Personality and Natural Selection

New ideas in human behavior genetics may be set in motion by construing psychological groups as Mendelian populations (Tryon, 1957; Thompson, 1957). The continuity, complexity, and fluidity of behavior (Thompson, 1964) together with the hazards of interpretation of phenotypic correlations impose barriers on those who do 'research in this area which may impair their vision of solutions to the particular problems of human behavior genetics. A major purpose of this paper is to entertain the notion that it may lbe fruitful to look at personality and natural selection simultaneously. Bridging the gap between population genetics on the one hand and social anthropology on the other may be one of the roles for the human behavior geneticist. ·Demonstration of a heritable component -in the -variation observed in several perso'nality traits and types (Gottesman, 1962, 1963b; Vandenberg, 1962) has immediate implications for the evolution of our species stemming from the theory of natural selection. The one nonrandom genetic process that accounts for the adaptive orientation of evolution is reproduction (Simpson, 1958, pp. 18-19): ':'1£ r~production is differential, if there is a correlation between distinctive genetic factors in the parents and their relatively greater success in reproductio~, then there will be an increase in the frequencies of those genetic factors (and combinations of them) within the population from one generation to another. . . . That, in brief, and shorn, of numerous complications, is the modern concept of natural selection.>' The evolution of personality can be explained by this process only to the extent that personality is heritable; differential reproduction based upon superior adaption which has been transmitted culturally, complements that adaptation which was associated with genetic variation. Simpson said