Evolutionary curveball for curvy?

Anthropological reports can be very subjective and biased, as the Maragaret Mead debacle showed. I would not put much weight on the summary below at all. The conclusions are entirely to be expected from the known anti-Western biases of anthropologists. Any fault may lie with the data she uses rather than with the author herself, however. In one of her papers she quotes one of my papers and agrees with its conclusions! The original article is Waist-to-Hip Ratio across Cultures: Trade-Offs between Androgen- and Estrogen-Dependent Traits" by Elizabeth Cashdan

Having something less than the classic "hourglass" figure may have its benefits after all. While women with curvy figures might enjoy more attention from men in Western culture, and find it easier to become pregnant, new research suggests they may also face some evolutionary disadvantages compared to women with thicker waists.

That's because the same hormones that increase fat around the waist can also make women stronger, more assertive, and more resistant to stress, according to a new study published in the December issue of Current Anthropology. Given those findings, it makes sense that the slim-waisted body has not evolved to become the universal norm, said the study's author, Elizabeth Cashdan, an anthropologist at the University of Utah.

Her study takes aim at a theory popular in evolutionary psychology and medicine: that men universally prefer women with narrow waists and larger hips because their higher levels of estrogen make them more likely to conceive a child, and less vulnerable to chronic diseases. These preferences, the theory goes, have defined women's ideal body shape over time.

The idea took root in the 1990s when psychologists showed men drawings of women's silhouettes and asked them which were most sexy. Researchers found that men gravitated toward images with a waist-to-hip ratio of 0.7 - in other words, with a waist about a third narrower than the hips. Those same hourglass proportions are reportedly shared by stars such as Marilyn Monroe and Jessica Alba, and linked in medical studies with a lower risk of heart disease.

The findings troubled feminists, and drew criticism from anthropologists who said researchers were generalizing about human evolution based on samples of young, mostly white men in industrialized societies. The debate endured for years. "Many of us anthropologists have been in traditional hunter-gatherer societies and most of the women there don't look like that," said Cashdan. "So the question is, if it is adaptive to have that body shape, what's going on?"

In a review of data gathered from cultures as diverse as East African foragers and Chinese immigrants in Britain, Cashdan found that the average waist-to-hip ratio both within and across populations was higher than 0.7. In more egalitarian societies, where women played a greater role in the economy, they also tended to have thicker waists.

That suggests a genetic trade-off, with nature selecting for factors in addition to fertility and attractiveness. One possibility, Cashdan argues, is that extra doses of the stress hormone cortisol and male hormones known as androgens helped our hunter-gatherer foremothers cope in an environment where they had to sidestep poisonous snakes and went to sleep to the serenade of leopards growling. Those same belly-boosting hormones may even help modern women face stressful situations, she says.

More here

Posted by John Ray. For a daily critique of Leftist activities, see DISSECTING LEFTISM. For a daily survey of Australian politics, see AUSTRALIAN POLITICS Also, don't forget your daily roundup of pro-environment but anti-Greenie news and commentary at GREENIE WATCH . Email me (John Ray) here

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