This article advances two theoretical schemas. The first concerns nomothetic human personality traits. We provide evidence that personality traits (a) exist, (b) are longitudinally stable, (c) can be assessed by several converging indices, (d) are inherited, and (e) have adaptive significance. We provide a review of some data on the inheritance of individual differences in activity level, aggression, altruism, chronogenetics, criminality, dominance, emotionality, intelligence, locus of control, political attitudes, sexuality, sociability, values, and vocational interests. We also suggest ways in which personality traits could arise in accordance with established genetic principles. p]The second half of the paper presents genetic similarity theory (GST). Going beyond kin selection, GST states that a gene may ensure its own survival by acting so as to bring about the reproduction of any organism in which copies of itself are to be found. An organism may have a tendency to exhibit favoritism toward genetically similar strangers as well as toward its own relatives. We order several data sets with this theory including (a) kin recognition studies in animals, (b) assortative mating, (c) intrafamilial relations, (d) human friendship and altruism, and (e) ethnic nepotism. We discuss a strong and weak version of GST and offer some predictions for future research.
Read full abstract