
In two different contexts, we examined the hypothesis that individualdifferences in working memory (WM) capacity are related to the tendency to infer complex, ordinal relationships "between" numerical symbols. In Experiment 1, we assessed whether this tendency arises in a learning context that involves mapping novel symbols to quantities by…
Metacognition refers to students' knowledge and regulation of cognition, as well as their accuracy in predicting their academic performance. This study addressed two major questions: 1) how do metacognitive knowledge, regulation and accuracy differ across domains?, and 2) how do students' individualdifferences relate to their reported…
Adolescents differ in the extent to which they believe that parents have legitimate authority to impose rules restricting adolescents' behavior. The purpose of the current study was to test predictors of individualdifferences in legitimacy beliefs during the middle school years. Annually, during the summers following Grades 5, 6, and 7, early…
Delay discounting refers to the reduction of the value of a future reward as the delay to that reward increases. The rate at which individuals discount future rewards varies as a function of both individual and contextual differences, and high delay discounting rates have been linked with problematic behaviors, including drug abuse and gambling. The current study investigated the effects of acute anticipatory stress on delay discounting, while considering two important factors: individual perceptions of stress and whether the stressful situation is future-focused or present-focused. Half of the participants experienced acute stress by anticipating giving a videotaped speech. This stress was either future-oriented (speech about future job) or present-oriented (speech about physical appearance). They then performed a delay discounting task, in which they chose between smaller, immediate rewards, and larger, delayed rewards. Their scores on the Perceived Stress Scale were also collected. The way in which one appraises stressful situations interacts with acute stress to influence choices; under stressful conditions, delay discounting rate was highest in individuals with low trait perceived stress and lowest for individuals with high trait perceived stress. This result might be related to individual variation in reward responsiveness under stress. Furthermore, the time orientation of the task interacted with its stressfulness to affect the individual’s propensity to choose immediate rewards. These findings add to our understanding of the intermediary factors between stress and decision-making.
Lempert, Karolina M.; Porcelli, Anthony J.; Delgado, Mauricio R.; Tricomi, Elizabeth
In the analysis of individual pharmacokinetic data by nonlinear regression it is important to allow for possible heterogeneity of variance in the response. Two common methods of doing this are weighted least squares with appropriate weights or data transformation using a suitable transform. With either approach it is appealing to let the data determine the appropriate choice of weighting scheme
Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of controlled ovarian stimulation (COS) as part of assisted reproductive technologies (ART). While the safety and efficacy of ART is well established, physicians should always be aware of the risk of OHSS in patients undergoing COS, as it can be fatal. This article will briefly present the pathophysiology of OHSS, including the key role of vascular endothelial growth factor (VEGF), to provide the foundation for an overview of current techniques for the prevention of OHSS. Risk factors and predictive factors for OHSS will be presented, as recognizing these risk factors and individualizing the COS protocol appropriately is the key to the primary prevention of OHSS, as the benefits and risks of each COS strategy vary among individuals. Individualized COS (iCOS) could effectively eradicate OHSS, and the identification of hormonal, functional and genetic markers of ovarian response will facilitate iCOS. However, if iCOS is not properly applied, various preventive measures can be instituted once COS has begun, including cancelling the cycle, coasting, individualizing the human chorionic gonadotropin trigger dose or using a gonadotropin-releasing hormone (GnRH) agonist (for those using a GnRH antagonist protocol), the use of intravenous fluids at the time of oocyte retrieval, and cryopreserving/vitrifying all embryos for subsequent transfer in an unstimulated cycle. Some of these techniques have been widely adopted, despite the scarcity of data from randomized clinical trials to support their use.
Data from three sources—an initial self sample (N = 108) and a friend sample (N = 103) and relative sample (N = 103) recruited by self sample participants—were used to test the consensual and behavioral validity of new individualdifferences\\u000a measures of 15 dimensions of motivation represented in the assessment of individual motives-questionnaire (AIM-Q). AIM-Q scores\\u000a for all three samples converged and hypotheses of their predicted
Since April 2011, the igs08.atx antenna calibration model is used in the routine IGS (International GNSS Service) data analysis. The model includes mean robot calibrations to correct for the offset and phase center variations of the GNSS receiver antennas. These so-called "type" calibrations are means of the individual calibrations available for a specific antenna/radome combination. The GNSS data analysis performed within the EUREF Permanent Network (EPN) aims at being as consistent as possible with the IGS analysis. This also applies to the receiver antenna calibrations. However, when available, individual antenna calibrations are used within the EPN analysis instead of the "type" calibration. When these individual calibrations are unavailable, then the EPN analysis falls back to (type) calibrations identical as the ones used within the IGS (igs08.atx). The aim of this study is to evaluate the significance of the offset caused by using different receiver antenna calibration models on the station position. Using the PPP (Precise Point Positioning) technique, we first investigate the differences in positioning obtained when switching between individual antenna calibrations and type calibrations. We analyze the observations of the 43 EPN stations equipped with receiver antenna individually calibrated over the period covering from 2003 to 2010 and we show that these differences can reach up to 4 mm in horizontal and 10 mm in vertical. Secondly, we study the accuracy of the individual calibrations models and we evaluate the effect of different sets of individual calibrations on the positioning. For that purpose, we use the data from 6 GNSS stations equipped with an antenna which has been individually calibrated at two calibration facilities recognized by the IGS: GEO++ and Bonn institute.
Baire, Q.; Pottiaux, E.; Bruyninx, C.; Defraigne, P.; Aerts, W.; Legrand, J.; Bergeot, N.; Chevalier, J. M.
The sequences of the hypervariable region 1 (HV1) of the mitochondrial DNA control region from multiple hair shafts from\\u000a 10 unrelated individuals were compared to determine the frequency of differences in hairs from one individual. The extraction\\u000a method described herein showed an average success rate of 67% for all 150 hair shafts tested in HV1. The mtDNA sequences from\\u000a the
Mass customization entails the mass production of individually customized goods and services. Co-design is a mass customization option where a product's design is based on the customer's selections from a range of design feature offerings. A model comprised of relationships between individualdifferences, motivations for using co-design, and willingness to use co-design was proposed and statistically supported using 521 university
When given challenging episodic memory tasks, young adults demonstrate notable individualdifferences in performance. Recent evidence suggests that individualdifferences in human behavior may be related to the strength of functional connectivity of large-scale functional networks as measured by spontaneous fluctuations in regional brain activity during quiet wakefulness (the "resting state"), in the absence of task performance. In this study, we sought to determine whether individualdifferences in memory performance could be predicted by the interhemispheric functional connectivity of the two hippocampi, hypothesized to reflect the intrinsic connectivity within the large-scale medial temporal lobe memory system. Results demonstrated that interhemispheric hippocampal functional connectivity during quiet wakefulness was predictive of the capacity to freely recall recently learned information (r = 0.47, P < 0.05). In contrast, functional connectivity of bilateral motor cortices had no relationship to free recall, supporting the specificity of the hippocampal data. Thus, individualdifferences in the capacity to perform episodic memory tasks, which may be persistent behavioral traits or transient states, may be at least partly subserved by individualdifferences in the functional connectivity of large-scale functional-anatomic memory networks. PMID:20087893
The pFC is critical for cognitive flexibility (i.e., our ability to flexibly adjust behavior to changing environmental demands), but also for cognitive stability (i.e., our ability to follow behavioral plans in the face of distraction). Behavioral research suggests that individualsdiffer in their cognitive flexibility and stability, and neurocomputational theories of working memory relate this variability to the concept of attractor stability in recurrently connected neural networks. We introduce a novel task paradigm to simultaneously assess flexible switching between task rules (cognitive flexibility) and task performance in the presence of irrelevant distractors (cognitive stability) and to furthermore assess the individual "spontaneous switching rate" in response to ambiguous stimuli to quantify the individual dispositional cognitive flexibility in a theoretically motivated way (i.e., as a proxy for attractor stability). Using fMRI in healthy human participants, a common network consisting of parietal and frontal areas was found for task switching and distractor inhibition. More flexible persons showed reduced activation and reduced functional coupling in frontal areas, including the inferior frontal junction, during task switching. Most importantly, the individual spontaneous switching rate antagonistically affected the functional coupling between inferior frontal junction and the superior frontal gyrus during task switching and distractor inhibition, respectively, indicating that individualdifferences in cognitive flexibility and stability are indeed related to a common prefrontal neural mechanism. We suggest that the concept of attractor stability of prefrontal working memory networks is a meaningful model for individualdifferences in cognitive stability versus flexibility. PMID:22905818
Strategic differences in spatial tasks can be explained in terms of different cognitive coordinate systems that subjects adopt. The strategy of mental rotation that occurs in many recent experiments uses a coordinate system defined by the standard axes of our visual world (i. e., horizontal, vertical, and depth axes). Several other possible coordinate systems (and hence other strategies) for solving
This study used a backward?masking paradigm to examine individualdifferences in rate of visual information processing among university basketball, ice hockey and Canadian football players. Displays containing four letters were presented for stimulus durations ranging from 25 to 300 ms. Following stimulus offset, a masking stimulus was presented for 200 ms. The subjects were instructed to write down as many
Individualdifferences in learning a motor task are rarely assessed even though they can potentially contribute to our understanding of the problem of motor redundancy-i.e., how individuals can exploit multiple different strategies to realize the task goal. This study examined individual variations in the preferred movement strategy of a redundant motor task. Thirty-two participants performed a star tracing task on a digitizing tablet with the goal of minimizing a performance score that was given as feedback. The performance score was a weighted combination of spatial error and movement time, meaning that multiple strategies could yield the same score. A cluster analysis revealed three distinct groups of individuals based on their initial movement strategy preferences. These groups were not only different on their initial performance, but also exhibited differences in both local (trial-to-trial change) and global (average change) search strategies that were reflected through differential modification of spatial and temporal components. Overall, the results in this space-time task reveal that the intrinsic dynamics of the individual channel the initial exploratory solutions to learning a redundant motor task. PMID:22914583
Background Analysis of high-frequency QRS amplitudes (HF-QRS) may provide an additional diagnostic tool in patients with heart disease, but the basic properties of these waveforms have not been sufficiently investigated. This study describes the spatial, individual, and temporal variation at rest of HF-QRS recorded with the 12 standard electrocardiographic leads in patients with ischemic heart disease.Methods and Results Two consecutive
Jonas Pettersson; Elena Carro; Lars Edenbrandt; Charles Maynard; Olle Pahlm; Michael Ringborn; Leif Sörnmo; Stafford G Warren; Galen S Wagner
The purpose of this study was to examine the relation of several individual and contextual difference factors to the perceived educational barriers of rural youth. Data were from a broader national investigation of students’ postsecondary aspirations and preparation in rural high schools across the United States. The sample involved more than 7,000 rural youth in 73 high schools across 34 states. Results indicated that some individual (e.g., African American race/ethnicity) and contextual (e.g., parent education) difference factors were predictive while others were not. Extensions to, similarities, and variations with previous research are discussed. Implications, limitations, and suggestions for future research are also discussed.
Irvin, Matthew J.; Byun, Soo-yong; Meece, Judith L.; Farmer, Thomas W.
We explored the etiology of individualdifferences in reading development from post-kindergarten to post-4th grade by analyzing data from 487 twin pairs tested in Colorado. Data from three reading measures and one spelling measure were fit to biometric latent growth curve models, allowing us to extend previous behavioral genetic studies of the etiology of early reading development at specific time points. We found primarily genetic influences on individualdifferences at post-1st grade for all measures. Genetic influences on variance in growth rates were also found, with evidence of small, nonsignificant, shared environmental influences for two measures. We discuss our results, including their implications for educational policy.
Christopher, Micaela E.; Hulslander, Jacqueline; Byrne, Brian; Samuelsson, Stefan; Keenan, Janice M.; Pennington, Bruce; DeFries, John C.; Wadsworth, Sally J.; Willcutt, Erik; Olson, Richard K.
We comment on three areas related to tinnitus. The standard of care should include counseling that is collaborative and that addresses the overall emotional well-being of the patient. Utilizing management and coping strategies is desirable. Our new tinnitus activities treatment is an example of such a protocol. We believe that the notions of fearfulness and acceptance have the potential to be integrated into tinnitus treatment. Some patients reject, control or accept their tinnitus. We believe in some instances there may be a common genetic cause of tinnitus and depression. A potential candidate is the serotonin transporter gene SLC6A4. PMID:16514258
Using a sample of individuals (277 males, 315 females) studied since birth in the NICHD Study of Early Child Care and Youth Development, the present study investigated how early pubertal maturation and school transition alter youth trajectories of social competence during the transition to adolescence. Social competence showed strong continuity, with the most socially competent children remaining so in adolescence. Early pubertal maturation and school transitions accentuate individualdifferences, increasing social competence among more competent youth, but further diminishing social competence among less competent individuals. In essence, facing challenges that require social competence may further separate competent individuals from less competent peers. Thus, the psychosocially rich become richer, while the psychosocially poor become poorer. PMID:21857776
Research on sex differences in the utilization of formal operations is equivocal, yet where such differences have been observed, males generally perform better than females. It is unclear, however, whether this sex difference reflects a difference in competence or performance. The purpose of this study was to investigate sex-role identity and learned helplessness as possible mediating factors affecting performance on formal operational tasks. Performance on 4 tasks requiring formal operations was assessed for 13-year-old males and females. Contrary to expectations, the performance of individuals with a feminine sex role did not differ significantly from that of individuals with a masculine sex role. While adolescents who were classified as both androgynous and helpless performed poorly on several of the measures, this result was not completely consistent across tasks. Possible explanations for this lack of consistency are explored. PMID:7172779
IN A SEMINAL PAPER WRITTEN FIVE DECADES AGO, CRONBACH DISCUSSED THE TWO HIGHLY DISTINCT APPROACHES TO SCIENTIFIC PSYCHOLOGY: experimental and correlational. Today, although these two approaches are fruitfully implemented and embraced across some fields of psychology, this synergy is largely absent from other areas, such as in the study of learning and behavior. Both Tolman and Hull, in a rare case of agreement, stated that the correlational approach held little promise for the understanding of behavior. Interestingly, this dismissal of the study of individualdifferences was absent in the biologically oriented branches of behavior analysis, namely, behavioral genetics and ethology. Here we propose that the distinction between "causation" and "causes of variation" (with its origins in the field of genetics) reveals the potential value of the correlational approach in understanding the full complexity of learning and behavior. Although the experimental approach can illuminate the causal variables that modulate learning, the analysis of individualdifferences can elucidate how much and in which way variables interact to support variations in learning in complex natural environments. For example, understanding that a past experience with a stimulus influences its "associability" provides little insight into how individual predispositions interact to modulate this influence on associability. In this "new" light, we discuss examples from studies of individualdifferences in animals' performance in the Morris water maze and from our own work on individualdifferences in general intelligence in mice. These studies illustrate that, opposed to what Underwood famously suggested, studies of individualdifferences can do much more to psychology than merely providing preliminary indications of cause-effect relationships. PMID:23847569
Preferences for different combinations of costs and benefits are a key source of variability in economic decision-making. However, the neurochemical basis of individualdifferences in these preferences is poorly understood. Studies in both animals and humans have demonstrated that direct manipulation of the neurotransmitter dopamine (DA) significantly impacts cost/benefit decision-making, but less is known about how naturally occurring variation in DA systems may relate to individualdifferences in economic behavior. In the present study, 25 healthy volunteers completed a dual-scan PET imaging protocol with [18F]fallypride and d-amphetamine to measure DA responsivity, and separately completed the Effort Expenditure for Rewards Task, a behavioral measure of cost/benefit decision-making in humans. We found that individualdifferences in DA function in the left striatum and ventromedial prefrontal cortex were correlated with a willingness to expend greater effort for larger rewards, particularly when probability of reward receipt was low. Additionally, variability in DA responses in the bilateral insula was negatively correlated with willingness to expend effort for rewards, consistent with evidence implicating this region in the processing of response costs. These findings highlight the role of DA signaling in striatal, prefrontal and insular regions as key neurochemical mechanisms underlying individualdifferences in cost/benefit decision-making.
Treadway, Michael T.; Buckholtz, Joshua W.; Cowan, Ronald L.; Woodward, Neil D.; Li, Rui; Ansari, M. Sib; Baldwin, Ronald M.; Schwartzman, Ashley N.; Kessler, Robert M.; Zald, David H.
Background The literature on social dilemmas and punishment focuses on the behaviour of the punisher. However, to fully explain the effect of punishment on cooperation, it is important to understand the psychological mechanisms influencing the behaviour of those who expect to be punished. This paper examines whether the expectation of punishment, rather than the implementation of punishment is sufficient to prevent individuals from free riding. Individualdifferences in the punishment sensitivity have been linked to both threat responses (flight, fight, fear system, or the FFFS) and to the response to the uncertainty of punishment (BIS-anxiety).The paper, therefore, examines if individualdifferences in BIS-anxiety and FFFS can explain some of the variability in free riding in the face of implemented and non-implemented punishment. Methods Participants took part in a series of one-shot Public Goods Games (PGGs) facing two punishment conditions (implemented and non-implemented) and two standard non-punishment PGGs. The punishment was implemented as a centralized authority punishment (i.e., if one participant contributed less than their group members, they were automatically fined). Individual contribution levels and presence/absence of zero contributions indexed free riding. Individualdifferences in behavioural inhibition were assessed. Results Individuals contributed more under the threat of punishment (both implemented and non-implemented). However, individuals contributed less when the punishment was not implemented compared to when it was. Those scoring high in BIS-anxiety contributed more when the punishment expectations were not implemented. This effect was not observed for FFFS. Conclusion Supporting previous research, punishment had a powerful effect in increasing contribution levels in the PGGs. However, when expected punishment was not implemented, individualdifferences in punishment sensitivity, specifically in BIS-anxiety, were related to fewer contributions (increased free riding) as compared to the situation when punishment was not implemented. This has implications for our understanding of why some people cannot resist the temptation to free ride, even when facing possible punishment for their actions. Our findings suggest that the diminished functioning of mechanisms, associated with trait behavioural inhibition, can partly explain such behaviours.
Percentage fat (%FM) and fat-free mass (FFM) were measured in 37 children from a sports academy and in 71 children from standard schools with dual x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) using the manufacturer's equation (Tanita) and an ethnic-specific prediction equation (Haroun). In the standard school, BIA overestimated FFM and underestimated %FM by a mean of 2.5 kg and 5.2%, respectively, using the Tanita equation. In girls from the sports academy, the Tanita equation underestimated FFM and overestimated %FM compared with DXA (mean difference BIA-DXA; FFM: -1.3 kg; %FM: 1.8%). The Haroun equation improved mean agreement between BIA and DXA in children (11 to 15 years) from the sports academy and for boys from standard schools, but reduced accuracy on individual assessments. These results have important practice implications for dietetics practitioners specializing in sports nutrition and exercise trainers. PMID:24021735
In this article, we report a study in which 109 research-active mathematicians were asked to judge the validity of a purported proof in undergraduate calculus. Significant results from our study were as follows: (a) there was substantial disagreement among mathematicians regarding whether the argument was a valid proof, (b) applied mathematicians were more likely than pure mathematicians to judge the argument valid, (c) participants who judged the argument invalid were more confident in their judgments than those who judged it valid, and (d) participants who judged the argument valid usually did not change their judgment when presented with a reason raised by other mathematicians for why the proof should be judged invalid. These findings suggest that, contrary to some claims in the literature, there is not a single standard of validity among contemporary mathematicians. PMID:23580451
Inglis, Matthew; Mejia-Ramos, Juan Pablo; Weber, Keith; Alcock, Lara
Many studies have shown that attention modulates the cortical representation of an auditory scene, emphasizing an attended source while suppressing competing sources. Yet, individualdifferences in the strength of this attentional modulation and their relationship with selective attention ability are poorly understood. Here, we ask whether differences in how strongly attention modulates cortical responses reflect differences in normal-hearing listeners' selective auditory attention ability. We asked listeners to attend to one of three competing melodies and identify its pitch contour while we measured cortical electroencephalographic responses. The three melodies were either from widely separated pitch ranges ("easy trials"), or from a narrow, overlapping pitch range ("hard trials"). The melodies started at slightly different times; listeners attended either the leading or lagging melody. Because of the timing of the onsets, the leading melody drew attention exogenously. In contrast, attending the lagging melody required listeners to direct top-down attention volitionally. We quantified how attention amplified auditory N1 response to the attended melody and found large individualdifferences in the N1 amplification, even though only correctly answered trials were used to quantify the ERP gain. Importantly, listeners with the strongest amplification of N1 response to the lagging melody in the easy trials were the best performers across other types of trials. Our results raise the possibility that individualdifferences in the strength of top-down gain control reflect inherent differences in the ability to control top-down attention. PMID:24821552
Choi, Inyong; Wang, Le; Bharadwaj, Hari; Shinn-Cunningham, Barbara
The purpose of this study was to explore changes in activation of the cortical network that serves auditory sentence comprehension in children in response to increasing demands of complex sentences. A further goal is to study how individualdifferences in children's receptive language abilities are associated with such changes in cortical responses. Fourteen children, 10-16 years old, participated in an event-related functional magnetic resonance imaging experiment using a cross modal sentence-picture verification paradigm. We manipulated sentence difficulty and length in a 2x2 factorial design. Task-related activation covered large regions of the left and right superior temporal cortex, inferior parietal lobe, precuneous, cingulate, middle frontal gyrus and precentral gyrus. Sentence difficulty, independent of length, led to increased activation in the left temporal-parietal junction and right superior temporal gyrus. Changes in activation in frontal regions positively correlated with age-standardized receptive vocabulary scores and negatively correlated with reaction time on a receptive grammar test outside the scanner. Thus, individualdifferences in language skills were associated with changes in the network in response to changing task demands. These preliminary findings in a small sample of typically developing children suggest that the investigation of individualdifferences may prove useful in elucidating the underlying neural mechanisms of language disorders in children. PMID:20053431
Yeatman, Jason D; Ben-Shachar, Michal; Glover, Gary H; Feldman, Heidi M
Recent research on children's conceptual and procedural knowledge has suggested that there are individualdifferences in the ways that children combine these two types of knowledge across a number of mathematical topics. Cluster analyses have demonstrated that some children have more conceptual knowledge, some children have more procedural…
Hallett, Darcy; Nunes, Terezinha; Bryant, Peter; Thorpe, Christina M.
Even simple perceptual decisions are influenced by the emotional content of a stimulus. Recent neuroimaging studies provide evidence about the neural mechanisms of perceptual decision making on emotional stimuli. However, the effect of individualdifferences in cognitive processing of emotions on perceptual decision making remains poorly understood. Here, we investigated how changes in the fMRI signal during perceptual decision making
Katja Mériau; Isabell Wartenburger; Philipp Kazzer; Kristin Prehn; Claas-Hinrich Lammers; Elke van der Meer; Arno Villringer; Hauke R. Heekeren
Purpose – The purpose of this paper is to paper examine goal orientation and organizational commitment in relation to employees' job attitudes and performance in a hospital. Specifically, it investigates the effects of mastery and performance goals on different facets of organizational commitment and how these effects impact individuals' job outcomes. Design\\/methodology\\/approach – The paper utilized an online survey to
Development and validation of a measure of individualdifferences in social comparison orientation (the Iowa-Netherlands Comparison Orientation Measure (INCOM)) are described. Assuming that the ten- dency toward social comparison is universal, the scale was constructed so as to be appropriate to and comparable in 2 cultures: American and Dutch. It was then administered to several thousand people in each country.
Longitudinal data provide an encouraging base for further investigation of early individualdifferences in attentiveness and possible early precursors of later attention deficits. In the study, full-term and preterm children were observed at 1, 2, and 3.5 years in free play and in more structured situations. (RH)
We extend prior research on involvement in employee development activity by including prominent individualdifference constructs that have been previously ignored in this area of research. These include two important personality characteristics (conscientiousness and openness to experience), mental ability and goal orientation constructs. We…
Maurer, Todd J.; Lippstreu, Michael; Judge, Timothy A.
The oxygen uptake and heart rate of men and boys were determined and compared using a continuous incremental bicycle ergometer test. Both groups had similar patterns for consistency, but the children had smaller individualdifference variations for both oxygen uptake and heart rate. (FG)
A program of theoretical and empirical research focusing on the ability determinants of individualdifferences in skill acquisition is reviewed. An integrative framework for information-processing and cognitive ability determinants of skills is reviewed, along with principles for ability-skill relations. Experimental manipulations were used to…
This study investigates the latent structure of individualdifferences in vocational, leisure, and family interests. The participants consisted of 302 French adults who rated their like or dislike for activities based on Holland's RIASEC typology and presented in three life domains: work, family and leisure. The multitrait-multimethod model…
This study focuses on the effects of situated learning on students' knowledge acquisition by investigating the influence of individualdifferences in such learning. Seventy-nine graduates were recruited from an educational department and were assigned to situated learning and traditional learning based on a randomized block design. Results…
Generics ("'Dogs' bark") convey important information about categories and facilitate children's learning. Two studies with parents and their 2- or 4-year-old children (N = 104 dyads) examined whether individualdifferences in generic language use are as follows: (a) stable over time, contexts, and domains, and (b) linked…
Gelman, Susan A.; Ware, Elizabeth A.; Kleinberg, Felicia; Manczak, Erika M.; Stilwell, Sarah M.
The current study examined individualdifferences in the effects of retrieval from long-term memory (i.e., the testing effect). The effects of retrieving from memory make tested information more accessible for future retrieval attempts. Despite the broad applied ramifications of such a potent memorization technique there is a paucity of research…
Working memory refers to a mental workspace, involved in controlling, regulating, and actively maintaining relevant information to accomplish complex cognitive tasks (e.g. mathematical processing). Despite the potential relevance of a relation between working memory and math for understanding developmental and individualdifferences in…
Raghubar, Kimberly P.; Barnes, Marcia A.; Hecht, Steven A.
The polysialylated neural cell adhesion molecule (PSA-NCAM) has been implicated in activity-dependent synaptic remodeling and memory formation. Here, we questioned whether training-induced modulation of PSA-NCAM expression might be related to individualdifferences in spatial learning abilities. At 12 h posttraining, immunohistochemical analyses…
Sandi, Carmen; Cordero, M. Isabel; Merino, Jose J.; Kruyt, Nyika D.; Regan, Ciaran M.; Murphy, Keith J.
This article examines the relationship between individualdifferences in speech perception and sublexical/phonological processing in reading. We used an auditory phoneme identification task in which a /ba/-/pa/ syllable continuum measured sensitivity to classify participants into three performance groups: poor, medium, and good categorizers. A…
Lopez-Zamora, Miguel; Luque, Juan L.; Alvarez, Carlos J.; Cobos, Pedro L.
Background/Context: Research is presented on teacher-centered instruction and individualdifferences among students within a sociocultural perspective specifically, within a co-regulation model. Purpose of Study: To determine the utility of a co-regulation model for understanding teacher and student adaptation to the press of cultural and social…
Investigates the antecedents of individualdifferences in cognitive/language competence for 121 24-month-olds who were also assessed at 6 and 13 months. Warm verbal interactions between mother and child at three ages were associated with child competence at 24 months. Socioeconomic status was also modestly correlated. (Author/CB)
The present study investigates the relation between spatial ability and visuo-spatial and verbal working memory in spatial text processing. In two experiments, participants listened to a spatial text (Experiments 1 and 2) and a non-spatial text (Experiment 1), at the same time performing a spatial or a verbal concurrent task, or no secondary task. To understand how individuals who differ
Chiara Meneghetti; Valérie Gyselinck; Francesca Pazzaglia; Rossana De Beni
This study examined how individualism, collectivism, and counselor emphasis of different client emotions were related to perceived counselor effectiveness. Data were collected from 192 (122 women and 70 men) Korean students attending a large university in South Korea and from 170 (115 women and 55 men) American students attending a large…
This study examined how individualdifferences in cognitive abilities account for variance in the attainment level of adult second language (L2) syntactic development. Participants completed assessments of declarative and procedural learning abilities. They subsequently learned an artificial L2 under implicit training conditions and received…
Morgan-Short, Kara; Faretta-Stutenberg, Mandy; Brill-Schuetz, Katherine A.; Carpenter, Helen; Wong, Patrick C. M.
Individualdifferences in temperament can be protective or risk factors that may enhance or interfere with children's healthy development and educational success. This study examined the concurrent and predictive relationships between temperament, school adjustment, and academic achievement in children at-risk. Seventy-seven children at-risk, ages…
Neuropathological and animal studies have implicated the hippocampus as having a possible role in autism. This study applied magnetic resonance imaging to the hippocampus of 35 autistic and 36 control subjects. Detailed MRI did not reveal differences in the volume of the hippocampus in autistic individuals. (Author/DB)
Piven, Joseph; Bailey, James; Ranson, Bonnie J.; Arndt, Stephan
Previous functional imaging studies have shown key roles of the dorsal anterior insula (dAI) and anterior midcingulate cortex (aMCC) in empathy for the suffering of others. The current study mapped structural covariance networks of these regions and assessed the relationship between networks and individualdifferences in empathic responding in 94 females. Individualdifferences in empathy were assessed through average state measures in response to a video task showing others' suffering, and through questionnaire-based trait measures of empathic concern. Overall, covariance patterns indicated that dAI and aMCC are principal hubs within prefrontal, temporolimbic, and midline structural covariance networks. Importantly, participants with high empathy state ratings showed increased covariance of dAI, but not aMCC, to prefrontal and limbic brain regions. This relationship was specific for empathy and could not be explained by individualdifferences in negative affect ratings. Regarding questionnaire-based empathic trait measures, we observed a similar, albeit weaker modulation of dAI covariance, confirming the robustness of our findings. Our analysis, thus, provides novel evidence for a specific contribution of frontolimbic structural covariance networks to individualdifferences in social emotions beyond negative affect. PMID:23535178
Bernhardt, Boris C; Klimecki, Olga M; Leiberg, Susanne; Singer, Tania
This study of normal young children in 100 two-parent Chicano households of widely varied socioeconomic levels assessed the ability of selected family sociodemographic and intellectual characteristics to predict individualdifferences in the children's performance on a measure of emergent school readiness. Data were collected longitudinally in the…
User analysis is a crucial aspect of user-centered systems design, yet Human-Computer Interaction (HCI) has yet to formulate reliable and valid characterizations of users beyond gross distinctions based on task and experience. Individualdifferences research from mainstream psychology has identified a stable set of characteristics that would appear to offer potential application in the HCI arena. Furthermore, in its evolution
The similarities and differences in dream content at the cross-cultural, gender, and individual levels provide one starting point for carrying out studies that attempt to discover correspondences between dream content and various types of waking cognition. Hobson and Kahn's (Hobson, J. A., & Kahn, D. (2007). Dream content: Individual and generic aspects. Consciousness and Cognition, 16, 850-858.) conclusion that dream content may be more generic than most researchers realize, and that individualdifferences are less salient than usually thought, provides the occasion for a review of findings based on the Hall and Van de Castle (Hall, C., & Van de Castle, R. (1966). The content analysis of dreams. New York: Appleton-Century-Crofts.) coding system for the study of dream content. Then new findings based on a computationally intensive randomization strategy are presented to show the minimum sample sizes needed to detect gender and individualdifferences in dream content. Generally speaking, sample sizes of 100-125 dream reports are needed because most dream elements appear in less than 50% of dream reports and the magnitude of the differences usually is not large. PMID:18835727
This paper reviews a program of research, conducted in collaboration with several of my colleagues, which examines individualdifferences in spatial ability from a biological\\/environmental interaction perspective. Our research strategy has been to identify the females who provide the exceptions to the male advantage in mental rotation ability. We tested a “bent twig” model, identifying a subgroup of females predicted
This paper presents a cognitive theory of multimedia learning from which predictions on individualdifferences in learning are derived and tested. Elementary students learned how to add and subtract integers with an interactive multimedia game that included visual and symbolic representations of the arithmetic procedure. They learned either with…
The basal ganglia support learning to exploit decisions that have yielded positive outcomes in the past. In contrast, limited evidence implicates the prefrontal cortex in the process of making strategic exploratory decisions when the magnitude of potential outcomes is unknown. Here we examine neurogenetic contributions to individualdifferences in these distinct aspects of motivated human behavior, using a temporal decision-making
Bradley B Doll; Jen Oas-Terpstra; Francisco Moreno; Michael J Frank
In this article, I describe studies conducted over 25 years with secondary and post-secondary L2 learners in the United States. The evidence from these studies shows that there are important connections between students' early L1 skills and their L2 aptitude and L2 proficiency and that individualdifferences in students' L1 skills in elementary…
The present study examined the effects of individualdifferences in working memory capacity (WMC) on learning from an historical inquiry multimedia tutorial in stationary versus mobile learning environments using a portable digital media player (i.e., iPod). Students with low (n = 44) and high (n = 40) working memory capacity, as measured by the…
In honor of Dr. Katherine Butler's extraordinary leadership of "Topics in Language Disorders," this article takes up her 1982 challenge to reach toward greater understanding of individualdifferences in the use of oral and written language by children with language learning disability. The article focuses on 3 interconnected dimensions of learning…
Administered Raven's Advanced Progressive Matrices to 22 adults and measured cerebral glucose activity as subjects viewed videos on 2 occasions. Data provide evidence that individualdifferences in intelligence correlate with brain function even when the brain is engaged in non-reasoning tasks. (SLD)
Haier, Richard J.; White, Nathan S.; Alkire, Michael T.
In the wake of the information explosion and rapidly progressing technology [Mayer, R. E. (2001). "Multimedia learning". Cambridge: University Press] formulated a theory that focused on human cognition, rather than technology capacity and features. By measuring the effect of cognitive individualdifferences and display design manipulations on…
An experiment was performed in primiparous dairy cows (n = 23) to examine consistency of individualdifferences in reactivity to milking, and correlations between measures of behavior, physiology, and milk ejection. Responsiveness to milking was monitored during the first machine milking, on d 2 of lactation, and during milkings on d 4 and 130 of lactation. Measurements included kicking and
Reenen van C. G; Werf van der J. T. N; R. M. Bruckmaier; H. Hopster; B. Engel; J. P. T. M. Noordhuizen; H. J. Blokhuis
Empirical work and models of visual word recognition have traditionally focused on group-level performance. Despite the emphasis on the prototypical reader, there is clear evidence that variation in reading skill modulates word recognition performance. In the present study, we examined differences among individuals who contributed to the English…
Yap, Melvin J.; Balota, David A.; Sibley, Daragh E.; Ratcliff, Roger
We evaluated the statistical power of single-indicator latent growth curve models to detect individualdifferences in change (variances of latent slopes) as a function of sample size, number of longitudinal measurement occasions, and growth curve reliability. We recommend the 2 degree-of-freedom generalized test assessing loss of fit when both…
Hertzog, Christopher; von Oertzen, Timo; Ghisletta, Paolo; Lindenberger, Ulman
This study documented how individualdifferences in personal experiences, cultures, learning styles, and interests affect the demonstrated abilities of children who are gifted, based on qualitative case study research with five children from early childhood classes at the University of Denver's Ricks Center for Gifted Children. Information was…
Using a theoretical framework of social support, and content analysis, the content and pattern of support in messages posted in a 4-week period on a commercial health network for individuals concerned with heart disease were observed and described. Special consideration was given to identifying gender differences.
Although the co-occurrence of negative affect and pain is well recognized, the mechanism underlying their association is unclear. To examine whether a common self-regulatory ability impacts the experience of both emotion and pain, we integrated neuroimaging, behavioral, and physiological measures obtained from three assessments separated by substantial temporal intervals. Our results demonstrated that individualdifferences in emotion regulation ability, as
Regina C. Lapate; Hyejeen Lee; Tim V. Salomons; Carien M. van Reekum; Lawrence L. Greischar; Richard J. Davidson
Although the co-occurrence of negative affect and pain is well recognized, the mechanism underlying their association is unclear. To examine whether a common self-regulatory ability impacts the experience of both emotion and pain, we integrated neuroimaging, behavioral, and physiological measures obtained from three assessments separated by substantial temporal intervals. Our results demonstrated that individualdifferences in emotion regulation ability, as
Regina C. Lapate; Hyejeen Lee; Tim V. Salomons; Carien M. van Reekum; Lawrence L. Greischar; Richard J. Davidson
Understanding how candidates cope with the demands of PhD candidature is important for institutions, supervisors and candidates. Individualdifferences in affective and metacognitive disposition were explored in 263 PhD candidates from two Australian universities. Several questionnaires relating to affective and metacognitive beliefs were…
Cantwell, Robert H.; Scevak, Jill J.; Bourke, Sid; Holbrook, Allyson
Two experiments investigated the relationship between masked form priming and individualdifferences in reading and spelling proficiency among university students. Experiment 1 assessed neighbor priming for 4-letter word targets from high- and low-density neighborhoods in 97 university students. The overall results replicated previous evidence of…
This research examined whether variations in salivary measures of the hypothalamic-pituitary-adrenal axis (cortisol) and autonomic nervous system (alpha amylase [sAA]) contribute to individualdifferences in the association between peer victimization and aggression. Children (N = 132; M age = 9.46 years, SD = 0.33) completed a measure of peer…
Rudolph, Karen D.; Troop-Gordon, Wendy; Granger, Douglas A.
We investigated whether individualdifferences in inhibitory control relate to bilingual spoken word recognition. While their eye movements were monitored, native English and native French English-French bilinguals listened to English words (e.g., "field") and looked at pictures corresponding to the target, a within-language competitor…
The purpose of this study was to examine the relation of several individual and contextual difference factors to the perceived educational barriers of rural youth. Data were from a broader national investigation of students' postsecondary aspirations and preparation in rural high schools across the United States. The sample involved more than…
Irvin, Matthew J.; Byun, Soo-yong; Meece, Judith L.; Farmer, Thomas W.; Hutchins, Bryan C.
Research in multimedia learning lacks an emphasis on individualdifference variables, such as working memory capacity (WMC). The effects of WMC and the segmentation of multimedia instruction were examined by assessing the recall and application of low (n = 66) and high (n = 67) working memory capacity students randomly assigned to either a…
Lusk, Danielle L.; Evans, Amber D.; Jeffrey, Thomas R.; Palmer, Keith R.; Wikstrom, Chris S.; Doolittle, Peter E.
The present study investigates the relationship between individualdifferences and flexible work arrangement use. Three need-based motivational factors (need for affiliation at work, need for segmentation of work from other life roles, need for occupational achievement) were examined in relation to extent of flextime and flexplace use.…
Sender demeanor is an individualdifference in the believability of message senders that is conceptually independent of actual honesty. Recent research suggests that sender demeanor may be the most influential source of variation in deception detection judgments. Sender demeanor was varied in five experiments (N = 30, 113, 182, 30, and 35) to…
Levine, Timothy R.; Serota, Kim B.; Shulman, Hillary; Clare, David D.; Park, Hee Sun; Shaw, Allison S.; Shim, Jae Chul; Lee, Jung Hyon
C. F. Bond and B. M. DePaulo reported a quantitative synthesis of individualdifferences in judging deception. Here, the authors respond to a pair of commentaries on this synthesis: a statistical critique by T. D. Pigott and M. J. Wu and a narrative reaction by M. O'Sullivan. In response to suggestions made by Pigott and Wu, the authors conduct…
This paper reports on a study which highlighted goal orientation as an approachable individualdifference (ID) variable which may further our understanding of foreign/second language learning experience. The study sought to (i) gauge the extent of goal orientation in foreign language learners' profile and (ii) examine how goal orientation affects…
Using cross-sectional (N=910) and longitudinal (N = 261) data from Gullone and King's (1993,1997) studies of normal fear in children and adolescents aged 7 to 18 years, the normative developmental pattern of social evaluation fear and the continuity of individualdifferences were investigated. Participants' responses were analysed according to two…
Westenberg, P. Michiel; Gullone, Eleonora; Bokhorst, Caroline L.; Heyne, David A.; King, Neville J.
While language learners and teachers have long known that individualdifferences (IDs) among students result in differential learning, we still do not know how traditional ID variables interact or the specific impact each one has on language learning. The present study proposes that instead of looking at isolated variables, researchers should…
A selective review of literature related to individualdifferences and instructional strategies is presented. The major purpose is to give the reader a flavor of the kind of thought that is currently prevalent and the type of research that is being conducted in selected areas. No attempt is made to provide either a comprehensive or a balanced…
Many learners of a foreign language (L2) struggle to correctly pronounce newly learned speech sounds, yet many others achieve this with apparent ease. Here we explored how a training study of learning complex consonant clusters at the very onset of L2 acquisition can inform us about L2 learning in general and individualdifferences in particular.…
Reading in another language (L2) is a complex, multidimensional process dependent upon both reader-based and text-based factors. The purpose of this study was to investigate the roles of reader-based individualdifference variables and of the text-based variable of genre in reading comprehension in French. The sample included 153 adult learners…
Theoretical models emphasize the importance of person and environmental variables in stress and coping processes. This article examines individualdifferences (extraversion and neuroticism), environmental factors (social support and work demand), and situational characteristics (type of stressful episode and its perceived importance) as predictors of three self-report measures of coping (general coping, direct coping, and suppression) derived from the Ways of
This research conceptualizes and develops a scale to measure individualdifferences in the centrality of visual product aesthetics (CVPA), defined as the level of significance that visual aesthetics hold for a particular consumer in his\\/her relationship with products. Three related dimensions of product aesthetics centrality emerged from the research: value, acumen, and response intensity. A series of eight studies provided
Self-regulation, or the ability to control one's actions and responses, is essential for healthy development across varied contexts. Self-regulation comes in several forms, including emotional, behavioral, and cognitive. The present study sought to examine whether individualdifferences in one form of self-regulation was related to children's…
The goal of this study was to explain individualdifferences in both native and non-native listening comprehension; 121 native and 113 non-native speakers of Dutch were tested on various linguistic and nonlinguistic cognitive skills thought to underlie listening comprehension. Structural equation modeling was used to identify the predictors of…
Andringa, Sible; Olsthoorn, Nomi; van Beuningen, Catherine; Schoonen, Rob; Hulstijn, Jan
There is substantial variance in the age at which children construct and deploy their first explicit theory of biology. This study tests the hypothesis that this variance is due, at least in part, to individualdifferences in their executive function (EF) abilities. A group of 79 boys and girls aged 5-7 years (with a mean age of 6½ years) were…
Rooted in the neurodiversity approach, this study provides an overview of the strengths and interests of individuals with Asperger's Syndrome. We interviewed136 individuals with Asperger's Syndrome and 155 neurotypical individuals via an online survey with regards to (a) demography, (b) occupational strengths, (c) general self-efficacy, (d) occupational self-efficacy, and (e) the job interest profile according to Holland. The vocational and educational fields of the individuals with Asperger's in the sample are more diverse than and surpass those classical fields stated in research and biographical literature. The comparison of both groups in cross-tables showed that the indicated strengths differ in several areas (?Cramer?=?.02–.47), which means that a specific strength profile can be derived, and this profile goes beyond the clinical view of the diagnostic criteria. Individuals with Asperger's indicate lower self-efficacy, both general and occupational. Furthermore, a high concentration of individuals with Asperger's can be found in the areas I (Investigative) and C (Conventional) of Holland's RIASEC model.
Human performance on diverse tests of intellect are impacted by a "general" regulatory factor that accounts for up to 50% of the variance between individuals on intelligence tests. Neurobiological determinants of general cognitive abilities are essentially unknown, owing in part to the paucity of animal research wherein neurobiological analyses are possible. We report a methodology with which we have assessed individualdifferences in the general learning abilities of laboratory mice. Abilities of mice on tests of associative fear conditioning, operant avoidance, path integration, discrimination, and spatial navigation were assessed. Tasks were designed so that each made unique sensory, motor, motivational, and information processing demands on the animals. A sample of 56 genetically diverse outbred mice (CD-1) was used to assess individuals' acquisition on each task. Indicative of a common source of variance, positive correlations were found between individuals' performance on all tasks. When tested on multiple test batteries, the overall performance ranks of individuals were found to be highly reliable and were "normally" distributed. Factor analysis of learning performance variables determined that a single factor accounted for 38% of the total variance across animals. Animals' levels of native activity and body weights accounted for little of the variability in learning, although animals' propensity for exploration loaded strongly (and was positively correlated) with learning abilities. These results indicate that diverse learning abilities of laboratory mice are influenced by a common source of variance and, moreover, that the general learning abilities of individual mice can be specified relative to a sample of peers. PMID:12878682
Matzel, Louis D; Han, Yu Ray; Grossman, Henya; Karnik, Meghana S; Patel, Dave; Scott, Nicholas; Specht, Steven M; Gandhi, Chetan C
Rooted in the neurodiversity approach, this study provides an overview of the strengths and interests of individuals with Asperger's Syndrome. We interviewed136 individuals with Asperger's Syndrome and 155 neurotypical individuals via an online survey with regards to (a) demography, (b) occupational strengths, (c) general self-efficacy, (d) occupational self-efficacy, and (e) the job interest profile according to Holland. The vocational and educational fields of the individuals with Asperger's in the sample are more diverse than and surpass those classical fields stated in research and biographical literature. The comparison of both groups in cross-tables showed that the indicated strengths differ in several areas (?Cramer?=?.02-.47), which means that a specific strength profile can be derived, and this profile goes beyond the clinical view of the diagnostic criteria. Individuals with Asperger's indicate lower self-efficacy, both general and occupational. Furthermore, a high concentration of individuals with Asperger's can be found in the areas I (Investigative) and C (Conventional) of Holland's RIASEC model. PMID:24950060
We studied the temporal stability of individualdifferences in the acquisition and generalization of fear. Seventy-one participants were tested in two almost identical fear-acquisition and fear-generalization sessions (separated by 8 months). Acquisition and generalization were measured by the fear-potentiated startle, the skin conductance response, and online expectancies of the unconditioned stimulus. To control for the effects of previous experience, different stimuli were used for half of the participants in Session 2. Acquisition and generalization did not differ across sessions or as a function of the stimuli used in Session 2, and a significant proportion of individualdifferences in these processes was stable over time (generalizability coefficients ranged from 0.17 to 0.38). When the same stimuli were used, acquisition measures showed compromised stability. The results are discussed in terms of their theoretical and applied implications. PMID:24673651
The present study investigates the relationship between individualdifferences, indicated by personality (FFM) and general mental ability (GMA), and job performance applying two different methods of correction for range restriction. The results, derived by analyzing meta-analytic correlations, show that the more accurate method of correcting for indirect range restriction increased the operational validity of individualdifferences in predicting job performance and that this increase primarily was due to general mental ability being a stronger predictor than any of the personality traits. The estimates for single traits can be applied in practice to maximize prediction of job performance. Further, differences in the relative importance of general mental ability in relation to overall personality assessment methods was substantive and the estimates provided enables practitioners to perform a correct utility analysis of their overall selection procedure. PMID:22612634
Sjöberg, Sofia; Sjöberg, Anders; Näswall, Katharina; Sverke, Magnus
One of the primary objectives of early visual processing is the detection of luminance variations, often termed image contrast. Normal observers can differ in this ability by at least a factor of 4, yet this variation is typically overlooked, and has never been convincingly explained. This study uses two techniques to investigate the main source of individual variations in contrast sensitivity. First, a noise masking experiment assessed whether differences were due to the observer’s internal noise, or the efficiency with which they extracted information from the stimulus. Second, contrast discrimination functions from 18 previous studies were compared (pairwise, within studies) using a computational model to determine whether differences were due to internal noise or the low level gain properties of contrast transduction. Taken together, the evidence points to differences in contrast gain as being responsible for the majority of individual variation across the normal population. This result is compared with related findings in attention and amblyopia.
Background\\/Objectives:Given the importance of nutrition therapy in diabetes management, we hypothesized that food intake differs between individuals with and without diabetes. We investigated this hypothesis in two large prospective studies including different countries and ethnic groups.Subjects\\/Methods:Study populations were the European Prospective Investigation into Cancer and Nutrition Study (EPIC) and the Multiethnic Cohort Study (MEC). Dietary intake was assessed by food
U Nöthlings; H Boeing; G Maskarinec; D Sluik; B Teucher; R Kaaks; A Tjønneland; J Halkjaer; C Dethlefsen; K Overvad; P Amiano; E Toledo; B Bendinelli; S Grioni; R Tumino; C Sacerdote; A Mattiello; J W J Beulens; J A Iestra; A M W Spijkerman; D L van der A; P Nilsson; E Sonestedt; O Rolandsson; P W Franks; A-C Vergnaud; D Romaguera; T Norat; L N Kolonel
The relationship among gender identity, sex typing, and adjustment has attracted the attention of social and developmental psychologists for many years. However, they have explored this issue with different assumptions and different approaches. Generally the approaches differ regarding whether sex typing is considered adaptive versus maladaptive, measured as an individual or normative difference, and whether gender identity is regarded as a unidimensional or multidimensional construct. In this chapter, we consider both perspectives and suggest that the developmental timing and degree of sex typing, as well as the multidimensionality of gender identity, be considered when examining their relationship to adjustment.
Lurye, Leah E.; Zosuls, Kristina M.; Ruble, Diane N.
Inhibition of return (IOR) represents a well-known mechanism of human perception that biases attentional orienting to novel locations in the environment. Behaviorally, IOR reflects slower reaction time (RT) to stimuli presented in previously cued locations. In this study, we examined within patients with schizophrenia this inhibitory aftereffect using two different cue types—eye gaze and standard peripheral cues. Results indicated that
Paul G. Nestor; Kristy Klein; Marc Pomplun; Margaret Niznikiewicz; Robert W. McCarley
Patients with calcaneus fractures experience considerable interferences with daily living activities. The quality of anatomical reconstruction is important because of its influence on functional outcome. The aim of this study was to develop an automatic algorithm based on computer tomographic (CT) images to quantify the integrity of calcaneal joint surfaces. Validation of this algorithm was done by assessing intra-individual variations of characteristic joint parameters. Bilateral hind foot CT data of 12 subjects were manually segmented, and 3D models from the calcaneus, talus and cuboid were generated. These models were implemented in a custom-made software to analyse the area, 3D orientations and bone distance of the joint surfaces of the calcaneus. Three joints were detected, and the calculated parameters were compared between right and left hind foot by the evaluation of the directional asymmetry (%DA). The results were statistically analysed with a paired t-test. The median of area (5-7 %DA) of the joint surfaces and the distance between two articulating surfaces (8-9 %DA) showed the greatest intra-individualdifferences. Median differences in 3D orientation were comparatively low (1-2 %DA). None of these differences was statistically significant. Inter-individual variations among subjects were several magnitudes larger than intra-individualdifferences. The presented computational tool provides 3D joint-specific parameters of the calcaneus, which enable to describe their respective joint integrity. The results show that only small intra-individualdifferences within the anatomy exist. Surgical treatment should take place with the aid of CT data from the contralateral side. Thus, a good restoration of the anatomy may be reached. The computational tool assesses the quality of reduction, and may be helpful to evaluate the outcome and quality of operative treatment based on the calculated joint-specific parameters of joint reconstructions in the hind foot. PMID:23406018
Stephan, Daniel; Panzer, Stephanie; Göttlinger, Michael; Augat, Peter
A central challenge for neuroscience lies in relating inter-individual variability to the functional properties of specific brain regions. Yet, considerable variability exists in the connectivity patterns between different brain areas, potentially producing reliable group differences. Using sex differences as a motivating example, we examined two separate resting-state datasets comprising a total of 188 human participants. Both datasets were decomposed into resting-state networks (RSNs) using a probabilistic spatial independent component analysis (ICA). We estimated voxel-wise functional connectivity with these networks using a dual-regression analysis, which characterizes the participant-level spatiotemporal dynamics of each network while controlling for (via multiple regression) the influence of other networks and sources of variability. We found that males and females exhibit distinct patterns of connectivity with multiple RSNs, including both visual and auditory networks and the right frontal-parietal network. These results replicated across both datasets and were not explained by differences in head motion, data quality, brain volume, cortisol levels, or testosterone levels. Importantly, we also demonstrate that dual-regression functional connectivity is better at detecting inter-individual variability than traditional seed-based functional connectivity approaches. Our findings characterize robust-yet frequently ignored-neural differences between males and females, pointing to the necessity of controlling for sex in neuroscience studies of individualdifferences. Moreover, our results highlight the importance of employing network-based models to study variability in functional connectivity. PMID:24662574
Smith, David V; Utevsky, Amanda V; Bland, Amy R; Clement, Nathan; Clithero, John A; Harsch, Anne E W; McKell Carter, R; Huettel, Scott A
Effects of physiological and/or psychological inter-individualdifferences on the resting brain state have not been fully established. The present study investigated the effects of individualdifferences in basal autonomic tone and positive and negative personality dimensions on resting brain activity. Whole-brain resting cerebral perfusion images were acquired from 32 healthy subjects (16 males) using arterial spin labeling perfusion MRI. Neuroticism and extraversion were assessed with the Eysenck Personality Questionnaire-Revised. Resting autonomic activity was assessed using a validated measure of baseline cardiac vagal tone (CVT) in each individual. Potential associations between the perfusion data and individual CVT (27 subjects) and personality score (28 subjects) were tested at the level of voxel clusters by fitting a multiple regression model at each intracerebral voxel. Greater baseline perfusion in the dorsal anterior cingulate cortex (ACC) and cerebellum was associated with lower CVT. At a corrected significance threshold of p < 0.01, strong positive correlations were observed between extraversion and resting brain perfusion in the right caudate, brain stem, and cingulate gyrus. Significant negative correlations between neuroticism and regional cerebral perfusion were identified in the left amygdala, bilateral insula, ACC, and orbitofrontal cortex. These results suggest that individual autonomic tone and psychological variability influence resting brain activity in brain regions, previously shown to be associated with autonomic arousal (dorsal ACC) and personality traits (amygdala, caudate, etc.) during active task processing. The resting brain state may therefore need to be taken into account when interpreting the neurobiology of individualdifferences in structural and functional brain activity. PMID:23771644
Kano, M; Coen, S J; Farmer, A D; Aziz, Q; Williams, S C R; Alsop, D C; Fukudo, S; O'Gorman, R L
Background Acupuncture is an effective yet complex therapy, integrating syndrome differentiation, selection of appropriate acupoints and skillful needling techniques. Clinicians carefully tailor acupuncture treatment to each patient. However, most clinical trials of acupuncture have been based on a standardized formula of points for every patient without properly accounting for individualdifferences and, as a result, have not been reflective of the true efficacy of clinical practice. To determine the efficacy of meridian-based syndrome differentiation and Sa-am acupuncture, we have designed a simple pragmatic trial providing individualized treatments while working within a general framework. Methods/Design The study is designed to be a parallel, patient- and assessor-blind, randomized controlled trial (RCT). A total of250 patients with knee osteoarthritis (OA) will be recruited from two independent hospitals, Semyung University Oriental Medicine Hospital in Chung-ju and Dongguk University Oriental Hospital in Ilsan, South Korea. Patients will be randomly allocated into four treatment groups: 1. individualized, meridian-based syndrome differentiation and Sa-am acupuncture treatment;2. standard acupuncture treatment;3. sham acupuncture treatment; and 4. no acupuncture treatment. Patients in groups 1 to 3 will be treated by certified oriental medicine doctors twice a week for 6?weeks. The primary outcome measure will be the self-reported total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score change. The trial will also include secondary outcome measures. Discussion This trial is designed to determine the efficacy of individualized acupuncture treatment in patients with knee OA by comparing the differences between individualized, standard, sham and no acupuncture treatments. The results of this trial may validate the efficacy of individualized acupuncture therapy, encouraging its widespread use. Trial registration ClinicalTrials.gov: NCT01569230
Individualdifferences in perception are ubiquitous within the chemical senses: taste, smell, and chemical somesthesis . A hypothesis of this fact states that polymorphisms in human sensory receptor genes could alter perception by coding for functionally distinct receptor types . We have previously reported evidence that sequence variants in a presumptive bitter receptor gene (hTAS2R38) correlate with differences in bitterness recognition of phenylthiocarbamide (PTC) . Here, we map individual psychogenomic pathways for bitter taste by testing people with a variety of psychophysical tasks and linking their individual perceptions of the compounds PTC and propylthiouracil (PROP) to the in vitro responses of their TAS2R38 receptor variants. Functional expression studies demonstrate that five different haplotypes from the hTAS2R38 gene code for operatively distinct receptors. The responses of the three haplotypes we also tested in vivo correlate strongly with individuals' psychophysical bitter sensitivities to a family of compounds. These data provide a direct molecular link between heritable variability in bitter taste perception to functional variations of a single G protein coupled receptor that responds to compounds such as PTC and PROP that contain the N-C=S moiety. The molecular mechanisms of perceived bitterness variability have therapeutic implications, such as helping patients to consume beneficial bitter-tasting compounds-for example, pharmaceuticals and selected phytochemicals. PMID:15723792
Bufe, Bernd; Breslin, Paul A S; Kuhn, Christina; Reed, Danielle R; Tharp, Christopher D; Slack, Jay P; Kim, Un-Kyung; Drayna, Dennis; Meyerhof, Wolfgang
Background Participants who are instructed to use reappraisal to downregulate negative emotion show decreased amygdala responses and increased prefrontal responses. However, it is not known whether individualdifferences in the tendency to use reappraisal manifests in similar neural responses when individuals are spontaneously confronted with negative situations. Such spontaneous emotion regulation might play an important role in normal and pathological responses to the emotional challenges of everyday life. Methods Fifty-six healthy women completed a blood oxygenation-level dependent functional magnetic resonance imaging challenge paradigm involving the perceptual processing of emotionally negative facial expressions. Participants also completed measures of typical emotion regulation use, trait anxiety, and neuroticism. Results Greater use of reappraisal in everyday life was related to decreased amygdala activity and increased prefrontal and parietal activity during the processing of negative emotional facial expressions. These associations were not attributable to variation in trait anxiety, neuroticism, or the use of another common form of emotion regulation, namely suppression. Conclusions These findings suggest that, like instructed reappraisal, individualdifferences in reappraisal use are associated with decreased activation in ventral emotion generative regions and increased activation in prefrontal control regions in response to negative stimuli. Such individualdifferences in emotion regulation might predict successful coping with emotional challenges as well as the onset of affective disorders.
Drabant, Emily M.; McRae, Kateri; Manuck, Stephen B.; Hariri, Ahmad R.; Gross, James J.
Inter-individualdifferences and behavioral stability assessed with the Brazelton scale were examined in twenty 3-8-day-old full-term newborns at a German newborn nursery. The extent of variability measurable with Brazelton scores was determined by the relative mean information value "Hrel" in each variable, which indicates the discriminating power of each scale. The value "Hrel" was high in irritability, consolability, cuddliness and alertness. Inter-individualdifferences, illustrated by individual mean scores, were lowest in orientating behaviors. Differences in alertness correlated with several other reaction patterns. No significant correlations were found between the NBAS variables and neonatal sex, birth weight, birth duration, and maternal age. However, the relative weight gain between day 1 and day 8 was correlated with alertness, orientation to face and to rattle, irritability, rapidity of build-up and state lability. Individual behavioral stability over time was generally low in most variables. The low degree of behavioral stability and the low relative mean information in several variables reduce the applicability of the scale for the originally suggested purposes. PMID:7472233
Neuroscience suggests that the anterior cingulate cortex (ACC) is responsible for conflict monitoring and the detection of errors in cognitive tasks, thereby contributing to the implementation of attentional control. Though individualdifferences in frontally mediated goal maintenance have clearly been shown to influence outward behavior in interference-rich contexts, it is unclear whether corresponding differences exist in neural responses that arise out of the ACC. To investigate this possibility, we conducted an electrophysiological study using a variant of the Simon Task, recording event-related potentials (ERPs) in healthy normal individuals with varying working memory capacity (high vs. low spans; a behavioral proxy for variability in goal maintenance). Primary analyses focused on the magnitude of the error-related negativity (ERN), a response-locked ERP component associated with the commission of errors thought to arise because of action monitoring in the ACC. Our results revealed that frontally mediated working memory capacity may alter error monitoring by the ACC, with high spans showing a greater ERN than low spans. These individualdifferences were also observed in the posterror positivity, a response-locked ERP component associated with updating cognitive strategies, suggesting greater awareness of errors with increased working memory capacity. These results are interpreted within 2-process models of attentional control, suggesting individuals with greater working memory capacity may better maintain task goals by more strongly biasing neural activity in frontal-executive networks. PMID:22250911
Human multisensory systems are known to bind inputs from the different sensory modalities into a unified percept, a process that leads to measurable behavioral benefits. This integrative process can be observed through multisensory illusions, including the McGurk effect and the sound-induced flash illusion, both of which demonstrate the ability of one sensory modality to modulate perception in a second modality. Such multisensory integration is highly dependent upon the temporal relationship of the different sensory inputs, with perceptual binding occurring within a limited range of asynchronies known as the temporal binding window (TBW). Previous studies have shown that this window is highly variable across individuals, but it is unclear how these variations in the TBW relate to an individual's ability to integrate multisensory cues. Here we provide evidence linking individualdifferences in multisensory temporal processes to differences in the individual's audiovisual integration of illusory stimuli. Our data provide strong evidence that the temporal processing of multiple sensory signals and the merging of multiple signals into a single, unified perception, are highly related. Specifically, the width of right side of an individuals' TBW, where the auditory stimulus follows the visual, is significantly correlated with the strength of illusory percepts, as indexed via both an increase in the strength of binding synchronous sensory signals and in an improvement in correctly dissociating asynchronous signals. These findings are discussed in terms of their possible neurobiological basis, relevance to the development of sensory integration, and possible importance for clinical conditions in which there is growing evidence that multisensory integration is compromised. PMID:22390292
Stevenson, Ryan A; Zemtsov, Raquel K; Wallace, Mark T
What is the function of disgust? Whereas traditional models have suggested that disgust serves to protect the self or neutralize reminders of our animal nature, an evolutionary perspective suggests that disgust functions to solve 3 qualitatively different adaptive problems related to pathogen avoidance, mate choice, and social interaction. The authors investigated this 3-domain model of disgust across 4 studies and examined how sensitivity to these functional domains relates to individualdifferences in other psychological constructs. Consistent with their predictions, factor analyses demonstrated that disgust sensitivity partitions into domains related to pathogens, sexuality, and morality. Further, sensitivity to the 3 domains showed predictable differentiation based on sex, perceived vulnerability to disease, psychopathic tendencies, and Big 5 personality traits. In exploring these 3 domains of disgust, the authors introduce a new measure of disgust sensitivity. Appreciation of the functional heterogeneity of disgust has important implications for research on individualdifferences in disgust sensitivity, emotion, clinical impairments, and neuroscience. PMID:19586243
Tybur, Joshua M; Lieberman, Debra; Griskevicius, Vladas
Recent investigations into the neural basis of elite sporting performance have focused on whether cortical activity might characterize individualdifferences in ability. However, very little is understood about how changes in brain structure might contribute to individualdifferences in expert motor control. We compared the behavior and brain structure of healthy controls with a group of karate black belts, an expert group who are able to perform rapid, complex movements that require years of training. Using 3D motion tracking, we investigated whether the ability to control ballistic arm movements was associated with differences in white matter microstructure. We found that karate experts are better able than novices to coordinate the timing of inter-segmental joint velocities. Diffusion tensor imaging revealed significant differences between the groups in the microstructure of white matter in the superior cerebellar peduncles (SCPs) and primary motor cortex—brain regions that are critical to the voluntary control of movement. Motor coordination, the amount of experience, and the age at which training began were all associated with individualdifferences in white matter integrity in the cerebellum within the karate groups. These findings suggest a role for the white matter pathways of the SCPs in motor expertise.
Much decision-making requires balancing benefits to the self with benefits to the group. There are marked individualdifferences in this balance such that individualists tend to favor themselves whereas prosocials tend to favor the group. Understanding the mechanisms underlying this difference has important implications for society and its institutions. Using behavioral and fMRI data collected during the performance of the ultimatum game, we show that individualdifferences in social preferences for resource allocation, so-called "social value orientation," is linked with activity in the nucleus accumbens and amygdala elicited by inequity, rather than activity in insula, ACC, and dorsolateral pFC. Importantly, the presence of cognitive load made prosocials behave more prosocially and individualists more individualistically, suggesting that social value orientation is driven more by intuition than reflection. In parallel, activity in the nucleus accumbens and amygdala, in response to inequity, tracked this behavioral pattern of prosocials and individualists. In addition, we conducted an impunity game experiment with different participants where they could not punish unfair behavior and found that the inequity-correlated activity seen in prosocials during the ultimatum game disappeared. This result suggests that the accumbens and amygdala activity of prosocials encodes "outcome-oriented emotion" designed to change situations (i.e., achieve equity or punish). Together, our results suggest a pivotal contribution of the nucleus accumbens and amygdala to individualdifferences in sociality. PMID:24564471
Haruno, Masahiko; Kimura, Minoru; Frith, Christopher D
Ultra-long AlN nanowire arrays are prepared by chemical vapor deposition, and the photoconductive performances of individual nanowires are investigated in our self-built measurement system. Individual ultra-long AlN nanowire (UAN) exhibits a clear photoconductive effect under different excited lights. We attribute the positive photocurrent response of individual UAN to the dominant molecular sensitization effect. It is found that they have a much faster response speed (a rise and decay time of about 1 ms), higher photocurrent response (2.7×106), and more reproductive working performance (the photocurrent fluctuation is lower than 2%) in the air environment. Their better photoconductive performances are comparable to many nanostructures, which are suggested to be a candidate for building promising photosensitive nanodevices in the future.
This study reports the effectiveness of a year-long, small-group, tertiary (Tier 3) intervention that examined 2 empirically derived but conceptually different treatments and a comparison condition. The researchers had randomly assigned all students to treatment or comparison conditions. The participants were seventh- and eighth-grade students…
Between-individual variation of salivary progesterone (P4) and cortisol levels does not always closely reflect blood hormone concentrations. This may be partly a function of individualdifferences in salivary hormone excretion. We tested whether time of day at sampling and ethnicity contributed to individual variation in salivary hormones after adjusting for blood hormone levels. Forty-three Caucasian and 15 Japanese women (18–34 years) collected four sets of matched dried blood spot (DBS) and saliva specimens across a menstrual cycle (N = 232 specimen sets). Linear fixed-effects (LFE) models were used to estimate the effects of diurnal variation and ethnicity on salivary P4 and cortisol while adjusting for DBS levels. For each hormone, women with exclusively positive or negative residuals (unexplained variance) from the LFE models were categorized as high- or low-saliva-to-DBS hormone ratio (SDR; high or low salivary secretors), respectively. We found that salivary P4 (P < 0.05) was significantly higher in early morning compared to the afternoon, after controlling for DBS levels, ethnicity, and BMI. After further adjusting for this diurnal effect, significant individual variation in salivary P4 and cortisol remained: sixteen and nine women, respectively were categorized as low or high salivary secretors for both hormones (P < 0.001), suggesting systematic individual-specific variation of salivary hormonal concentration. We conclude that when saliva is used to quantify P4 or cortisol levels, time of day at sampling should be controlled. Even with this adjustment, salivary P4 and cortisol do not closely mirror between-individual variation of serum P4 and cortisol in a substantial proportion of individuals.
Konishi, Shoko; Brindle, Eleanor; Guyton, Amanda; O'Connor, Kathleen A.
We have proposed that the current amplitude in electroconvulsive therapy (ECT) be lowered to produce stimulation closer to the neural activation threshold and individualized to account for anatomical variability across patients. A novel approach to individualize the ECT current amplitude could be via motor threshold (MT) determination with transcranial electric stimulation (TES) applied through the ECT electrodes instead of the fixed high current approach. This study derives an estimate of the electric field (E-field) neural activation threshold and tests whether individualdifferences in TES MT are explained by anatomical variability measurements and simulations in individual head models. The E-field distribution induced by a right unilateral (RUL) ECT electrode configuration was computed in subject-specific finite element head models of four nonhuman primates (NHPs) for whom MT was measured. By combining the measured MTs and the computed E-field maps, the neural activation threshold is estimated to be 0.45 ± 0.07 V/cm for 0.2 ms stimulus pulse width. The individual MT was correlated with the electrode-to-cortex distance under the superior electrode (R(2)=.96, p=.022) as well as with the simulated electrode-current/induced-E-field ratio (R(2)=.95, p=.026), indicating that both anatomical measurements and computational models could predict the individual current requirements for transcranial stimulation. These findings could be used with realistic human head models and in clinical studies to explore novel ECT dosing paradigms, and as a new noninvasive means to determine individual dosage requirement with ECT. PMID:24109812
Lee, Won Hee; Lisanby, Sarah H; Laine, Andrew F; Peterchev, Angel V
Many studies on working memory have assumed that one can determine an individual's fixed memory capacity. In the current study, we took an individualdifferences approach to investigate whether visual working memory (VWM) capacity was stable irrespective of the number of to-be-remembered objects and participant age. Younger and older adults performed a change detection task using several objects defined by color. Results showed wide variability in VWM capacity across memory set sizes, age, and individuals. A marked decrease in the number of objects held in VWM was observed in both younger and older adults with low memory capacity, but not among high-capacity individuals, when set size went well beyond the limits of VWM capacity. In addition, a decrease in the number of objects held in VWM was alleviated among low-capacity younger adults by increasing VWM encoding time; however, increasing encoding time did not benefit low-capacity older adults. These findings suggest that low-capacity individuals are likely to show decreases in VWM capacity induced by overload, and aging exacerbates this deficit such that it cannot be recovered by simply increasing encoding time. Overall, our findings challenge the prevailing assumption that VWM capacity is fixed and stable, encouraging a revision to the strict view that VWM capacity is constrained by a fixed number of distinct “slots” in which high-resolution object representations are stored.
This study examined the relationships between body image importance (BII) and perfectionism and body satisfaction in a Canadian sample of undergraduate students. Specifically, perfectionism was conceptualized as a common cause of BII and body satisfaction. Furthermore, gender-schematic processing was examined as a moderator of sex differences in BII, which have been inconsistently found. As hypothesized, there was no significant partial correlation between BII and body satisfaction, controlling for perfectionism. Also, a significant Sex?×?Gender Schematicity interaction indicated that gender schematicity moderates sex differences in BII. Implications for understanding individualdifferences in, and elevated levels of BII are discussed. PMID:23421695
Much attention has been focused recently on the detection and physical characterization of individual molecules. Using such methods to study the chemical properties, such as reactivity, of single molecules offers the potential to investigate how these might vary from molecule to molecule, and for individual molecules as a function of time. The complex structures of biomolecules such as enzymes make them particularly attractive targets for studying how subtle changes or differences at the molecular level might influence chemical reactivity. We have shown previously that very small (zeptomole) amounts of enzymes can be studied using a fluorescence microassay; single enzyme molecules have also been detected in oil-dispersed droplets by fluorescence microscopy. Here we report the observation of reactions of individual molecules of lactate dehydrogenase (LDH-1), which produces NADH from lactate and nicotinamide adenine dinucleotide (NAD+). When they are present at very low concentrations in a narrow capillary, each enzyme molecule produces a discrete zone of NADH; these can be manipulated electrophoretically and monitored by fluorescence spectroscopy. We find that the activity of individual electrophoretically pure enzyme molecules can vary by up to a factor of four, and that these activities remain unchanged over a two-hour period. We suggest that the origin of the activity differences may lie in the presence of several stable forms of the enzyme. PMID:7854448
Purpose Stigmatizing attitudes toward people with disabilities can jeopardize such individuals' well-being and recovery through denial of employment and community isolation. By shaping social norms that define group membership, the construct of individualism may partially explain differences in stigmatizing attitudes across cultures. Further, widespread globalization has brought intensely individualistic social practices to certain segments of non-Western cultures. This paper examines whether the construct of individualism can help to explain cross-cultural differences in stigmatizing attitudes observed between American and Chinese employers. Design Employers (N = 879) from Beijing, Hong Kong, and Chicago provided information on their attitudes toward hiring people with disabilities, and Path Analyses were conducted to examine potential mediating relationships. Results Path analyses indicated that vertical individualism, along with perceived responsibility for acquiring a condition, partially mediated the relationship between culture and employers' negative attitudes about job candidates with disabilities. Conclusion These results suggested that greater espousal of competitive and individualist values may drive stigmatizing attitudes across cultures.
Rao, Deepa; Horton, Randall A.; Tsang, Hector W.H.; Shi, Kan; Corrigan, Patrick W.
Recent research investigating decisions from experience suggests that not all information is treated equally in the decision process, with more recently encountered information having a greater impact. We report 2 studies investigating how this differential treatment of sequentially encountered information affects subjective valuations of risky prospects when observations of past outcomes must be used to estimate the prospect's payoff distribution, and examine how individualdifferences in cognitive capacities influence information usage. In Study 1 we found that a sliding window of information model that averages a subset of (only) the most recently encountered outcomes (samples) fit the subjective valuation data for a portion of individuals better than models that integrate all observed outcomes. This pattern of results is replicated in Study 2, in which we also found that the amount of information used to form valuations varies greatly between individuals, and that individualdifference in memory span explains a portion of this variation. Combined, these results suggest a process in which information usage is in part reliant on cognitive capacity, and where information aggregation appears to be memory based rather than online, providing new insight into the processes involved in the construction of valuation in experiential decisions. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24707783
Males often produce elaborate displays that increase their attractiveness to females, and some species extend their displays to include structures or objects that are not part of their body. Such “extended phenotypes” may communicate information that cannot be transmitted by bodily signals or may provide a more reliable signal than bodily signals. However, it is unclear whether these signals are individually distinct and whether they are consistent over long periods of time. Male bowerbirds construct and decorate bowers that function in mate choice. Bower display courts constructed by male great bowerbirds (Ptilonorhynchus nuchalis) induce a visual illusion known as forced perspective for the female viewing the male’s display over the court, and the quality of illusion is associated with mating success. We improved the quality of the forced perspective to determine whether males maintained it at the new higher level, decreased the perspective quality back to its original value, or allowed it to decay at random over time. We found that the original perspective quality was actively recovered to individual original values within 3 d. We measured forced perspective over the course of one breeding season and compared the forced perspective of individual males between two successive breeding seasons. We found that differences in the quality of visual illusion among males were consistent within and between two breeding seasons. This suggests that forced perspective is actively and strongly maintained at a different level by each individual male.
The interaction of drugs with biologic targets is a critical area of research, particularly for the development of medications to treat substance use disorders. In addition to understanding these drug-target interactions, however, there is a need to understand more fully the psychosocial influences that moderate these interactions. The first section of this review introduces some examples from human behavioral pharmacology that illustrate the clinical importance of this research. The second section covers preclinical evidence to characterize some of the key individualdifferences that alter drug sensitivity and abuse vulnerability, related primarily to differences in response to novelty and impulsivity. Evidence is presented to indicate that critical neuropharmacological mechanisms associated with these individualdifferences involve integrated neurocircuits underlying stress, reward, and behavioral inhibitory processes. The third section covers social influences on drug abuse vulnerability, including effects experienced during infancy, adolescence, and young adulthood, such as maternal separation, housing conditions, and social interactions (defeat, play, and social rank). Some of the same neurocircuits involved in individualdifferences also are altered by social influences, although the precise neurochemical and cellular mechanisms involved remain to be elucidated fully. Finally, some speculation is offered about the implications of this research for the prevention and treatment of substance abuse.
The mechanisms by which attentional control biases mnemonic representations have attracted much interest but remain poorly understood. As attention and memory develop gradually over childhood and variably across individuals, assessing how participants of different ages and ability attend to mnemonic contents can elucidate their interplay. In Experiment 1, 7-year-olds, 10-year-olds, and adults were asked to report whether a probe item had been part of a previously presented four-item array. The initial array could either be uncued, be preceded ("precued"), or followed ("retrocued") by a spatial cue orienting attention to one of the potential item locations. Performance across groups was significantly improved by both cue types, and individualdifferences in children's retrospective attentional control predicted their visual short-term and working memory span, whereas their basic ability to remember in the absence of cues did not. Experiment 2 imposed a variable delay between the array and the subsequent orienting cue. Cueing benefits were greater in adults than in 10-year-olds, but they persisted even when cues followed the array by nearly 3 seconds, suggesting that orienting operated on durable short-term representations for both age groups. The findings indicate that there are substantial developmental and individualdifferences in the ability to control attention to memory and that in turn these differences constrain visual short-term memory capacity. PMID:20680889
The administration of amphetamine to rats results in a relatively wide range of individualdifferences in responsiveness, both in the initial behavioral patterns as well as in the augmentation response to repeated administration. Therefore we examined the possibility that such differences might reflect intrinsic variation in neurochemical mechanisms regulating responsiveness to amphetamine. Animals were administered a transitional dose (1.75 mg/kg) of amphetamine with regard to the induction of locomotion and continuous stereotypy. On the basis of individual response profiles animals could be separated into two markedly different subgroups, one displaying continuous locomotion (S1), characteristic of lower amphetamine doses, and the other exhibiting a multiphasic pattern, including a prolonged focused stereotypy phase (S2), typically associated with higher amphetamine doses. Examination of regional brain monoamine and metabolite levels revealed distinguishing patterns between the subgroups only in the mesolimbic and mesocortical dopamine systems. With repeated amphetamine administration, the two prominent factors of the augmentation, the emergence of stereotypy and the enhancement of locomotion during the last half of the response, were dissociable between the subgroups. The emergence of stereotypy was confined to S1 animals, whereas only the S2 subgroup displayed the progressive increase in locomotion. Differences in the responsiveness of neurochemical systems to amphetamine rather than pharmacokinetic factors appear to underly the distinct behavioral profiles associated with the two subgroups. The results indicate that characterization of individual responses may be required to determine accurately the neurochemical mechanisms involved in the behavioral effects of amphetamine. PMID:3656119
Several neuropsychological hypotheses have been formulated to explain the transition to addiction, including hedonic allostasis, incentive salience, and the development of habits. A key feature of addiction that remains to be explored is the important individual variability observed in the propensity to self-administer drugs, the sensitivity to drug-associated cues, the severity of the withdrawal state, and the ability to quit. In this review, we suggest that the concept of self-regulation, combined with the concept of modularity of cognitive function, may aid in the understanding of the neural basis of individualdifferences in the vulnerability to drugs and the transition to addiction. The thesis of this review is that drug addiction involves a failure of the different subcomponents of the executive systems controlling key cognitive modules that process reward, pain, stress, emotion, habits, and decision-making. A subhypothesis is that the different patterns of drug addiction and individualdifferences in the transition to addiction may emerge from differential vulnerability in one or more of the subcomponents.
Recent research on children's conceptual and procedural knowledge has suggested that there are individualdifferences in the ways that children combine these two types of knowledge across a number of mathematical topics. Cluster analyses have demonstrated that some children have more conceptual knowledge, some children have more procedural knowledge, and some children have an equal level of both. The current study investigated whether similar individualdifferences exist in children's understanding of fractions and searches for explanations for these differences. Grade 6 students (n=119) and Grade 8 students (n=114) were given measures of conceptual and procedural knowledge of fractions as well as measures of general fraction knowledge, general conceptual ability, and general procedural ability. Grade 6 children demonstrated a four-cluster solution reflecting those who do poorly on procedural and conceptual fraction knowledge, those who do well on both, those whose strength is procedural knowledge, and those whose strength is conceptual knowledge. Grade 8 children demonstrated a two-cluster solution reflecting those whose strength is procedural knowledge and those whose strength is conceptual knowledge. Cluster in either grade, however, did not vary in distribution across schools and was not related to general conceptual ability or general procedural ability. Overall, these results provide a more detailed picture of individualdifferences in conceptual and procedural knowledge in mathematical cognition. PMID:22995445
Hallett, Darcy; Nunes, Terezinha; Bryant, Peter; Thorpe, Christina M
In the aftermath of a traumatic event, many people suffer from psychological distress, but only a minority develops posttraumatic stress disorder (PTSD). Pre-trauma individualdifferences in fear conditioning, most notably reduced extinction learning, have been proposed as playing an important role in the etiology of PTSD. However, prospective data are lacking. In this study, we prospectively tested whether reduced extinction was a predictor for later posttraumatic stress. Dutch soldiers (N = 249) were administered a conditioning task before their four-month deployment to Afghanistan to asses individualdifferences in extinction learning. After returning home, posttraumatic stress was measured. Results showed that reduced extinction learning before deployment predicted subsequent PTSD symptom severity, over and beyond degree of pre-deployment stress symptoms, neuroticism, and exposure to stressors on deployment. The findings suggest that reduced extinction learning may play a role in the development of PTSD. PMID:23261706
Lommen, Miriam J J; Engelhard, Iris M; Sijbrandij, Marit; van den Hout, Marcel A; Hermans, Dirk
The current study examined some key developmental and individualdifferences in how elementary school-aged children evaluate sources of information. A sample of 130 children ages 6 to 9years participated in a task designed to measure children's understanding of ways that claims can be distorted (i.e., biased decisions, skewed self-reports, and misleading persuasive claims). Children also completed several individualdifference measures, including a brief intelligence task and an advanced social cognition measure (interpretive theory of mind). Overall, older children were less trusting and better than younger children at explaining the reasons to doubt sources that might provide distorted claims. Crucially, the results also suggest that beyond age, both general intelligence and advanced social cognitive skills play roles in children's ability to understand when and why they must doubt sources of distortion. PMID:24727295
The present study investigates the relationship between inter-individualdifferences in fearful face recognition and amygdala volume. Thirty normal adults were recruited and each completed two identical facial expression recognition tests offline and two magnetic resonance imaging (MRI) scans. Linear regression indicated that the left amygdala volume negatively correlated with the accuracy of recognizing fearful facial expressions and positively correlated with the probability of misrecognizing fear as surprise. Further exploratory analyses revealed that this relationship did not exist for any other subcortical or cortical regions. Nor did such a relationship exist between the left amygdala volume and performance recognizing the other five facial expressions. These mind-brain associations highlight the importance of the amygdala in recognizing fearful faces and provide insights regarding inter-individualdifferences in sensitivity toward fear-relevant stimuli.
The present study investigates the relationship between inter-individualdifferences in fearful face recognition and amygdala volume. Thirty normal adults were recruited and each completed two identical facial expression recognition tests offline and two magnetic resonance imaging (MRI) scans. Linear regression indicated that the left amygdala volume negatively correlated with the accuracy of recognizing fearful facial expressions and positively correlated with the probability of misrecognizing fear as surprise. Further exploratory analyses revealed that this relationship did not exist for any other subcortical or cortical regions. Nor did such a relationship exist between the left amygdala volume and performance recognizing the other five facial expressions. These mind-brain associations highlight the importance of the amygdala in recognizing fearful faces and provide insights regarding inter-individualdifferences in sensitivity toward fear-relevant stimuli. PMID:24009767
Feature extraction for mental fatigue and relaxation states is helpful to understand the mechanisms of mental fatigue and search effective relaxation technique in sustained work environments. Experiment data of human states are often affected by external and internal factors, which increase the difficulties to extract common features. The aim of this study is to explore appropriate methods to eliminate individualdifference and enhance common features. Mental fatigue and relaxation experiments are executed on 12 subjects. An integrated and evaluation system is proposed, which consists of subjective evaluation (visual analogue scale), calculation performance and neurophysiological signals especially EEG signals. With consideration of individualdifference, the common features of multi-estimators testify the effectiveness of relaxation in sustained mental work. Relaxation technique can be practically applied to prevent accumulation of mental fatigue and keep mental health. The proposed feature extraction methods are widely applicable to obtain common features and release the restriction for subjection selection and experiment design.
Anthropomorphism is a far-reaching phenomenon that incorporates ideas from social psychology, cognitive psychology, developmental psychology, and the neurosciences. Although commonly considered to be a relatively universal phenomenon with only limited importance in modern industrialized societies—more cute than critical—our research suggests precisely the opposite. In particular, we provide a measure of stable individualdifferences in anthropomorphism that predicts three important consequences for everyday life. This research demonstrates that individualdifferences in anthropomorphism predict the degree of moral care and concern afforded to an agent, the amount of responsibility and trust placed on an agent, and the extent to which an agent serves as a source of social influence on the self. These consequences have implications for disciplines outside of psychology including human–computer interaction, business (marketing and finance), and law. Concluding discussion addresses how understanding anthropomorphism not only informs the burgeoning study of nonpersons, but how it informs classic issues underlying person perception as well.
Elucidating the neural basis of joint attention in infancy promises to yield important insights into the development of language and social cognition, and directly informs developmental models of autism. We describe a new method for evaluating responding to joint attention performance in infancy that highlights the 9 to 10 month period as a time interval of maximal individualdifferences. We then demonstrate that fractional anisotropy in the right uncinate fasciculus, a white matter fiber bundle connecting the amygdala to the ventral-medial prefrontal cortex and anterior temporal pole, measured in 6 month-olds predicts individualdifferences in responding to joint attention at 9 months of age. The white matter microstructure of the right uncinate was not related to receptive language ability at 9 months. These findings suggest that the development of core nonverbal social communication skills in infancy is largely supported by preceding developments within right lateralized frontotemporal brain systems.
Elison, Jed T.; Wolff, Jason J.; Heimer, Debra C.; Paterson, Sarah J.; Gu, Hongbin; Hazlett, Heather C.; Styner, Martin; Gerig, Guido; Piven, Joseph
The relations between classroom experience and individualdifferences in motivation and self-regulated learning were examined in a correlational study of seventh graders (N = 100, mean age = 12.3 years) from a middle school in the Midwest. Motivational beliefs (intrinsic value, self-efficacy, and test anxiety) and self-regulated learning (cognitive strategy use and self-regulation) were assessed in the fall and spring
Paul R. Pintrich; Robert W. Roeser; Elisabeth A. M. de Groot
When the side effect of an action involves moral considerations (e.g. when a chairman’s pursuit of profits harms the environment) it tends to influence theory-of-mind judgments. On average, bad side effects are judged intentional whereas good side effects are judged unintentional. In a series of two experiments, we examined the largely uninvestigated roles of individualdifferences in this judgment asymmetry.
In order to determine differences in absorption of polycyclic aromatic hydrocarbons (PAH) between anatomical sites and individuals, coal?tar ointment was applied to skin of volunteers at various sites. The surface disappearance of PAH and the excretion of urinary 1?OH?pyrene after skin application of coal?tar ointment were used as parameters for dermal PAH absorption. The surface disappearance was determined by the
J. G. M. VanRooij; J. H. C. De Roos; F. J. Jongeneelen
This study investigated the roles of the executive functions of inhibition and switching, and of verbal and visuo-spatial working memory capacities, in insight and non-insight tasks. A total of 18 insight tasks, 10 non-insight tasks, and measures of individualdifferences in working memory capacities, switching, and inhibition were administered to 120 participants. Performance on insight problems was not linked with
BackgroundDifferent immunotherapy approaches for the treatment of cancer and autoimmune diseases are being developed and tested in clinical studies worldwide. Their resulting complex experimental data should be properly evaluated, therefore reliable normal healthy control baseline values are indispensable.Methodology\\/Principal FindingsTo assess intra- and inter-individual variability of various biomarkers, peripheral blood of 16 age and gender equilibrated healthy volunteers was sampled on
Kristina Gruden; Matjaž Hren; Ana Herman; Andrej Blejec; Tanja Albrecht; Joachim Selbig; Chris Bauer; Johannes Schuchardt; Michal Or-Guil; Klemen Zupan?i?; Urban Švajger; Borut Štabuc; Alojz Ihan; Andreja Nataša Kopitar; Maja Ravnikar; Miomir Kneževi?; Primož Rožman; Matjaž Jeras
\\u000a Individualdifferences in cognition are important for both theories of cognition and for theories of differential psychology.\\u000a Furthermore, this topic is important for the unification and future development of psychology that runs the risk of fragmenting\\u000a into a disparate number of loosely connected disciplines with no central theoretical core. The aim of this chapter is to provide\\u000a an overview of
The authors examined the validity of an Implicit Association Test (Greenwald, McGhee, & Schwartz, 1998) for assessing individualdifferences in achievement tendencies. Eighty-eight students completed an IAT and explicit self-ratings of achievement orientation, and were then administered a mental concentration test that they performed either in the presence or in the absence of achievement-related feedback. Implicit and explicit measures of
In three experiments, the dominance of global versus local visual properties was investigated in 4-month-old infants as a function of individualdifferences in fixation duration (i.e., “long-” versus “short-looking” infants). Dominance was assessed through paired-comparison discrimination tasks in which global and local visual properties were placed in competition with one another for infants' attention. Familiarization time was varied parametrically across
This study examined how individualdifferences in personality style influenced children's receptivity to HIV primary prevention. Prior to taking part in a HIV prevention program, 123 fifth graders from an ethnically diverse inner city school district were administered the Weinberger Adjustment Inventory (WAI) and scales measuring HIV-related beliefs, attitudes, and knowledge. The HIV scales were readministered at the conclusion of the program. WAI groups (formed by contrasting dimensions of restraint and distress) were found to differ significantly on measures of knowledge about HIV, HIV-related fears, safe behavior attitudes, and risk behavior at pre-test. The intervention's impact, as reflected in scale change scores, did not show significant differences among WAI groups. Although subtle differences were evident among groups, findings suggest that HIV primary prevention programs may be equally effective among children with differing degrees of self-restraint and distress. PMID:24254753
Large individualdifferences exist in the ability to delay gratification for the sake of satisfying longer-term goals. These individualdifferences are commonly assayed by studying intertemporal preferences, as revealed by choices between immediate and delayed rewards. In the brain, reward-based and goal-oriented decisions are believed to rely on the striatum and its interactions with other cortical and subcortical networks. However, it remains unknown which specific cortical-striatal tracts are involved in intertemporal decision making. We use connectivity analyses in both structural and functional MRI to further our understanding of the relationship between distinct corticostriatal networks and intertemporal preferences in humans. Our results revealed distinct striatal pathways that are differentially related to delay discounting. Structural and functional connectivity between striatum and lateral prefrontal cortex was associated with increased patience, whereas connectivity between subcortical areas and striatum was associated with increased impulsivity. These findings provide novel insights into how the anatomy and functioning of striatal circuits mediate individualdifferences in intertemporal choice. PMID:25080591
van den Bos, Wouter; Rodriguez, Christian A; Schweitzer, Julie B; McClure, Samuel M
Mathematical skills are of critical importance, both academically and in everyday life. Neuroimaging research has primarily focused on the relationship between mathematical skills and functional brain activity. Comparatively few studies have examined which white matter regions support mathematical abilities. The current study uses diffusion tensor imaging (DTI) to test whether individualdifferences in white matter predict performance on the math subtest of the Preliminary Scholastic Aptitude Test (PSAT). Grades 10 and 11 PSAT scores were obtained from 30 young adults (ages 17-18) with wide-ranging math achievement levels. Tract based spatial statistics was used to examine the correlation between PSAT math scores, fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD). FA in left parietal white matter was positively correlated with math PSAT scores (specifically in the left superior longitudinal fasciculus, left superior corona radiata, and left corticospinal tract) after controlling for chronological age and same grade PSAT critical reading scores. Furthermore, RD, but not AD, was correlated with PSAT math scores in these white matter microstructures. The negative correlation with RD further suggests that participants with higher PSAT math scores have greater white matter integrity in this region. Individualdifferences in FA and RD may reflect variability in experience dependent plasticity over the course of learning and development. These results are the first to demonstrate that individualdifferences in white matter are associated with mathematical abilities on a nationally administered scholastic aptitude measure. PMID:23108272
Matejko, Anna A; Price, Gavin R; Mazzocco, Michèle M M; Ansari, Daniel
The aim of this study was to evaluate the performance, as well as neuromuscular activity, in a strength task in subjects with different training backgrounds. Participants (n = 26) were divided into three groups according to their training backgrounds (aerobic, strength or mixed) and submitted to three sessions: (1) determination of the maximum oxygen uptake during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half squat; (2) 1RM determination; and (3) strength exercise, four sets at 80% of the 1RM, in which the maximum number of repetitions (MNR), the total weight lifted (TWL), the root mean square (RMS) and median frequency (MF) of the electromyographic (EMG) activity for the second and last repetition were computed. There was an effect of group for MNR, with the aerobic group performing a higher MNR compared to the strength group (P = 0.045), and an effect on MF with a higher value in the second repetition than in the last repetition (P = 0.016). These results demonstrated that individuals with better aerobic fitness were more fatigue resistant than strength trained individuals. The absence of differences in EMG signals indicates that individuals with different training backgrounds have a similar pattern of motor unit recruitment during a resistance exercise performed until failure, and that the greater capacity to perform the MNR probably can be explained by peripheral adaptations.
Azevedo, Neto R.M.; Julio, U.F.; Andreato, L.V.; Pinto e Silva, C.M.; Hardt, F.; Franchini, E.
Post-traumatic stress disorder (PTSD) is characterized by deficits in cognitive functioning, particularly cognitive control. Moreover, these deficits are thought to play a critical role in the etiology and maintenance of core PTSD symptoms such as intrusive thoughts and memories. However, the psychophysiological concomitants of cognitive control remain largely unexamined. In this article, we suggest that individualdifferences in heart rate variability (HRV), a physiological index of self-regulatory capacity, may underlie the association between cognitive control ability and intrusive cognitions in PTSD. We review evidence showing that individualdifferences in HRV at rest are related to prefrontal cortical activity and performance on a broad range of cognitive control tasks. We highlight the importance of inhibition as a mechanism by which HRV promotes successful cognitive control. In addition, we summarize recent research linking individualdifferences in HRV to performance on laboratory tasks that assess the ability to control unwanted memories and intrusive thoughts. We conclude by suggesting that future studies should examine the role of low HRV as a risk factor for developing PTSD.
Individual variability in emotion processing may be associated with genetic variation as well as with psychological predispositions such as dispositional affect styles. Our previous fMRI study demonstrated that amygdala reactivity was independently predicted by affective-cognitive styles (phobic prone or eating disorders prone) and genotype of the serotonin transporter in a discrimination task of fearful facial expressions. Since the insula is associated with the subjective evaluation of bodily states and is involved in human feelings, we explored whether its activity could also vary in function of individualdifferences. In the present fMRI study, the association between dispositional affects and insula reactivity has been examined in two groups of healthy participants categorized according to affective-cognitive styles (phobic prone or eating disorders prone). Images of the faces of partners and strangers, in both painful and neutral situations, were used as visual stimuli. Interaction analyses indicate significantly different activations in the two groups in reaction to a loved one's pain: the phobic prone group exhibited greater activation in the left posterior insula. These results demonstrate that affective-cognitive style is associated with insula activity in pain empathy processing, suggesting a greater involvement of the insula in feelings for a certain cohort of people. In the mapping of individualdifferences, these results shed new light on variability in neural networks of emotion.
Background Foraging in groups offers animals a number of advantages, such as increasing their likelihood of finding food or detecting and avoiding predators. In order for a group to remain together, there has to be some degree of coordination of behaviour and movement between its members (which may in some cases be initiated by a decision-making leader, and in other cases may emerge as an underlying property of the group). For example, behavioural synchronisation is a phenomenon where animals within a group initiate and then continue to conduct identical behaviours, and has been characterised for a wide range of species. We examine how a pair of animals should behave using a state-dependent approach, and ask what conditions are likely to lead to behavioural synchronisation occurring, and whether one of the individuals is more likely to act as a leader. Results The model we describe considers how the energetic gain, metabolic requirements and predation risks faced by the individuals affect measures of their energetic state and behaviour (such as the degree of behavioural synchronisation seen within the pair, and the value to an individual of knowing the energetic state of its colleague). We explore how predictable changes in these measures are in response to changes in physiological requirements and predation risk. We also consider how these measures should change when the members of the pair are not identical in their metabolic requirements or their susceptibility to predation. We find that many of the changes seen in these measures are complex, especially when asymmetries exist between the members of the pair. Conclusion Analyses are presented that demonstrate that, although these general patterns are robust, care needs to be taken when considering the effects of individualdifferences, as the relationship between individualdifferences and the resulting qualitative changes in behaviour may be complex. We discuss how these results are related to experimental observations, and how the model and its predictions could be extended.
Background/Objectives Given the importance of nutrition therapy in diabetes management, we hypothesized that food intake differs between individuals with and without diabetes. We investigated this hypothesis in two large prospective studies including different countries and ethnic groups. Methods Study populations were the EPIC (European Prospective Investigation into Cancer and Nutrition)-Study and the Multiethnic Cohort Study (MEC). Dietary intake was assessed via food frequency questionnaires, and calibrated using 24h-recall information for the EPIC-Study. Only confirmed self-reports of diabetes at cohort entry were included: 6192 diabetes patients in EPIC and 13 776 in the MEC. For the cross-sectional comparison of food intake and lifestyle variables at baseline, individuals with and without diabetes were matched 1:1 on sex, age in five year categories, BMI in 2.5 kg/m2 categories, and country. Results Higher intake of softdrinks (by 13 and 44% in the EPIC and MEC), and lower consumption of sweets, juice, wine, and beer (>10% difference) were observed in participants with diabetes compared to those without. Consumption of vegetables, fish and meat was slightly higher in individuals with diabetes in both studies, but the differences were less than 10%. Findings were more consistent across different ethnic groups than countries, but generally showed largely similar patterns. Conclusions Although diabetes patients are expected to undergo nutritional education, we found only small differences in dietary behavior in comparison to cohort members without diabetes. These findings suggest that emphasis on education is needed to improve the current behaviors in order to assist in the prevention of complications.
Individualdifferences in cognitive style can be characterized along two dimensions: ‘systemizing’ (S, the drive to analyze or build ‘rule-based’ systems) and ‘empathizing’ (E, the drive to identify another's mental state and respond to this with an appropriate emotion). Discrepancies between these two dimensions in one direction (S > E) or the other (E > S) are associated with sex differences in cognition: on average more males show an S > E cognitive style, while on average more females show an E > S profile. The neurobiological basis of these different profiles remains unknown. Since individuals may be typical or atypical for their sex, it is important to move away from the study of sex differences and towards the study of differences in cognitive style. Using structural magnetic resonance imaging we examined how neuroanatomy varies as a function of the discrepancy between E and S in 88 adult males from the general population. Selecting just males allows us to study discrepant E-S profiles in a pure way, unconfounded by other factors related to sex and gender. An increasing S > E profile was associated with increased gray matter volume in cingulate and dorsal medial prefrontal areas which have been implicated in processes related to cognitive control, monitoring, error detection, and probabilistic inference. An increasing E > S profile was associated with larger hypothalamic and ventral basal ganglia regions which have been implicated in neuroendocrine control, motivation and reward. These results suggest an underlying neuroanatomical basis linked to the discrepancy between these two important dimensions of individualdifferences in cognitive style.
Lai, Meng-Chuan; Lombardo, Michael V.; Chakrabarti, Bhismadev; Ecker, Christine; Sadek, Susan A.; Wheelwright, Sally J.; Murphy, Declan G.M.; Suckling, John; Bullmore, Edward T.; Baron-Cohen, Simon
Typically, approach behaviour is displayed in the context of moving towards a desired goal, while avoidance behaviour is displayed in the context of moving away from threatening or novel stimuli. In the current research, we detected three sub-populations of C57BL/6J mice that spontaneously responded with avoiding, balancing or approaching behaviours in the presence of the same conflicting stimuli. While the balancing animals reacted with balanced responses between approach and avoidance, the avoiding or approaching animals exhibited inhibitory or advance responses towards one of the conflicting inputs, respectively. Individualdifferences in approach and avoidance motivation might be modulated by the normal variance in the level of functioning of different systems, such as endocannabinoid system (ECS). The present research was aimed at analysing the ECS involvement on approach and avoidance behavioural processes. To this aim, in the three selected sub-populations of mice that exhibited avoiding or balancing or approaching responses in an approach/avoidance Y-maze we analysed density and functionality of CB1 receptors as well as enzyme fatty acid amide hydrolase activity in different brain regions, including the networks functionally responsible for emotional and motivational control. The main finding of the present study demonstrates that in both approaching and avoiding animals higher CB1 receptor density in the amygdaloidal centro-medial nuclei and in the hypothalamic ventro-medial nucleus was found when compared with the CB1 receptor density exhibited by the balancing animals. The characterization of the individualdifferences to respond in a motivationally based manner is relevant to clarify how the individualdifferences in ECS activity are associated with differences in motivational and affective functioning.
Rodriguez-Gaztelumendi, Antonio; Ferlazzo, Fabio; Petrosini, Laura; Fowler, Christopher J.
The error likelihood effect in anterior cingulate cortex (ACC) has recently been shown to be a special case of an even more general risk prediction effect, which signals both the likelihood of an error and the potential severity of its consequences. Surprisingly, these error likelihood and anticipated consequence effects are strikingly absent in risk-taking individuals. Conversely, conflict effects in ACC were found to be stronger in these same individuals. Here we show that the error likelihood computational model can account for individualdifferences in error likelihood, predicted error consequence, and conflict effects in ACC with no changes from the published version of the model. In particular, the model accounts for the counter-intuitive inverse relationship between conflict and error likelihood effects as a function of the ACC learning rate in response to errors. As the learning rate increases, ACC learns more effectively from mistakes, which increases risk prediction effects at the expense of conflict effects. Thus, the model predicts that individuals with faster error-based learning in ACC will be more risk averse and show greater ACC error likelihood effects but smaller ACC conflict effects. Furthermore, the model suggests that apparent response conflict effects in ACC may actually consist of two related effects: increased error likelihood and a greater number of simultaneously cued responses, whether or not the responses are mutually incompatible. The results clarify the basic computational mechanisms of learned risk aversion and may have broad implications for predicting and managing risky behavior in healthy and clinical populations.
The consistency with which people interpret relationship-based information has important implications for attachment theory and research. Our objective is to determine whether there are attachment-related individualdifferences in the manner and the consistency with which individuals interpret hypothetical relationship behaviors. In two studies (N?=?629, 79% female, 63% American, Mage ?=?29; N?=?820, 78% female, 65% American, Mage ?=?29), we assessed participants' ability and consistency in relationship behavior interpretation across two blocks and estimated how they would have performed had they interpreted information perfectly consistently. Secure participants were generally more consistent in their interpretations relative to insecure participants. Estimates of perfectly consistent interpretation revealed that improvements to both systematic factors related to behavior interpretation (e.g., working models) and consistency would have led to a more secure interpretation style for participants of all attachment styles. Results imply that both secure and insecure individuals process relationship-based information according to secure scripts, but insecure individuals do so inconsistently. Our results imply that, due to the inconsistent behavioral responses that may occur as a result of inconsistent information processing, the consistency with which people process relationship-related information will be related to relationship satisfaction. Further directions for future research are discussed. PMID:23750636
Marks, Michael J; Trafimow, David; Rice, Stephen C
Research on audiovisual speech integration has reported high levels of individual variability, especially among young infants. In the present study we tested the hypothesis that this variability results from individualdifferences in the maturation of audiovisual speech processing during infancy. A developmental shift in selective attention to audiovisual speech has been demonstrated between 6 and 9 months with an increase in the time spent looking to articulating mouths as compared to eyes (Lewkowicz & Hansen-Tift. (2012) Proc. Natl Acad. Sci. USA, 109, 1431-1436; Tomalski et al. (2012) Eur. J. Dev. Psychol., 1-14). In the present study we tested whether these changes in behavioural maturational level are associated with differences in brain responses to audiovisual speech across this age range. We measured high-density event-related potentials (ERPs) in response to videos of audiovisually matching and mismatched syllables /ba/ and /ga/, and subsequently examined visual scanning of the same stimuli with eye-tracking. There were no clear age-specific changes in ERPs, but the amplitude of audiovisual mismatch response (AVMMR) to the combination of visual /ba/ and auditory /ga/ was strongly negatively associated with looking time to the mouth in the same condition. These results have significant implications for our understanding of individualdifferences in neural signatures of audiovisual speech processing in infants, suggesting that they are not strictly related to chronological age but instead associated with the maturation of looking behaviour, and develop at individual rates in the second half of the first year of life. PMID:23889202
Kushnerenko, Elena; Tomalski, Przemyslaw; Ballieux, Haiko; Ribeiro, Helena; Potton, Anita; Axelsson, Emma L; Murphy, Elizabeth; Moore, Derek G
This paper focuses on the study of self-citations at the meso and micro (individual) levels, on the basis of an analysis of the production (1994-2004) of individual researchers working at the Spanish CSIC in the areas of Biology and Biomedicine and Material Sciences. Two different types of self-citations are described: author self-citations (citations received from the author him/herself) and co-author self-citations (citations received from the researchers' co-authors but without his/her participation). Self-citations do not play a decisive role in the high citation scores of documents either at the individual or at the meso level, which are mainly due to external citations. At micro-level, the percentage of self-citations does not change by professional rank or age, but differences in the relative weight of author and co-author self-citations have been found. The percentage of co-author self-citations tends to decrease with age and professional rank while the percentage of author self-citations shows the opposite trend. Suppressing author self-citations from citation counts to prevent overblown self-citation practices may result in a higher reduction of citation numbers of old scientists and, particularly, of those in the highest categories. Author and co-author self-citations provide valuable information on the scientific communication process, but external citations are the most relevant for evaluative purposes. As a final recommendation, studies considering self-citations at the individual level should make clear whether author or total self-citations are used as these can affect researchers differently. PMID:20234766
Costas, Rodrigo; van Leeuwen, Thed N; Bordons, María
Understanding which brain regions regulate the execution, and suppression, of goal-directed behavior has implications for a number of areas of research. In particular, understanding which brain regions engaged during tasks requiring the execution and inhibition of a motor response provides insight into the mechanisms underlying individualdifferences in response inhibition ability. However, neuroimaging studies examing the relation between activation and stopping have been inconsistent regarding the direction of the relationship, and also regarding the anatomical location of regions that correlate with behavior. These limitations likely arise from the relatively low power of vox-elwise correlations with small sample sizes. Here, we pooled data over five separate fMRI studies of the Stop-signal task in order to obtain a sufficiently large sample size to robustly detect brain/behavior correlations. In addition, rather than performing mass univariate correlation analysis across all voxels, we increased statistical power by reducing the dimensionality of the data set using independent components analysis and then examined correlations between behavior and the resulting component scores. We found that components reflecting activity in regions thought to be involved in stopping were associated with better stopping ability, while activity in a default-mode network was associated with poorer stopping ability across individuals. These results clearly show a relationship between individualdifferences in stopping ability in specific activated networks, including regions known to be critical for the behavior. The results also highlight the usefulness of using dimensionality reduction to increase the power to detect brain/behavior correlations in individualdifferences research.
Congdon, Eliza; Mumford, Jeanette A.; Cohen, Jessica R.; Galvan, Adriana; Aron, Adam R.; Xue, Gui; Miller, Eric; Poldrack, Russell A.
ABSTRACT. Objective: The current study aimed to describe what proportion of variation in adult alcohol intake is attributable to genetic differences among individuals and what proportion to differences in environmental experiences individuals have been exposed to. Effects of age, gender, spousal resemblance, and cultural transmission of alcohol intake from parents to offspring were taken into account. Method: In a twin-family design, the effects of genetic and cultural transmission and shared and nonshared environment on alcohol intake were estimated with genetic structural equation models. Data originated from adult twins, their siblings, parents (n = 12,587), and spouses (n = 429) registered with the population-based Netherlands Twin Register (63.5% female; ages 18-97 years). Results: Alcohol intake (grams per day) was higher among men than women and increased with age. Broad-sense heritability estimates were similar across sex and age (53%). Spousal resemblance was observed (r = .39) but did not significantly affect the heritability estimates. No effects of cultural transmission were detected. In total, 23% of the variation in alcohol intake was explained by additive genetic effects, 30% by dominant (nonadditive) gene action, and 47% by environmental effects that were not shared among family members. Conclusions: Individualdifferences in adult alcohol intake are explained by genetic and individual-specific environmental effects. The same genes are expressed in males and females and in younger and older participants. A substantial part of the heritability of alcohol intake is attributable to nonadditive gene action. Effects of cultural transmission that have been reported in adolescence are not present in adulthood. (J. Stud. Alcohol Drugs, 75, 201-210, 2014). PMID:24650813
van Beek, Jenny H D A; de Moor, Marleen H M; Geels, Lot M; Willemsen, Gonneke; Boomsma, Dorret I
Although many functional imaging studies have reported frontal activity associated with ‘cognitive control’ tasks, little is understood about factors underlying individualdifferences in performance. Here we compared the behaviour and brain structure of healthy controls with fighter pilots, an expert group trained to make precision choices at speed in the presence of conflicting cues. Two different behavioural paradigms – Eriksen Flanker and Change of plan tasks – were used to assess the influence of distractors and the ability to update ongoing action plans. Fighter pilots demonstrated superior cognitive control as indexed by accuracy and post-conflict adaptation on the flanker task, but also showed increased sensitivity to irrelevant, distracting choices. By contrast, when pilots were examined on their ability to inhibit a current action plan in favour of an alternative response, their performance was no better than the control group. Diffusion weighted imaging revealed differences in white matter radial diffusivity between pilots and controls not only in the right dorsomedial frontal region but also in the right parietal lobe. Moreover, analysis of individualdifferences in reaction time costs for conflict trials on the flanker task demonstrated significant correlations with radial diffusivity at these locations, but in different directions. Post-conflict adaptation effects, however, were confined to the dorsomedial frontal locus. The findings demonstrate that in humans expert cognitive control may surprisingly be mediated by enhanced response gain to both relevant and irrelevant stimuli, and is accompanied by structural alterations in the white matter of the frontal and parietal lobe.
Some personality traits and comorbid psychiatric diseases are linked to a propensity for excessive alcohol drinking. The objective of this study was to investigate the association between individualdifferences in risk-related behaviors, voluntary alcohol intake and preference. Outbred male Wistar rats were tested in a novel open field, followed by assessment of behavioral profiles using the multivariate concentric square field (MCSF) test. Animals were classified into high risk taking and low risk taking on the basis of open-field behavior and into high risk-assessing (HRA) and low risk-assessing (LRA) on the basis of the MCSF profile. Finally, voluntary alcohol intake was investigated using intermittent access to 20% ethanol and water for 5 weeks. Only minor differences in voluntary alcohol intake were found between high risk taking and low risk taking. Differences between HRA and LRA rats were more evident, with higher intake and increased intake over time in HRA relative to LRA rats. Thus, individualdifferences in risk-assessment behavior showed greater differences in voluntary alcohol intake than risk taking. The findings may relate to human constructs of decision-making and risk taking associated with a predisposition to rewarding and addictive behaviors. Further studies are needed to clarify the relationship between risk-related behaviors, including risk-assessment behavior, and liability for excessive alcohol intake. PMID:24776488
Conspiracy theories are ubiquitous when it comes to explaining political events and societal phenomena. Individualsdiffer not only in the degree to which they believe in specific conspiracy theories, but also in their general susceptibility to explanations based on such theories, that is, their conspiracy mentality. We present the Conspiracy Mentality Questionnaire (CMQ), an instrument designed to efficiently assess differences in the generic tendency to engage in conspiracist ideation within and across cultures. The CMQ is available in English, German, and Turkish. In four studies, we examined the CMQ's factorial structure, reliability, measurement equivalence across cultures, and its convergent, discriminant, and predictive validity. Analyses based on a cross-cultural sample (Study 1a; N?=?7,766) supported the conceptualization of conspiracy mentality as a one-dimensional construct across the three language versions of the CMQ that is stable across time (Study 1b; N?=?141). Multi-group confirmatory factor analysis demonstrated cross-cultural measurement equivalence of the CMQ items. The instrument could therefore be used to examine differences in conspiracy mentality between European, North American, and Middle Eastern cultures. In Studies 2-4 (total N?=?476), we report (re-)analyses of three datasets demonstrating the validity of the CMQ in student and working population samples in the UK and Germany. First, attesting to its convergent validity, the CMQ was highly correlated with another measure of generic conspiracy belief. Second, the CMQ showed patterns of meaningful associations with personality measures (e.g., Big Five dimensions, schizotypy), other generalized political attitudes (e.g., social dominance orientation and right-wing authoritarianism), and further individualdifferences (e.g., paranormal belief, lack of socio-political control). Finally, the CMQ predicted beliefs in specific conspiracy theories over and above other individualdifference measures. PMID:23641227
Bruder, Martin; Haffke, Peter; Neave, Nick; Nouripanah, Nina; Imhoff, Roland
Visual memory is vulnerable to epilepsy surgery in adults, but studies in children suggest no change or small improvements. We investigated visual memory after epilepsy surgery, both group-wise and in individual children, using two techniques to assess change: 1) repeated measures analysis of variance (ANOVA) and 2) an empirically based technique for detecting cognitive change [standardized regression-based (SRB) analysis]. A prospective cohort consisting of 21 children completed comprehensive assessments of memory both before surgery (T0) and 6 (T1), 12 (T2), and 24months (T3) after surgery. For each patient, two age- and gender-matched controls were assessed with the same tests at the same intervals. Repeated measures ANOVA replicated the results of previous studies reporting no change or minor improvements after surgery. However, group analysis of SRB results eliminated virtually all improvements, indicating that the ANOVA results were confounded by practice effects. Standardized regression-based group results showed that in fact patients scored lower after surgery than would be predicted based on their presurgical performance. Analysis of individual SRB results showed that per visual memory measure, an average of 18% of patients obtained a significantly negative SRB score, whereas, on average, only 2% obtained a significantly positive SRB score. At T3, the number of significantly negative SRB scores outweighed the number of significantly positive SRB scores in 62% of patients. There were no clear associations of clinical variables (including side and site of surgery and postsurgical seizure freedom) with memory outcome. The present analysis revealed that given their individual presurgical functioning, many children obtained disappointing results on some visual memory tests after epilepsy surgery. Comparison of the SRB analysis with ANOVA results emphasizes the importance of empirically based techniques for detecting cognitive effects of epilepsy surgery in childhood. PMID:24857810
Meekes, Joost; Braams, Olga B; Braun, Kees P J; Jennekens-Schinkel, Aag; van Rijen, Peter C; Alpherts, Willem C J; Hendriks, Marc P H; van Nieuwenhuizen, Onno
College students were separated into 2 groups (high and low) on the basis of 3 measures: subjective familiarity ratings of words, self-reported language experiences, and a test of vocabulary knowledge. Three experiments were conducted to determine if the groups also differed in visual word naming, lexical decision, and semantic categorization. High Ss were consistently faster than low Ss in naming visually presented words. They were also faster and more accurate in making difficult lexical decisions and in rejecting homophone foils in semantic categorization. Taken together, the results demonstrate that Ss who differ in lexical familiarity also differ in processing efficiency. The relationship between processing efficiency and working memory accounts of individualdifferences in language processing is also discussed.
Lewellen, Mary Jo; Goldinger, Stephen D.; Pisoni, David B.; Greene, Beth G.
Speech categories are defined by multiple acoustic dimensions, and listeners give differential weighting to dimensions in phonetic categorization. The informativeness (predictive strength) of dimensions for categorization is considered an important factor in determining perceptual weighting. However, it is unknown how the perceptual system weighs acoustic dimensions with similar informativeness. This study investigates perceptual weighting of two acoustic dimensions with similar informativeness, exploiting the absolute and relative durations that are nearly equivalent in signaling Japanese singleton and geminate stop categories. In the perception experiments, listeners showed strong individualdifferences in their perceptual weighting of absolute and relative durations. Furthermore, these individual patterns were stable over repeated testing across as long as 2 months and were resistant to perturbation through short-term manipulation of speech input. Listeners own speech productions were not predictive of how they weighted relative and absolute duration. Despite the theoretical advantage of relative (as opposed to absolute) duration cues across contexts, relative cues are not utilized by all listeners. Moreover, examination of individualdifferences in cue weighting is a useful tool in exposing the complex relationship between perceptual cue weighting and language regularities. PMID:23231125
The goal of this research is to utilize a transdisciplinary framework to guide the selection of putative moderators of the effectiveness of an intervention to promote physical activity behavior adoption and maintenance in the context of a randomized controlled intervention trial. Effective interventions to increase physical activity are sorely needed, and one barrier to the identification and development of such interventions is the lack of research targeted at understanding both the mechanisms of intervention efficacy and for whom particular interventions are effective. The purpose of this paper is to outline our transdisciplinary approach to understanding individualdifferences in the effectiveness of a previously successful exercise promotion intervention. We explain the rationale for and operationalization of our framework, characteristics of the study to which we apply the framework, and planned analyses. By embracing a transdisciplinary orientation for individualdifferences important in the prediction of physical activity (spanning molecular approaches, animal models, human laboratory models, and social psychological models), we hope to have a better understanding of characteristics of individuals that are important in the adoption and maintenance of physical activity.
Nilsson, Renea; Tompkins, Sara Anne; Magnan, Renee E.; Marcus, Bess H.; Hutchison, Kent E.
Genes and culture are often thought of as opposite ends of the nature–nurture spectrum, but here we examine possible interactions. Genetic association studies suggest that variation within the genes of central neurotransmitter systems, particularly the serotonin (5-HTTLPR, MAOA-uVNTR) and opioid (OPRM1 A118G), are associated with individualdifferences in social sensitivity, which reflects the degree of emotional responsivity to social events and experiences. Here, we review recent work that has demonstrated a robust cross-national correlation between the relative frequency of variants in these genes and the relative degree of individualism–collectivism in each population, suggesting that collectivism may have developed and persisted in populations with a high proportion of putative social sensitivity alleles because it was more compatible with such groups. Consistent with this notion, there was a correlation between the relative proportion of these alleles and lifetime prevalence of major depression across nations. The relationship between allele frequency and depression was partially mediated by individualism–collectivism, suggesting that reduced levels of depression in populations with a high proportion of social sensitivity alleles is due to greater collectivism. These results indicate that genetic variation may interact with ecological and social factors to influence psychocultural differences.
Background Different immunotherapy approaches for the treatment of cancer and autoimmune diseases are being developed and tested in clinical studies worldwide. Their resulting complex experimental data should be properly evaluated, therefore reliable normal healthy control baseline values are indispensable. Methodology/Principal Findings To assess intra- and inter-individual variability of various biomarkers, peripheral blood of 16 age and gender equilibrated healthy volunteers was sampled on 3 different days within a period of one month. Complex “crossomics” analyses of plasma metabolite profiles, antibody concentrations and lymphocyte subset counts as well as whole genome expression profiling in CD4+T and NK cells were performed. Some of the observed age, gender and BMI dependences are in agreement with the existing knowledge, like negative correlation between sex hormone levels and age or BMI related increase in lipids and soluble sugars. Thus we can assume that the distribution of all 39.743 analysed markers is well representing the normal Caucasoid population. All lymphocyte subsets, 20% of metabolites and less than 10% of genes, were identified as highly variable in our dataset. Conclusions/Significance Our study shows that the intra-individual variability was at least two-fold lower compared to the inter-individual one at all investigated levels, showing the importance of personalised medicine approach from yet another perspective.
Empirical work and models of visual word recognition have traditionally focused on group-level performance. Despite the emphasis on the prototypical reader, there is clear evidence that variation in reading skill modulates word recognition performance. In the present study, we examined differences among individuals who contributed to the English Lexicon Project (http://elexicon.wustl.edu), an online behavioral database containing nearly 4 million word recognition (speeded pronunciation and lexical decision) trials from over 1,200 participants. We observed considerable within- and between-session reliability across distinct sets of items, in terms of overall mean response time (RT), RT distributional characteristics, diffusion model parameters (Ratcliff, Gomez, & McKoon, 2004), and sensitivity to underlying lexical dimensions. This indicates reliably detectable individualdifferences in word recognition performance. In addition, higher vocabulary knowledge was associated with faster, more accurate word recognition performance, attenuated sensitivity to stimuli characteristics, and more efficient accumulation of information. Finally, in contrast to suggestions in the literature, we did not find evidence that individuals were trading-off their utilization of lexical and nonlexical information. PMID:21728459
Yap, Melvin J; Balota, David A; Sibley, Daragh E; Ratcliff, Roger
Numerous studies have documented the phenomenon of phonetic imitation: the process by which the production patterns of an individual become more similar on some phonetic or acoustic dimension to those of her interlocutor. Though social factors have been suggested as a motivator for imitation, few studies has established a tight connection between language-external factors and a speaker’s likelihood to imitate. The present study investigated the phenomenon of phonetic imitation using a within-subject design embedded in an individual-differences framework. Participants were administered a phonetic imitation task, which included two speech production tasks separated by a perceptual learning task, and a battery of measures assessing traits associated with Autism-Spectrum Condition, working memory, and personality. To examine the effects of subjective attitude on phonetic imitation, participants were randomly assigned to four experimental conditions, where the perceived sexual orientation of the narrator (homosexual vs. heterosexual) and the outcome (positive vs. negative) of the story depicted in the exposure materials differed. The extent of phonetic imitation by an individual is significantly modulated by the story outcome, as well as by the participant’s subjective attitude toward the model talker, the participant’s personality trait of openness and the autistic-like trait associated with attention switching.
Yu, Alan C. L.; Abrego-Collier, Carissa; Sonderegger, Morgan
Genes and culture are often thought of as opposite ends of the nature-nurture spectrum, but here we examine possible interactions. Genetic association studies suggest that variation within the genes of central neurotransmitter systems, particularly the serotonin (5-HTTLPR, MAOA-uVNTR) and opioid (OPRM1 A118G), are associated with individualdifferences in social sensitivity, which reflects the degree of emotional responsivity to social events and experiences. Here, we review recent work that has demonstrated a robust cross-national correlation between the relative frequency of variants in these genes and the relative degree of individualism-collectivism in each population, suggesting that collectivism may have developed and persisted in populations with a high proportion of putative social sensitivity alleles because it was more compatible with such groups. Consistent with this notion, there was a correlation between the relative proportion of these alleles and lifetime prevalence of major depression across nations. The relationship between allele frequency and depression was partially mediated by individualism-collectivism, suggesting that reduced levels of depression in populations with a high proportion of social sensitivity alleles is due to greater collectivism. These results indicate that genetic variation may interact with ecological and social factors to influence psychocultural differences. PMID:20592043
Any disease manifests itself individually either by a bright or restricted spectrum of clinical signs and resultant clinical courses that range from asymptomatic to deadly, from acute to chronic, etc. Until recently, the origin of this kind of biodiversity was poorly investigated and understood, but advances in immunology--especially in identifying constitutional (genetic) mechanisms of immunity--have contributed to our understanding of the origin of individual diversity in diseases. Any disease destroys only focal areas in the affected organisms, and the amounts, sizes, and distribution of such focal lesions vary from patient to patient. In a population predilected to a relevant pathogenic agent, individuals can be conveniently divided into three categories: totally resistant organisms that contain no susceptible structures and are not affected; mildly susceptible organisms in which a few foci appear and in which the disease runs a benign course; organisms in which the number of constitutionally susceptible structures is high and the disease develops in a severe form. The diversity is formed by the mating of genetically different parents that determines the differences in susceptibility of genetically various parts of the descendant organism. PMID:17195867
The present paper suggests an individualdifferences approach to the issue of whether responses on computerized survey are more candid than those on paper-and-pencil scales. It was hypothesized that skilled and motivated impression managers--individuals h...
L. M. Doherlty P. Rosenfeld R. A. Giacalone S. B. Knouse S. M. Vicino
The effect of textural modifications of solid milk gels on in vivo aroma release and aroma perception was investigated with a panel of 14 subjects. Great inter-individualdifferences were observed on aroma-release data, and the consequences of these differences on aroma perception were studied. From a hierarchical cluster analysis performed with several parameters extracted from release curves, the subjects were gathered into two groups, and a specific aroma-release profile was identified for each one. Then, by using a sensory profile, we showed that the intensity of the aroma perception was dependent on the release profile presented by the panelist. Second, we observed that, during the chewing phase, the aroma was perceived as more intense for the firmer gel and for panelists for whom the aroma release begins during the chewing of the product. PMID:18271545
Gierczynski, Isabelle; Laboure, Helene; Guichard, Elisabeth
Mental health provider attitudes toward adoption of innovation in general, and toward evidence-based practice (EBP) in particular, are important in considering how best to disseminate and implement EBPs. This article first explores the role of attitudes in acceptance of innovation and proposes a model of organizational and individual factors that may affect or be affected by attitudes toward adoption of EBP. Next, a recently developed measure of mental health provider attitudes toward adoption of EBP is presented along with a summary of preliminary reliability and validity findings. Attitudes toward adoption of EBP are then discussed in regard to provider individualdifferences and the context of mental health services. Finally, potential applications of attitude research to adoption of EBP are discussed.
Gesture facilitates language production, but there is debate surrounding its exact role. It has been argued that gestures lighten the load on verbal working memory (VWM; Goldin-Meadow, Nusbaum, Kelly, & Wagner, 2001), but gestures have also been argued to aid in lexical retrieval (Krauss, 1998). In the current study, 50 speakers completed an individualdifferences battery that included measures of VWM and lexical retrieval. To elicit gesture, each speaker described short cartoon clips immediately after viewing. Measures of lexical retrieval did not predict spontaneous gesture rates, but lower VWM was associated with higher gesture rates, suggesting that gestures can facilitate language production by supporting VWM when resources are taxed. These data also suggest that individual variability in the propensity to gesture is partly linked to cognitive capacities. PMID:24813571
Gillespie, Maureen; James, Ariel N; Federmeier, Kara D; Watson, Duane G
A survey of airline pilots was undertaken to determine normative patterns and individualdifferences in mood and sleep during short-haul flight operations. The results revealed that over the course of a typical 2-d trip, pilots experience a decline in positive mood, or activity, and an increase in negative mood, or tension. On layovers, pilots report experiencing sleep of shorter duration and poorer quality than at home. These patterns are very similar to those reported by Gander and Graeber (1987) and by Gander et al. (1988), using high-fidelity sleep and activity monitoring equipment. Examination of the impact of two personality dimensions extracted from the Jenkins Activity Survey measure of the Type A personality, Achievement Striving and Impatience/Irritability, suggested that Impatience/Irritability may serve as a marker of individuals most likely to experience health-related problems on trips. Achievement Striving may serve as a predictor of performance in crew settings.
A survey of airline pilots was undertaken to determine normative patterns and individualdifferences in mood and sleep during short-haul flight operations. The results revealed that over the course of a typical 2-d trip, pilots experience a decline in positive mood, or activity, and an increase in negative mood, or tension. On layovers, pilots report experiencing sleep of shorter duration and poorer quality than at home. These patterns are very similar to those reported by Gander and Graeber and by Gander et al. using high-fidelity sleep and activity monitoring equipment. Examination of the impact of two personality dimensions extracted from the Jenkins Activity Survey measure of the Type A personality, Achievement Striving and Impatience/Irritability, suggested that Impatience/Irritability may serve as a marker of individuals most likely to experience health-related problems on trips. Achievement Striving may serve as a predictor of performance in crew settings.
Maturational differences in brain responsiveness to rewards have been implicated in the increased rates of injury and death in adolescents from behavior-related causes. However, much of this morbidity is related to drug intoxication or other externalizing behaviors, and may be concentrated in a subset of adolescents who are at psychosocial or neurobiological risk. To examine whether individualdifferences in psychosocial and behavioral symptomatology relate to activation of motivational neurocircuitry, we scanned 26 psychiatrically-healthy adolescents using fMRI as they performed a monetary incentive delay task. Overall Problem Density on the Drug Use Screening Inventory (DUSI-OPD) correlated positively with activation of ventral mesofrontal cortex (mFC) during anticipation of responding for rewards (versus responding for no incentive). In addition, DUSI-OPD also correlated positively with right ventral striatum recruitment during anticipation of responding to win rewards (versus responding for no incentive or to avoid losses of identical magnitudes). Finally, a psychophysiological interaction (PPI) analysis indicated that increased connectivity between nucleus accumbens and portions of anterior cingulate and mFC as a function of reward prospects also correlated with DUSI-OPD. These findings extend previous reports demonstrating that in adolescents, individualdifferences in reactivity of motivational neurocircuitry relate to different facets of impulsivity or externalizing behaviors.
Bjork, James M.; Smith, Ashley R.; Chen, Gang; Hommer, Daniel W.
It can be remarkably difficult to determine whether two photographs of unfamiliar faces depict the same person or two different people. This fallibility is well established in the face perception and eyewitness domain, but most of this research has focused on the "average" observer by measuring mean performance across groups of participants. This study deviated from this convention to provide a detailed description of individualdifferences and observer consistency in unfamiliar face identification by assessing performance repeatedly, across a 3-day (Experiment 1) and a 5-day period (Experiment 2). Both experiments reveal considerable variation between but also within observers. This variation is such that the same observers frequently made different identification decisions to the same faces on different days (Experiment 1). And when new faces were shown on each day, observers that produced perfect accuracy on one day made many misidentifications on another (Experiment 2). However, a few individuals also performed with consistent high accuracy in these tests. These findings suggest that accuracy and consistency are separable indices of face-matching ability, and both measures are necessary to provide a precise index of a person's face processing skill. We discuss whether these measures could provide the basis for a selection tool for occupations that depend on accurate person identification. PMID:22905851
This experiment was designed to investigate the individualdifferences in the cerebrovascular responses to orthostatic stress. Seven male volunteers were exposed to head-up tilt (HUT) at 60 degrees for 15 min and to lower body negative pressure (LBNP) at 30 mmHg for 25 min. We measured the flow velocity of the middle cerebral artery and the quantity of the oxygenated and deoxygenated hemoglobin (oxy-Hb and deoxy-Hb) in the brain. Based upon oxy-Hb change during exposure to HUT, we classified the subjects into two groups: 1) the "good responder" group in which the oxy-Hb gradually increased from the 5th to 10th minute of HUT; 2) the "bad responder" group in which the oxy-Hb stabilized at lower levels after the initial decrease. The oxy-Hb changes between the two groups were significantly different during exposure to LBNP. During exposure to HUT and LBNP, no significant difference was observed in blood pressure and heart rate between the two groups. Our results suggest that there might be an individualdifference in the cerebrovascular responses to orthostatic stress.
Background The daily life of patients suffering from orofacial pain is considerably impaired as compared to healthy subjects. The aim of this study was to investigate the influence of different categories of orofacial pain on the habitual life of adult individuals. Methods Seven hundred eighty-one individuals with orofacial pain were recruited from an initial sample of 1,058 patients. All the individuals were allocated to groups according to their diagnosis: myofascial pain (group A, 676 subjects, 525 females and 151 males; mean age?±?SD?=?35.2?±?12.6), migraine (group B, 39 subjects, 29 females and 10 males; mean age?±?SD 36.0?±?10.7), and both myofascial pain and migraine (group C, 66 subjects, 56 females and 10 males, mean age?±?SD?=?35.6?±?10.8). Characteristic pain intensity (CPI), disability days (DD), disability score (DS), and graded chronic pain intensity (GCPS) were calculated according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis II. Depression and somatization (nonspecific physical symptoms) scores were also calculated. Results A significant association between groups and GCPS categories was found (p?0.0001). Post hoc tests showed a significant difference between groups A and B and between A and C, but not between B and C. In group A, the most frequent GCPS score was grade II. The most frequent GCPS score in groups B and C was grade III, indicating a moderate limiting impairment. This score was more frequent in group B (41%) than in the other groups (group A?=?20.6%, group C?=?34.8%). GCPS grade IV was more frequent in group C (19.7%) than in the other groups. Group C had significantly higher scores for nonspecific physical symptoms than group A (p?0.05). Conclusions Myofascial pain and migraine sensibly affect the common daily life of adult individuals. The comorbidity of both conditions determines a major impairment.
Individualdifferences in the forced swimming test (FST) could be associated with differential temporal dynamics of gene expression and neurotransmitter activity. We tested juvenile male rats in the FST and classified the animals into those with low and high immobility according to the amount of immobility time recorded in FST. These groups and a control group which did not undergo the FST were sacrificed either 1, 6 or 24 h after the test. We analyzed the expression of the CRF, CRFR1, BDNF and TrkB in the prefrontal cortex, hippocampus and nucleus accumbens as well as norepinephrine, dopamine, serotonin, glutamate, GABA and glutamine in the hippocampus and nucleus accumbens. Animals with low immobility showed significant reductions of BDNF expression across time points in both the prefrontal cortex and the nucleus accumbens when compared with non-swim control. Moreover, rats with high immobility only showed a significant decrease of BDNF expression in the prefrontal cortex 6h after the FST. Regarding neurotransmitters, only accumbal dopamine turnover and hippocampal glutamate content showed an effect of individualdifferences (i.e. animals with low and high immobility), whereas nearly all parameters showed significant differences across time points. Correlational analyses suggest that immobility in the FST, probably reflecting despair, is related to prefrontal cortical BDNF and to the kinetics observed in several other neurochemical parameters. Taken together, our results suggest that individualdifferences observed in depression-like behavior can be associated not only with changes in the concentrations of key neurochemical factors but also with differential time courses of such factors. PMID:24518862
Neurotypical individuals cope flexibly with the full range of semantic relations expressed in human language, including metaphoric relations. This impressive semantic ability may be associated with distinct and flexible patterns of hemispheric interaction, including higher right hemisphere (RH) involvement for processing novel metaphors. However, this ability may be impaired in specific clinical conditions, such as Asperger syndrome (AS) and schizophrenia. The impaired semantic processing is accompanied by different patterns of hemispheric interaction during semantic processing, showing either reduced (in Asperger syndrome) or excessive (in schizophrenia) RH involvement. This paper interprets these individualdifferences using the terms Rigidity, Chaos and Integration, which describe patterns of semantic memory network states that either lead to semantic well-being or are disruptive of it. We argue that these semantic network states lie on a rigidity-chaos semantic continuum. We define these terms via network science terminology and provide network, cognitive and neural evidence to support our claim. This continuum includes left hemisphere (LH) hyper-rigid semantic memory state on one end (e.g., in persons with AS), and RH chaotic and over-flexible semantic memory state on the other end (e.g., in persons with schizophrenia). In between these two extremes lie different states of semantic memory structure which are related to individualdifferences in semantic creativity. We suggest that efficient semantic processing is achieved by semantic integration, a balance between semantic rigidity and semantic chaos. Such integration is achieved via intra-hemispheric communication. However, impairments to this well-balanced and integrated pattern of hemispheric interaction, e.g., when one hemisphere dominates the other, may lead to either semantic rigidity or semantic chaos, moving away from semantic integration and thus impairing the processing of metaphoric language.
This study investigated the complex influences of individualdifferences and school contexts on the growth of mathematical reasoning skills in high school, with particular emphasis on differences in academic preparation, demographics (i.e., race\\/ethnicity, gender and socioeconomic status), and school characteristics. Students' growth of mathematical reasoning skills, measured using standardized tests developed by the College Board (i.e., the PSAT\\/NMSQT and SAT),
Two experiments investigated the relation between individualdifferences in working memory capacity and differences in the efficiency of syntactic processing. In one experiment, readers comprehended sentences containing main-verb/reduced-relative ambiguities that all resolved to the reduced-relative interpretation. High-span (but not low-span) readers processed sentences more slowly when the sentences were biased to the preferred, main-verb interpretation than when they were biased to the reduced-relative interpretation. Moreover, high-span (but not low-span) readers used information about the plausibility of the different interpretations even though low-span readers appeared to possess the requisite knowledge. In Experiment 2, readers received intensive exposure to sentences with main-verb/reduced-relative ambiguities. Exposure enhanced low-span readers’ use of plausibility information. Moreover, the effect of exposure generalized to sentences that were not included in the training materials.
One of the most important effect sizes used in meta-analysis is the standardized mean difference (SMD). In this article, the conditions under which SMD effect sizes based on different measures of the same construct are directly comparable are investigated. The results show that SMD effect sizes from different measures of the same construct are…
Background When two targets are presented in close temporal succession, the majority of people frequently fail to report the second target. This phenomenon, known as the ‘attentional blink’ (AB), has been a major topic in attention research for the past twenty years because it is informative about the rate at which stimuli can be encoded into consciously accessible representations. An aspect of the AB that has long been ignored, however, is individualdifferences. Methodology/Principal Findings Here we compare a group of blinkers (who show an AB) and non-blinkers (who show little or no AB), and investigate the boundary conditions of the non-blinkers' remarkable ability. Second, we directly test the properties of temporal selection by analysing response errors, allowing us to uncover individualdifferences in suppression, delay, and diffusion of selective attention across time. Thirdly, we test the hypothesis that information concerning temporal order is compromised when an AB is somehow avoided. Surprisingly, compared to earlier studies, only a modest amount of suppression was found for blinkers. Non-blinkers showed no suppression, were more precise in selecting the second target, and made less order reversals than blinkers did. In contrast, non-blinkers made relatively more intrusions and showed a selection delay when the second target immediately followed the first target (at lag 1). Conclusion/Significance The findings shed new light on the mechanisms that may underlie individualdifferences in selective attention. The notable ability of non-blinkers to accurately perceive targets presented in close temporal succession might be due to a relatively faster and more precise target selection process compared to large blinkers.
Willems, Charlotte; Wierda, Stefan M.; van Viegen, Eva; Martens, Sander
This study assessed to what extent genetic and environmental factors contributed to individualdifferences in adolescent sleep duration, and whether genetic and environmental contributions to sleep duration changed throughout adolescence. A twin-family design was used to gain insight into the genetic and environmental contributions to variation in sleep duration. The study sample consisted of 6,319 adolescent twins (44% males) and 1,359 non-twin siblings (44% males) in the age range of 12 to 20 years (mean age = 16.85, SD = 1.40). The participants self-reported usual sleep duration, which was categorized as less than 8 hours per night, 8-9 hours per night, and more than 9 hours per night. Results showed that the prevalence of shorter than optimum sleep duration, that is, less than 8 hours per night, was high, with the highest prevalence rates in later adolescence. The contribution of genetic and environmental factors to individualdifferences in sleep duration was dependent on age. Variation in sleep duration at the age of 12 years was accounted for by genetic (boys: 34%, girls: 36%), shared environmental (boys: 28%, girls: 45%), and non-shared environmental factors (boys: 38%, girls: 19%). At the age of 20 years, the role of genetic (boys: 47%, girls: 33%) and non-shared environmental factors (boys: 53%, girls: 67%) was more pronounced. It can be concluded from the results that individualdifferences in sleep duration were accounted for by genetic and non-shared environmental factors throughout adolescence, whereas shared environmental factors account for a substantial part of variation during early adolescence only. PMID:24182415
te Velde, Saskia J; van der Aa, Niels; Boomsma, Dorret I; van Someren, Eus J W; de Geus, Eco J C; Brug, Johannes; Bartels, Meike
Ratios of effective populations size, N(e), to census population size, N, are used as a measure of genetic drift in populations. Several life-history parameters have been shown to affect these ratios, including mating system and age at sexual maturation. Using a stochastic matrix model, we examine how different levels of persistent individualdifferences in mating success among males may affect N(e)/N, and how this relates to generation time. Individualdifferences of this type are shown to cause a lower N(e)/N ratio than would be expected when mating is independent among seasons. Examining the way in which age at maturity affects N(e)/N, we find that both the direction and magnitude of the effect depends on the survival rate of juveniles in the population. In particular, when maturation is delayed, lowered juvenile survival causes higher levels of genetic drift. In addition, predicted shifts in N(e)/N with changing age at maturity are shown to be dependent on which of the commonly used definitions of census population size, N, is employed. Our results demonstrate that patterns of mating success, as well as juvenile survival probabilities, have substantial effects on rates of genetic drift. PMID:21436183
Adolescents’ attachment hierarchies were assessed in a sample of 212 high school and 198 college students. The Important People Interview (IPI) differentiated attachment bonds from other supportive or affiliative relationships and indicated that adolescents show a hierarchical ordering of preferences for multiple attachment figures. Differences in the composition and structure of adolescents’ attachment hierarchies were found between the early high school (9th and 10th grades), later high school (11th and 12th grades), and college samples. In the college sample, romantic partners were placed in higher positions in adolescents’ hierarchies, fathers were placed in lower positions, and the structure of adolescents’ hierarchies were less differentiated than in the high school samples. Individualdifferences in the composition of adolescents’ hierarchies were associated with adjustment outcomes. Friends’ placement in higher positions and fathers’ exclusion from or placement in quaternary positions was associated with increased behavior problems. Findings demonstrate that the IPI provides a measure of adolescents’ attachment hierarchies that is sensitive to developmental stage and individualdifferences.
The ability to adapt face-to-face social behavior in response to an interaction's changing contingencies is an important aspect of social skill. Individualdifferences in social ability may depend on how well people learn from social rewards and punishments. Here we relate people's social aptitude to their ability to learn from differences in the reward values of two common social reinforcers, genuine and polite smiles. In a series of experiments, participants experienced a hidden social contingency in which they either learned to repeat actions that received genuine smile feedback and switch after polite smiles or the reverse. A condition with nonsocial feedback served as a comparison measure. Participants showed better ability to repeat actions reinforced with genuine smile feedback than with nonsocial feedback. When participants were required to switch actions following genuine smiles, performance was inhibited relative to nonsocial reinforcement. The ability to detect task contingencies and learn from social rewards predicted self-reported social ability. These novel results suggest that individualdifferences in reinforcement learning, and particularly in people's motivation to receive social rewards, may relate to social ability in face-to-face interactions. This finding has important implications for understanding the social difficulties that characterize disorders such as autism, depression, and schizophrenia, in which the ability to learn from rewards may be compromised. PMID:23339334
Simulator sickness in a fixed-base simulator is a form of visually-induced motion sickness. Visual-vestibular interaction on spatial orientation and postural control predicts that vection information in the visual stimuli triggers compensatory head sways to stabilize body orientation to perceived visual motion. Simulator sickness might result from perceptual conflicts caused by the visual-vestibular interaction in unusual environments (i.e., fixed-base simulators). Relationship between simulator sickness, vection, and compensatory head sways to perceived vection might help to quantify and predict presence and magnitude of simulator sickness in simulated environments. It was hypothesized that there was significant and positive relationship between sickness, vection, and compensatory head sways. Existence of individualdifferences was also possible, depending on individual sensitivity to vection. It was also hypothesized that females would experience more intense vection than males because females have wider periphery and shorter vection latencies. Correlations and the multiple linear regression analyses were performed to test the linear relationship between simulator sickness, vection, head sway, gender, and age. There was significant linear relationship between variables. It was concluded that vection and Y-velocity are significant predictors by itself and in interaction forms. Interaction between gender and vection, Y-velocity, and age in the regression function implied that gender difference is significant and gender is also a significant predictor of simulator sickness. Therefore, it was also concluded that there was significant gender difference in susceptibility to simulator sickness between males and females. General linear model also indicates that mean difference in magnitudes of vection, and Y-velocity and difference in gender and age have effects on the magnitude of simulator sickness. Time-course of vection implies that magnitude of vection increases as exposure duration increases. It seemed that females had stronger vection than did males in the beginning, which may imply females might have had shorter vection latencies. But no significant difference of vection intensity between males and females was found throughout. Recommendations were made for future research to study other physical factors that could contribute to individualdifferences in susceptibility to vection and simulator sickness.
Mindfulness is the state of being attentive to and aware of what is taking place in the present, which is beneficial for reducing stress-related symptoms and improving mental and physical health. Previous studies have demonstrated that meditation practice can improve individuals' mindfulness through modifying functions and structures of multiple brain regions, including the anterior cingulate cortex (ACC), insula, fronto-limbic network, posterior cingulate cortex (PCC), and temporal-parietal junction. However, little is known about the neuroanatomical correlates of trait mindfulness. In the current study, we used voxel-based morphometry to investigate the neural correlates of individualdifferences in trait mindfulness by correlating the gray matter (GM) volume of each voxel across the whole brain with trait mindfulness measured by the Mindful Attention Awareness Scale in a large sample of young adults (N=247). We found that individuals who were more mindful of the present had greater GM volume in the right hippocampus/amygdala and bilateral ACC, but less GM volume in bilateral PCC and the left orbitofrontal cortex. These results suggest that trait mindfulness is associated with brain regions involved in executive attention, emotion regulation, and self-referential processing, through which mindfulness may exert its beneficial effects on psychological and physical well-being. PMID:24797333
Pathological gambling, alongside addictive and antisocial disorders, forms part of a broad psychopathological spectrum of externalizing disorders, which share an underlying genetic vulnerability. The shared externalizing propensity is a highly heritable, continuously varying trait. Disinhibitory personality traits such as impulsivity and novelty seeking (NS) function as indicators of this broad shared externalizing tendency, which may reflect, at the neurobiological level, variation in the reactivity of dopaminergic (DAergic) brain reward systems centered on the ventral striatum (VS). Here, we examined whether individualdifferences in ventral striatal dopamine (DA) synthesis capacity were associated with individual variation in disinhibitory personality traits. Twelve healthy male volunteers underwent 6-[18F]Fluoro-L-DOPA (FDOPA) positron emission tomography (PET) scanning to measure striatal DA synthesis capacity, and completed a measure of disinhibited personality (NS). We found that levels of ventral, but not dorsal, striatal DA synthesis capacity were significantly correlated with inter-individual variation in disinhibitory personality traits, particularly a propensity for financial extravagance and irresponsibility. Our results are consistent with preclinical models of behavioral disinhibition and addiction proneness, and provide novel insights into the neurobiology of personality based vulnerability to pathological gambling and other externalizing disorders.
It is widely assumed that the human brain contains genetically identical cells through which post-genomic mechanisms contribute to its enormous diversity and complexity. The relatively recent identification of neural cells throughout the neuraxis showing somatically generated mosaic aneuploidy indicates that the vertebrate brain can be genomically heterogeneous (Rehen et al., 2001; Rehen et al., 2005; Westra et al., 2008; Yurov et al., 2007). The extent of human neural aneuploidy is currently unknown because of technically limited sample sizes, but is reported to be small (Iourov et al., 2006). During efforts to interrogate larger cell populations using DNA content analyses, a surprising result was obtained: human frontal cortex brain cells were found to display “DNA content variation (DCV)” characterized by an increased range of DNA content both in cell populations and within single cells. On average, DNA content increased by ~250 megabases often representing a substantial fraction of cells within a given sample. DCV within individual human brains showed regional variation, with increased prevalence in the frontal cortex and less variation in the cerebellum. Further, DCV varied between individual brains. These results identify DCV as a new feature of the human brain, encompassing and further extending genomic alterations produced by aneuploidy, which may contribute to neural diversity in normal and pathophysiological states, altered functions of normal and disease-linked genes, and differences amongst individuals.
Westra, Jurjen W.; Rivera, Richard R.; Bushman, Diane M.; Yung, Yun C.; Peterson, Suzanne E.; Barral, Serena; Chun, Jerold
A mediation model of the relation between gender and attitudes toward affirmative action in favor of working women was tested. Four mediation variables were considered: perceived unfairness in the situation of working women, perceived threat to the non-designated group (men), self-esteem, and gender self-concept (masculinity and femininity). 192 women and 128 men, with differing occupations, participated. Gender affects individuals' attitudes toward affirmative actions for women, mediated by perceived unfairness in the situation of working women, perceived threat to the non-designated group, and feminine self-concept. Implications for research and practice are discussed. PMID:22897083
Moscoso, Silvia; García-Izquierdo, Antonio L; Bastida, María
This research examined whether variations in salivary measures of the hypothalamic-pituitary-adrenal axis (cortisol) and autonomic\\u000a nervous system (alpha amylase [sAA]) contribute to individualdifferences in the association between peer victimization and\\u000a aggression. Children (N?=?132; M age?=?9.46 years, SD?=?0.33) completed a measure of peer victimization, teachers rated children’s aggression, and children’s saliva was collected\\u000a prior to, and following, participation in a laboratory-based
Karen D. Rudolph; Wendy Troop-Gordon; Douglas A. Granger
The main purpose of the present study was to investigate the individual variables contributing to determine the high variability in the consumption behaviours of caffeine, a psychoactive substance which is still poorly investigated in comparison with other drugs. The effects of a large set of specific personality traits (i.e., Impulsivity, Sensation Seeking, Anxiety, Reward Sensitivity and Circadian Preference) were compared along with some relevant socio-demographic variables (i.e., gender and age) and cigarette smoking behaviour. Analyses revealed that daily caffeine intake was significantly higher for males, older people, participants smoking more cigarettes and showing higher scores on Impulsivity, Sensation Seeking and a facet of Reward Sensitivity. However, more detailed analyses showed that different patterns of individual variables predicted caffeine consumption when the times of day and the caffeine sources were considered. The present results suggest that such detailed analyses are required to detect the critical predictive variables that could be obscured when only total caffeine intake during the entire day is considered. PMID:22326679
Penolazzi, Barbara; Natale, Vincenzo; Leone, Luigi; Russo, Paolo Maria
Handrim wheelchair propulsion is a cyclic skill that needs to be learned during rehabilitation. Yet it is unclear how inter-individualdifferences in motor learning impact wheelchair propulsion practice. Therefore we studied how early-identified motor learning styles in novice able-bodied participants impact the outcome of a low-intensity wheelchair-practice intervention. Over a 12-minute pre-test, 39 participants were split in two groups based on a relative 10% increase in mechanical efficiency. Following the pretest the participants continued one of four different low-intensity wheelchair practice interventions, yet all performed in the same trial-setup with a total 80-minute dose at 1.11 m/s at 0.20 W/kg. Instead of focusing on the effect of the different interventions, we focused on differences in motor learning between participants over the intervention. Twenty-six participants started the pretest with a lower mechanical efficiency and a less optimal propulsion technique, but showed a fast improvement during the first 12 minutes and this effect continued over the 80 minutes of practice. Eventually these initially fast improvers benefitted more from the given practice indicated by a better propulsion technique (like reduced frequency and increased stroke angle) and a higher mechanical efficiency. The initially fast improvers also had a higher intra-individual variability in the pre and posttest, which possibly relates to the increased motor learning of the initially fast improvers. Further exploration of the common characteristics of different types of learners will help to better tailor rehabilitation to the needs of wheelchair-dependent persons and improve our understanding of cyclic motor learning processes. PMID:24586992
Vegter, Riemer J K; Lamoth, Claudine J; de Groot, Sonja; Veeger, Dirkjan H E J; van der Woude, Lucas H V
Background Modeling latent variables such as physical disability is challenging since its measurement is performed through proxies. This poses significant methodological challenges. The objective of this article is to present three different methods to predict latent variables based on classical summed scores, individual item responses, and latent variable models. Methods This is a review of the literature and data analysis using "layers of information". Data was collected from the North Carolina Back Pain Project, using a modified version of the Roland Questionnaire. Results The three models are compared in relation to their goals and underlying concepts, previous clinical applications, data requirements, statistical theory, and practical applications. Initial linear regression models demonstrated a difference in disability between genders of 1.32 points (95% CI 0.65, 2.00) on a scale from 0–23. Subsequent item analysis found contradictory results across items, with no clear pattern. Finally, IRT models demonstrated three items were demonstrated to present differential item functioning. After these items were removed, the difference between genders was reduced to 0.78 points (95% CI, -0.99, 1.23). These results were shown to be robust with re-sampling methods. Conclusions Purported differences in the levels of a latent variable should be tested using different models to verify whether these differences are real or simply distorted by model assumptions.
This study examines individualdifferences in the directional transfer functions (DTFs), the directional components of head-related transfer functions of gerbils, and seeks a method for reducing these differences. The difference between the DTFs of a given animal pair was quantified by the intersubject spectral difference (ISSD), which is the variance in the difference spectra of DTFs for frequencies between 5 and 45 kHz and for 361 source directions. An attempt was made to reduce the ISSD by scaling the DTFs of one animal in frequency and/or rotating the DTFs along the source coordinate sphere. The ISSD was reduced by a median of 12% after optimal frequency scaling alone, by a median of 19% after optimal spatial rotation alone, and by a median of 36% after simultaneous frequency scaling and spatial rotation. The optimal scaling factor (OSF) and the optimal coordinate rotation (OCR) correlated strongly with differences in head width and pinna angles (i.e., pinna inclination around the vertical and front-back axes), respectively. Thus, linear equations were derived to estimate the OSF and OCR from these anatomical measurements. The ISSD could be reduced by a median of 22% based on the estimated OSF and OCR.
Profiles of LH and FSH levels and pituitary LH responses to exogenous luteinizing hormone releasing hormone (LHRH) have been characterized in rams, castrated rams (wethers), and wethers implanted with testosterone. Rams were castrated when adult, and, at the time of castration, two groups of wethers were implanted with either four or eight testosterone capsules. Rams showed random pulses of LH and testosterone which were temporally related. The number of LH and testosterone pulses per 24 hours differed among rams, giving rise to large differences in the mean levels of these hormones. Mean FSH levels and pituitary LH responses to LHRH also differed among rams and were positively correlated to differences in LH levels. All three nonimplanted wethers showed a rhythmic pulsatile pattern of LH secretion and had elevated mean LH and FSH levels. There were, however, appreciable differences between wethers with regard to mean LH and FSH levels and pituitary LH responses to LHRH. Both four and eight testosterone capsules were effective in suppressing pulsatile LH secretion and mean LH and FSH levels in two out of three wethers. In a third animal within each of these groups, however, LH and FSH profiles and LH responses to LHRH were characteristic of nonimplanted wethers. These data suggest that individual rams have different inherent capacities to secrete gonadotropins which influence LH and FSH responses to castration and testosterone replacement therapy. PMID:6409867
Instrumental decision making has long been argued to be vulnerable to emotional responses. Literature on multiple decision making systems suggests that this emotional biasing might reflect effects of a system that regulates innately specified, evolutionarily preprogrammed responses. To test this hypothesis directly, we investigated whether effects of emotional faces on instrumental action can be predicted by effects of emotional faces on bodily freezing, an innately specified response to aversive relative to appetitive cues. We tested 43 women using a novel emotional decision making task combined with posturography, which involves a force platform to detect small oscillations of the body to accurately quantify postural control in upright stance. On the platform, participants learned whole body approach-avoidance actions based on monetary feedback, while being primed by emotional faces (angry/happy). Our data evidence an emotional biasing of instrumental action. Thus, angry relative to happy faces slowed instrumental approach relative to avoidance responses. Critically, individualdifferences in this emotional biasing effect were predicted by individualdifferences in bodily freezing. This result suggests that emotional biasing of instrumental action involves interaction with a system that controls innately specified responses. Furthermore, our findings help bridge (animal and human) decision making and emotion research to advance our mechanistic understanding of decision making anomalies in daily encounters as well as in a wide range of psychopathology.
Ly, Verena; Huys, Quentin J. M.; Stins, John F.; Roelofs, Karin; Cools, Roshan
Objective Many adolescents with substance use problems show poor response to evidence based treatments. Treatment outcome has been associated with individualdifferences in impulsive decision making as reflected by delay discounting (DD) rates (preference for immediate rewards). Adolescents with higher rates of DD were expected to show greater neural activation in brain regions mediating impulsive/habitual behavioral choices and less activation in regions that mediate reflective/executive behavioral choices. Method Thirty adolescents being treated for substance abuse completed a DD task optimized to balance choices of immediate versus delayed rewards and a control condition accounted for activation during magnitude valuation. A group independent component analysis on functional magnetic resonance imaging (fMRI) time courses identified neural networks engaged during DD. Network activity was correlated with individualdifferences in discounting rate. Results Higher discounting rates were associated with diminished engagement of an executive attention control network involving the dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, inferior parietal cortex, cingulate cortex, and precuneus. Higher discounting rates were also associated with less deactivation in a “bottom up” reward valuation network involving the amygdala, hippocampus, insula, and ventromedial prefrontal cortex. These 2 networks were significantly negatively correlated. Conclusions Results support relations between competing executive and reward valuation neural networks and temporal decision making, an important potentially modifiable risk factor relevant for prevention and treatment of adolescent substance abuse. Clinical trial registration information—The Neuroeconomics of Behavioral Therapies for Adolescent Substance Abuse; http://clinicaltrials.gov/; NCT01093898.
Stanger, Catherine; Elton, Amanda; Ryan, Stacy R.; James, G. Andrew; Budney, Alan J.; Kilts, Clinton D.
We used diffusion tensor imaging (DTI) to investigate relationships between white matter anatomy and different reading subskills in typical-reading adults. A series of analytic approaches revealed that phonological decoding ability is associated with anatomical markers that do not relate to other reading-related cognitive abilities. Thus, individualdifferences in phonological decoding might relate to connectivity between a network of cortical regions, while skills like sight word reading might rely less strongly on integration across regions. Specifically, manually-drawn ROIs and probabilistic tractography revealed an association between the volume and integrity of white matter underlying primary auditory cortex and nonword reading ability. In a related finding, more extensive cross-hemispheric connections through the isthmus of the corpus callosum predicted better phonological decoding. Atlas-based white matter ROIs demonstrated that relationships with nonword reading were strongest in the inferior fronto-occipital fasciculus and uncinate fasciculus that connect occipital and anterior temporal cortex with inferior frontal cortex. In contrast, tract volume underlying the left angular gyrus was related to nonverbal IQ. Finally, connectivity underlying functional ROIs that are differentially active during phonological and semantic processing predicted nonword reading and reading comprehension, respectively. Together, these results provide important insights into how white matter anatomy may relate to both typical reading subskills, and perhaps a roadmap for understanding neural connectivity in individuals with reading impairments. PMID:24704456
Background. There has been little research on the relative importance of frailty markers. The objective was to investigate the association among seven frailty domains (nutrition, physical activity, mobility, strength, energy, cognition, and mood) and their relative contribution in explaining differences among individuals in five samples of older persons. Methods. Data from five studies of aging were analyzed using multiple correspondence analysis. Aggregation of frailty markers was evaluated using graphical output. Decomposition of variability was used to assess the relative contribution of each marker in each sample. Results were combined across the samples to assess the average contribution. Results. Frailty markers were found to consistently aggregate in each sample, suggesting a possible underlying construct. Physical strength had the highest contribution on average in explaining differences among individuals. Mobility and energy also had large contributions. Nutrition and cognition had the smallest contributions. Conclusions. Our results provide further evidence supporting the notion that frailty domains may belong to a common construct. Physical strength may be the most important discriminating characteristic.
Sourial, Nadia; Karunananthan, Sathya; Wolfson, Christina; Guralnik, Jack; Payette, Helene; Gutierrez-Robledo, Luis; Deeg, Dorly J. H.; Fletcher, John D.; Puts, Maria T. E.; Zhu, Bin; Beland, Francois
Affiliative relationship formation in nonhuman primates is known to be influenced by kinship, rank, and sex, but such factors do not fully explain observed variation in primate social relations. Individualdifferences in temperament have a number of important behavioural and physiological correlates that might influence relationship formation. We observed 57 yearling rhesus macaques at the California National Primate Research Center for 10 weeks to determine whether individualdifferences in temperament relate to the number and quality of affiliative relationships formed with peers. Subjects’ temperament characteristics had previously been quantified during a colony-wide biobehavioural assessment at 90–120 days of age. Yearlings that had scored high on Equability (demonstrating calmness and low levels of physical activity) as infants had fewer peer relationships compared to animals low on this dimension. Additionally, yearlings preferentially affiliated with peers that were similar to themselves in Equability as well as in Adaptability (reflecting the degree of behavioural flexibility that subjects displayed during the biobehavioural assessment). Although kinship, rank, and sex influenced relationship formation as expected, temperament remained a significant predictor of affiliative preferences even after controlling for these variables. Our findings suggest that temperament is a proximate determinant of variation in affiliative relationship formation in group-living primates.
The Iowa Gambling Task (IGT) is widely used in investigations of decision making. A growing number of studies have linked performance on this task to personality differences, with the aim of explaining the large degree of variability in healthy individuals' performance of the task. However, this line of research has yielded inconsistent results. In the present study, we tested whether increasing the conflict between short-term and long-term gains in the IGT can clarify personality-related modulations of decision making. We assessed performance on the original IGT as a function of the personality traits typically involved in risky decision making (i.e., impulsivity, sensation seeking, sensitivity to reward and punishment). The impact of these same personality traits was also evaluated on a modified version of the task in which the difference in immediate reward magnitude between disadvantageous and advantageous decks was increased, while keeping the net gain fixed. The results showed that only in this latter IGT variant were highly impulsive individuals and high sensation seekers lured into making disadvantageous choices. The opposite seems to be the case for participants who were highly sensitive to punishment, although further data are needed to corroborate this finding. The present preliminary results suggest that the IGT variant used in this study could be more effective than the original task at identifying personality effects in decision making. Implications for dispositional and situational effects on decision making are discussed.
Penolazzi, Barbara; Leone, Luigi; Russo, Paolo Maria
There is a widespread belief that weather affects mood. However, few studies have investigated this link, and even less is known about individualdifferences in people's responses to the weather. In the current study, we sought to identify weather reactivity types by linking self-reported daily mood across 30 days with objective weather data. We identified four distinct types among 497 adolescents and replicated these types among their mothers. The types were labeled Summer Lovers (better mood with warmer and sunnier weather), Unaffected (weak associations between weather and mood), Summer Haters (worse mood with warmer and sunnier weather), and Rain Haters (particularly bad mood on rainy days). In addition, intergenerational concordance effects were found for two of these types, suggesting that weather reactivity may run in the family. Overall, the large individualdifferences in how people's moods were affected by weather reconciles the discrepancy between the generally held beliefs that weather has a substantive effect on mood and findings from previous research indicating that effects of weather on mood are limited or absent. PMID:21842988
Klimstra, Theo A; Frijns, Tom; Keijsers, Loes; Denissen, Jaap J A; Raaijmakers, Quinten A W; van Aken, Marcel A G; Koot, Hans M; van Lier, Pol A C; Meeus, Wim H J
Maternal infection during pregnancy elevates risk for schizophrenia and related disorders in offspring. Converging evidence suggests the maternal inflammatory response mediates the interaction between maternal infection, altered brain development, and behavioral outcome. The extent to which individualdifferences in the maternal response to immune challenge influence the development of these abnormalities is unknown. The present study investigated the impact of individualdifferences in maternal response to the viral mimic polyinosinic:polycytidylic acid (poly I:C) on offspring behavior. We observed significant variability in body weight alterations of pregnant rats induced by administration of poly I:C on gestational day 14. Furthermore, the presence or absence of maternal weight loss predicted MK-801 and amphetamine stimulated locomotor abnormalities in offspring. MK-801 stimulated locomotion was altered in offspring of all poly I:C treated dams; however, the presence or absence of maternal weight loss resulted in decreased and modestly increased locomotion, respectively. Adult offspring of poly I:C treated dams that lost weight exhibited significantly decreased amphetamine stimulated locomotion, while offspring of poly I:C treated dams without weight loss performed similarly to vehicle controls. Social isolation and increased maternal age predicted weight loss in response to poly I:C but not vehicle injection. In combination, these data identify environmental factors associated with the maternal response to immune challenge and functional outcome of offspring exposed to maternal immune activation.
Bronson, Stefanie L.; Ahlbrand, Rebecca; Horn, Paul S.; Kern, Joseph R.; Richtand, Neil M.