Intelligence: genetics, genes, and genomics

More is known about the genetics of intelligence than about any other trait, behavioral or biological, which is selectively reviewed in this article. Two of the most interesting genetic findings are that heritability of intelligence increases throughout the life span and that the same genes affect diverse cognitive abilities. The most exciting direction for genetic research on intelligence is to harness the power of the Human Genome Project to identify some of the specific genes responsible for the heritability of intelligence. The next research direction will be functional genomics--for example, understanding the brain pathways between genes and intelligence. Deoxyribonucleic acid (DNA) will integrate life sciences research on intelligence; bottom-up molecular biological research will meet top-down psychological research in the brain.     

What Explains Boys’ Stronger Confidence in their Intelligence?

This study investigated whether boys’ stronger confidence in their intelligence is explained by gender differences in measured intelligence and gender-stereotypical parental perceptions of their children’s intelligence. Verbal, numeric, figural, and reasoning intelligence and corresponding self-ratings were assessed for 496 German 11th and 12th graders (284 girls; age: M?=?16.95). Parents also rated their children’s intelligence (339 parents; 205 mothers; age: M?=?46.66). With and without controlling for intelligence, boys rated their numerical, figural, and reasoning abilities higher than girls. The same pattern appeared in parental intelligence perceptions. Boys even judged themselves as more intelligent controlling for both measured intelligence and parental intelligence estimates. Thus, neither intelligence nor gender-stereotypical parental perceptions totally explains boys’ stronger confidence in their intelligence.     

Human values: Genetic and environmental effects on five lexically derived domains and their facets

Whereas a substantial genetic component of Conservatism and Religiosity is well documented, there is little evidence with respect to the behavior genetics of other aspects of human values. A sample of 157 monozygotic and 74 dizygotic twins reared together received the Austrian Value Questionnaire (AVQ), which measures a broad variety of value domains and their facets, found by the lexical approach in the German language. Family resemblance of Intellectualism, Harmony, Materialism, and Conservatism was best explained by additive or dominance genetic and non-shared environmental effects, whereas the influence of the environment shared by twins was negligible. In contrast, Religiosity was transmitted by additive genetic, shared and non-shared environmental influences. At the level of facets, the Intellectualism and Harmony showed a homogenous etiology while Religiosity, Materialism, and Conservatism were etiologically heterogeneous.     

Predicting school achievement from cognitive and non-cognitive variables in a Chinese sample of elementary school children

The present study had two aims: First, to investigate the joint and specific roles of working memory (WM) and intelligence as predictors of school achievement. And second, to replicate and extend earlier findings (Spinath, Spinath, Harlaar, & Plomin, 2006) on the incremental validity of non-cognitive over cognitive abilities in the prediction of school achievement. The present sample consisted of N = 179 Chinese primary school children in the fourth grade. All measures including working memory (WM), intelligence and motivational items were assessed in class. Teachers provided test scores for the domains of Chinese and Math. We found that WM was a good predictor of school achievement and comparable in predictive power to intelligence. Together, cognitive ability including both WM and intelligence explained 17.8% and 36.4% of the variance in children's Chinese and Math scores, respectively. The relative importance of WM and intelligence varied with school domains with greater predictive power of WM for Math while intelligence explained a greater proportion of the variance in Chinese although the magnitude of this difference was only moderate. Domain-specific motivational constructs contributed only marginally to the prediction of school achievement for both Chinese and Math.     

Is the genetic structure of human personality universal? A cross-cultural twin study from North America, Europe, and Asia

This study examined whether universality of the 5-factor model (FFM) of personality operationalized by the Revised NEO Personality Inventory is due to genetic influences that are invariant across diverse nations. Factor analyses were conducted on matrices of phenotypic, genetic, and environmental correlations estimated in a sample of 1,209 monozygotic and 701 dizygotic twin pairs from Canada, Germany, and Japan. Five genetic and environmental factors were extracted for each sample. High congruence coefficients were observed when phenotypic, genetic, and environmental factors were compared in each sample as well as when each factor was compared across samples. These results suggest that the FFM has a solid biological basis and may represent a common heritage of the human species.     

Burnout risk among first-year teacher students: The roles of personality and motivation

The present study identified individual variables by which first-year teacher students' risk for burnout can be detected at an early stage. We analyzed a sample of teacher students (n = 559) and a control group of psychology students (n = 150) by using multinomial logistic regression analyses. We estimated the impact of personality (Five-Factor model) and motivation for choosing teacher education on work-related coping behavior and experiences (WCEP types: healthy-ambitious, unambitious, excessively-ambitious, and risk for burnout). Neuroticism and the extrinsic motivation of choosing teacher education (the assumed low difficulty of studies) were risk factors for unhealthy, stress-related coping behavior and experiences. In contrast, high levels of extraversion and conscientiousness as well as intrinsic motivation for choosing teacher education (subject-specific interest) were related to healthy-ambitious behavior. Relations of personality and stress-related WCEP types were partially moderated according to field of study (teaching versus psychology). Our results are of particular importance for improving counseling programs that advise prospective teacher students regarding their individual fit to the requirements and challenges of the teaching profession and for correcting false expectations about study demands.     

The interrelationship between speeded and unspeeded divergent thinking and reasoning, and the role of mental speed

The relationship between intelligence and creativity is still subject to substantial debate in the research literature. In the present study, we focused on core dimensions of both constructs, that is divergent thinking and reasoning. We hypothesized their relationship to depend both on the speededness of test tasks and on the subject's mental speed, positing that with increasing speededness of the tasks, mental speed would have a stronger impact on task outcomes. We disentangled the effects of task speededness and mental speed experimentally, testing 261 participants (mean age 14.48 years) with 12 divergent thinking and 12 reasoning tasks, 6 of each under power conditions, 6 time-constrained. In addition, we assessed mental speed with 6 tasks. We analyzed the data through structural equation modeling. Results confirmed our expectations: test speededness contributed significantly to mental speed variance in divergent thinking task performance. Divergent thinking assessed under time constraints was fully explained by divergent thinking assessed under power conditions and by mental speed. Divergent thinking and reasoning showed no correlation when controlling for mental speed. Our findings suggest that the correlations between divergent thinking and reasoning are mainly the result of variance both constructs share with mental speed, and that timed versus untimed test-taking plays a minor role.     

Genetic and environmental determinants of temperament: a comparative study based on Polish and German samples

This study of 1555 adult mono‐ and dizygotic twins reared together estimates the heritability of temperament traits in a Polish and a German sample. We test whether the etiology of temperament traits differs between the two cultures and between different temperament traits. We assessed temperament traits with the Formal Characteristics of Behaviour–Temperament Inventory (FCB‐TI), the Pavlovian Temperament Survey (PTS), the Revised Dimensions of Temperament Survey (DOTS‐R), and the Emotionality–Activity–Sociability Temperament Survey (EAS‐TS). Taking error of measurement into account, genetic sources of variance explained about 50% of the variance of temperament traits. We found neither reliable cultural differences nor robust differences in the etiology of the traits. However, the four questionnaires differed systematically with respect to the proportion of genetic and environmental influences on their scales. Copyright © 2002 John Wiley & Sons, Ltd.     

Thin slices of behavior as cues of personality and intelligence

Self-reports, peer reports, intelligence tests, and ratings of personality and intelligence from 15 videotaped episodes were collected for 600 participants. The average cross-situational consistency of trait impressions across the 15 episodes was .43. Shared stereotypes related to gender and age were mostly accurate and contributed little to agreement among judges. Agreement was limited mainly by nonshared meaning systems and by nonoverlapping information. Personality inferences from thin slices of behavior were significantly associated with reports by knowledgeable informants. This association became stronger when more episodes were included, but gains in prediction were low beyond 6 episodes. Inferences of intelligence from thin slices of behavior strongly predicted intelligence test scores. A particularly strong single predictor was how persons read short sentences.     

Explaining Social Disparities in Mathematical Achievement: The Role of Motivation

This study examined the role of motivation as a mediator of the relationship between parents' socio‐economic status (SES) and children's standardized test achievement in math. We employed a one‐year longitudinal approach using Programme for International Student Assessment (PISA) 2003 and a follow‐up exam in 2004. The sample consisted of N = 6020 German students (mean age 15.5 years, SD = .55) who continued school after Grade 9 (PISA 2003) and were in Grade 10 at the time of PISA 2004. Children completed measures related to their parents' SES, math‐specific self‐concept, task‐specific and global self‐efficacy, and interest, intelligence and mathematical competence. We found a small to moderate correlation between parents' SES and children's achievement. All motivational constructs partially mediated the relationship between father's SES as well as a family index for SES (economic, social, and cultural status) and children's mathematical competence, but only math‐specific self‐concept and self‐efficacy were significant mediators for mother's SES. Even when simultaneously considering the mediating effect of children's intelligence and prior achievement, the mediation effects of motivation remained significant. These results are important for our understanding of educational equality. Copyright © 2016 European Association of Personality Psychology