You know my hips don’t lie. And I’m starting to feel it’s right. BUT…let’s check your IIEF-5 score and our PVI frequency baby. Oh yeah~

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Kramare and Treichler (1996): “Feminism is the radical notion that women are people.”

Geher (2009): “Evolutionary psychology is the radical notion that human behavior is part of the natural world.”

There is no reason on earth to believe that these two “radical” notions are irreconcilable.

(Feminist Evolutionary Psychology Society)

Yet evolutionary psychology still has such a bad reputation among feminists.

Partially, that’s because many feminist criticisms of the discipline and its researchers — and vice-versa — are really just based on strawmen and stereotypes.

That said, it’s also true that evolutionary psychologists can indeed sometimes make outlandish, sexist claims based on little to no evidence.

Or at least, they can seem to. More often than not, it’s actually journalists that are doing that for them, who rarely have time for their caveats and qualifications. Also, journalists can sometimes simply make mistakes and/or misunderstand too, or evolutionary psychologists fail to clearly explain the purpose, methodology, and conclusions of their research.

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These maxims are worth repeating, especially when you read a headline that brings an instant, smug satisfaction of being proven right. In this case, with “Why Dating Women With Slim Waists Lowers Men’s Risk for Erectile Dysfunction” by Christine Hsu in Medical Daily, which not only makes sense given everything else I’ve read about women with hourglass figures — that they’re significantly more fertile than those with other body types, which likely plays a strong role in why that one is so popular amongst heterosexual men (to the extent that even congenitally blind men prefer them) — but, sharing that preference, also reminds me that I’ve got great taste in women too.

Just taking Hsu’s word for it though, would be nothing more than confirmation bias. So, starting with her introduction (my emphasis):

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Possessing a ‘figure 8′ body has long been a trademark of feminine beauty, and now new research has revealed the reason why men tend to prefer women with a waspish waist.

The study also linked the middle proportion of a woman’s body to the likelihood of satisfaction and erectile dysfunction in her partner.

Researchers found that the slimmer a woman’s waist, the more satisfied her partner and the less likely he is to suffer impotence in the bedroom, according to the study published in the [December 2012 issue of the] journal Archives of Sexual Behavior.

That study is “Slimmer Women’s Waist is Associated with Better Erectile Function in Men Independent of Age” by Stuart Brody and Petr Weiss, and I’ve highlighted that last section because — admittedly in hindsight — it should already raise alarm bells: sexual satisfaction isn’t actually mentioned in the title of the article, nor the original study. That doesn’t necessarily mean that it’s not there, but the combination of the titles and the highlighted part does strongly imply that, somewhere within, the study will mention that female participants’ waists were measured and the sexual satisfaction and levels of impotence of their male partners.

At first glance, it appears to be done so in the abstract, (my emphasis; source, right):

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Clik here to view.….To assess the association of women’s waist size with a more tangible measure of perceived sexual attractiveness (as well as reward value for both sexes), we examined the association of women’s age and waist circumference with an index of men’s erectile function (IIEF-5 scores), frequency of penile-vaginal intercourse (PVI), and sexual satisfaction in a representative sample of Czechs (699 men and 715 women) aged 35–65 years. Multivariate analyses indicated that better erectile function scores were independently associated with younger age of self and partner and women’s slimmer waist. PVI frequency was independently associated with women’s younger age and women’s slimmer waist. Sexual satisfaction was independently associated with men’s younger age and slimmer waist for both sexes. Better erectile function, greater PVI frequency, and greater sexual satisfaction were associated with women’s slimmer waist, independently of both sexes’ ages….

But then I moved on to the methodology (the first 2 pages are available at the above link), which ends the section on how the participants were chosen with (my emphasis):

The rationale for using participants who were not both members of the same couple includes prioritizing a representative sample and decreasing risk of a couple comparing responses (Weiss & Brody, 2011). The 649 women who provided complete data had a mean (SD) age of 48.1 (8.6) years, and the 685men who provided complete data had a mean (SD) age of 49.6 (8.7) years.

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Clik here to view.Which begged the question of how on Earth, if data on the waist sizes and sexual satisfaction of both partners in a couple was not gathered (and erectile function of the male partner), it was determined that “the slimmer a woman’s waist, the more [sexually] satisfied her partner and the less likely he is to suffer impotence in the bedroom.” This in turn spawned an interesting all-day conversation on The Grand Narrative Facebook page, and ultimately led — thank you! — to my getting my hands on the full study itself.

As it’s only 8 pages long, I highly recommend that you read it for yourselves (please email me or let me know in the comments if you would like a copy) so let me just sum it up here. As it turns out, Hsu did indeed make some mistakes (source, right).

First, the methodology:

Page 3, paragraph 1, mentions that “The same wording for the IIEF-5″ — the test of erectile function — “was used for both sexes with the added instruction that the woman should complete it on behalf of her partner.” Earlier, it also mentions that the test is very reliable, with men’s and their female partners’ assessment of the men’s erectile function being very similar (obviously, their female partners would know!).
Page 3, paragraph 2, mentions that only participants completed the survey on sexual satisfaction; and page 3, paragraph 3, that participants measured only their own waists. In short, it’s these points that already prove the error of Hsu’s link between male sexual satisfaction and female waist size that I highlighted in the introduction.

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Clik here to view.Next, the results (source, right):

The younger the men and women, the less problems with erectile dysfunction the men (or the women’s male partners) had.
The slimmer the women’s waists, the less problems their male partners had with erectile dysfunction.
The slimmer the women’s waists, or the younger the women, the more often they had sexual intercourse.
The slimmer both sexes were, the more likely they were to have satisfying sex lives. The younger the men were (not the women) the more likely they were to have satisfying sex lives.
The more often men and women had sex, the less problems with erectile dysfunction they (or the women’s male partners) had; and the younger the men (not the women), the more likely they were to have satisfying sex lives.
Women with slimmer waists tended to have sex more often; their male partners had less problems with erectile dysfunction; and they (the women) were more likely to have satisfying sex lives.
And finally, crucially, “It was noteworthy that the association of women’s slimmer waist with all measures of sexual function was independent of both partners’ age” (from the end of page 6).

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That’s a lot to take in, many points seem obvious and to follow naturally from each other, and there’s certainly the possibility that I’ve misunderstood and/or misrepresented some of them myself — if you think so, by all means please correct me. Also, I don’t mean to harshly criticize a reporter who undoubtedly had less time to spend on the study than the 3 days of my semester break(!) that I ultimately did. But, although it’s very very easy to take away the message that “the slimmer a woman’s waist, the more satisfied her partner” from it, with the conclusion stating —

The findings were generally in accord with evolutionary perspectives. Men’s erectile function scores were independently associated with younger age of self and partner, and women’s slimmer waist (all factors generally associated with greater reproductive fitness). Similarly, PVI frequency was independently associated with women’s younger age and women’s slimmer waist. Sexual satisfaction was independently associated with men’s younger age, and slimmer waist for both sexes. Better erectile function, greater PVI frequency, and greater sexual satisfaction were associated with women’s slimmer waist, independently of both sexes’ ages. Thus, capacity for potentially reproductive sexual behavior, frequency thereof, and a psychological response that might support pair-bonding were all linked to women’s slimmer waist.

— for instance, Hsu does appear to have misunderstood it, also mentioning that “researchers also recorded how often the 699 study participants — Czech men between the ages of 35 and 65 years old — had sexual intercourse,” whereas actually (page 2, paragraph 5) 699 men and 715 women were surveyed, and of those 685 men and 649 women provided complete data.

Either way, I can just imagine what many journalists and advertisers would — and probably will? — make of a study which seems to say that men with slimmer wives and partners have more satisfying sex lives!