It turns out you can deny evolution and still get published on the New York Times op-ed page. Dan Slater did just that, in a piece yesterday called “Darwin Was Wrong About Dating.”

Slater–who has a new book out in which he claims that online dating, of all things, is revolutionizing the sexual marketplace–sets out to debunk a subspecialty known as evolutionary psychology, which seeks to explain differences between men and women in terms of Darwin’s theory of sexual selection.

In brief, the theory of sexual selection posits that members of each sex will employ different evolutionary “strategies” in order to ensure that their genes survive into future generations. Since the male makes the lesser investment in reproduction, men are driven to favor quantity over quality. They are especially attracted to youth and beauty because these are signs of fertility. But one man can reproduce with many women, so that there is no evolutionary need to be selective. The most efficient way to pass on his genetic legacy is to have intercourse with as many women as possible.

Reproductively speaking, that’s not an option for a woman, whose potential number of offspring is much smaller because she must endure the demands of carrying, bearing and nurturing every child she produces. Thus it is in her evolutionary “interest” to value quality over quantity–that is, to be selective, choosing men who enhance her offspring’s chances of survival via some combination of their own genetic endowment and the resources they can contribute to the rearing of children.

It is crucial to understand that these are only metaphorical “strategies” and that evolutionary “interests”–the interests of one’s genes–are not the same as individual interests. Evolutionary psychology posits not that men decide to be promiscuous and women hypergamous because they want to have as many or as robust children as possible, but that these sexual and emotional instincts developed because they were conducive to reproduction over many generations in the ancestral environment.

Yet Slater claims “a new cohort of scientists have been challenging the very existence” of such sex differences:

Take the question of promiscuity. Everyone has always assumed–and early research had shown–that women desired fewer sexual partners over a lifetime than men. But in 2003, two behavioral psychologists, Michele G. Alexander and Terri D. Fisher, published the results of a study that used a “bogus pipeline”–a fake lie detector. When asked about actual sexual partners, rather than just theoretical desires, the participants who were not attached to the fake lie detector displayed typical gender differences. Men reported having had more sexual partners than women. But when participants believed that lies about their sexual history would be revealed by the fake lie detector, gender differences in reported sexual partners vanished. In fact, women reported slightly more sexual partners (a mean of 4.4) than did men (a mean of 4.0).

Which proves . . . absolutely nothing. The average number of sex partners by sex is a meaningless statistic. To illustrate why, we shall establish an uncontroversial empirical fact and then proceed to prove, by means of pure logic, that the average female human has more lifetime heterosexual partners than the average male human.

The empirical fact is that more boys are born than girls. “In mammals, male live births exceed female ones,” according to a 2002 study published in the British Medical Journal. “In humans, the ratio of male births to total births is expected to be 0.515.” That translates into a male-to-female ratio of just above 1.06. Data on sex ratios at birth from the CIA World Factbook confirm this expectation. Of 228 countries (including dependent territories like Greenland and Puerto Rico), 226 had sex ratios at birth greater than 1. The only exceptions were little Liechtenstein, with a ratio of exactly 1, and negligible Nauru, a genuine outlier at 0.837. The practice of female abortion and infanticide in China and India skews the ratio upward, but the trend is clear in countries where such practices are unknown.

Now for the proof. If one had access to perfect information–a database that compiled and cross-referenced the sexual history of every human being ever born–how would one go about calculating the average number of sex partners? One would begin by compiling a list of all unique heterosexual partnerships (hereinafter UHPs)–that is, every couple that has had sex one or more times. Since each such pair by definition includes one male and one female, the aggregate number of both sex’s partners would be equal to the count of UHPs.

To calculate the average number of partners per female, you would divide the UHP count by the total number of females. Likewise, to calculate the average number of partners per male, you would divide the UHP count by the total number of males. The numerators are the same; only the denominators differ. Since there are fewer females than males, the number of partners per female is necessarily higher than the number of partners per male.

The key to understanding this is the Hoffman-Manning Axiom: “It takes two to tango.” A man cannot add a sex partner unless a woman also adds one. Thus an uneven sex ratio is the only factor that can account for a difference in the sexes’ actual average number of partners. If we assume the sex ratio is 1.06 and the average male has 4.0 sex partners, then the average female has 4.24 partners.

Lo and behold, that’s very close to Alexander and Fisher’s figure of 4.4 partners per woman. Big deal. Their study is analogous to an empirical investigation demonstrating that 2 and 2 equal not 22, contrary to popular belief, but somewhere in the vicinity of 4.1.

What they do seem to have demonstrated is that if earlier studies found mathematically impossible variations in the reported number of sex partners, it is because the survey subjects were dishonest: Either men wishfully overreported their numbers of partners, women regretfully underreported them, or both. That would confirm the evolutionary psychology hypothesis that men have a greater desire than women for sexual variety.

Darwin 1, Slater 0.

Slater also purports to refute “the assumption that an enormous gap exists between men’s and women’s attitudes toward casual sex”:

Evolutionary psychologists typically cite a classic study published in 1989. Men and women on a college campus were approached in public and propositioned with offers of casual sex by “confederates” who worked for the study. The confederate would say: “I have been noticing you around campus and I find you to be very attractive.” The confederate would then ask one of three questions: (1) “Would you go out with me tonight?” (2) “Would you come over to my apartment tonight?” or (3) “Would you go to bed with me tonight?”

Roughly equal numbers of men and women agreed to the date. But women were much less likely to agree to go to the confederate’s apartment. As for going to bed with the confederate, zero women said yes, while about 70 percent of males agreed.

Terri Conley, a University of Michigan psychologist, thought this was baloney:

Ms. Conley found the methodology of the 1989 paper to be less than ideal. “No one really comes up to you in the middle of the quad and asks, ‘Will you have sex with me?’ ” she told me recently. “So there needs to be a context for it. If you ask people what they would do in a specific situation, that’s a far more accurate way of getting responses.” In her study, when men and women considered offers of casual sex from famous people, or offers from close friends whom they were told were good in bed, the gender differences in acceptance of casual-sex proposals evaporated nearly to zero.

It’s unclear why we should think that responses to hypothetical proposals, such as those in the Conley study, would be a better guide to actual behavior than responses to play-acts that the experimental subjects believe to be genuine proposals. Do words speak louder than actions in Ann Arbor?

That objection aside, the results of Conley’s study are in no way inconsistent with those of the famous 1989 one. The latter found that men are far likelier than women to say yes to a proposal of sex on the basis of no information except physical appearance and a fleeting first impression. The former found that women are as apt as men to say yes to an offer of sex with a high-status partner, one who has proved himself either by becoming famous or by sexually satisfying a presumably trusted common friend.

Men incline toward promiscuity, women toward hypergamy. Darwin 2, Slater 0.

Why would the New York Times, which scoffs at creationism, publish such an intellectually slipshod attack on evolution? Because evolutionary psychology contradicts the feminist dogma that the sexes are created equal, that all differences between men and women (or at least those differences that represent male dominance or superiority) are pure products of cultural conditioning.

Feminism is the new creationism. The left loves to scoff at people who believe that Genesis is literally true, but these days feminist beliefs are a lot more influential.

James Taranto - http://on.wsj.com/RVT8Sj