Ovulating Woman Seeks Better Science

What Women Really Think
Jan. 19 2011 8:22 AM

Ovulating Woman Seeks Better Science

Amanda , Emily , I’m with you from the handgrip to the hipswing. Evolutionary psychology should live or die, like other science, on the quality of its evidence. And where the data are weak or messy, journalists and scientists should say so. Biologist Jerry Coyne, whom you also cite, Amanda, does a great job taking down Bering’s wide-eyed Slate piece : "it takes more than a small study on American college women at a single school to convince me that a behavior is an evolved adaptation to prevent rape," he writes. And:

"…for crying out loud, let’s have the journalists and scientists show a little more responsibility when reporting on evolutionary psychology. If there are problems with a study, describe them.  If an idea is pure speculation, say it. If there are other explanations for a phenomenon, give them."
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I’ll just add a note on Bering’s most offensive claim, that "women become more racist when they’re ovulating." In the single, unreplicated study he cites, researchers gave women several tests of racial prejudice and tried to correlate the results with their menstrual cycles. On a few measures of implicit or unconscious racial bias, they found that women who were more likely to be ovulating tended to score higher. On a measure of explicit or conscious racial bias, however, they found no link between ovulation and prejudice. Now, we could delve into the minutiae of those tests and argue about whether implicit or explicit attitudes about race matter most. But Bering doesn’t do that. He simply ignores the negative finding.

Meanwhile, that same study complicates his argument in another, unacknowledged way. The researchers measured women’s feelings of "vulnerability to sexual coercion" using something called the "fear of rape scale." And they reported that women who are both more likely to be ovulating and more afraid of sexual coercion were more likely to show racial bias. But here’s the confusing part: they also looked at the more basic question of whether ovulating women were, in fact, more likely to fear rape or take measures to avoid it in the first place – and they found no connection . That would seem to be a problem for Bering. Higher up in his piece, after all, he argues that "ovulating women overestimate strange males’ probability of being rapists." He cites a study that claims: " women perceive men as more sexually coercive at fertile points of their cycle than at non-fertile points ." This is supposed to help prove that rape-avoidance around ovulation is an evolved adaptation. Yet when another study in his grab bag turns up negative evidence, as in no link between fertility and fear of rape, he never mentions it. The study authors don’t highlight it either-it’s tucked in a data table. And they all go blithely on their story-telling way.

Amanda Schaffer is a science and medical columnist for Slate.