Contributions to the history of psychology: XC. Evolutionary biology and heritable traits (with reference to oriental-white-black differences): the 1989 AAAS paper.

Genetic distance estimates calculated from DNA sequencing indicate that in years since emergence from the ancestral hominid line, Mongoloids = 41,000, Caucasoids = 110,000, and Negroids = 200,000. Data also show that this succession is matched by numerous other differences such that Mongoloids > Caucasoids > Negroids in brain size and intelligence (cranial capacity = 1448, 1408, 1334 cm3; brain weight = 1351, 1336, 1286 gm.; millions of excess neurons = 8900, 8650, 8550; IQ = 107, 100, 85); maturational delay (age to walk alone, age of first intercourse, age of death); sexual restraint (ovulation rate, intercourse frequencies, sexually transmitted diseases including AIDS); quiescent temperament (aggressiveness, anxiety, sociability); and social organization (law abidingness, marital stability, mental health). This pattern is ordered by a theory of r/K reproductive strategies in which Mongoloids are posited to be more K-selected than Caucasoids and especially more than Negroids. (K-selected reproductive strategies emphasize parental care and are to be contrasted with r-selected strategies which emphasize fecundity, the bioenergetic trade-off between which is postulated to underlie cross-species differences in brain size, speed of maturation, reproductive effort, and longevity.) It is suggested that this pattern came about because the ice ages exerted greater selection pressures on the later emerging populations to produce larger brains, longer lives, and more K-like behavior. One theoretical possibility is that evolution is progressive and that some populations are more "advanced" than others. Predictions are made concerning economic projections and the spread of AIDS.