Brainpower
Justin Arneson, Paul Sackett & Adam Beatty
Psychological Science, October 2011, Pages 1336-1342
Abstract:
The nature of the relationship between ability and performance is of critical importance for admission decisions in the context of higher education and for personnel selection. Although previous research has supported the more-is-better hypothesis by documenting linearity of ability-performance relationships, such research has not been sensitive enough to detect deviations at the top ends of the score distributions. An alternative position receiving considerable attention is the good-enough hypothesis, which suggests that although higher levels of ability may result in better performance up to a threshold, above this threshold greater ability does not translate to better performance. In this study, the nature of the relationship between cognitive ability and performance was examined throughout the score range in four large-scale data sets. Monotonicity was maintained in all instances. Contrary to the good-enough hypothesis, the ability-performance relationship was commonly stronger at the top end of the score distribution than at the bottom end.
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Limits on the Predictive Power of Domain-Specific Experience and Knowledge in Skilled Performance
David Hambrick & Elizabeth Meinz
Current Directions in Psychological Science, October 2011, Pages 275-279
Abstract:
It is clear from decades of research that, to a very large degree, success in music, games, sports, science, and other complex domains reflects knowledge and skills acquired through experience. However, it is equally clear that basic abilities, which are known to be substantially heritable, also contribute to performance differences in many domains, even among highly skilled performers. As we discuss here, our research shows that working memory capacity predicts performance in complex tasks even in individuals with high levels of domain-specific experience and knowledge. We discuss implications of our findings for the understanding of individual differences in skill and identify challenges for future research.
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IQ, skin color, crime, HIV/AIDS, and income in 50 U.S. states
Donald Templer & Philippe Rushton
Intelligence, forthcoming
Abstract:
In 50 U.S. states, we found a positive manifold across 11 measures including IQ, skin color, birth rate, infant mortality, life expectancy, HIV/AIDS, violent crime, and state income with the first principal component accounting for 33% of the variance (median factor loading = .34). The correlation with a composite of total violent crime was higher with skin color (r = .55), a more biologically influenced variable than with GDP (r = -.17), a more culturally influenced variable. These results corroborate and extend those found at the international level using INTERPOL crime statistics and at the county, provincial, and state levels within countries using local statistics. We interpret the cross-cultural consistency from an evolutionary life history perspective in which hierarchically organized traits culminate in a single, heritable, super-factor. Traits need to be genetically organized to meet the trials of life - survival, growth, and reproduction. We discuss brain size and the g nexus as central to understand individual and group differences and we highlight melanin and skin color as a potentially important new life history variable.
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The Wiring Economy Principle: Connectivity Determines Anatomy in the Human Brain
Ashish Raj & Yu-hsien Chen
PLoS ONE, September 2011, e14832
Abstract:
Minimization of the wiring cost of white matter fibers in the human brain appears to be an organizational principle. We investigate this aspect in the human brain using whole brain connectivity networks extracted from high resolution diffusion MRI data of 14 normal volunteers. We specifically address the question of whether brain anatomy determines its connectivity or vice versa. Unlike previous studies we use weighted networks, where connections between cortical nodes are real-valued rather than binary off-on connections. In one set of analyses we found that the connectivity structure of the brain has near optimal wiring cost compared to random networks with the same number of edges, degree distribution and edge weight distribution. A specifically designed minimization routine could not find cheaper wiring without significantly degrading network performance. In another set of analyses we kept the observed brain network topology and connectivity but allowed nodes to freely move on a 3D manifold topologically identical to the brain. An efficient minimization routine was written to find the lowest wiring cost configuration. We found that beginning from any random configuration, the nodes invariably arrange themselves in a configuration with a striking resemblance to the brain. This confirms the widely held but poorly tested claim that wiring economy is a driving principle of the brain. Intriguingly, our results also suggest that the brain mainly optimizes for the most desirable network connectivity, and the observed brain anatomy is merely a result of this optimization.
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Short-Term Music Training Enhances Verbal Intelligence and Executive Function
Sylvain Moreno et al.
Psychological Science, forthcoming
Abstract:
Researchers have designed training methods that can be used to improve mental health and to test the efficacy of education programs. However, few studies have demonstrated broad transfer from such training to performance on untrained cognitive activities. Here we report the effects of two interactive computerized training programs developed for preschool children: one for music and one for visual art. After only 20 days of training, only children in the music group exhibited enhanced performance on a measure of verbal intelligence, with 90% of the sample showing this improvement. These improvements in verbal intelligence were positively correlated with changes in functional brain plasticity during an executive-function task. Our findings demonstrate that transfer of a high-level cognitive skill is possible in early childhood.
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Intelligence and attractiveness in the face: Beyond the attractiveness halo effect
F.R. Moore, D. Filippou & D.I. Perrett
Journal of Evolutionary Psychology, September 2011, Pages 205-217
Abstract:
Positive relationships between perceived intelligence, actual intelligence and facial attractiveness have been attributed to (a) an attractiveness halo effect in which attractive individuals are attributed with positive personality traits and (b) a "good genes" model of mate choice. We sought to determine whether cues to intelligence exist in the face beyond an attractiveness halo effect and to explore relationships between residual cues to intelligence and personality attributions in male and female faces. In Study 1, we attempted to parametrically manipulate the perceived intelligence of faces while controlling for attractiveness. Results demonstrated that we manipulated perceived intelligence but may not have adequately controlled for an attractiveness halo effect: faces that were manipulated to look high in perceived intelligence were rated as more attractive. In Study 2, we found perceived intelligence to be related positively to perceived friendliness and sense of humour in male and female faces and inversely to perceived dominance in female faces. Results are discussed in the context of models of "good genes" and "attractiveness halo" models of the relationships between intelligence and attractiveness.
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Albert Link & Christopher Ruhm
NBER Working Paper, September 2011
Abstract:
In this paper we show that the patenting behavior of creative entrepreneurs is correlated with the patenting behavior of their fathers, which we refer to as a source of the entrepreneurs' human capital endowments. Our argument for this relationship follows from established theories of developmental creativity, and our empirical analysis is based on survey data collected from MIT's Technology Review winners.
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A Specific Brain Structural Basis for Individual Differences in Reality Monitoring
Marie Buda et al.
Journal of Neuroscience, 5 October 2011, Pages 14308-14313
Abstract:
Much recent interest has centered on understanding the relationship between brain structure variability and individual differences in cognition, but there has been little progress in identifying specific neuroanatomical bases of such individual differences. One cognitive ability that exhibits considerable variability in the healthy population is reality monitoring; the cognitive processes used to introspectively judge whether a memory came from an internal or external source (e.g., whether an event was imagined or actually occurred). Neuroimaging research has implicated the medial anterior prefrontal cortex (PFC) in reality monitoring, and here we sought to determine whether morphological variability in a specific anteromedial PFC brain structure, the paracingulate sulcus (PCS), might underlie performance. Fifty-three healthy volunteers were selected on the basis of MRI scans and classified into four groups according to presence or absence of the PCS in their left or right hemisphere. The group with absence of the PCS in both hemispheres showed significantly reduced reality monitoring performance and ability to introspect metacognitively about their performance when compared with other participants. Consistent with the prediction that sulcal absence might mean greater volume in the surrounding frontal gyri, voxel-based morphometry revealed a significant negative correlation between anterior PFC gray matter and reality monitoring performance. The findings provide evidence that individual differences in introspective abilities like reality monitoring may be associated with specific structural variability in the PFC.
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Bethany Stangl, Elliot Hirshman & Joseph Verbalis
Behavioral Neuroscience, October 2011, Pages 742-752
Abstract:
The current article examines the effect of administering dehydroepiandrosterone (DHEA) on visual-spatial performance in postmenopausal women (N = 24, ages 55-80). The concurrent reduction of serum DHEA levels and visual-spatial performance in this population, coupled with the documented effects of DHEA's androgenic metabolites on visual-spatial performance, suggests that DHEA administration may enhance visual-spatial performance. The current experiment used a double-blind, placebo-controlled crossover design in which 50 mg of oral DHEA was administered daily in the drug condition to explore this hypothesis. Performance on the Mental Rotation, Subject-Ordered Pointing, Fragmented Picture Identification, Perceptual Identification, Same-Different Judgment, and Visual Search tasks and serum levels of DHEA, DHEAS, testosterone, estrone, and cortisol were measured in the DHEA and placebo conditions. In contrast to prior experiments using the current methodology that did not demonstrate effects of DHEA administration on episodic and short-term memory tasks, the current experiment demonstrated large beneficial effects of DHEA administration on Mental Rotation, Subject-Ordered Pointing, Fragmented Picture Identification, Perceptual Identification, and Same-Different Judgment. Moreover, DHEA administration enhanced serum levels of DHEA, DHEAS, testosterone, and estrone, and regression analyses demonstrated that levels of DHEA and its metabolites were positively related to cognitive performance on the visual-spatial tasks in the DHEA condition.
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Gil Greengross, Rod Martin & Geoffrey Miller
Psychology of Aesthetics, Creativity, and the Arts, forthcoming
Abstract:
Individual differences in humor production ability are understudied, especially among experts. This is the first quantitative study of personality traits, humor production ability, humor styles, and intelligence among stand-up comedians. It analyzes data from 31 comedians and 400 college students with regard to the Big Five personality traits (NEO-FFI-R), the Humor Styles Questionnaire (HSQ), a humor production task, verbal intelligence, and, for the comedians, a measure of professional success. Comedians scored higher than students on verbal intelligence, humor production ability, and each of the four styles of humor. Among comedians, openness, agreeableness, and extraversion correlated positively with affiliative humor, and intelligence correlated negatively with self-defeating humor. Professional success was predicted positively by affiliative humor and negatively by self-defeating humor.
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Cerebral Blood Flow during Rest Associates with General Intelligence and Creativity
Hikaru Takeuchi et al.
PLoS ONE, September 2011, e25532
Abstract:
Recently, much scientific attention has been focused on resting brain activity and its investigation through such methods as the analysis of functional connectivity during rest (the temporal correlation of brain activities in different regions). However, investigation of the magnitude of brain activity during rest has focused on the relative decrease of brain activity during a task, rather than on the absolute resting brain activity. It is thus necessary to investigate the association between cognitive factors and measures of absolute resting brain activity, such as cerebral blood flow (CBF), during rest (rest-CBF). In this study, we examined this association using multiple regression analyses. Rest-CBF was the dependent variable and the independent variables included two essential components of cognitive functions, psychometric general intelligence and creativity. CBF was measured using arterial spin labeling and there were three analyses for rest-CBF; namely mean gray matter rest-CBF, mean white matter rest-CBF, and regional rest-CBF. The results showed that mean gray and white matter rest-CBF were significantly and positively correlated with individual psychometric intelligence. Furthermore, mean white matter rest-CBF was significantly and positively correlated with creativity. After correcting the effect of mean gray matter rest-CBF the significant and positive correlation between regional rest-CBF in the perisylvian anatomical cluster that includes the left superior temporal gyrus and insula and individual psychometric intelligence was found. Also, regional rest-CBF in the precuneus was significantly and negatively correlated with individual creativity. Significance of these results of regional rest-CBF did not change when the effect of regional gray matter density was corrected. The findings showed mean and regional rest-CBF in healthy young subjects to be correlated with cognitive functions. The findings also suggest that, even in young cognitively intact subjects, resting brain activity (possibly underlain by default cognitive activity or metabolic demand from developed brain structures) is associated with cognitive functions.
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Anton Lager et al.
International Journal of Epidemiology, forthcoming
Background: Intelligence at a single time-point has been linked to health outcomes. An individual's IQ increases with longer schooling, but the validity of such increase is unclear. In this study, we assess the hypothesis that individual change in the performance on IQ tests between ages 10 and 20 years is associated with mortality later in life.
Methods: The analyses are based on a cohort of Swedish boys born in 1928 (n = 610) for whom social background data were collected in 1937, IQ tests were carried out in 1938 and 1948 and own education and mortality were recorded up to 2006. Structural equation models were used to estimate the extent to which two latent intelligence scores, at ages 10 and 20 years, manifested by results on the IQ tests, are related to paternal and own education, and how all these variables are linked to all-cause mortality.
Results: Intelligence at the age of 20 years was associated with lower mortality in adulthood, after controlling for intelligence at the age of 10 years. The increases in intelligence partly mediated the link between longer schooling and lower mortality. Social background differences in adult intelligence (and consequently in mortality) were partly explained by the tendency for sons of more educated fathers to receive longer schooling, even when initial intelligence levels had been accounted for.
Conclusions: The results are consistent with a causal link from change in intelligence to mortality, and further, that schooling-induced changes in IQ scores are true and bring about lasting changes in intelligence. In addition, if both these interpretations are correct, social differences in access to longer schooling have consequences for social differences in both adult intelligence and adult health.
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Hormones and cognitive functioning during late pregnancy and postpartum: A longitudinal study
Jessica Henry & Barbara Sherwin
Behavioral Neuroscience, forthcoming
Abstract:
This longitudinal study investigated the possible influence of estradiol (E2), progesterone (P), testosterone (T), cortisol (CORT), and prolactin (PRL) levels on cognitive functioning during late pregnancy and the early postpartum period. The performance of 55 pregnant women on a battery of neuropsychological tests, tested once during the third trimester of pregnancy and once during the early postpartum period, was compared with that of 21 nonpregnant controls matched for age and education. Women in the pregnancy group had significantly lower scores than the controls during both the pre- and postpartum visits on tasks of verbal recall and processing speed. CORT levels were significantly associated, in an inverted-∪ function, with verbal recall scores at both the pregnancy and at postpartum periods and with spatial abilities at postpartum only. During pregnancy, PRL levels were associated in both a linear and an inverted-∪ function with scores on tests of paragraph recall and in a linear function with scores on tests of executive function. At postpartum, E2 and CORT were negatively associated in a linear fashion with attention scores. These findings provide new evidence that fluctuating hormone levels during late pregnancy and early postpartum may modulate selected cognitive abilities.
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GSM mobile phone radiation suppresses brain glucose metabolism
Myoung Soo Kwon et al.
Journal of Cerebral Blood Flow & Metabolism, forthcoming
Abstract:
We investigated the effects of mobile phone radiation on cerebral glucose metabolism using high-resolution positron emission tomography (PET) with the 18F-deoxyglucose (FDG) tracer. A long half-life (109 minutes) of the 18F isotope allowed a long, natural exposure condition outside the PET scanner. Thirteen young right-handed male subjects were exposed to a pulse-modulated 902.4 MHz Global System for Mobile Communications signal for 33 minutes, while performing a simple visual vigilance task. Temperature was also measured in the head region (forehead, eyes, cheeks, ear canals) during exposure. 18F-deoxyglucose PET images acquired after the exposure showed that relative cerebral metabolic rate of glucose was significantly reduced in the temporoparietal junction and anterior temporal lobe of the right hemisphere ipsilateral to the exposure. Temperature rise was also observed on the exposed side of the head, but the magnitude was very small. The exposure did not affect task performance (reaction time, error rate). Our results show that short-term mobile phone exposure can locally suppress brain energy metabolism in humans.