Jensen Effects and African/Coloured/Indian/White differences on Raven's Standard Progressive Matrices in South Africa

A test is made to determine whether various ethnic group differences on tests of cognitive performance in South Africa are like the Black/White differences in the United States in being positively associated with a tests' g loadings, where g is the general factor of intelligence. A non-parametric re-analysis is made of data from 1056 White, 1063 Indian, 778 mixed-race “Coloured,” and 1093 Black 14 year olds on the Raven's Standard Progressive Matrices Test in South Africa, given without time limits by Owen (1992) [Personality and Individual Differences, 13, 149]. The new analyses showed that the more highly correlated an item was with g, the more it predicted the White/Indian/Coloured/African differences on the test (Spearman's rhos from 0.35 to 0.85; all Ps<0.01). The effects remained regardless of which group g was extracted from. Understanding group differences around the world requires new research on the nature and nurture of g.     

The genetics and evolution of the general factor of personality

Three studies tested the hypothesis that a general factor of personality (GFP) underlies diverse individual differences including altruism, the Big Five factors of Openness, Conscientiousness, Extraversion, Agreeableness, and Emotional Stability, and the EAS temperament traits of Emotional Stability, Activity, and Sociability. In Study 1, 214 university students completed 36 personality scales. In Study 2, 322 pairs of monozygotic (MZ) and dizygotic (DZ) twins completed 29 5-point rating scales plus questionnaires. In Study 3, 575 pairs of 2- to 9-year-old Korean twins were rated by their mothers on 25 temperament scales. Factor analyses revealed a hierarchical organization with GFP at the apex and the Big Five and/or EAS temperament scales intermediate. The twin data show GFP has an early age of onset with 50% of the variance attributable to non-additive (dominance) genetic influence and 50% to unique, non-shared environmental influence. We discuss a life history matrix encompassing brain size, maturational speed, and longevity, plus emotional intelligence and the personality disorders, and suggest natural selection acted directionally to endow people with more cooperative and less contentious personalities than their archaic ancestors, or nearest living relatives, the chimpanzees.     

A General Factor of Personality (GFP) from two meta-analyses of the Big Five: and

In two studies, we used structural equation models to test the hypothesis that a General Factor of Personality (GFP) occupies the apex of the hierarchy of personality. In Study 1, we found a GFP that explained 45% of the reliable variance in a model that went from the Big Five to the Big Two to the Big One in the 14 studies of inter-scale correlations (N = 4496) assembled by Digman (1997). A higher order factor of Alpha/Stability was defined by Conscientiousness, Emotional Stability, and Agreeableness, with loadings of from 0.61 to 0.70, while Beta/Plasticity was defined by Openness and Extraversion with loadings of 0.55 and 0.77. In turn, the GFP was defined by Alpha and Beta with loadings of 0.67. In Study 2, a GFP explained 44% of the reliable variance in a similar model using data from a published meta-analysis of the Big Five (N = 4000) by Mount, Barrick, Scullen, and Rounds (2005). Strong general factors such as these, based on large data sets with good model fits that cross validate perfectly, are unlikely to be due to artifacts and response sets.     

Performance on Raven's Matrices by African and White University Students in South Africa

Untimed Raven's Standard Progressive Matrices (SPM) were administered to 309 17- to 23-year-old students at the University of the Witwatersrand and the Rand Afrikaans University in Johannesburg, South Africa (173 Africans, 136 Whites; 205 women, 104 men). African students solved an average of 44 of the 60 problems whereas White students solved an average of 54 of the problems (p<.001). By the standards of the 1993 US normative sample, the African university students scored at the 14th percentile and the White university students scored at the 61st percentile (IQ equivalents of 84 and 104, respectively). The African–White differences were found to be greater on those items of the SPM with the highest item–total correlations, indicating a difference in g, or the general factor of intelligence. A small sex difference favoring males was found in both the African and the White samples, but unrelated to g.     

Life History theory and social deviance: The mediating role of Executive Function

The present work examined predicted relations among Life History strategies, Executive Functions, socially antagonistic attitudes, socially antagonistic behaviors, and general intelligence. Life History (LH) theory predicts that Executive Functions and socially antagonistic attitudes and behaviors underpin an interrelated and coherent set of behavioral strategies (LH strategies) designed to enhance reproductive success. Specifically, LH theory predicts a positive relation between Executive Functioning and LH strategies; a negative relation between socially antagonistic attitudes and behaviors and LH strategies; and that Executive Functions mediate relations among LH strategies and socially antagonistic attitudes and behaviors. Results from a Structural Equation Model (SEM), based on self-reported Life History strategies, Executive Functioning, socially antagonistic attitudes and behaviors, and general intelligence support these predictions. The structure of the model suggests that Executive Functions serve a mediating role in the relations between LH strategy and social deviance.     

IQ, skin color, crime, HIV/AIDS, and income in 50 U.S. states

In 50 U.S. states, we found a positive manifold across 11 measures including IQ, skin color, birth rate, infant mortality, life expectancy, HIV/AIDS, violent crime, and state income with the first principal component accounting for 33% of the variance (median factor loading = .34). The correlation with a composite of total violent crime was higher with skin color (r = .55), a more biologically influenced variable than with GDP (r = −.17), a more culturally influenced variable. These results corroborate and extend those found at the international level using INTERPOL crime statistics and at the county, provincial, and state levels within countries using local statistics. We interpret the cross-cultural consistency from an evolutionary life history perspective in which hierarchically organized traits culminate in a single, heritable, super-factor. Traits need to be genetically organized to meet the trials of life—survival, growth, and reproduction. We discuss brain size and the g nexus as central to understand individual and group differences and we highlight melanin and skin color as a potentially important new life history variable.     

Differential K theory and race differences in E and N

Differential K Theory was recently proposed relating personality to reproductive strategy (Rushton, 1985). The more K the person is (the symbol derives from population biology), the more he or she will delay reproductive effort, produce fewer children and more intensely care for them. Concomitant characteristics include intelligence, altruism, law-abidingness and behavioural restraint. Race differences are hypothesized such that, in terms of K, Mongoloids > Caucasoids > Negroids. Barratt and Eysenck (1984) recently published standardized Extraversion (E), Neuroticism (N), Psychoticism (P) and Social Desirability (L) scores for males and females from 25 different countries, but did not analyse the data in such a way that racial differences were found. In the current study Barratt and Eysenck's data are aggregated across sex and over countries to examine whether theoretical predictions regarding race differences in behavioural restraint do in fact occur. Behavioural restraint was indexed by low E and high N scores. The means for 8 Mongoloid samples (N = 4044) were contrasted with those of 38 Caucasoid (N = 19, 807) and 4 Negroid ones (N = 1906), and the resultant comparisons confirmed expectations. Mongoloids are lower on E and higher on N than Caucasoids, who in turn are lower in E and higher on N than Negroids.