Significance of Aggression for Hominoid Evolution

Abstract

A principal component analysis of the correlation matrix array 25 items concerning the status of adult male and female as well as of offspring in 108 societies revealed that the more polygynous the society is, the more aggressive adult males in society are toward adult females. The more the subsistence of a society is dependent on the labor of males, the more aggressive adults are towards offspring. Swaddling and infanticide are considered to work as that buffering the aggression and to simultaneously act as a r-strategy or a K-strategy, respectively, in terms of reproductive success in human societies. Overall high level of aggression in greate apes and humans is discussed in terms of possible dietary changes that have occurred to produce high sociability in primates.