Polygyny

The Distribution of Polygyny

Polygyny has been widely distributed in human societies through prehistory and recorded history. Ireänus Eibl-Eibesfelt found that it occurred in 83.5% of a large sample of modern societies, although monogamous unions were 2.5 times more frequent than polygynous unions. Its occurrence has been reported in many recent and contemporary hunter-gatherer and horticultural societies, in precolonial South America, Africa, Polynesia, and Australia, for example. Polygyny was practiced in ancient Hebrew society, and with the exception of certain liberal Islamic movements, is accepted in Islamic societies. It was not officially permitted, however, in ancient Greece and Rome, or in Christian societies, with the exception of early Mormonism.

Perspectives from Sociobiology and Evolutionary Psychology

Sociobiologists and evolutionary psychologists have sought to explain the incidence of polygyny in terms of natural selection. Trivers's theory of sexual selection and parental investment has been influential. Sociō biologists have explained the widespread institution of polygyny in terms of the differences in male and female reproductive strategies. Pregnancy, it has been argued, involves a much greater investment than male insemination. Men have evolved a desire for sexual access to a large number of women and will compete for access to women, whereas natural selection predisposes women to assess men as potential providers, and for the quality of their genes, as indicated by various markers such as symmetry.

Sexual strategies theory attempts to explain why men tend to adopt short-term mating tactics to a greater extent than women, but recent studies emphasize that both men and women have evolved mixed strategies, and that strategies are conditional in particular circumstances. Depending on environmental conditions, women ought to make a trade-off between male genetic quality and parental investment. For example, with latitude and geographical regions held constant it has been shown that polygyny is more common in societies where pathogens are more prevalent. This has been explained as resulting from women's favoring indicators of good genes (and hence, resistance to pathogens) as against indicators of exclusive parental investment. Polygyny has also been found to be more prevalent where women have more control over resources. This has been explained by their decreased dependence on male parental investment.

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