Kevin Lewis

January 05, 2013

Studying Intellectual Outliers: Are There Sex Differences, and Are the Smart Getting Smarter?

Jonathan Wai, Martha Putallaz & Matthew Makel
Current Directions in Psychological Science, December 2012, Pages 382-390

By studying samples of intellectual outliers across 30 years, researchers can leverage right-tail data (i.e., samples at or above the 95th percentile on tests of ability) to uncover missing pieces to two psychological puzzles: whether there are sex differences in cognitive abilities among smart people, and whether test scores are rising (a phenomenon known as the Flynn effect) among smart people. For the first puzzle, data indicate that the high male-to-female ratio among extremely high scorers on measures of math ability has decreased dramatically, but is still likely one factor among many explaining female underrepresentation in some professions. For the second puzzle, data indicate that the right tail has risen at a similar rate as the general (or middle portion of the) distribution; it is thus likely that the entire curve is rising at a relatively constant rate, consistent with the Flynn effect, which may explain why a greater number of gifted students have been identified in recent years. However, the causes for these gains and whether they reflect real gains in intelligence continue to remain a mystery. We show how these two puzzles are linked and stress the importance of paying attention to the entire distribution when attempting to address some scientific questions.


Fractionating Human Intelligence

Adam Hampshire et al.
Neuron, 20 December 2012, Pages 1225-1237

What makes one person more intellectually able than another? Can the entire distribution of human intelligence be accounted for by just one general factor? Is intelligence supported by a single neural system? Here, we provide a perspective on human intelligence that takes into account how general abilities or "factors" reflect the functional organization of the brain. By comparing factor models of individual differences in performance with factor models of brain functional organization, we demonstrate that different components of intelligence have their analogs in distinct brain networks. Using simulations based on neuroimaging data, we show that the higher-order factor "g" is accounted for by cognitive tasks corecruiting multiple networks. Finally, we confirm the independence of these components of intelligence by dissociating them using questionnaire variables. We propose that intelligence is an emergent property of anatomically distinct cognitive systems, each of which has its own capacity.


Beliefs in being unlucky and deficits in executive functioning

John Maltby et al.
Consciousness and Cognition, March 2013, Pages 137-147

The current paper proposes the Dysexecutive Luck hypothesis; that beliefs in being unlucky are associated with deficits in executive functioning. Four studies suggest initial support for the Dysexecutive Luck hypothesis via four aspects of executive functioning. Study 1 established that self-reports of dysexecutive symptoms predicted unique variance in beliefs in being unlucky after controlling for a number of other variables previously reported to be related to beliefs around luck. Studies 2 to 4 demonstrated support for the Dysexecutive Luck hypothesis via assessment of executive functioning via: (1) two fundamental executive functions (shifting and inhibition), (2) emotional processes related to executive functioning as described by the Somatic Marker hypothesis, and (3) higher executive functions as accessed via divergent thinking. The findings suggest that individuals' beliefs in being unlucky are accompanied by a range of deficits in executive functioning.


Average county-level IQ predicts county-level disadvantage and several county-level mortality risk rates

J.C. Barnes, Kevin Beaver & Brian Boutwell
Intelligence, January-February 2013, Pages 59-66

Research utilizing individual-level data has reported a link between intelligence (IQ) scores and health problems, including early mortality risk. A growing body of evidence has found similar associations at higher levels of aggregation such as the state- and national-level. At the same time, individual-level research has suggested the IQ-mortality risk association may be mediated by socioeconomic status, but no aggregate research has considered this possibility. This paper extended the current knowledge base in two important ways: 1) by analyzing the association between county-level IQ and county-level mortality risk; and 2) by testing a theoretical model where county IQ influences county disadvantage which, in turn, influences county mortality risk. The findings indicated a consistent relationship between county IQ and several measures of county mortality risk. The IQ-mortality risk association was mediated by county disadvantage for some county mortality risk measures but not others, suggesting the relationship between county IQ and county mortality risk is more nuanced than was hypothesized.


Physical growth and cognitive skills in early-life: Evidence from a nationally representative US birth cohort

Jason Murasko
Social Science & Medicine, forthcoming

This paper establishes associations between length/height and cognitive skills in infancy, toddlerhood, and school-entry. The data come from the Early Childhood Longitudinal Study - Birth Cohort (ECLS-B), a representative longitudinal sample of US children born in 2001. A positive association between length/height and cognition is found as early as 9 months and continues through school-entry. These associations are robust to controls for birthweight and economic status. Early growth is also shown to be a stronger predictor of reading and math skills in kindergarten than attained height. Girls exhibit stronger evidence of this latter result than boys. These findings have implications for the interpretation of early life as a critical period for the growth-cognition relationship.


Siblings, Theory of Mind, and Executive Functioning in Children Aged 3-6 Years: New Longitudinal Evidence

Anna McAlister & Candida Peterson
Child Development, forthcoming

Longitudinal data were obtained from 157 children aged 3 years 3 months to 5 years 6 months at Time 1. At Time 2 these children had aged an average of 12 months. Theory of mind (ToM) and executive functioning (EF) were measured at both time points. Results suggest that Time 1 ToM scores predict Time 2 EF scores. Detailed examination of sibling influences suggests that benefits - in terms of advanced ToM development - accrue to children with siblings versus without, and to those with a larger number of child-aged siblings. Any advance in either area (ToM or EF) is likely to benefit the other, and early sibling interaction appears to act as a catalyst.


Teams Make You Smarter: How Exposure to Teams Improves Individual Decisions in Probability and Reasoning Tasks

Boris Maciejovsky et al.
Management Science, forthcoming

Many important decisions are routinely made by transient and temporary teams, which perform their duty and disperse. Team members often continue making similar decisions as individuals. We study how the experience of team decision-making affects subsequent individual decisions in two seminal probability and reasoning tasks, the Monty Hall problem and the Wason selection task. Both tasks are hard and involve a general rule, thus allowing for knowledge transfers, and can be embedded in the context of markets that offer identical incentives to teams and individuals. Our results show that teams trade closer to the rational level, learn the solution faster, and achieve this with weaker, less specific, performance feedback than individuals. Most importantly, we observe significant knowledge transfers from team decision-making to subsequent individual performances that take place up to five weeks later, indicating that exposure to team decision-making has strong positive spillovers on the quality of individual decisions.


Relations among peer acceptance, inhibitory control, and math achievement in early adolescence

Eva Oberle & Kimberly Schonert-Reichl
Journal of Applied Developmental Psychology, January-February 2013, Pages 45-51

This study examined relations among peer acceptance, inhibitory control, and math achievement in ninety-nine 4th and 5th grade early adolescents. Teachers rated students on peer acceptance and students completed a computerized executive function task assessing inhibitory control. Math achievement was assessed via end of year math grades. Results indicated that both inhibitory control and peer acceptance were positively and significantly related to math achievement. In addition, peer acceptance significantly mediated the relationship between inhibitory control and math grades when all three variables were entered simultaneously in a linear regression model. These results suggest that peer acceptance is an important indicator of social functioning and plays a significant part in academic success in the classroom. Results also suggest that indicators of social functioning - such as peer acceptance - need to be included in addition to cognitive functioning, when examining academic achievement in early adolescence.


The Association between Perinatal Testosterone Concentration and Early Vocabulary Development: A Prospective Cohort Study

Lauren Hollier et al.
Biological Psychology, February 2013, Pages 212-215

Prenatal exposure to testosterone is known to affect fetal brain maturation and later neurocognitive function. However, research on the effects of prenatal testosterone exposure has been limited by indirect measures of testosterone and small unrepresentative samples. This study investigated whether bioavailable testosterone (BioT) concentrations in umbilical cord blood are associated with expressive vocabulary development, in a large birth cohort. Cord blood samples were taken immediately after delivery and expressive vocabulary was measured at two years of age using the Language Development Survey (LDS). BioT concentration significantly predicted vocabulary size in males (n = 197), such that higher concentrations were associated with lower LDS scores, indicating smaller vocabulary. This relationship between BioT concentrations and vocabulary at aged 2 years was not observed in girls (n= 176). Higher circulating prenatal testosterone concentrations at birth may be associated with reduced vocabulary in early childhood among boys.


Effects of a school-based instrumental music program on verbal and visual memory in primary school children: A longitudinal study

Ingo Roden, Gunter Kreutz & Stephan Bongard
Frontiers in Psychology, December 2012

This study examined the effects of a school-based instrumental training program on the development of verbal and visual memory skills in primary school children. Participants either took part in a music program with weekly 45 min sessions of instrumental lessons in small groups at school, or they received extended natural science training. A third group of children did not receive additional training. Each child completed verbal and visual memory tests three times over a period of 18 months. Significant Group by Time interactions were found in the measures of verbal memory. Children in the music group showed greater improvements than children in the control groups after controlling for children's socio-economic background, age, and IQ. No differences between groups were found in the visual memory tests. These findings are consistent with and extend previous research by suggesting that children receiving music training may benefit from improvements in their verbal memory skills.


Education Is Associated With Higher Later Life IQ Scores, but Not With Faster Cognitive Processing Speed

Stuart Ritchie et al.
Psychology and Aging, forthcoming

Recent reports suggest a causal relationship between education and IQ, which has implications for cognitive development and aging-education may improve cognitive reserve. In two longitudinal cohorts, we tested the association between education and lifetime cognitive change. We then tested whether education is linked to improved scores on processing-speed variables such as reaction time, which are associated with both IQ and longevity. Controlling for childhood IQ score, we found that education was positively associated with IQ at ages 79 (Sample 1) and 70 (Sample 2), and more strongly for participants with lower initial IQ scores. Education, however, showed no significant association with processing speed, measured at ages 83 and 70. Increased education may enhance important later life cognitive capacities, but does not appear to improve more fundamental aspects of cognitive processing.


The development of creative cognition across adolescence: Distinct trajectories for insight and divergent thinking

Sietske Kleibeuker, Carsten De Dreu & Eveline Crone
Developmental Science, January 2013, Pages 2-12

We examined developmental trajectories of creative cognition across adolescence. Participants (N = 98), divided into four age groups (12/13 yrs, 15/16 yrs, 18/19 yrs, and 25-30 yrs), were subjected to a battery of tasks gauging creative insight (visual; verbal) and divergent thinking (verbal; visuo-spatial). The two older age groups outperformed the two younger age groups on insight tasks. The 25-30-year-olds outperformed the two youngest age groups on the originality measure of verbal divergent thinking. No age-group differences were observed for verbal divergent thinking fluency and flexibility. On divergent thinking in the visuo-spatial domain, however, only 15/16-year-olds outperformed 12/13-year-olds; a model with peak performance for 15/16-years-old showed the best fit. The results for the different creativity processes are discussed in relation to cognitive and related neurobiological models. We conclude that mid-adolescence is a period of not only immaturities but also of creative potentials in the visuo-spatial domain, possibly related to developing control functions and explorative behavior.


Forty Years On: Childhood Intelligence Predicts Health in Middle Adulthood

Marius Wrulich et al.
Health Psychology, forthcoming

Objective: To investigate whether childhood general intelligence, fluid intelligence (Gf), and crystallized intelligence (Gc) predict various health outcomes in middle adulthood.

Method: This prospective longitudinal study followed a nationally representative sample of 717 Luxembourgers. Intelligence and socioeconomic status (SES) were measured at age 12; physical, functional, and subjective health were assessed at age 52.

Results: Childhood general intelligence and fluid intelligence showed substantial positive effects on adult health outcomes, whereas the corresponding effects of crystallized intelligence were considerably smaller.

Conclusion: Childhood intelligence incrementally predicts various dimensions of adult health across 40 years-even in a country in which all citizens are guaranteed access to high-quality health care.


Incubation and creativity: Do something different

Ken Gilhooly, George Georgiou & Ultan Devery
Thinking & Reasoning, forthcoming

The experiment reported here investigated interactions between the type of creative task (verbal or spatial) and the type of incubation activity (verbal or spatial) on creative performance. The experiment used a verbal creative divergent thinking task (Alternative Uses) and a spatial creative task (Mental Synthesis). After 5 minutes of conscious work on Alternative Uses or Mental Synthesis, experimental groups had 5-minute incubation periods which involved either spatial (Mental Rotation) or verbal tasks (Anagrams). Following incubation, the experimental participants resumed their main task for a further 5 minutes. Control groups undertook Alternative Uses or Mental Synthesis for 10 minutes without any incubation periods. Significant incubation effects were found overall and there were interactions in that spatial incubation benefited verbal fluency and verbal-rated creativity, and verbal incubation benefited spatial-task fluency and spatial-rated creativity but not vice versa. The results supported a role for unconscious work during incubation periods in creative thinking tasks and did not support the hypotheses that incubation effects are due to selective forgetting or attention shifting.


Selling points: What cognitive abilities are tapped by casual video games?

Pauline Baniqued et al.
Acta Psychologica, January 2013, Pages 74-86

The idea that video games or computer-based applications can improve cognitive function has led to a proliferation of programs claiming to "train the brain." However, there is often little scientific basis in the development of commercial training programs, and many research-based programs yield inconsistent or weak results. In this study, we sought to better understand the nature of cognitive abilities tapped by casual video games and thus reflect on their potential as a training tool. A moderately large sample of participants (n = 209) played 20 web-based casual games and performed a battery of cognitive tasks. We used cognitive task analysis and multivariate statistical techniques to characterize the relationships between performance metrics. We validated the cognitive abilities measured in the task battery, examined a task analysis-based categorization of the casual games, and then characterized the relationship between game and task performance. We found that games categorized to tap working memory and reasoning were robustly related to performance on working memory and fluid intelligence tasks, with fluid intelligence best predicting scores on working memory and reasoning games. We discuss these results in the context of overlap in cognitive processes engaged by the cognitive tasks and casual games, and within the context of assessing near and far transfer. While this is not a training study, these findings provide a methodology to assess the validity of using certain games as training and assessment devices for specific cognitive abilities, and shed light on the mixed transfer results in the computer-based training literature. Moreover, the results can inform design of a more theoretically-driven and methodologically-sound cognitive training program.


Meta-analysis of LCPUFA Supplementation of Infant Formula and Visual Acuity

Ahmad Qawasmi, Angeli Landeros-Weisenberger & Michael Bloch
Pediatrics, 1 January 2013, Pages e262 -e272

Background and objective: Long-chain polyunsaturated fatty acids (LCPUFAs) are hypothesized to affect visual acuity development in infants. Randomized controlled trials (RCTs) have been conducted to assess whether supplementation of LCPUFAs of infant formulas affects infant visual acuity. This meta-analysis was conducted to evaluate whether LCPUFA supplementation of infant formulas improves infants' visual acuity.

Methods: PubMed and PsycInfo were searched for RCTs assessing the efficacy of LCPUFA supplementation of infant formulas on infant visual acuity. RCTs assessing the effects of LCPUFA supplementation on visual acuity (by using either visual evoked potential or behavioral methods) in the first year of life were included in this meta-analysis. Our primary outcome was the mean difference in visual resolution acuity (measured in logarithm of minimum angle of resolution [logMAR]) between supplemented and unsupplemented infants. We also conducted secondary subgroup analyses and meta-regression examining the effects of LCPUFA dose and timing, preterm versus term birth status, and trial methodologic quality.

Results: Nineteen studies involving 1949 infants were included. We demonstrated a significant benefit of LCPUFA supplementation on infants' visual acuity at 2, 4, and 12 months of age when visual acuity was assessed by using visual evoked potential and at 2 months of age by using behavioral methods. There was significant heterogeneity between trials but no evidence of publication bias. Secondary analysis failed to show any moderating effects on the association between LCPUFA supplementation and visual acuity.

Conclusions: Current evidence suggests that LCPUFA supplementation of infant formulas improves infants' visual acuity up to 12 months of age.

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