In our directed reading, we have discussed many topics revolving around a few fairly basic ideas. The concept of sexual selection is predicated on the assumption that males and females, though united in their goal to reproduce, have different interests; that is to say, circumstances or behaviors that positively impact a female’s reproductive success may be detrimental to a male’s. This is a fairly inane statement if one is referring to giraffes or seahorses, but when you say this about humans, it becomes offensive to some. I’ll be honest – I had trouble reconciling what I consider to be my feminist sensibilities and the idea that men and women are significantly different.
Since my initial qualms, I have come to some conclusions that I think are reasonably important to the study of humans in biology. The first may seem very conciliatory, but it is really important to me. It is this: studies on humans are cannot be applied directly to our daily lives. When I talk about a paper that I read for this class with a friend, often they will immediately apply it to themselves or their friends. For example, if I mention that I read a study finding that males of above-average height do better reproductively in general, I’ll get a response along the lines of “Well, I guess [insert short male’s name here] is out of luck.” This is a pet peeve of mine, because general trends of reproductive success may have slim to none perceivable correlation with dating in college; even knowing this, it is our knee-jerk reaction as humans to put everything in terms of ourselves. I find myself doing that all the time when thinking about the animal world. Nevertheless, it is an impulse that needs to be checked periodically.
The second conclusion in regards to feminism and evolution is that evolution is essentially the underlying “why” behind all of the processes we study, but it is most certainly not our moral code. In The Red Queen, Ridley aptly points out that murder is as natural as misogyny is, as long as we define “natural” as something integral to the lives of our pre-human ancestors. I think it is worth discussing (as Avery pointed out in an earlier post) whether, or to what extent, our success in Western society is based on reproduction. Either way, I know that I do not personally see reproduction as equal to success. I would be more inclined to define success as how effectively one can spread one’s ideas, and that reproduction is just one valid way to do so. In this way, you could say that Brad Pitt is successful, because his views (on adoption, for example) are given the world stage because of his fame, and his talent and attractiveness allow him to be more persuasive to certain audiences. In any case, there’s no reason that evidence revealing that women’s reproductive goals have evolved in a certain way should inform the our laws or moral rules, for reasons I’ve already mentioned.
My third conclusion is that the differences between men and women are one of averages. This is also a Ridley idea, but I dislike how he phrases it. Basically, how I understand it is that descriptions of male and female behavior are based on averages of the data collected from varied samples of men and women. Once again, instinct inclines us to mentally apply these findings to all men and women, not taking into account that this may be really misleading when comparing one man with one woman.
With all of this in mind, I would like to take a brief look at the evolutionary perspective on the female orgasm. Sadly, there are still some scientists who believe that the female orgasm originates from a lack of selection pressure to remove the processes producing the male orgasm, much in the way breast structures are preserved in men. John Bancroft sums up this idea: “women have orgasmic capacity and clitoral development, and men have nipples, because there is no good reproductive reason to suppress their development. In that respect, at least, one could say that women have had the better deal!” (2002). This attitude is somewhat of a throwback to Freud – scientific language is being used to make the claim that women’s sexuality is secondary and derived from male sexuality, but with no supporting data.
"Are we there yet?"
Several theories, focusing on an evolutionary incentive rather than some sort of selective indifference, have been proposed to explain the female orgasm; some of these make a certain degree of sense, and others seem dubious. One of the older ideas, first popularized in the 70s, was the so-called “upsuck” hypothesis, which theorized that the contractions involved in a female orgasm served to actively take up the sperm into the uterus. The actual mechanism of this is extremely foggy, but some self-collected data does suggest that not only does whether the woman orgasms affect sperm retention, but also the timing of the orgasm in relation to when the man ejaculates. As women often report that they feel tired or sleepy after having an orgasm, it has been suggested that the behaviors associated with fatigue and rest increase sperm retention.
As we all know, female orgasm is not necessary for conception to be successful. Logic leads scientists to believe, then, that it has to have a mate choice-like function to it, as it would be unlikely to evolve in the absence of some other purpose. I’ve read two thought-provoking papers on the subject that I would like to discuss. The first states that the female orgasm could select for good genes in males by means of ascertaining the quality of the (you guessed it) immune system. The measure of this was something called fluctuating asymmetry (FAS), which is very similar to facial symmetry, but applied to the whole body. The concept behind this is that the same gene controls development on both sides of the body, so asymmetry is instead an indication of how smoothly (read: parasite-free) development went for an individual. Excitingly, the researchers found that when women had sex with men with low FAS, they had more orgasms than when they had sex with men with higher FAS. The researchers seemed like they eliminated a lot of potential confounding variables by also ascertaining the affects of age, relationship type, something called “social potency” that I didn’t quite understand, and, most intriguingly, physical attractiveness. Even though FAS might correlate with physical attractiveness, this did not translate to physical attractiveness, or any other factor other than FAS, affecting female orgasms. A mechanism for this is most certainly absent from the paper, however.
The other really interesting study was one that tested the idea of selective sperm retention with multiple mates. It turns out that self-reporting data is to the effect that female orgasms before male ejaculation are not nearly as retentive as ones that occur during or up to 45 minutes after the male ejaculates. The study dealt with women who had “extrapair copulations”, or affairs. The orgasm pattern (note that the orgasm pattern also includes lack of orgasm) seemed to shift to favor retention of the sperm of the extrapair male. This data fits a model similar to a bird example in The Red Queen, and we’ve also discussed the idea in terms of facial attractiveness: it is in the female’s best interest to take advantage of reproducing with the highest-quality, most attractive males. These males are not going to be the best fathers, however, because they are in high demand from many females. Therefore, if a female can strike a balance between maintaining a relationship with a mediocre male (whose best chances at reproducing lie in contributing his resources to one female) and reproducing as much as possible with the more attractive ones, she will be very successful.
As nicely as this predicts bird behavior, it’s obvious that humans are a lot more complicated than birds. At the same time, these mechanisms might really have some validity, we just need to study them more and try to be as objective as possible. Paradoxically, we also need to be aware of how this stuff is presented. As much as it makes sense, I would also like to talk to you guys about whether it is worth caring about that female strategy can always be spun to sound subversive or sneaky. This is obviously not the case, as it is whichever circumstance has produced the fittest offspring in our history that makes the choice, not the individual. Oblivious to this, people will want to have sex. And orgasms.
Baker, R.R., & Bellis, M.A. (1993). Human sperm competition: ejaculate manipulation by females and a function for the female orgasm. Animal Behavior, 46, 887-909.
Lloyd, E.A. (1993). Pre-theoretical assumptions in evolutionary explanations of female sexuality. Philosophical Studies: An International Journal for Philosophy in the Analytic Tradition, 69, 139-153.
Thornill, R., Gangestad, S.W., & Comer, R. (1995). Human female orgasm and mate fluctuating asymmetry. Animal Behavior, 50, 1601-1615.
