This is part II of my reply to Lynn Phillips's recent post in which she was very irked by my reporting of several studies showing that women are less interested in having sex with random strangers. I'll focus on the relevant evolutionary literature, which explicitly recognizes women's proclivities for short-term mating (see part I of my rebuttal here). I'll do so because Ms. Phillips insinuates that evolutionary psychologists seem to be unaware of this fact. Her lack of familiarity with the evolutionary literature is breathtaking. It takes effort to familiarize one's self with the relevant scientific literature. It is much easier to huff and puff with moral indignation about the "sexist" agenda of evolutionary psychology.
(1) Evolutionary psychologists recognize that both sexes are interested in both short-term and long-term mating opportunities (Sexual Strategies Theory, Buss & Schmitt, 1993). There are numerous evolutionary-based reasons for women to be desirous of short-term sexual dalliances, one of which is to shop for good genes. In line with this hypothesis, researchers have found that women are more likely to cheat on their long-term partners when maximally fertile, are less likely to insist on using contraception during such a dalliance, and are more likely to desire men possessing phenotypic markers of good genes when engaging in such extrapair copulations. Does this sound as though evolutionary psychologists are unaware that women are at times desirous of casual sex? What say you Ms. Phillips?
(2) That said, this does not mean that women have an equal penchant for unrestrained sexuality or that their motives for such dalliances are the same as those of men. In a recent paper titled "Evolutionary Psychology and Feminism," (note the title) Buss and Schmitt (2011, Table 1) offer the following summaries of findings (along with numerous references for the findings in question). I reproduce these as one long quote here:
"Men are more likely than women to engage in extradyadic sex; to be sexually unfaithful multiple times with different sexual partners; to seek short-term sex partners that are already married; to have sexual fantasies involving short-term sex and multiple opposite-sex partners; to pay for short-term sex with (male or female) prostitutes; to enjoy sexual magazines and videos containing themes of short-term sex and sex with multiple partners; to desire, have, and reproductively benefit from multiple mates and spouses; to desire larger numbers of sex partners than women do over brief periods of time; to seek one-night stands; are quicker than women to consent to having sex after a brief period of time; are more likely than women to consent to sex with a stranger; are more likely than women to want, initiate, and enjoy a variety of sex practices; to have more positive attitudes than women toward casual sex and short-term mating; are less likely than women to regret short-term sex or ‘hook-ups'; have more unrestricted sociosexual attitudes and behaviors than women; generally relax mate preferences (whereas women increase selectivity for physical attractiveness) in short-term mating contexts; and perceive more sexual interest from strangers than women."
The latter findings are only a sample of all results that point to men's greater proclivity for unrestrained sexuality. Do you think that all of the latter findings conducted across countless cultures and using very different dependent measures are all due to the evil patriarchy and its imposition of arbitrary gender roles? Might these universal and pervasive sexes differences be due to the differential costs and benefits associated with mating across the two sexes? Nah. It would be gauche and misogynistic to proclaim so.
(2) Strategic pluralism (Gangestad & Simpson, 2000) is another deeply sophisticated evolutionary-based theory that enunciates the conditions that might promote the pursuit of short versus long-term mating strategies by EITHER sex. In other words, the theory explicitly recognizes a wide range of contexts where women might engage in short-term mating. Does this suggest that evolutionary psychologists are unaware that women might be at times interested in casual sex?
(3) Simpson and Gangestad (1991) developed the Sociosexual Inventory Scale, which captures an individual's desire for unrestricted sex. This scale inherently recognizes that some women might be more "open" in their sexuality than some men. However, on average women are more restrained in their sexuality than men. To draw an analogy that might be helpful to Ms. Phillips, men are taller than women even though most WNBA (female) players are taller than most men on the planet (see my post on this point here). Several global studies conducted across a wide range of cultures have established the universality of this sex effect (cf. Lippa, 2009 in his analysis of data stemming from 53 nations, spanning six continents, thirteen islands, and twenty-eight languages). Ms. Phillips thought that the studies that I discussed in my post were restricted to "white, Caucasian young people"... "in a modern, Western, Christianized, post-industrial urban culture. Ms. Phillips: Is the data reported by Lippa sufficiently universal, or should evolutionary psychologists conduct the studies in every culture that has ever existed prior to your considering that the sex difference might be robust?
(4) It has long been known by evolutionary scientists that there is a positive correlation between testes size and female promiscuity across primate species (cf. Harcourt et al., 1981). More specifically, the size of male testicles is an adaptation to sperm competition as triggered by female promiscuity. In the human context, men's testicles are considered relatively large and as such this would imply that human females are anything but sexually coy in the right circumstances. Furthermore, the work of R. Robin Baker and Mark A. Bellis on sperm competition has posited the intriguing idea that men's ejaculate contains three types of spermatozoa (fertilizers, blockers, and killers), each of which exists for a different purpose: fertilize eggs, block other men's sperm from fertilizing, and kill other men's sperm that are present in a woman's reproductive tract. Since sperm is typically viable for roughly seventy-two hours, this implies that evolutionarily speaking, women are quite likely to have mated with multiple males within a short time frame. I should mention that Baker and Bellis's work is controversial, as other researchers have failed to replicate their findings (cf. Moore, Martin, & Birkhead, 1999). Note that evolutionary hypotheses can indeed be falsified. Irrespective of the veracity of the "sperm competition hypothesis," does the latter debate suggest that evolutionary scientists are not aware that women are capable of engaging in casual sex? Incidentally, on several occasions feminists have advised me that they are pleased when I discuss this hypothesis. Hence, if an evolutionary principle is in line with feminist ideology, it is good science. If it contradicts the ideology, it is weak and sexist science. Nice.
(5) Charles Darwin proposed two parallel processes that drive the evolution of species: natural selection (confers survival advantage) and sexual selection (confers reproductive advantage). In the great majority of cases, sexual selection operates via the discriminating process of female mate choice (including in the human context). Thus, that females are so central to the evolution of a large number of species should be a scientific fact that feminists would hail. Males (including men) are pawns that dance to the tune of female choosiness. What could be more empowering to female power than that?
I will refrain from dissecting all of the errors in Ms. Phillips's post (perhaps other evolutionary psychologists might wish to take her to task), and I'll leave it to others to tackle some of the references that she cites in her post (e.g., the speed dating study). However, I can't help but point out the following quote:
"Imagine if none of the women tested in the cited experiments had ever been asked to think sex sinful, had not grown up under a double standard of male and female promiscuity and had no reason to fear being date-raped if they changed their minds mid-encounter. And imagine if the men could get pregnant. Social, economic and biological risk factors were so skewed against women's free expression of sexual impulses, one hardly needs to hark back to eons of natural selection to explain why acting on pure lust was more of a no-brainer for men than for women."
This reminds me of a classic Arabic saying: If my grandmother had testicles, we would have called her my grandfather. Yes, Ms. Phillips. Women stand the very real and horrifying chance of being sexually assaulted, and yes women and not men get pregnant. These BIOLOGICAL realities are at the root of the differential costs and benefits of mating that drives the evolutionary-based sex differences in human mating.
Final point: Evolutionary behavioral scientists are not in the business of conducting their research in the service of any political or social ideology. They seek to elucidate the mysteries of our human nature using the scientific method as the guiding framework. If I took considerable time responding to Ms. Phillips's post, it is not with the hope of changing her mind (I doubt that this is possible). Rather, it is important that the public at large is accurately informed about the existing scientific knowledge regarding the biological forces that generate many similarities between the two sexes, as well as important differences. I thank Ms. Phillips for having reminded me of the import of pursuing this objective.
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