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.