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Both working memory capacity (WMC) and processing speed (PS) have been discussed as important covariates of individual differences in intelligence. Recent results indicated that especially latencies of ERP components associated with higher-order processing (P2, N2, and P3) may share up to 80% of variance with individual differences in intelligence. WMC has a similar predictive power and thus these two processes cannot explain individual differences in intelligence independently. The current study explores in how far individual differences in executive functions (EFs) may bridge the gap between WMC and PS as predictors of intelligence. We recruited 101 participants who completed three EF tasks – one for each of the three executive functions shifting, updating, and inhibition. Additionally, we assessed participants' intelligence, WMC, and PS. Results showed that only variance of behavioral RTs consistent across manipulations in the EF tasks was related to WMC, PS, and intelligence. The variance specific to the manipulations in EF tasks was small and showed no consistent correlations with each other or with any of the three covariates. These results suggest that EF tasks capture mostly manipulation-unspecific cognitive processes. Hence, individual differences in the impairment due to additional executive processing demands cannot explain why WMC and PS are related predictors of individual differences in intelligence. • We recruited a community sample of 101 participants. • Participants performed three executive function (EF) tasks. • Additionally, intelligence, working memory capacity, and processing speed were assessed. • Individual differences in EFs were not related to intelligence, working memory capacity, and processing speed. • EFs did not integrate working memory capacity and processing speed as inter-related predictors of intelligence. [ABSTRACT FROM AUTHOR]

There exists a moderate correlation between MRI-measured brain size and the general factor of IQ performance (g), but the question of whether the association reflects a theoretically important causal relationship or spurious confounding remains somewhat open. Previous small studies (n 〈 100) looking for the persistence of this correlation within families failed to find a tendency for the sibling with the larger brain to obtain a higher test score. We studied the within-family relationship between brain volume and intelligence in the much larger sample provided by the Human Connectome Project (n = 1022) and found a highly significant correlation (disattenuated ρ = 0. 18, p <. 001). We replicated this result in the Minnesota Center for Twin and Family Research (n = 2698), finding a highly significant within-family correlation between head circumference and intelligence (disattenuated ρ = 0. 19, p <. 001). We also employed novel methods of causal inference relying on summary statistics from genome-wide association studies (GWAS) of head size (n ≈ 10,000) and measures of cognition (257,000 < n < 767,000). Using bivariate LD Score regression, we found a genetic correlation between intracranial volume (ICV) and years of education (EduYears) of 0.41 (p <. 001). Using the Latent Causal Variable method, we found a genetic causality proportion of 0.72 (p <. 001); thus the genetic correlation arises from an asymmetric pattern, extending to sub-significant loci, of genetic variants associated with ICV also being associated with EduYears but many genetic variants associated with EduYears not being associated with ICV. This is the pattern of genetic results expected from a causal effect of brain size on intelligence. These findings give reason to take up the hypothesis that the dramatic increase in brain volume over the course of human evolution has been the result of natural selection favoring general intelligence. [ABSTRACT FROM AUTHOR]

Video games are among the most popular leisure activities in current Western societies. Psychology research has shown correlations, at the latent level, between intelligence and video games ranging from 0.60 to 0.93. Here we analyze whether video games genre can account for this range of correlations by testing one hundred and thirty-four participants playing ten video games of different genres for iPad® and WiiU® (Art of Balance®, Blek, Crazy Pool, EDGE®, Hook, Rail Maze, SkyJump, Space Invaders, Splatoon® and Unpossible) within a controlled playing environment. Gaming performance was correlated with standard measures of fluid reasoning, visuospatial ability, and processing speed. Results revealed a correlation value of 0.79 between latent factors representing general intelligence (g) and video games general performance (g VG). This finding leads to conclude that: (1) performance intelligence tests and video games is supported by shared cognitive processes and (2) brain-games are not the only genre able to produce performance measures comparable to intelligence standardized tests. From a theoretical perspective, the observed result supports the principle of the indifference of the indicator that has been addressed in intelligence research across decades. • A battery of video games other than brain games, from very different genres, was administered in a very controlled setting. • Participants also completed tests for Gf, Gv and Gs (group administered). • From each battery a latent factor was obtained; correlation between g and gVG (General factor of video games) is.79 • Cognitive requirements, but not genre of the video games, are the relevant features to consider for intelligence testing. [ABSTRACT FROM AUTHOR]

For over a century, theories of human intelligence have concentrated on a single general factor, the psychometric g , which is used to estimate reasoning ability and cognitive flexibility, i.e. general intelligence. To better understand the evolution of general intelligence, it is important to identify the presence of a psychometric g in nonhuman animals, especially in primates, and to further disentangle the influences affecting its development. We therefore investigated the cognitive abilities of 53 Bornean and Sumatran orangutans to assess the presence of a psychometric g , and to explore possible influences on its expression. We did so using a set of carefully selected physical cognition tasks addressing abilities of inhibitory control, behavioral flexibility, causal reasoning, tool use, and associative- and reversal learning, and presented tasks to the subjects in the absence of human experimenters. A principal component analysis of the individuals' performances revealed a single component, which accounted for 31% of the individual variation in task performance. This g could not be explained by non-cognitive confounding variables, such as health status, island of origin, or rearing background. Furthermore, we found a modest correlation between an individual's independently assessed curiosity and g , which is consistent with the notion that accumulating experience affects the developmental construction of g. Together, our results suggest there is evidence for general intelligence in orangutans comparable to humans and chimpanzees, and thus evolutionary continuity in this trait. • Extensive evidence supports a general factor g in humans as a measure of general intelligence • We present the first evidence for g in orangutans, based on a battery of cognitive tests • g is not correlated with confounding variables, consistent with general intelligence • An individual's g is correlated with its experiences, emphasising its developmental construction • The results support the idea that general intelligence is phylogenetically older than humans [ABSTRACT FROM AUTHOR]

Abstract People can estimate their own and their romantic partner's intelligence (IQ) with some level of accuracy, which may facilitate the observation of assortative mating for IQ. However, the degree to which people may overestimate their own (IQ), as well as overestimate their romantic partner's IQ, is less well established. In the current study, we investigated four outstanding issues in this area. First, in a sample of 218 couples, we examined the degree to which people overestimate their own and their partner's IQ, on the basis of comparisons between self-estimated intelligence (SEI) and objectively measured IQ (Advanced Progressive Matrices). Secondly, we evaluated whether assortative mating for intelligence was driven principally by women (the males-compete/females choose model of sexual selection) or both women and men (the mutual mate model of sexual selection). Thirdly, we tested the hypothesis that assortative mating for intelligence may occur for both SEI and objective IQ. Finally, the possibility that degree of intellectual compatibility may relate positively to relationship satisfaction was examined. We found that people overestimated their own IQ (women and men ≈ 30 IQ points) and their partner's IQ (women = 38 IQ points; men = 36 IQ points). Furthermore, both women and men predicted their partner's IQ with some degree of accuracy (women: r = 0.30; men: r = 0.19). However, the numerical difference in the correlations was not found to be significant statistically. Finally, the degree of intellectual compatibility (objectively and subjectively assessed) failed to correlate significantly with relationship satisfaction for both sexes. It would appear that women and men participate in the process of mate selection, with respect to evaluating IQ, consistent with the mutual mate model of sexual selection. However, the personal benefits of intellectual compatibility seem less obvious. Highlights • Males and females overestimated the IQ of their partners by ≈ 7 IQ points more than the overestimation of their own IQ. • Both females (r = 0.30) and males (r = 0.19) predicted their partner's IQ with some degree of accuracy. • Degree of IQ compatibility failed to relate to relationship satisfaction significantly. [ABSTRACT FROM AUTHOR]

Abstract Mean scores on English-based graduate admissions exams vary strongly country by country. Here we test four hypotheses for this variance. The first is that samples of would-be graduate students are not representative of the countries from which they came. Second, English Language familiarity might account for cross-national variance on these exams. Third, national differences in well-being explain national differences in exam scores. Finally, variance in national IQ (NIQ) captures most of the variance in scores on admissions exams. We thus coded two extant measures of NIQ, and national scores on the following three admissions exams: The Graduate Management Admission Test (GMAT; n = 200 countries), Graduate Record Exam (GRE; n = 149), and Test of English as a Foreign Language (TOEFL; n = 175). Partial support was found for both the unrepresentative samples and language familiarity hypotheses. The well-being hypothesis was not supported because despite large correlations between it and exam scores, these effects were wiped out when NIQ also appeared in the regression equations. The NIQ hypothesis received the most support in that it strongly predicted admissions exam total scores (GMAT, r = 0.68 (N = 161); GRE, r = 0.71 (N = 141); TOEFL, r = 0.61 (N = 153). Moreover, these relationships (excluding those with the TOEFL) were robust to the controls of English familiarity and well-being. We end by discussing how our data also validate the existence of Rindermann's (2007) "Big G" nexus. Highlights • We examined associations between National IQ and graduate admissions exam scores. • GRE, GMAT, and TOEFL exam scores correlated strongly with National IQ. • Associations mostly persisted when controlling English familiarity and well-being. • National IQ explained most of the variance in graduate admissions exam scores. [ABSTRACT FROM AUTHOR]

Abstract In 1977, I read Arthur Jensen about how the weakness of environment within groups suggested the same weakness between groups. This meant, in his mind, that no environmental explanation of the IQ gap between black and white was possible. It raised problems, in my mind, about whether we could ignore the role of environment between generations. In 1987, I showed that there had been massive IQ gains (later called the "Flynn Effect"). Jensen (1998) responded that most of these gains were not true intelligence (or g) gains. In 2000, Dickens and Flynn showed that environment could be powerful between groups despite its weakness within groups. By 2007, I could show that even though IQ gains were not g gains, this did not undermine their significance and actually raised questions about the significance of g. Today, I can offer a range of insights: how to measure the factors that enhance IQ over time; how parents try to be fair to their children; how age affects cognitive competence; what signs environment gives of its ever-present causal potency; how the genetic determination (that twin studies imply) leaves room for human autonomy. Highlights • Flynn's account of his chief contributions. • Why IQ gains are not g gains. • The social and neurological significance of IQ gains. • What signs environment gives of its ever-present causal potency. • How twin studies leave room for human autonomy. [ABSTRACT FROM AUTHOR]

Abstract Background It is possible that estimates of normal age-related decline in intellectual function have been biased negatively by undetected preclinical Alzheimer's disease (AD). This prospective study aimed to determine the nature and magnitude of changes in crystallized and fluid intelligence, as well as their relationship to one another, in normal aging, taking into account the effects of preclinical AD. Methods Cognitively normal older adults (n = 494) aged between 60 and 84 years underwent serial assessment of fluid and crystallized intelligence at 18-month intervals over 72 months and PET neuroimaging for the presence of abnormal amyloid-β (Aβ+; n = 184). The effects of age and Aβ + on changes in fluid and crystallized intelligence were analysed using linear mixed models. An intelligence discrepancy score was developed from linear regression analysis of the extent to which fluid intelligence could be predicted from crystallized intelligence. The predictive validity of the intelligence discrepancy score for Aβ status or clinical disease progression was evaluated. Results Relative to the Aβ- group, the Aβ + group showed greater age-related decline on fluid, but not crystallized, intelligence. The intelligence discrepancy score predicted progression to clinically recognized disease (i.e., mild cognitive impairment or dementia), but was unrelated to Aβ status. Conclusions Preclinical AD is associated with more rapid age-related decline in fluid, but not crystallized, intelligence. Accordingly, a discrepancy between fluid and crystallized intelligence does indicate risk of progression to early AD. Highlights • Cognitively normal older adults with elevated amyloid-β are considered to have preclinical Alzheimer's disease • Preclinical Alzheimer's disease is associated with greater age-related decline in fluid intelligence • Preclinical Alzheimer's disease is not associated with age-related decline in crystallized intelligence • Greater discrepancy between fluid and crystallized intelligence is associated with increased risk of disease progression [ABSTRACT FROM AUTHOR]

Abstract A number of studies have reported that higher intelligence is associated with socially liberal attitudes. Less clear, however, is whether this link extends to economic attitudes, although there are indications that higher intelligence is associated with economically conservative attitudes. Here in two large, longitudinal UK cohorts (each N > 7100) we assessed whether childhood intelligence predicted adulthood economic attitudes. In both cohorts we saw that higher levels of childhood (age 10–11) intelligence were related to higher levels of economic conservatism in adulthood (age 30–33). These effects were robust to the inclusion of potential confounders (sex, parental social class, childhood conduct problems). Moreover, this pathway was at least partially mediated by educational attainment and achieved social class/income. These findings confirm the importance of intelligence as an important phenotype for understanding the origins of economic attitudes. Implications for self-interest and rational-interest theories are discussed. Highlights • Higher intelligence is associated with lower levels of social conservatism. • Does intelligence also predict economically conservative attitudes? • We addressed this question using two large, longitudinal UK based cohorts. • Childhood intelligence positively predicted economic conservatism in adulthood. • This link was partially mediated by educational attainment and achieved social class/income. [ABSTRACT FROM AUTHOR]

Abstract A few previous attempts to isolate cognitive types—groups of individuals with similar profiles of cognitive skills—have been reported in the literature. For the most part, they have not arrived at the same types. The present study sought to identify cognitive types via cluster analysis in an available sample of adolescent twins. Analyses were carried out using one randomly selected twin from each of 16-year-old Australian twin pairs who had taken a five-scale cognitive test battery (N = 677 pairs—a further sample of 628 pairs was reserved for replication purposes). Three levels of tightness of clusters were examined—minimum mutual intercorrelations among cluster members of 0.10, 0.30 and 0.50. The higher intercorrelations led to more clusters—18 at the 0.10 criterion, 25 at 0.30, and 36 at 0.50. The 0.10 level was most similar to the number of clusters reported in previous studies, and was chosen for further analysis. Clustering at this level yielded 18 clusters of individuals from the random twins, and 17 from their co-twins. Fifteen of these matched, as evidenced by a correlation of 0.80 or more between the cluster means. A second method of clustering based on a different approach, SPSS Cluster, gave similar results—15 clusters matched those from the original analysis. Agreement for cluster membership was compared for identical and fraternal twins. A greater agreement for identical twin pairs was found, and interpreted as evidence of a genetic contribution to the clustering. Most of the above analyses were successfully replicated on the reserved sample of twin pairs. Thus there was evidence for stability of initial clustering in this population. However there was not much evidence across studies for discrete and dependable cognitive types. Highlights • Are there stable clusters of persons on cognitive abilities? • Data: Five cognitive measures on 1305 16-year-old Australian twin pairs • Two clustering methods and three levels of cluster tightness were examined. • Stable clusters were found, but they differed from those found by others. • Identical twins matched clusters more often than fraternal twins, suggesting genetic involvement. [ABSTRACT FROM AUTHOR]

Abstract Trait-Anger and Neuroticism are substantially inter-correlated positively. However, there is some theoretical and empirical research that supports the notion that Trait-Anger and Neuroticism are influenced by several processes differentially. For instance, Trait-Anger is linked to optimistic bias, increased sense of control, approach motivation and high Narcissism. In contrast, Neuroticism correlates with pessimism, low sense of control, withdrawal motivation and low Narcissism. Building on these previous findings, we hypothesized that Trait-Anger and Neuroticism would be positively and negatively, respectively, associated with subjectively assessed intelligence (SAI). Furthermore, we expected that these two traits would act as mutual suppressors in predicting SAI. The results of two studies (n s = 303 and 225) supported our hypotheses. Trait-Anger was positively and Neuroticism negatively related to SAI, even after controlling for objective intelligence. These results are consistent with previous research which suggests that SAI is more substantially associated with personality than objective intelligence. Additionally, in study 2, we found that Narcissism mediated (partially) the relationship between Trait-Anger and SAI. In the discussion, we suggest that there might be two faces of Trait-Anger: one related to anxiety and one to overconfidence. Finally, a potential role of intelligence positive illusions in Trait-Anger is proposed. Highlights • Trait-Anger and Neuroticism are substantially inter-correlated positively. • Trait-Anger is positively related to subjectively assessed intelligence (SAI). • Neuroticism is negatively related to SAI. • Neuroticism suppresses the association of anger and SAI. • The effects hold even after controlling for objective intelligence. [ABSTRACT FROM AUTHOR]

Abstract Intelligence is rarely studied as a predictor of vote choice, and at first glance our data supports this neglect: In samples from the U.S. and Denmark (Ns = 1419 and 953), intelligence does not predict the standard operationalization of vote choice in which parties are placed on a single left-vs-right dimension. (Standardized coefficients predicting right-wing vote choice were 0.05 and −0.03, respectively.) However, this apparent non-effect in fact reflects approximately equal and opposite effects of intelligence on vote choice as transmitted through social and economic ideology. In both countries, higher ability predicts left-wing social and right-wing economic views. The impact of intelligence on vote choice is thus most visible in true multi-party systems like Denmark, in which parties do not simply pair similar levels of social and economic conservatism, but instead provide diverse combinations of social and economic ideology. Comparing the parties closest to representing authoritarian egalitarianism (social-right plus economic-left) and libertarianism (social-left plus economic-right), we observed a 0.9 SD intelligence gap. Highlights • In both the U.S. and Denmark intelligence failed to predict standard party choice. • This was due to opposing effects of intelligence on economic and social ideology. • Denmark's multi-party system allows non-standard representations of party choice. • In Denmark, significant systematic intelligence differences observed between parties. [ABSTRACT FROM AUTHOR]

Abstract The present study investigated whether the relationship between temporal resolution power (TRP) and general intelligence (g) is more fundamental than the relationship between speed of information processing (SIP) and g when a) TRP and SIP are assessed with an equally effective test battery, and b) when the relationship between SIP and g is strengthened by an increase of task demands. A heterogeneous sample of 110 male and 118 female participants completed a short version of the Berlin Intelligence Structure test as a measure of g. TRP was assessed with three psychophysical timing tasks and SIP with three different reaction time tasks in which cognitive task demands were systematically increased across task conditions. SIP variance was divided into a component representing speed of processing increasing cognitive task demands and a component representing processing speed independent of the experimental manipulation. The relationship between TRP and g was robust and unaffected by both SIP components. SIP caused by the enhanced cognitive task demands explained variance in g irrespective of TRP, whereas TRP completely accounted for the relationship between speed unaffected by the experimental manipulation and g. In contrast to previous findings, however, the effect of TRP on the SIP- g relationship ceases when SIP is derived from cognitively more demanding reaction time tasks. Highlights • Temporal resolution power is a reliable and robust predictor of general intelligence. • Task demand-dependent as well as task demand-independent speed was negatively correlated with general intelligence. • Task demand-dependent speed explained unique variance in general intelligence independent of temporal resolution power. • Temporal resolution power fully mediated the relationship between task demand-independent speed and general intelligence. [ABSTRACT FROM AUTHOR]

The role of intelligence and motivational constructs in school achievement is well attested. Beliefs and attitudes about assessment (including classroom assessment, homework and tests) can be adaptive within a self-regulation of learning framework. However, the role of intelligence upon the student and parent coping with school assessment practices is less well known. This paper examines responses of Swedish Grade 6 (modal age 13) students ( N  = 4749) participating in the Education Through Follow-up (ETF) project to four cognitive tests and survey items concerning achievement demands. Their responses were integrated with parent perceptions of grading and school pressure. Robust factors for intelligence, student perceptions, and parental perceptions were found and introduced into a structural equation model with intelligence as the predictor. The well-fitting SEM model showed that intelligence had statistically significant predictions on all four student and three parent perceptions factors, of which two predicted student factors. However, only one prediction was substantive; intelligence on coping with school demands (β = 0.48). Although not allowing for causal inference, the results support the claim that general cognitive abilities act as a predictor of self-regulating capability of coping with school demands. [ABSTRACT FROM AUTHOR]

Several studies suggest a different effect of intelligence and personality on creative achievement in the arts and sciences. There is also research showing that all these variables are influenced by both genes and environmental factors. The aim of this study was to move further and investigate whether the relative influence of genes and environment on the associations between personality, intelligence, and creative achievement differs between the arts and sciences. Measures of intelligence (Wiener Matrizen Test), personality traits (BFI-44), and creative achievement (Creative Achievement Questionnaire) were obtained from a twin cohort. The sample size differed between measures, ranging between 6606 and 9537 individuals (1349 and 2250 complete twin pairs). Firstly, we performed several phenotypic analyses. These analyses collectively showed that intelligence and the personality trait ‘openness to experience’ were the only traits which contributed significantly to achievement, in either creative domain. Intelligence showed a stronger association with science than with art (non-linear and linear form, respectively), while relations between openness and achievement showed the opposite pattern. Secondly, we performed genetic modeling. Univariate analyses showed artistic creative achievement to be the only variable significantly influenced by shared environment. Individual differences in the remaining traits could be accounted for by additive genetic effects and non-shared environment. Results from two trivariate analyses, which included intelligence, openness, and creative achievement in either the arts or sciences, indicated a substantial and fairly equal genetic overlap between openness and achievement in the two creative domains. Genes associated with intelligence however, played a significantly greater role in scientific achievement than in artistic achievement. In fact, the majority of genetic influences on intelligence were also involved in scientific creative achievement. There was also an overlap of unique environmental influences between intelligence and scientific creative achievement that was not present between intelligence and artistic creative achievement. [ABSTRACT FROM AUTHOR]

Subjective age predicts consequential outcomes in old age, including risk of hospitalization, dementia, and mortality. Studies investigating the determinants of subjective age have mostly focused on aging-related factors measured in adulthood and old age. Little is known about the extent to which early life factors may contribute to later life subjective age. The present study examined the prospective association between IQ in adolescence and subjective age in later life and tested education, disease burden, adult cognition, and personality traits as potential mediators. Participants ( N  = 4494) were drawn from the Wisconsin Longitudinal Study. Data on IQ were obtained in 1957 when participants were in high school. Education, disease burden, cognition, and personality were assessed in 1992–1993, and subjective age was measured in 2011 at age 71 (SD = 0.93). Accounting for demographic factors, results revealed that higher IQ in adolescence was associated with a younger subjective age in late life. Bootstrap analysis further showed that this association was mediated by higher openness. The present study suggests that how old or young individuals feel is partly influenced by lifespan developmental processes that may begin with early life cognitive ability. [ABSTRACT FROM AUTHOR]

The current study examined the relation between mental rotation and fluid intelligence using performance measures augmented with brain potential indices. Participants took a Raven's Progressive Matrices Test and performed on a mental rotation task presenting upright and rotated letter stimuli (60°, 120° or 180°) in normal and mirror image requiring a response execution or inhibition depending on instructions. The performance results showed that the linear slope relating performance accuracy, but not speed, to the angular rotation of the stimuli was related to individual differences in fluid intelligence. For upright stimuli, P3 amplitude recorded at frontal and central areas was positively associated with fluid intelligence scores. The mental rotation process was related to a negative shift of the brain potential recorded over the parietal cortex. The linear function relating the amplitude of the rotation-related negativity to rotation angle was associated with fluid intelligence. The slope was more pronounced for high- relative to low-ability participants suggesting that the former flexibly adjust their expenditure of mental effort to the mental rotation demands while the latter ones are less proficient in doing so. [ABSTRACT FROM AUTHOR]

Why do some children under-perform at school relative to their level of cognitive abilities? So far, previous studies on the topic have been conducted on cross-sectional data or have focused on a limited range of predictors. In this large longitudinal study on 23,258 French middle school students, we examined the relative effects of a wide range of contextual and individual factors on academic performance beyond the effect of non-verbal IQ. Data were analyzed using a structural equation modeling approach, cross-sectionally and longitudinally. Cross-sectional models revealed that self-efficacy, school environment, parental education and sex were the most predictive factors of achievement independently from non-verbal IQ (the latter being by far the best predictor). A longitudinal analysis showed that school environment and parental education also significantly affected progression between grade 6 (11–12 years old) and grade 9 (14–15 years old), while non-verbal IQ and other factors played a minor role. [ABSTRACT FROM AUTHOR]

The extent that the structure of cognitive abilities changes across the lifespan or across ability levels is an ongoing debate in intelligence research. The differentiation-dedifferentiation theory states that cognitive abilities differentiate until the beginning of maturity, after which relations increase or dedifferentiate until late adulthood. Spearman's law of diminishing returns proposes that cognitive abilities are more differentiated at higher ability levels. However, the evidence for ability differentiation and age dedifferentiation, in particular, is mixed. A prerequisite for the evaluation of dedifferentiation processes, expressed as changes in ability factor correlations, is the invariance of intelligence across age. However, a strong interpretation of the dedifferentiation hypothesis states that changes in model parameters, such as factor loadings and residual variances, can also be indicative of dedifferentiation. Traditional statistical tools for testing measurement invariance are not feasible for studying parameter changes over a continuous context variable, such as age. However, a recently developed non-parametric method, Local Structural Equation Modeling (LSEM), closes this gap. LSEM is a powerful and versatile method for studying structural changes; it is an improvement over competing methods, because it avoids artificial categorization of a moderator that is continuous in nature and also renounces the determination of a priori parameter functions. Using cross-sectional data from the standardization sample of the Woodcock-Johnson IV Intelligence Test Battery, we present an application and extension of the LSEM approach to accommodate two moderator variables. Specifically, we studied measurement invariance across two context variables, age and years of education, in models testing the unique moderating effect of each, and in a model examining their combined effects. We found no significant moderating effects of age and no effects of years of education on the relation between fluid and crystallized intelligence. Moreover, an interaction of age and years of education with respect to model parameter change cannot be supported. [ABSTRACT FROM AUTHOR]

Objective We investigated the association between intelligence in youth and a range of health-related behaviours in middle age. Method Participants were the 5347 men and women who responded to the National Longitudinal Survey of Youth 1979 (NLSY-79) 2012 survey. IQ was recorded with the Armed Forces Qualification Test (AFQT) when participants were aged 15 to 23 years of age. Self-reports on exercise (moderate activity, vigorous activity, and strength training), dietary, smoking, drinking, and oral health behaviours were recorded when participants were in middle age (mean age = 51.7 years). A series of regression analyses tested for an association between IQ in youth and the different health related behaviours in middle age, while adjusting for childhood socio-economic status (SES) and adult SES. Results Higher IQ in youth was significantly associated with the following behaviours that are beneficial to health: being more likely to be able to do moderate cardiovascular activity (Odds Ratio, 95% CI) (1.72, 1.35 to 2.20, p  < .001) and strength training (1.61, 1.37 to 1.90, p  < .001); being less likely to have had a sugary drink in the previous week (0.75, 0.71 to 0.80, p  < .001); a lower likelihood of drinking alcohol heavily (0.67, 0.61 to 0.74, p  < .001); being less likely to smoke (0.60, 0.56 to 0.65, p < .001); being more likely to floss (1.47, 1.35 to 1.59, p  < .001); and being more likely to say they “often” read the nutritional information (1.20, 1.09 to 1.31, p  < .001) and ingredients (1.24, 1.12 to 1.36, p < .001) on food packaging compared to always reading them. Higher IQ was also linked with dietary behaviours that may or may not be linked with poorer health outcomes (i.e. being more likely to have skipped a meal (1.10, 1.03 to 1.17, p  = .005) and snacked between meals (1.37, 1.26 to 1.50, p  < .001) in the previous week). An inverted u-shaped association was also found between IQ and the number of meals skipped per week. Higher IQ was also linked with behaviours that are known to be linked with poorer health (i.e. a higher likelihood of drinking alcohol compared to being abstinent from drinking alcohol (1.58, 1.47 to 1.69, p  < .001)). A u-shaped association was found between IQ and the amount of alcohol consumed per week and an inverted u-shaped association was found between IQ and the number of cigarettes smoked a day. Across all outcomes, adjusting for childhood SES tended to attenuate the estimated effect size only slightly. Adjusting for adult SES led to more marked attenuation but statistical significance was maintained in most cases. Conclusion In the present study, a higher IQ in adolescence was associated with a number of healthier behaviours in middle age. In contrast to these results, a few associations were also identified between higher intelligence and behaviours that may or may not be linked with poor health (i.e. skipping meals and snacking between meals) and with behaviours that are known to be linked with poor health (i.e. drinking alcohol and the number of cigarettes smoked). To explore mechanisms of association, future studies could test for a range of health behaviours as potential mediators between IQ and morbidity or mortality in later life. [ABSTRACT FROM AUTHOR]

According to the cognitive human capital theory, cognitive ability furthers at the individual, institutional and societal level productivity, production, income and wealth. Cross-sectional and longitudinal studies using various indicators (psychometric IQs, student assessment tests, education vs. GDP per capita, growth), different methods (correlations, regressions, path models) and different controls have supported this theory in two research paradigms (psychology, economics). An especially revealing test is, whether historical increases in IQ within countries would lead to later economic growth, i.e. about 10 to 20 years later. This design can exclude national differences being associated with human capital and growth (e.g., in culture, economic freedom and politics) which may bias the results. We used a data set of national IQ changes (“FLynn effect”) from Pietschnig and Voracek (2015). For a maximum of 28 nations and 262 periods between 1909 and 2013 IQ development was related to concurrent or lagged GDP per capita development (growth; 5, 10, 15, 20 years). In a second analysis with at least three IQ-GDP periods per country the single within-country correlations for concurrent and later intervals were estimated (13 nations). Finally, we controlled for previous wealth (advantages of backwardness). All analyses show substantial relationships between increases in IQ and GDP, the highest were found for the 5 to 15 years lagged economic growth ( r  = .25 to .44 resp. .46 to .77). The results back the theory that cognitive ability contributes to wealth. [ABSTRACT FROM AUTHOR]

I study the relationship between intelligence and the rationality of political preferences. Intelligence is operationalized as achievement in standard mental ability tests, rationality as consistency between political attitudes and political preferences and consistency as the effect of the interaction between intelligence and political attitudes on political preferences. Political preferences are measured by party affiliation – support for the Democratic versus the Republican Party in the US – and political attitudes are measured on a conservative-liberal dimension. I analyze three large representative American databases and find that for global political attitudes and for specific social attitudes, but not for specific economic attitudes, intelligence is associated with a considerable more attitude-preference consistency (ΔR 2 of 2.7% 0.9%, and 0.9%, in Study 1, 2 and 3, respectively, corresponding to f 2 of 0.014, 0.011 and 0.035, respectively). I conclude with a discussion of possible causal processes underlying the observed relationship between intelligence and consistency of political attitudes. [ABSTRACT FROM AUTHOR]

We examine the role of General Mental Ability (GMA or g ), versus specific abilities, in predicting wages among 69,901 participants from 19 countries in the Programme for International Assessment of Adult Competencies (PIAAC). We define GMA as the first principal component in a battery of three ability tests, and specific abilities as the low order components. Our initial results – a difference of 52%, between a g only model and a g  + specific abilities model (R 2 s of 0.061 and 0.093, respectively) – is considerably different from earlier results suggesting that "there is not much more than g " in predicting performance. However, further analyses show that this difference is reduced to 0.5% when crucial non-cognitive individual differences (age and sex) are controlled for (R 2 s of 0.0763 and 0.0767, respectively). Path models of the relationships between individual differences, specific abilities, GMA and wage shed light on these results. Implications for the understanding of the relationship between mental abilities and wage, and to the understanding of cognitive test scores as representing various skills versus general ability, are discussed. [ABSTRACT FROM AUTHOR]

This study examined the stability of the latent construct of intelligence from infancy through adolescence, using latent variable modeling to account for measurement error. Based on the Fullerton Longitudinal Study data, the present study modeled general intelligence across four developmental periods from infancy through adolescence. The Fullerton Longitudinal Study included twelve assessments of intellectual performance over a sixteen-year interval. Three assessments of intellectual performance at each of four developmental periods served as indicators of latent intelligence during infancy (1, 1.5, and 2 years old), preschool (2.5, 3, and 3.5 years old), childhood (6, 7, and 8 years old), and adolescence (12, 15, and 17 years old). Intelligence exhibited a high degree of stability across the four developmental periods. For instance, infant intelligence revealed a strong cross-time correlation with preschool intelligence ( r  = 0.91) and moderate correlations with childhood and adolescent intelligence ( r  = 0.69 and 0.57, respectively). Intelligence followed a stage-autoregressive pattern whereby correlations between IQ scores decreased as the timespan between assessment waves increased. Further, from infancy to adolescence, the effect of intelligence during earlier periods was completely mediated by intelligence during the adjacent developmental period. In contrast to much prior research, this study demonstrated the stability of general intelligence, beginning in infancy. [ABSTRACT FROM AUTHOR]

Multiple object-tracking (MOT) paradigms have the potential to highlight attention resource capacities. However, there is a dearth in research exploring the relationship between individual differences in MOT capability and higher-level cognition, such as intelligence. Previous research has demonstrated that manipulating task demands, or the task's cognitive load, can help describe this relationship. Therefore, we assessed the relationship between performance on a 3D-MOT task at different levels of cognitive load (average speed for tracking 1, 2, 3 and 4 target objects out of 8 total objects), and fluid reasoning intelligence measured by the Wechsler Abbreviated Scale of Intelligence-2nd edition (WASI-II). Also, we compared MOT performance between intellectual styles classified as: (i) low, medium or high fluid reasoning IQ, and (ii) fluid reasoning or verbal styles. As expected, speed scores decreased as target objects increased. This trend represents a proxy for attentional resource capacity as manipulations to both speed and target objects are able to highlight individual differences in available attentional resources. Furthermore, MOT capability at high load (4-targets) was the best predictor of fluid reasoning intelligence compared to lower loads (1–3 targets), and individuals with a fluid reasoning style and/or medium-high fluid reasoning intelligence outperformed individuals with a verbal style and low fluid reasoning IQ, respectively. These results describe the underlying commonalities between fluid reasoning intelligence and attention resource capacity, extending previous findings with working memory capacity. This study demonstrates that examining MOT as a measure of attention, rather than a phenomenon, can illustrate the potential to repurpose the use of this task to characterize attentional resource capacity. [ABSTRACT FROM AUTHOR]

Differences in intelligence have previously been found to be related to a wide range of inter-individual and international social outcomes. There is evidence indicating that intelligence differences are also related to different regional outcomes within nations. A quantitative and narrative review is provided for twenty-two countries (number of regions in parentheses): Argentina (24 to 437), Brazil (27 to 31), British Isles (12 to 392), Chile (15), China (31), Colombia (33), Denmark (7), Finland (4), France (90), Germany (16), India (33), Italy (12 to 19), Japan (47), Mexico (31 to 32), Peru (1468), Portugal (5), Russia (29 to 79), Spain (15 to 48), Switzerland (47), Turkey (12), the USA (30 to 3100), and Vietnam (61). Between regions, intelligence is significantly associated with a wide range of economic, social, and demographic phenomena, including income ( r unweighted  =  .56), educational attainment ( r unweighted  =  .59), health ( r unweighted  =  .49), general socioeconomic status ( r unweighted  =  .55), and negatively with fertility ( r unweighted  = −.51) and crime ( r unweighted  = −.20). Proposed causal models for these differences are noted. It is concluded that regional differences in intelligence within nations warrant further focus; methodological concerns that need to be addressed in future research are detailed. [ABSTRACT FROM AUTHOR]

The response bias hypothesis specifies that the predictive capacity of a predictor should be enhanced by controlling for the effects of bias on the predictor variable, in particular, socially desirable responding (SDR) bias. To-date, the vast majority of the SDR research in the area, which is principally personality related, has failed to support the response bias hypothesis, as SDR suppressor effects have not been observed. Consequently, it has been contended that SDR is not a problem for self-report measurement, that SDR measures may themselves be indicators of trait variance, and that it was likely impossible to determine whether an elevated SDR score reflected a trait or response bias. However, in contrast to personality, intelligence is an area within which comparisons between subjective scores (self-reported) and objective scores (task-based) can be made. Consequently, the purpose of this investigation was to test the response bias hypothesis ( N  = 253) with self-report measures of intellectual and emotional intelligence (SRIQ and SREI) and task-based measures of intellectual and emotional intelligence (TBIQ and TBEI), in conjunction with a multi-dimensional measure of SDR (Balanced Inventory of Desirable Responding; BIDR). The percentage of variance accounted for in TBIQ by SRIQ, and in TBEI by SREI, increased by 1% and 2.1%, respectively, when SDR was included in the model. The 1% to 2.1% increases in criterion (concurrent) validity were interpreted as practically significant, based on previously published simulation work. Finally, it was concluded that self-report measures may be non-negligibly influenced by individual differences in SDR, and that the BIDR may possess some validity as an indicator of individual differences in socially desirable responding. [ABSTRACT FROM AUTHOR]

This paper analyses data on average IQ and four measures of political attitudes at both the regional level ( n  = 11) and the local authority level in Britain ( n  = 372). At the regional level, average IQ is positively associated with right-wing economic attitudes and trust in experts, but is not significantly associated with liberal social attitudes or intention to vote Remain in the EU referendum. At the local authority level, average IQ is positively associated with all four measures of political attitudes, although the associations with right-wing economic attitudes and trust in experts are stronger than the associations with liberal social attitudes and intention to vote Remain in the EU referendum. In multivariate models, average SES is a better and more robust predictor of political attitudes than average IQ. [ABSTRACT FROM AUTHOR]

We estimate the net effect of intelligence on the prevalence of atheists in the United States. We evaluate such an effect both at the mean and at different quantiles of the conditional distribution of the proportion of atheists using data on all fifty U.S. states. The results show that the net effect of intelligence on religious disbelief is strictly increasing. This pattern is different from that found elsewhere (Cribari-Neto and Souza, 2013) using data from over 100 countries in which the effect peaks and then weakens. We show that in the U.S. the effect is also stronger outside what we call the ‘Extended Bible Belt’. Our results also point to the existence of a ‘hurdle effect’ that only takes place the U.S. most religious area. In that area, the effect of average intelligence on the prevalence of religious disbelievers, albeit positive, loses strength above the conditional median, i.e., where there already are more atheists. Such a loss in strength above the conditional median does not happen in the rest of the country. [ABSTRACT FROM AUTHOR]

In this study, we aimed to explore the relationships between intuitive abilities, intelligence (explicit cognitive ability) and personality. We found that intuition is not homogenous and there are three types of intuitive ability: Coherence & Insight , Implicit Learning and Subjective Intuitive Abilities that showed different patterns of relationships with explicit cognitive ability and personality. Coherence & Insight was predicted by intelligence and Openness to Aesthetics. Implicit Learning was weakly predicted by explicit cognitive ability. Subjective Intuitive Abilities was predicted only by Openness subscales: Fantasy, Action and Ideas. We demonstrated that intuition is not a unitary psychological construct but rather a complex cognitive conglomerate that incorporates diverse processes and mechanisms and these intuitive abilities are largely independent from psychometric intelligence. [ABSTRACT FROM AUTHOR]

I update and expand upon Wicherts' (2009) editorial in Intelligence . He reported citation counts of papers published in this journal from 1977 to 2007. All these papers are now at least a decade old, and many more new articles have been published since Wichert's analysis. An updated study is needed to help (1) quantify the journal's more recent impact on the scientific study of intelligence, and (2) alert researchers and educators to highly-cited articles; especially newer ones. Thus, I conducted a bibliometric analysis of all articles published here from 2008 to 2015. Data sources included both the Web of Science (WOS), and Google Scholar (GS). The eight-year set comprised 619 articles, published by 1897 authors. The average article had 17.0 (WOS), and 32.9 (GS) citations overall (2.75, and 5.33 citations per year, respectively). These metrics compare favorably with those from other psychology journals. In addition, a list of the most prolific authors is provided. Also reported is a list showing many articles in this set with counts greater than one hundred, and an updated top 25 list for the history of this journal. [ABSTRACT FROM AUTHOR]

Retest effects are referred to as the increase in test scores due to the repeated administration of cognitive ability tests. This meta-analysis attempts to update and extend previous meta-analyses by examining the size of retest effects and its determinants in a high number of cognitive ability tests for up to four test administrations. Strict inclusion and exclusion criteria were applied regarding study design, participant age and health status, and cognitive ability tests. An extensive literature search detected 174 samples from 122 studies, which resulted in 786 test outcomes and an overall sample size of 153,185. A comprehensive longitudinal multilevel meta-analysis revealed significant retest effects and no further score gains after the third test administration. Moderator analyses for multiple retests indicated that cognitive ability operation and content, equivalence of test forms, retest interval and participant age have a significant influence on the size of the retest effect. Implications for future research and retesting practice are discussed. [ABSTRACT FROM AUTHOR]

Spatial suppression refers to the increasingly difficult identification of motion direction with increasing size of the moving stimulus. Previous research indicated a close association between stronger spatial suppression and higher psychometric intelligence. Since the measurement of spatial suppression is based on the time needed to correctly identify the motion direction of small vs. large stimuli, the present study aimed to elucidate the unique and shared effects of mental speed, as assessed by reaction times from the Hick task, and spatial suppression on psychometric intelligence. In 177 young adults, neither manifest nor latent variables representing spatial suppression were related to psychometric intelligence. Irrespective of stimulus size, however, individuals with higher intelligence detected motion direction faster than individuals with lower intelligence. While we cannot fully rule out stimulus and apparatus differences as being behind this discrepancy with prior work, our results indicate that the link between spatial suppression and intelligence is at best confined to a specific range of stimulus parameters. The relation between intelligence and speed of motion direction detection (independent from stimulus size) overlapped with the relation between psychometric intelligence and reaction times in the Hick task. This latter result is consistent with the assumption that there is a general (task-independent) speed of information processing, which is robustly related to psychometric intelligence. [ABSTRACT FROM AUTHOR]

Improving fluid intelligence is an enduring research aim in the psychological and brain sciences that has motivated public interest and scientific scrutiny. At issue is the efficacy of prominent interventions—including fitness training, computer-based cognitive training, and mindfulness meditation—to improve performance on untrained tests of intellectual ability. To investigate this issue, we conducted a comprehensive 4-month randomized controlled trial in which 424 healthy adults (age 18–43 years) were enrolled in one of four conditions: (1) Fitness training; (2) Fitness training and computer-based cognitive training; (3) Fitness, cognitive training, and mindfulness meditation; or (4) Active control. Intervention effects were evaluated within a structural equation modeling framework that included repeated-testing gains, as well as novel tests of fluid intelligence that were administered only at post-intervention. The combination of fitness and cognitive training produced gains in visuospatial reasoning that were greater than in the Active Control, but not in performance on novel tests administered only at post-intervention. Individuals more variably responded to multi-modal training that additionally incorporated mindfulness meditation (and less time spent on cognitive training), and those who demonstrated repeated-testing gains in visuospatial reasoning also performed better on novel tests of fluid intelligence at post-intervention. In contrast to the multi-modal interventions, fitness only training did not produce Active Control-adjusted gains in task performance. Because fluid intelligence test scores predict real-world outcomes across the lifespan, boosting intelligence ability via multi-modal intervention that is effective even in young, healthy adults is a promising avenue to improve reasoning and decision making in daily life. [ABSTRACT FROM AUTHOR]

In order to evaluate recent claims that individual differences in strategy use (i.e., using either constructive matching or response elimination to solve a gf problem) can explain away, or at least significantly weaken, the strong relationship between working memory capacity (WMC) and fluid intelligence ( gf ), in two large-sample studies we applied multiple measures of WMC, gf , and strategy use, and tested if the mediation of strategy use affected the WMC- gf relationship. We observed no significant drop in the WMC- gf link due to mediation, thus refuting the alleged role of strategy use in the involvement of working memory processes in fluid reasoning. Moreover, our results suggest that it is the significant correlation of both strategy use and cognitive style with WMC which is the driving force for their moderate correlation with gf . [ABSTRACT FROM AUTHOR]

The IQ gains of the 20th century have faltered. Losses in Nordic nations after 1995 average at 6.85 IQ points when projected over thirty years. On Piagetian tests, Britain shows decimation among high scorers on three tests and overall losses on one. The US sustained its historic gain (0.3 points per year) through 2014. The Netherlands shows no change in preschoolers, mild losses at high school, and possible gains by adults. Australia and France offer weak evidence of losses at school and by adults respectively. German speakers show verbal gains and spatial losses among adults. South Korea, a latecomer to industrialization, is gaining at twice the historic US rate. When a later cohort is compared to an earlier cohort, IQ trends vary dramatically by age. Piagetian trends indicate that a decimation of top scores may be accompanied by gains in cognitive ability below the median. They also reveal the existence of factors that have an atypical impact at high levels of cognitive competence. Scandinavian data from conventional tests confirm the decimation of top scorers but not factors of atypical impact. Piagetian tests may be more sensitive to detecting this phenomenon. [ABSTRACT FROM AUTHOR]

This paper reports an investigation of whether data on intelligence obtained by speeded testing have to be represented in confirmatory factor analysis (CFA) by an additional factor besides the ability factor, and whether the additional factor can be identified as a speed factor. The paper further examined whether the hypothesized speed factor influences the relationship between intelligence and working memory. Two independent datasets including data obtained by speeded intelligence testing, measures of processing speed and of working memory were investigated by means of CFA. A hybrid bifactor model was employed to represent the hypothesized speed and the ability factor of the intelligence data. Whereas the factor loadings for representing ability were set free for estimation, the factor loadings for representing speed were constrained according to theory-based expectations. The results showed that a speed factor is necessary for achieving a good fit to the data with speeded testing. The convergent validity of the speed factor was shown by data on measures of processing speed. Furthermore, it turned out that the consideration of the latent speed factor led to a decrease of the correlation between intelligence and working memory. These results suggest that speeded testing influences the assessment of intelligence and may also bias empirical findings regarding the relationships between intelligence and other constructs. [ABSTRACT FROM AUTHOR]

High intelligence is touted as being predictive of positive outcomes including educational success and income level. However, little is known about the difficulties experienced among this population. Specifically, those with a high intellectual capacity (hyper brain) possess overexcitabilities in various domains that may predispose them to certain psychological disorders as well as physiological conditions involving elevated sensory, and altered immune and inflammatory responses (hyper body). The present study surveyed members of American Mensa, Ltd. ( n = 3715) in order to explore psychoneuroimmunological (PNI) processes among those at or above the 98th percentile of intelligence. Participants were asked to self-report prevalence of both diagnosed and/or suspected mood and anxiety disorders, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and physiological diseases that include environmental and food allergies, asthma, and autoimmune disease. High statistical significance and a remarkably high relative risk ratio of diagnoses for all examined conditions were confirmed among the Mensa group 2015 data when compared to the national average statistics. This implicates high IQ as being a potential risk factor for affective disorders, ADHD, ASD, and for increased incidence of disease related to immune dysregulation. Preliminary findings strongly support a hyper brain/hyper body association which may have substantial individual and societal implications and warrants further investigation to best identify and serve this at-risk population. [ABSTRACT FROM AUTHOR]

The emergence of the popular culture notion of a sapiosexual, an individual who finds high levels of intelligence (IQ) the most sexually attractive characteristic in a person, suggests that a high IQ may be a genuinely sexually attractive trait, at least for some people. Consequently, mean desirability ratings of IQ on a percentile continuum were estimated, across sexual attraction specifically and long-term partner interest conditions ( N = 383). Furthermore, we evaluated the psychometric properties of a newly developed measure, the Sapiosexuality Questionnaire (SapioQ). Finally, we estimated the correlation between objective intelligence and the SapioQ. On average, the 90th percentile of intelligence (IQ ≈ 120) was rated to be the most sexually attractive and the most desirable in a long-term partner. However, 8.1% and 1.3% of the sample scored above 4.0 and 4.5, respectively, on the SapioQ (theoretical range: 1 to 5), which had respectable psychometric properties. The desirability ratings across the IQ percentile continuum interacted with the two conditions (i.e., sexual attraction specifically versus partner interest), such that the rater desirability of IQ increased more substantially for partner interest than sexual attraction specifically across the 25th to 75th IQ percentiles. Finally, objective intelligence correlated negatively with rated sexual attraction specifically and partner interest for a hypothetical person at 25th and 50th percentiles of IQ ( r ≈ − 0.25). By contrast, objective intelligence failed to correlate with sapiosexuality ( r = − 0.02, p = 0.765; BF 01 = 12.84). The results were interpreted to suggest that, for most people, a very high IQ in a partner (IQ 135 +) is not the most attractive level of intelligence, which may be considered supportive of a version of the threshold hypothesis of intelligence. Finally, although sapiosexuality may be a genuine psychological construct, it appears to be influenced by non-intellective factors. [ABSTRACT FROM AUTHOR]

Intelligence has previously been associated with mortality, although it is unclear whether the inverse association is independent of other related cognitive factors, such as information processing, or of measures related to physical health, such as cardiorespiratory fitness. We investigate whether fluid intelligence, reaction time and cardiorespiratory fitness are independently associated with mortality within the general population. UK Biobank recruited adults across England, Scotland and Wales, between March 2006 and July 2010: 54,019 participants (women 52%) with complete data were included in the analysis. Those who died in the first year of follow-up (n = 58) were excluded. Fluid intelligence was measured as the number of correct answers during a two minute logic/reasoning-test, reaction time was measured as average time taken to respond to matching symbols on a computer screen and cardiorespiratory fitness was measured through a sub-maximal exercise test. Associations with mortality were assessed by Cox-proportional hazard models adjusted for age, sex, ethnicity, social deprivation, cancer and non-cancer illnesses, medications, employment, education, smoking, BMI, diet, sleep, and physical activity. Over 5.8 years of follow-up, there were 779 deaths. Higher intelligence (hazard ratio [HR] per SD = 0.91; 95% CI 0.84, 0.99), faster reaction time (HR per SD = 0.92; 0.85, 0.98) and higher fitness (HR per SD = 0.85; 0.78, 0.93) were associated with a lower risk of mortality after adjustment for each other and other covariates. No interaction was observed between fluid intelligence and reaction time (p = 0.147) or between fluid intelligence and cardiorespiratory fitness (p = 0.238). In conclusion, fluid intelligence, reaction time and cardiorespiratory fitness were independently associated with mortality. [ABSTRACT FROM AUTHOR]

Relatively little is known about the dynamic neural processes most critical to chronometric effects, and the ways in which task demands influence their various contributions to intelligence. The present study ( n = 111) used the Hick paradigm to measure the effects of task complexity on decision time (DT) and event-related potentials (ERPs), and on their relations in turn with IQ. The surface Laplacian transform increased the spatial resolution of the recorded neural activity, and revealed four ERP components in the time range of DT. Zero-order correlations of DT, ERP amplitudes and latencies, and IQ were used to motivate multilevel models (MLM) that examined moderating effects of IQ on potential condition effects. Although DT consistently increased with greater complexity and was related to IQ across conditions, IQ did not moderate the increase in DT with increasing complexity. Similarly, while most ERP amplitudes and latencies also increased over conditions, and often predicted DT, only the amplitude of the P2 component was associated with IQ. Unlike the effects for DT, while IQ did not moderate P2 amplitudes during simple DT, it did predict greater increases between simple and choice conditions. Overall, these findings highlight the need to distinguish neural correlates of adaptive performance in general from those related to individual differences. [ABSTRACT FROM AUTHOR]

Does the intelligence quotient (IQ) in a nation regulate the ease of doing business? Based on the normal distribution of IQ scores within a nation, the population was classified into three groups, specifically intellectual class, average ability, and non-intellectual class, which were represented by the 95th, 50th, and the 5th percentiles of IQ level respectively. Using a robust regression method, the impact of each IQ class on the ease of doing business (EDB) index was examined. The sub-indicators of the ten business regulatory environment across 71 countries were studied. In this study, the effect of IQ was controlled for the levels of economic freedom, GDP per capita, freedom of corruption, and tertiary education. Results revealed strong evidence that the IQ of the intellectual class had contributed most to the enhancement of the regulatory environment, which is supportive for entrepreneurship. This result was consistent with the term ‘creative minority’ coined by the prominent historian Arnold Toynbee. It was concluded that the IQ of the people from the intellectual class is the most significant factor for creating a business regulatory environment that eases the entrepreneurs. This occurs through their competent and virtuous leadership that enhances the quality and efficiency of institutions across countries. [ABSTRACT FROM AUTHOR]

This study compared various exploratory and confirmatory factor methods for recovering factors of cognitive test-like data. We first note the problems encountered by several widely used methods, such as parallel analysis, minimum average partial procedure, and confirmatory factor analysis, in estimating the number of dimensions underlying performance on test batteries. We then argue that a new method, Exploratory Graph Analysis (EGA), can more accurately uncover underlying dimensions or factors and demonstrate how this method outperforms the other methods. We use several published data sets to demonstrate the advantages of EGA. We conclude that a combination of EGA and confirmatory factor analysis or structural equation modeling may be the ideal in precisely specifying latent factors and their relations. [ABSTRACT FROM AUTHOR]

We explored relations between attention control, shifting flexibility, working memory, reasoning in different domains, awareness about reasoning, and language from 9 to 15 years of age. For this aim 198 9-, 11-, 13-, and 15-years old participants were examined with tasks addressed to all processes. All processes developed systematically throughout the period studied. Structural equation modeling revealed a powerful common construct underlying reasoning and language processes. All domain-specific cognitive, language, or awareness processes represented this common factor equally well. This factor was related to attention control, shifting flexibility, and working memory but this relation varied with development, being dominated by attention control at 9–11, inferential-representational processes at 11–13, and awareness-symbolic processes at 13–15. Piecewise linear modeling showed that transition points between phases are marked by phase-dominating processes. Modeling ability and age differentiation with increasing g suggested some ability differentiation at the end of developmental cycles suggesting that g-ability relations are re-worked anew in successive developmental cycles. Implications for developmental, cognitive, and brain science are discussed. [ABSTRACT FROM AUTHOR]

We examined whether the link between intelligence and musical expertise is better explained by formal music lessons or music aptitude. Musically trained and untrained adults completed tests of nonverbal intelligence (Raven's Advanced Progressive Matrices) and music aptitude (Musical Ear Test). They also provided information about their history of music lessons and socioeconomic status (SES). Duration of music training was associated positively with SES (mother's education), nonverbal intelligence, melody aptitude, and rhythm aptitude. Intelligence and music aptitude were also positively associated. The association between music training and intelligence remained evident after controlling for SES, but it disappeared after controlling for music aptitude. By contrast, music aptitude had a strong correlation with intelligence even after accounting for music training and SES. Thus, the association between music training and intelligence may arise because high-functioning individuals are more likely than other individuals to have good aptitude for music and to take music lessons. [ABSTRACT FROM AUTHOR]

We compared the relation between educational performance scores in the Programme for International Student Assessment (PISA) and Trends in International Mathematics and Science Study (TIMSS) on the one hand, and religiosity, as measured with the World Values Survey and the European Social Survey , on the other hand. We found that higher levels of religiosity (at national level) were associated with lower educational performance in science and mathematics ( r s ranging from − 0.65 to − 0.74). One of the unique contributions of our data set is the ability to examine these trends by sex. Interestingly, even though women reported considerably higher levels of religiosity than men, this gap was not related to sex differences in educational performance. This latter finding constrains conclusions about the possible causal pathways between education, religiosity, and intelligence. Further, the mediating role of human development and time spent on religious education appear to account for the relation between education and religiosity. One possibility is that the relation between education and religiosity at the national level is related to overall levels of economic and human development, including investment in secular education. [ABSTRACT FROM AUTHOR]

We examine the effects of child sibship size on intelligence, school performance and adult income for a sample of Swedish school children ( n = 1326). These children were measured in grade three in 1965 (age 10) and in grades six (age 13) and nine (age 16), and the women and men were later followed up in adulthood at ages 43 and 47, respectively. Using Bayesian varying-intercept modeling we account for differences between school classes in each of our three response variables: IQ-scores, school grades and adult income, and control for background variables such as gender, socioeconomic status, and maternal- and paternal age. Consistent with previous research, we find patterns of decreasing IQ scores for increasing sibship sizes, specifically for an increasing number of older siblings. No relationships between sibship size and children's school grades are found. We find, however, patterns of decreasing adult income for an increasing number of younger siblings. In addition, considerable amounts of variations in intelligence scores as well as school grades are found between school classes. Some implications of the findings and suggestions for future research are provided. [ABSTRACT FROM AUTHOR]