Human Sexuality and Evolution
Bear in mind that some day all our provisional formulations in psychology will have to be based on an organic foundation. . . . It will then probably be seen that it is special chemical substances and processes which achieve the effects of sexuality.
-- Sigmund Freud
Underlying the human species' great cultural diversity is our common humanity, our human nature. Perhaps no other species-specific behavior is more predictable across cultures and across time than are patterns of human sexuality ( Symons 1979, 1992; Buss, 1989; Ellis, 1992; Wilson & Daly, 1992). It is recognized that there are many different patterns of sexual behavior reflecting different cultural conditions and which, therefore, require cultural or proximate explanations. However, I wish to emphasize the more fundamental and distal phylogenetic causes underlying the superficially different patterns anthropologists observe, while again emphasizing that distal and proximate explanations are no more conflicting explanations than phylogeny and ontogeny are conflicting processes.
All human beings share the same evolutionary history and, therefore, share common mechanisms in our genes and brains that direct the desire to reproduce. Culture is a human adaptation that allows humanity to adapt quickly to changing environments, including those changes we ourselves produce. But let us not forget that culture does not proceed in a biological vacuum. Current patterns of behavior are always informed by our evolutionary history. An understanding of this history provides a framework for an enhanced understanding of the currently pressing social problems of marriage and divorce, sexual violence, illegitimacy, crime rates, and the spread of sexually transmitted diseases (STDs).