Monday, April 19, 2010

Thinking about Sex

Here is a bit from an article by Satoshi Kanazawa in his Psychology Today blog, The Scientific Fundamentalist:
Throughout evolutionary history, humans were mildly polygynous. A species-typical degree of polygyny correlates with the extent of sexual dimorphism in size (the extent to which the male is larger than the female). The more sexually dimorphic the species, the more polygynous it is. This is either because males of polygynous species become larger in order to compete with other males and monopolize females, or because females of polygynous species become smaller in order to mature early and start mating.

I personally believe it’s the latter; I believe men and women could potentially be the same size except for the fact all human societies are invariably polygynous to various degrees. In fact, women’s (but not men’s) average height in society is partly determined by its degree of polygyny. The more polygynous the society, the shorter women are on average, while men’s average height is unaffected.


Sexual exclusivity prescribed under socially imposed monogamy today is therefore evolutionarily novel for men, but not for women. The Hypothesis would therefore predict that more intelligent men may value sexual exclusivity – having only one sexual partner in a committed relationship – more than less intelligent men, but intelligence may not affect women’s likelihood of espousing the value of sexual exclusivity.

Consistent with this prediction of the Hypothesis, data from a large, representative American sample shows that more intelligent boys are more likely to grow up to value sexual exclusivity in early adulthood than less intelligent boys. In contrast, childhood IQ does not affect girls’ value on sexual exclusivity in early adulthood. The effect of intelligence on the value of sexual exclusivity is more than four times as strong among men than among women. Among women, the association is not statistically significant.
It is funny. When you use scientific technique to "step back" and look at the big picture, it isn't at all the same as what you think you see when you are up close and involved in your society. On a day-to-day basis, it is the women who are jealous and rage at mates that dally. But this scientific data goes against that. It claims that when you step back and gather data more broadly, you the picture changes.

I will simply note the two points of view. I have no special insight. I can understand both. Female jealously is obvious. But the claim that females are indifferent to polygyny would be consistent only if you can make some distinction between philandering and a socially approved and regulated system of multiple wives with a strictly enforced "no philandering" clause. I don't think that is realistic, so I'm left puzzled.

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