Monday, February 07, 2005

The Evolution of the Human Female Orgasm

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So I just finished reading Lisa Lloyd's new book The Case of the Female Orgasm: Bias in the Science of Evolution. It's a facinating case study in the way bias, particularly androcentric bias, can ruin a scientific investigation. It’s not out officially yet, but I want to blog about it, both to encourage you, the internet, to buy it when it does come out, and because I want to sort out my thoughts.

Mostly the thoughts I want to sort out revolve around my continuing belief that the human female orgasm is an adaptation. It’s not like the male nipple, which is just there as a byproduct of female nipples. Moreover, I think the human female orgasm was selected for because it facilitated social relations in one or more ways, including preventing conflicts and aiding reconciliation after conflicts, regulating tension, solidifying same sex and different sex alliances, and expressing social status. These are the functions that sexual pleasure seems in general to serve in everyone’s favorite super-sexy-love-primate, the bonobo (see Huhmann and Fruth 2000), and the bonobo strikes me as the right super-sexy-love-primate on which to model human evolution.


So this is the deal. Lloyd surveys all of the available evolutionary accounts of the human female orgasm, 20 in all. (She misses the one in my tiny little head, which on the one hand is understandable, since I've never told anyone about it, but on the other hand is kinda odd, because it seems to be in a lot of other people's tiny little heads that I've talked to, so you'd think it was actually written up somewhere, especially since everyone is all into bonobos these days.)

So where was I, oh yes, Lloyd surveys all of the available evolutionary accounts and finds all sorts of gross mistakes in reasoning and handling of data in all but one of them. She then argues that these mistakes come from two biases, one purely methodological and one with serious political overtones. On purely methodological side, she identifies adaptationism, the persistent belief that any important trait must be somehow adaptive. This bias is most in evidence in the bizarre fealty people feel to failed adaptive accounts, even when far more natural nonadaptive accounts are available. On the more political side, she identifies the problem as coming from androcentrism, specifically, the assumption that female sexuality is like male sexuality. This comes out, for instance, in models that assume females become sleepy after orgasm, as males do.

All this is clearly right, and her case is well made. The problem is that in making the case, Lloyd herself makes some androcentric assumptions. A big one is her almost Clintonesque definition of sex. An important point in almost all of her arguments is that women orgasm more readily in masturbation than in sex, a fact which she refers to as the orgasm/intercourse discrepancy. The root of this discrepincy, according to Lloyd, is that in masturbation, the clitoris is stimulated directly, where intercourse--defined as vaginal penetration--only stimulates the clitoris indirectly.

The orgasm/intercourse discrepancy is what allows her to dismiss all the evolutionary models that revolve around social bonding. All of the social bonding models Lloyd finds in the literature are actually pair-bond models--they assume that if orgasm helped social bonding, it must have helped lifetime monogamous pairings. All of these models are ultimately decended from the ur-nonsense on human evolution from Desmond Morris. According to Lloyd, the root problem with all these models is the orgasm/intercourse discrepancy. If women orgasm more easily solo, how could orgasm have helped the pair bond?

Now, I'm not a fan of the Desmond Morris models either, but Lloyd's objection to them is flawed. The orgasm/intercourse discrepancy only exists if you assume that sex is vaginal penetration. Now I know this definition of sex is popular among ex-presidents and Christian teens who wish to maintain that they are virgins, but it never made much sense to me. I mean, the word “sex” is right there in the name “oral sex.” Once you count oral sex as sex, the orgasm/intercourse discrepancy disappears. Really, the orgasm/intercourse discrepancy is a discrepancy between clitoral and vaginal stimulation. But clitoral stimulation has no special tie to masturbation, and vaginal stimulation has no special tie to intercourse.

The real problem with the Morris pair bond models is the "pair" part of social bonding. There's no reason to assume that our ancestors used our odd mating system. Moreover, we already know that sexual pleasure in general is adaptive in Bonobos, who are flagrantly nonmonogamous. So why isn't there a model out there which tells the story of the evolution of the human female orgasm based on an analogy to the currant adaptive of sexual pleasure in general in bonobos? Shouldn't Frans de Waal be on this?


Hohmann, G, and B. Fruth. 2000. Use and function fo genital contacts among female bonobos. Animal Behavior 60:107-120.


Anonymous said...

I found this article certainly was interesting, Evolution of the female orgasim... The only thing that concearns me is why spend all your time trying to explain the evolution of the female orgasim, and not on working on coming up with any reliable or relavant proof/evidence or even means of evolution at all. It seems to me the dieing theory is in need of more help then the female orgaism is in need of explaination. (this being said again very interesting article well written)

Lord Pasternack said...

I look forward to the day when all catfights can be resolved with a bit of spontaneous vulva-bashing...

justin of maryland said...

First off, does this chode who left the comment a couple prior really think evolution is a dying theory? Lets set aside all unintelligent remarks and get to the facts; pondering this seemingly unexplainable inigma in evolution could be a result of many possible scenarios. The one that seems most likely is that we don't completely know the culture of our preceding species. We generalize that their culture was simple and they could have not have possibly behaved in the sexual ways we do. Yet, wouldn't that seem a more plausible explaination? Is there any way we can prove elsewise? Plus, the possibilty of the indirect stimulation of the clit in past times could possibly have been a tool of sexual preference. The female would want a male that could make her feel like no other male could... Can he get the good spot? Lastly, to the comment directly prior to my own.... why not look forward to catfight-less days and allow me to dominate your volva. GET SOME!

Jessica said...

I always thought that womens orgasms made biological common-sense. 1. orgasms help lubricate the vagina = easier for intercourse and a higher chance of fertilization. 2. orgasms feel great= more procreation; the purpose of just about every living thing on this planet. If orgasms didn't exist, the human population would be millions less than it is now (and of course everyone would be stressed and uptight).. so it seems to come together that this is the reason why orgasms feel great and exist in the first place, so that we humans reproduce and like it!

Rob Helpy-Chalk said...

Lloyd is looking at orgasm separately from all the other enjoyable aspects of sex. By 'orgasm' she means just the rhythmic contractions of vaginal muscles at climax. Obviously, you want to be lubed up well before then!

This was really a smart move on her part, because we simply don't know enough yet about the history of the species to talk about the evolution of human sexuality as a whole. That said, it is nice that we humans are driven by joy and love to reproduce, rather than being one of those species that procreates largely by rape.

sherry said...

well i would go with jessica's comments... simple but brilliant... Many females would not have sex if not for the urge of orgasm... so eventually ppl would stop having sex and that would be the end of reproduction... So i guess female orgasm is part of evolution..