Put your mind to it
The Idea of Money Counteracts Ego Depletion Effects
Helen Boucher & Monthe Kofos
Journal of Experimental Social Psychology, forthcoming
Abstract:
Self-control draws upon a resource that is limited, such that acts of self-control deplete the resource, causing performance on subsequent acts of self-control to suffer. In this research, we demonstrate that activating the concept of money can buffer this ego depletion effect. Across two experiments using varied operationalizations of self-control, participants completed an initial task that depleted self-control resources or not, were then reminded of money or neutral concepts, and finally, completed a second task requiring self-control. In both experiments, among depleted participants, those reminded of money performed better on the second self-control task than those reminded of neutral concepts. Additional analyses in Experiment 2 suggest that this buffering effect was due to money reducing both the subjective difficulty and effort required on the second self-control task.
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A Combination of Dopamine Genes Predicts Success by Professional Wall Street Traders
Steve Sapra, Laura Beavin & Paul Zak
PLoS ONE, January 2012, e30844
Abstract:
What determines success on Wall Street? This study examined if genes affecting dopamine levels of professional traders were associated with their career tenure. Sixty professional Wall Street traders were genotyped and compared to a control group who did not trade stocks. We found that distinct alleles of the dopamine receptor 4 promoter (DRD4P) and catecholamine-O-methyltransferase (COMT) that affect synaptic dopamine were predominant in traders. These alleles are associated with moderate, rather than very high or very low, levels of synaptic dopamine. The activity of these alleles correlated positively with years spent trading stocks on Wall Street. Differences in personality and trading behavior were also correlated with allelic variants. This evidence suggests there may be a genetic basis for the traits that make one a successful trader.
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At 6-9 months, human infants know the meanings of many common nouns
Elika Bergelson & Daniel Swingley
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
It is widely accepted that infants begin learning their native language not by learning words, but by discovering features of the speech signal: consonants, vowels, and combinations of these sounds. Learning to understand words, as opposed to just perceiving their sounds, is said to come later, between 9 and 15 mo of age, when infants develop a capacity for interpreting others' goals and intentions. Here, we demonstrate that this consensus about the developmental sequence of human language learning is flawed: in fact, infants already know the meanings of several common words from the age of 6 mo onward. We presented 6- to 9-mo-old infants with sets of pictures to view while their parent named a picture in each set. Over this entire age range, infants directed their gaze to the named pictures, indicating their understanding of spoken words. Because the words were not trained in the laboratory, the results show that even young infants learn ordinary words through daily experience with language. This surprising accomplishment indicates that, contrary to prevailing beliefs, either infants can already grasp the referential intentions of adults at 6 mo or infants can learn words before this ability emerges. The precocious discovery of word meanings suggests a perspective in which learning vocabulary and learning the sound structure of spoken language go hand in hand as language acquisition begins.
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Positive and Negative Mental Health Consequences of Early Childhood Television Watching
Michael Waldman, Sean Nicholson & Nodir Adilov
NBER Working Paper, January 2012
Abstract:
An extensive literature in medicine investigates the health consequences of early childhood television watching. However, this literature does not address the issue of reverse causation, i.e., does early childhood television watching cause specific health outcomes or do children more likely to have these health outcomes watch more television? This paper uses a natural experiment to investigate the health consequences of early childhood television watching and so is not subject to questions concerning reverse causation. Specifically, we use repeated cross-sectional data from 1972 through 1992 on county-level mental retardation rates, county-level autism rates, and county-level children's cable-television subscription rates to investigate how early childhood television watching affects the prevalence of mental retardation and autism. We find a strong negative correlation between average county-level cable subscription rates when a birth cohort is below three and subsequent mental retardation diagnosis rates, but a strong positive correlation between the same cable subscription rates and subsequent autism diagnosis rates. Our results thus suggest that early childhood television watching has important positive and negative health consequences.
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Familial Linkage between Neuropsychiatric Disorders and Intellectual Interests
Benjamin Campbell & Samuel Wang
PLoS ONE, January 2012, e30405
Abstract:
From personality to neuropsychiatric disorders, individual differences in brain function are known to have a strong heritable component. Here we report that between close relatives, a variety of neuropsychiatric disorders covary strongly with intellectual interests. We surveyed an entire class of high-functioning young adults at an elite university for prospective major, familial incidence of neuropsychiatric disorders, and demographic and attitudinal questions. Students aspiring to technical majors (science/mathematics/engineering) were more likely than other students to report a sibling with an autism spectrum disorder (p = 0.037). Conversely, students interested in the humanities were more likely to report a family member with major depressive disorder (p = 8.8×10-4), bipolar disorder (p = 0.027), or substance abuse problems (p = 1.9×10-6). A combined PREdisposition for Subject MattEr (PRESUME) score based on these disorders was strongly predictive of subject matter interests (p = 9.6×10-8). Our results suggest that shared genetic (and perhaps environmental) factors may both predispose for heritable neuropsychiatric disorders and influence the development of intellectual interests.
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David Moreau et al.
Journal of Individual Differences, Spring 2012, Pages 83-88
Abstract:
This experiment investigated the relationship between mental rotation and sport training. Undergraduate university students (n = 62) completed the Mental Rotation Test (Vandenberg & Kuse, 1978), before and after a 10-month training in two different sports, which either involved extensive mental rotation ability (wrestling group) or did not (running group). Both groups showed comparable results in the pretest, but the wrestling group outperformed the running group in the posttest. As expected from previous studies, males outperformed women in the pretest and the posttest. Besides, self-reported data gathered after both sessions indicated an increase in adaptive strategies following training in wrestling, but not subsequent to training in running. These findings demonstrate the significant effect of training in particular sports on mental rotation performance, thus showing consistency with the notion of cognitive plasticity induced from motor training involving manipulation of spatial representations. They are discussed within an embodied cognition framework.
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Genetic contributions to stability and change in intelligence from childhood to old age
Ian Deary et al.
Nature, 9 February 2012, Pages 212-215
Abstract:
Understanding the determinants of healthy mental ageing is a priority for society today. So far, we know that intelligence differences show high stability from childhood to old age and there are estimates of the genetic contribution to intelligence at different ages. However, attempts to discover whether genetic causes contribute to differences in cognitive ageing have been relatively uninformative. Here we provide an estimate of the genetic and environmental contributions to stability and change in intelligence across most of the human lifetime. We used genome-wide single nucleotide polymorphism (SNP) data from 1,940 unrelated individuals whose intelligence was measured in childhood (age 11 years) and again in old age (age 65, 70 or 79 years). We use a statistical method that allows genetic (co)variance to be estimated from SNP data on unrelated individuals. We estimate that causal genetic variants in linkage disequilibrium with common SNPs account for 0.24 of the variation in cognitive ability change from childhood to old age. Using bivariate analysis, we estimate a genetic correlation between intelligence at age 11 years and in old age of 0.62. These estimates, derived from rarely available data on lifetime cognitive measures, warrant the search for genetic causes of cognitive stability and change.
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Ambiguity aversion and familiarity bias: Evidence from behavioral and gene association studies
Soo Hong Chew, Richard Ebstein & Songfa Zhong
Journal of Risk and Uncertainty, February 2012, Pages 1-18
Abstract:
It is increasingly recognized that decision making under uncertainty depends not only on probabilities, but also on psychological factors such as ambiguity and familiarity. Using 325 Beijing subjects, we conduct a neurogenetic study of ambiguity aversion and familiarity bias in an incentivized laboratory setting. For ambiguity aversion, 49.4% of the subjects choose to bet on the 50-50 deck despite the unknown deck paying 20% more. For familiarity bias, 39.6% choose the bet on Beijing's temperature rather than the corresponding bet with Tokyo even though the latter pays 20% more. We genotype subjects for anxiety-related candidate genes and find a serotonin transporter polymorphism being associated with familiarity bias, but not ambiguity aversion, while the dopamine D5 receptor gene and estrogen receptor beta gene are associated with ambiguity aversion only among female subjects. Our findings contribute to understanding of decision making under uncertainty beyond revealed preference.
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Kenneth Kishida et al.
Philosophical Transactions of the Royal Society: Biological Sciences, 5 March 2012, Pages 704-716
Abstract:
Measures of intelligence, when broadcast, serve as salient signals of social status, which may be used to unjustly reinforce low-status stereotypes about out-groups' cultural norms. Herein, we investigate neurobehavioural signals manifest in small (n = 5) groups using functional magnetic resonance imaging and a ‘ranked group IQ task' where implicit signals of social status are broadcast and differentiate individuals based on their expression of cognitive capacity. We report an initial overall decrease in the expression of cognitive capacity in the small group setting. However, the environment of the ‘ranked group IQ task' eventually stratifies the population into two groups (‘high performers', HP and ‘low performers', LP) identifiable based on changes in estimated intelligence quotient and brain responses in the amygdala and dorsolateral prefrontal cortex. In addition, we demonstrate signals in the nucleus accumbens consistent with prediction errors in expected changes in status regardless of group membership. Our results suggest that individuals express diminished cognitive capacity in small groups, an effect that is exacerbated by perceived lower status within the group and correlated with specific neurobehavioural responses. The impact these reactions have on intergroup divisions and conflict resolution requires further investigation, but suggests that low-status groups may develop diminished capacity to mitigate conflict using non-violent means.
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Bogdan Kostic, Chastity McFarlan & Anne Cleary
Journal of Experimental Psychology: Learning, Memory, and Cognition, forthcoming
Abstract:
Recent work (e.g., Nairne & Pandeirada, 2010) has shown that words are remembered better when they have been processed for their survival value in a grasslands context than when processed in other contexts. It has been suggested that this is because human memory systems were shaped by evolution specifically to help humans survive. Thus far, the survival processing advantage has mainly been shown with grasslands contexts, which are thought to be particularly relevant to human evolution. The present study demonstrated the survival processing advantage with other contexts (e.g., lost in a jungle), including with contexts that should not, in and of themselves, be relevant to human evolution (e.g., lost in outer space). We further examined whether implied social isolation plays a critical role in the survival advantage to memory by comparing scenarios in which the person is alone versus with other people present (e.g., lost at sea alone or with others), and whether the perceived source of danger is social isolation or other human attackers. A survival advantage was shown in both the isolation and the group settings, and whether the primary source of danger was isolation or other human attackers did not matter. These findings suggest that the survival advantage in memory is not dependent on evolutionarily relevant physical contexts (e.g., grasslands) or particular sources of perceived danger (social isolation vs. perceived attackers), showing the advantage to be robust and applicable to a variety of scenarios.
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Arne Öhman et al.
Journal of Cognitive Psychology, January 2012, Pages 17-32
Abstract:
In this paper we present an evolutionary analysis of attention to stimuli that are threatening from an evolutionary perspective, such as angry faces and snakes. We review data showing that angry, photographically depicted angry faces are more rapidly detected than happy faces in a visual search setting provided that they are male and that distractors are redundant in the sense that they are drawn from a small set of faces. Following Isbell's (2009) novel Snake Detection Theory, we predicted that snakes, as the prototypical predators, should be more rapidly detected than spiders, given that spiders have provided less of a predatory threat for primates. We review a series of experiments from our laboratory showing that snakes indeed are more rapidly detected than spiders provided that the target stimuli are presented in a demanding visual context, such as many distractor stimuli, or in peripheral vision. Furthermore, they are more distracting than spiders on the performance of a primary attention task. Because snakes were not affected by perceptual load, whereas spiders followed the usual rule of better detection with low perceptual load, we concluded that attending to snakes might constitute an evolutionary adaptation.
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The Association Between Physicians' Cognitive Skills and Quality of Diabetes Care
Brian Hess et al.
Academic Medicine, February 2012, Pages 157-163
Purpose: To examine the association between physicians' cognitive skills and their performance on a composite measure of diabetes care that included process, outcome, and patient experience measures.
Method: The sample was 676 physicians from the United States with time-limited certification in general internal medicine between 2005 and 2009. Scores from the American Board of Internal Medicine (ABIM) internal medicine maintenance of certification (MOC) examination were used to measure practicing physicians' cognitive skills (scores reflect fund of medical knowledge, diagnostic acumen, and clinical judgment). Practice performance was assessed using a diabetes composite measure aggregated from clinical and patient experience measures obtained from the ABIM Diabetes Practice Improvement Module.
Results: Using multiple regression analyses and controlling for physician and patient characteristics, MOC examination scores were significantly associated with the diabetes composite scores (β = .22, P < .001). The association was particularly stronger with intermediate outcomes than with process and patient experience measures. Performance in the endocrine disease content domain of the examination was more strongly associated with the diabetes composite scores (β = .19, P < .001) than the performance in other medical content domains (β = .06-.14).
Conclusions: Physicians' cognitive skills significantly relate to their performance on a comprehensive composite measure for diabetes care. Although significant, the modest association suggests that there are unique aspects of physician competence captured by each assessment alone and that both must be considered when assessing a physician's ability to provide high-quality care.
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Earthquakes on the Mind: Implications of Disasters for Human Performance
William Helton & James Head
Human Factors: The Journal of the Human Factors and Ergonomics Society, forthcoming
Objective: The present study explored the impact a natural disaster has on human performance.
Background: Previous research indicates that traffic accidents increase after disasters. A plausible explanation for this finding is that disasters induce cognitive disruption and this disruption negatively affects performance (e.g., driving quality).
Method: A total of 16 participants (7 men and 9 women) performed a sustained-attention-to-response task before and after a 7.1-magnitude earthquake. Performance (errors of omission, errors of commission, and reaction time) was compared before and after the earthquake.
Results: Errors of omission increased after the earthquake. Changes in errors of commission and reaction times were, however, dependent on individual differences in stress response to the earthquake.
Conclusion: The results indicate that natural disasters may have a negative impact on performance.
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Anna Vinkhuyzen et al.
Behavior Genetics, March 2012, Pages 187-198
Abstract:
Heritability estimates of general intelligence in adulthood generally range from 75 to 85%, with all heritability due to additive genetic influences, while genetic dominance and shared environmental factors are absent, or too small to be detected. These estimates are derived from studies based on the classical twin design and are based on the assumption of random mating. Yet, considerable positive assortative mating has been reported for general intelligence. Unmodeled assortative mating may lead to biased estimates of the relative magnitude of genetic and environmental factors. To investigate the effects of assortative mating on the estimates of the variance components of intelligence, we employed an extended twin-family design. Psychometric IQ data were available for adult monozygotic and dizygotic twins, their siblings, the partners of the twins and siblings, and either the parents or the adult offspring of the twins and siblings (N = 1314). Two underlying processes of assortment were considered: phenotypic assortment and social homogamy. The phenotypic assortment model was slightly preferred over the social homogamy model, suggesting that assortment for intelligence is mostly due to a selection of mates on similarity in intelligence. Under the preferred phenotypic assortment model, the variance of intelligence in adulthood was not only due to non-shared environmental (18%) and additive genetic factors (44%) but also to non-additive genetic factors (27%) and phenotypic assortment (11%).This non-additive nature of genetic influences on intelligence needs to be accommodated in future GWAS studies for intelligence.
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Nash Unsworth, Gregory Spillers & Gene Brewer
Memory, February 2012, Pages 167-176
Abstract:
Remembering previous experiences from one's personal past is a principal component of psychological well-being, personality, sense of self, decision making, and planning for the future. In the current study the ability to search for autobiographical information in memory was examined by having college students recall their Facebook friends. Individual differences in working memory capacity manifested itself in the search of autobiographical memory by way of the total number of friends remembered, the number of clusters of friends, size of clusters, and the speed with which participants could output their friends' names. Although working memory capacity was related to the ability to search autobiographical memory, participants did not differ in the manner in which they approached the search and used contextual cues to help query their memories. These results corroborate recent theorising, which suggests that working memory is a necessary component of self-generating contextual cues to strategically search memory for autobiographical information.
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Omega-3 polyunsaturated fatty acids and cognition in a college-aged population
Justin Karr, Tyler Grindstaff & Joel Alexander
Experimental and Clinical Psychopharmacology, forthcoming
Abstract:
The cognitive influences of omega-3 polyunsaturated fatty acids (n-3 PUFA) remain unclear throughout the life span. Dietary n-3 PUFA appear cognitively beneficial prenatally and neuroprotective at later age; however, researchers using supplementation designs have reported disparate findings across age groups. Few studies have examined the cognitive impact of n-3 PUFA during young adulthood. This study assessed the cognitive effects of fish oil supplementation at college age, hypothesizing benefits on affect, executive control, inhibition, and verbal learning and memory. College-aged participants were assigned to active (n = 20, 5 men; xage = 19.9, sage = 1.8) or placebo (n = 21, 7 men; xage = 20.4, sage = 1.6) treatments, receiving fish oil (480 mg DHA/720 mg EPA) or coconut oil, respectively. Both groups completed four weeks of supplementation. At baseline and posttreatment, the researchers administered the Rey Auditory Verbal Learning Test (RAVLT; Lezak, 1995), Stroop Color and Word Test (SCWT; Golden & Freshwater, 2002), Trail Making Test (TMT; Corrigan & Hinkeldey, 1987; Gaudino, Geisler, & Squires, 1995; Lezak, 1995), and Positive and Negative Affect Schedule (PANAS; Watson, Clark, & Tellegen, 1988). Repeated-measures ANOVAs indicated no benefits of fish oil on the SCWT, RAVLT Stages 1 to 5, or PANAS. An interaction occurred between condition and time of measurement (i.e., baseline and posttreatment) on RAVLT Stages 6 and 7, and placebo significantly improved TMT performance over fish oil. The benefits of n-3 PUFA on RAVLT performance derived more from depreciated placebo performance than improved performance due to fish oil. The placebo gain on TMT performance likely derived from a learning effect. Together, these results present limited cognitive benefits of n-3 PUFA at college age; however, the treatment may have been subtherapeutic, with a larger sample needed to generalize these results.
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Digit ratio and academic performance in dentistry students
Renato Nicolás Hopp, Juliana Pucci de Moraes & Jacks Jorge
Personality and Individual Differences, April 2012, Pages 643-646
Abstract:
It has been suggested that prenatal testosterone (PT) is positively related to intelligence or learning-ability skills. Digit ratio (2D:4D) is a negative correlate of PT. This study considered the correlations between 2D:4D and success in practical and theoretical examinations in the Dental School curriculum of a Brazilian University. Overall, 80 subjects (40 males) had their right hand palm photographed by a digital camera attached to a standardising device. The index and ring fingers were measured using Adobe Photoshop. Digit ratio was correlated to the grades obtained by the students through four semesters. Theoretical and practical grades were significantly negatively correlated to digit ratio in males (and this was particularly so after the influence of age and hours of study were removed, p = 0.02 and 0.004, respectively), but not in females (p = 0.89 and 0.77, respectively). This finding supports a link between high PT and intelligence in males. Our finding of no relationship between 2D:4D and examination marks in female students, suggests that PT may not influence intelligence in females.
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Steven Young, Christina Brown & Nalini Ambady
Cognition & Emotion, forthcoming
Abstract:
Research suggests that attention is attracted to evolutionary threats (e.g., snakes) due to an evolved "fear-module" that automatically detects biological threats to survival. However, recent evidence indicates that non-evolutionary threats (e.g., guns) capture and hold attention as well, suggesting a more general "threat-relevance" mechanism that directs attentional resources toward any potential danger in the environment. The current research measured how selective attentional resources were influenced both by the type of threat (e.g., snake vs. gun) and by the context in which the threat was encountered. Participants were primed with either natural or human-made environments to assess how these contexts influence attention to evolutionary and non-evolutionary threats, as measured by a spatial-cueing task. The results indicate that whether biological or non-biological threats receive greater attentional processing is determined by the context in which they are encountered.