Western societies beginning with the ancient Greeks and Romans and extending up to the present have had a powerful tendency toward monogamy.
In general, cultural uniqueness could derive from either nature or nurture—the same old ageless dichotomy, but I think now we are in a better position to deal with these issues than in times past, and I will be arguing that both are important. Western cultures have experienced certain unique cultural transformations that cannot be predicted by any biological/evolutionary theory, but they also have had a unique evolutionary history. Western culture was built by people who differ genetically from those who have built the other civilizations and cultures of the world. In the following I will argue that Western cultures have a unique cultural profile compared to other traditional civilizations:
- The Catholic Church and Christianity.
- A tendency toward monogamy.
- A tendency toward simple family structure based on the nuclear family.
- A greater tendency for marriage to be companionate and based on mutual affection of the partners.
- A de-emphasis on extended kinship relationships and its correlative, a relative lack of ethnocentrism.
- A tendency toward individualism and all of its implications: individual rights against the state, representative government, moral universalism, and science.
My background is in the field of evolutionary biology, and one of the first questions that struck me when I was exposed to the evolutionary theory of sex was “why are Western cultures monogamous?” The evolutionary theory of sex is quite simple: Females must invest greatly in reproduction – pregnancy, lactation, and often childcare require an extraordinary amount of time. As a result, the reproduction of females is highly limited. Even under the best of conditions women could have, say, 20 children. But the act of reproduction is cheap for men. As a result, males benefit from multiple mates, and it is expected that males with wealth and power should use their wealth and power to secure as many mates as possible. In short, intensive polygamy by wealthy, powerful males is an optimal male strategy i.e., it is behavior that optimizes individual male reproductive success.