That So-Called Sexual Peak
By Dr. Pisaster | Pajiba Dirty Talk | July 13, 2010 |
By Dr. Pisaster | Pajiba Dirty Talk | July 13, 2010 |
Those of you that are fans of the webcomic Piled Higher and Deeper may remember this comic, which points out the frequent differences in the actual conclusions from scientific studies and the way they are reported both in university press releases and the general news. Universities are in the business of making money off of research, and newsworthy studies usually improve their chances of getting more funds, so they tend to be quick to play up those aspects of research most likely to draw attention while downplaying all the caveats and exceptions to any conclusions, and news reports often base their write-ups on the press release material rather than the full study, often further distorting the conclusions in the process. Case in point: this press release from the University of Texas at Austin, which refers to this paper. The press release is titled “Ticking biological clock increases women’s libido,” and states that the research in question found that women in the 27-45 year old range (defined in the study as the age range of declining fertility) had higher sex drives than both younger, more fertile women, and post-menopausal women. The release implies that this research proves that women have evolved to be more sexually active after age 27 in order to improve their chances of having children, and while the quote from the professor who conducted the research also plays up this aspect, in the actual paper the authors are more careful in their conclusions and more willing to acknowledge some of the limitations of their research.
The study in question, Reproduction expediting: Sexual motivations, fantasies, and the ticking biological clock, by Judith A. Easton, Jaime C. Confer, Cari D. Goetz, and David M. Buss, looked at the frequency of sexual thoughts, fantasies, and activities, as well as willingness to sleep with someone after different lengths of time for 827 women. The subjects were drawn from a database of college students who had volunteered to be subjects of studies like this one and … Craigslist. The respondents were grouped into three categories: “fertile” women, aged 18-26 (of which there were 554), women in the age range of declining fertility, aged 27-45 (222 subjects) and menopausal women 46 and older (51 subjects). The age groups are arbitrary, based on population averages, and the number of women in the menopausal group is a little low for my taste, but the approximations are likely to show aggregate differences, which is all this particular study is interested in. The study also explicitly excluded women who did not identify as heterosexual. The results indicated that women in the declining fertility group spent more time thinking about sex and fantasized more than women in either other group. They also reported more intense fantasies and higher frequency of sexual activity than the high-fertility group, although the menopausal group had comparable results for these variables. In all cases, the differences were relatively small but statistically significant. Both the 27-45 and 46+ groups reported fantasizing about their current partners only about half the time, while the under 27 group fantasized about their current partners about 73.5 percent of the time and someone else only 26.5 percent of the time. Women in the declining fertility group also reported being more likely to sleep with someone after knowing them for a short period of time (whether it was 1 day, 1 week, or 1 month) than the other groups, although the menopausal women were also more likely to consider it than the youngest group.
The authors do interpret these results in terms of evolutionary psychology — that often questionable branch of research that uses conjecture about the evolutionary past of humans to explain observed behaviors of modern humans. There are a lot of problems with evo psych — not least that it is pure conjecture, but also that it often treats human behavior as if it exists in a cultural vacuum in which the only influence is our genetic past. The evolutionary psychology explanation — that women amp up their sexual game as their fertility declines to increase their chances of conceiving (whether they consciously want to conceive or not) is not unreasonable, but it isn’t the only possible explanation for the results. As the authors themselves state, the results, “may reflect mere sexual experience increasing comfort with sexuality, and not a reproduction expediting adaptation designed to capitalize on remaining fertility.” They also note that the questionnaire did not ask women about other factors, such as hormone replacement in the menopausal women, fertility medications, or birth control, all of which can affect sex drive. Another issue I almost always have with evo psych studies is that the subjects usually all come from a single culture. The subjects for this paper were recruited from the university and the local community, so these results may turn out to be specific to western women, or possibly an even narrower group, such as middle class white women. The youngest group was primarily made up of college students, who tend to come from relatively affluent backgrounds, and the other respondents would have had to be at least well-enough off to have internet access, but there are no demographics reported in the paper, so it’s impossible to tell anything about the makeup of the study’s subjects such as race, religion, education level, financial status, etc. Such factors would ideally be accounted for in study like this. Admittedly, it’s very difficult to get a truly diverse sample in psychology studies, but the lack of such information should be kept in mind when analyzing studies like this one.
Aside from those obvious problems, the results do indicate that during the years of declining fertility women tend to be more sexual than their younger counterparts, adding to the general body of research that indicates that women become more sexual as they get older. There’s no solid evidence for a specific dramatic peak, but women do seem to become more sexually confident, if nothing else, as they age. There’s no solid evidence that this is due to an evolutionary drive to have as many babies as possible before the well runs dry, but I see no reason to completely dismiss the possibility.
Dr. Pisaster has a doctorate in biophysics, not actually anything sexy. She does however enjoy having sex, reading about sex, and talking about sex. Especially when she’s had a little whiskey.