Boneheaded Ev Psych "Explanations" for Why "Older" Women Like Sex

Via the Daily Dish, here’s some rank foolishness from evolutionary psychology. Time magazine has a woefully uncritical recap:

A new journal article suggests that evolutionary forces also push women to be more sexual, although in unexpected ways. University of Texas psychologist David Buss wrote the article, which appears in the July issue of Personality and Individual Differences, with the help of three graduate students, Judith Easton (who is listed as lead author), Jaime Confer and Cari Goetz. Buss, Easton and their colleagues found that women in their 30s and early 40s are significantly more sexual than younger women. Women ages 27 through 45 report not only having more sexual fantasies (and more intense sexual fantasies) than women ages 18 through 26 but also having more sex, period. And they are more willing than younger women to have casual sex, even one-night stands. In other words, despite the girls-gone-wild image of promiscuous college women, it is women in their middle years who are America’s most sexually industrious.

So far, so good – or so I thought, until Time noted one of the most egregious failings of this “study”: the older women (or “cougars,” as Time repeatedly calls them) were recruited from Craigslist! Dudez!!! Has anyone explained to Buss Easton & Co. that folks on Craigslist – even the women – are mostly looking for one thing, and it ain’t quality used furniture? Did they even stop to make sure that the Craigslist participants weren’t offering paid erotic services? And did they notice that there’s no section in Craigslist for “women not seeking anything”? No rubric for “not interested in sex”?

I’m willing to believe that women do gain interest in sex from their late twenties through menopause, but the authors haven’t even proved this. Also, they’re comparing apples and oranges. The other one-quarter of participants were students at UT Austin, who presumably participated for extra credit and weren’t actively advertising for sex partners.

But let’s grant Buss Easton at al. their facts. Their interpretation (again via Time) is still complete bunk:

Why would women be more sexually active in their middle years than in their teens and 20s? Buss and his students say evolution has encouraged women to be more sexually active as their fertility begins to decline and as menopause approaches.

Here’s how their theory works:

Our female ancestors grew accustomed to watching many of their children — perhaps as many as half — die of various diseases, starvation, warfare and so on before being able to have kids of their own. This trauma left a psychological imprint to bear as many children as possible. Becoming pregnant is much easier for women and girls in their teens and early 20s — so much easier that they need not spend much time having sex.

However, after the mid-20s, the lizard-brain impulse to have more kids faces a stark reality: it’s harder and harder to get pregnant as a woman’s remaining eggs age. And so women in their middle years respond by seeking more and more sex.

(The rest of the Time article is here.)

First, why conclude that seeing children die would always spur women to have more babies? An alternative would be to invest more resources in a smaller number of children. Women also regularly saw other women die in childbirth. By the authors’ own logic, this trauma would have motivated women to avoid excessive pregnancies.

Also, jumping from individual psychological trauma to species-level hard-wiring of our lizard brains? They might as well leap over the Grand Canyon.

And then there’s the idea that just because we have some procreative hard-wiring, our sex drives can be reduced to our lizard brains, even today. Again: Dudez!! Lots of us lizard-brained women will not have sex with partner unless we’re confident we won’t get pregnant. A few years have passed since the advent of paleo-women. I do not think the same as a woman 200,000 years ago. (I wonder, though, if she’d reject the Pill out of hand. I kind of suspect she wouldn’t. After all, she would have known numerous women who died in childbirth.)

Interpreting the “data” is confounded by researchers’ age categories, which are incoherent and puzzling. For many women, there’s a huge developmental gap between 27 and 45. We become different people, changed by our work, our romantic relationships, and (often) motherhood. All of those changes also impact our sexuality.

There are also major issues with the way that age group is characterized. By whose calculus is a woman in her “middle years” already at age 27? Sure, paleo-women were lucky to live past menopause. So were my great-grandmothers. Today, the only people who consider 27 to be “middle years” are middle-aged men who think they’re entitled to a 20-year-old girlfriend. (I’m sure they’re prowling Craigslist, too).

But even in terms of biology, 27 is not past a woman’s supposed reproductive prime. Fertility undergoes a gradual decline. It’s still pretty high until one’s mid-thirties. It only plunges steeply past age 40.

(Source: Management of the Infertile Woman by Helen A. Carcio and The Fertility Sourcebook by M. Sara Rosenthal, via BabyCentre UK)

The arm of biology that’s relevant here isn’t evolutionary psychology, it’s endocrinology. Women’s hormonal levels do contribute to libido (though in ways that aren’t yet well understood; otherwise, testosterone would offer an easy fix to women troubled by low desire). Hormones begin to fluctuate in the run-up to menopause. For a few women, hormonal changes become noticeable in their late thirties. Others notice them in their forties. Some women note a drop in sexual desire during perimenopause, while others feel it surge, and still others see it fluctuate.

But even granting hormones their due, it would be silly to think they’re the only – or even main – factor in shaping women’s desires. A recent study (via Charlie Glickman’s sexuality blog) found that even at menopause, social and psychological factors matter at least as much as hormones when it comes to sexual desire and activity. Science Daily summarizes the findings of Dr. Sharron Hinchliff et al. in the Journal of Health Psychology (15:5):

Almost all [study participants] had experienced some form of change but the findings indicated that these were down to a number of external factors such as providing care for a relative, partner´s low sexual desire and the quality of the relationship, alongside biological factors such as perceived changes in levels of hormones. The findings therefore concluded that women go through many lifestyle changes during mid-life which are also contributing factors.

(The full summary is here.)

This study  further found great variability among women, with a minority actually reporting a resurgence of desire post-menopause. It’s easy to imagine social and psychological reasons for an uptick in libido: Kids leave home and empty nesters can romp with abandon. Menopause frees women from fears of unwanted pregnancy. Birth control is no longer a hassle. Experience and self-knowledge beget better sex. A great follow-up research project would be to identify those women who get more enjoyment from their sexuality after menopause, and figure out why their mojo has increased. This study suggests that looking at women’s relationships with their partners would be the obvious place to start.

Similarly, anyone with an imagination bigger than an earthworm’s could cook up more convincing interpretations of the Buss Easton et al. data. (Again, we’re overlooking that little Craigslist issue.) Past their mid-twenties, most women are more likely to be in a stable relationship than during their college years. Stable relationships lead to more opportunities for sex. We’re more likely to feel at home in our bodies. With more confidence, we find it easier to let our partners know what warms us. Not least, experience makes sex more fun, not less.

I’m not asking for rocket science. I only expect researchers to remember that we’re more than our reptile brains – and that even our reptile brains might be driven by more than just the drive to reproduce. Like the drive to feel pleasure. Or the desire for intimacy.

In other words, I’m looking for plain old science. The Buss Easton et al. study is LOLscience. Too bad I’ve stopped laughing. (Except for the Craigslist brainfart – that still tickles me.)

Note: I haven’t taken the time to read the original journal article by Buss et al, as its problems are on such a macro level that a closer look doesn’t seem necessary. I did look at the Hinchliff piece, whose major limitation is its small size (twelve in-depth interviews). Still, it suggests interesting avenues for future research.

Update, 7/21/2010: Upon being challenged by a commenter, I did go dig up the original journal article by Easton et al. (This commenter also pointed out – correctly – that Easton is listed as lead author, though it’s clear that Buss – as the only investigator with a Ph.D. – bears ultimate responsibility for overseeing the three graduate students on the project.) Here’s how I revised my assessment.

I read the original journal article closely and carefully. And I don’t think Time was unfair to this study at all.

In their original article, the authors never explain or defend their use of Craigslist to recruit study participants. That’s a massive omission. It boggles.

The full-length article raises other methodological issues, too. For instance, menopausal women made up only 6.2% of study participants (51 out of 827). This calls into question the robustness of any statistical conclusions drawn about the menopausal group – and this is a quantiative study, so sample size does matter.

Perhaps more damningly, the pool of respondents in the 27 to 45 group skewed very heavily toward the younger end of that range. Average age within that group was just 32.86. In other words, women over 35, whose fertility was beginning to decline more steeply, are not underrepresented within that group.

With respect to the researchers’ interpretation, Easton et al. do admit that sexual experience could play a role in women wanting more sex, but they immediately discount it because desire typically drops after menopause, when women have even more experience. Yet they don’t consider obvious confounders: the hormonal and social changes that accompany menopause. That makes their dismissal of experience awfully unconvincing.

Also, nowhere do they acknowledge that women’s material lives (children, relationships, homes, jobs) and psychological outlooks often change quite drastically between 27 and 45. This age group is drawn entirely from their hypothesis that declining fertility is the driver in making women more horny. It does not allow for any other distinctions to be made. (For instance, in the real world, I’ve known very few women in their late twenties who were worried about their fertility, while I’ve known quite a number of them in their late thirties. This matters crucially – unless we’re prepared to believe we’re merely automatons responding to the evolutionary pressures that existed many millennia ago.)

Finally, in actually reading through the study, I am dumbfounded by how teleologically the researchers proceeded. The women in the 27-45 bracket (those Time so cutely branded “cougars”) appear in the study as “reproduction expediting” women. In other words, something that the study ought to be testing for (are these women really seeking to become mothers?) is completely short-circuited and posited as fact by labeling these women as seeking to reproduce as fast and as often as possible. Once it’s assumed that sexual activity is identical with trying to maximize fertility, you no longer have to prove it. It becomes a background assumption. And yet, this is a massive logical leap.

Now, you might argue that women today are still just following the same program their foremothers did, back in the hunter-gatherer age – the so-called environment of evolutionary adaptedness (EEA) – and that even when we think we don’t want a baby, we actually do, because our evolved hard-wiring says so. Fine. But women today overwhelmingly break the link between sex and reproduction. Most of us quite consciously pursue sex lives that will allow us pleasure – to the point that many women (and men!) find it odd when they actually, intentionally try to conceive. The authors completely ignore the convulsive changes that effective birth control has wrought in women’s desires and their willingness/ability to pursue them.

Humans continue to adapt. We didn’t stop adapting in the EEA. Birth control is a monumental adaptation. Easton et al. would be far more convincing it they took it into account. Same goes for other social factors, such as slut shaming, which affects young women most acutely, and would tend to inhibit sexual behaviors. I’m not arguing that we’re blank slates. We have some biological hard-wiring (but with tremendous variation – not all women want children!). I’m even willing to say that some of that hard-wiring is a result of the EEA. However, when science dabbles in teleological thinking and unsupported assumptions and assertions, we might just as well discuss theology instead.

Mixed flowers in Berlin’s Rose Garden. I took the picture but can’t speak to their evolved psychology. The blossoms on the right appear to be hardy geraniums. The lavender flowers are not actually lavender, as far as I could tell. The dried foliage on the left may be post-menopausal?