the evolution of a woman

So here’s a hard question that someone emailed me:

WHY do women respond to such a wide range of stimuli?

(Respond genitally, we mean, because by now you’re all well versed in the non-concordance issue, right? Right.)

Well. I don’t know. No one does, really. I’ll tell you my opinion, but I could turn out to be wrong. (I think I’m right, but when did thinking you were right every guarantee anything?)

I think women respond to a wide range of stimuli for two possible reasons, tied to the function of arousal in women.

What IS the ultimate function of arousal in women? In men, it’s fairly obvious: erection facilitates penetration, which is the one and only means to fertilization. Excellent. Men need arousal in order to reproduce. Indeed, they need arousal and ejaculation in order to reproduce.

Women, on the other hand, don’t. We can get pregnant and give birth just fine without being the least interested in the sex that initiated the pregnancy. Why bother getting aroused?

No really, why bother?

1. Protection. The lubrication of the vagina functions to minimize friction associated with penetration. Reducing friction reduces tearing of the vaginal walls, which in turn reduces risk of infection.

So why would a woman respond genitally to, like, pictures of monkeys having sex? Because her body is preparing itself for penetration, to prevent infection. Her body is protecting itself. Therefore reason 1 why (I think) women respond genitally to more or less anything: generic physical preparation for potential sex, in order to reduce harmful consequences associated with penetration. This is what Meredith Chivers suggested at a conference a few years ago, and it sounded good to me.

(However, it doesn’t account at all for women presented with sexual stimuli who DON’T get physiologically aroused. So. It’s imperfect.)

2. Reward. This one is HIGHLY speculative, even though it will sound perfectly sensible. It’s sensible because it’s based on a common assumption – and as far as I’ve been able to figure it’s an untestable assumption. The assumption is that orgasm was selected for in MALES because it rewarded behavior that resulted in ejaculation, which is a man’s one and only buy-in to the evolutionary game. Make it feel real good, evolution says, so he’ll want to do it more.

Let’s assume that’s right.

Now. Orgasm has not been under primary selection pressure in women; that much seems to be definitely true. This is a big part of the explanation for why women vary so much more than men do – they vary in orgasmicity, clitoris size, all kinds of things. Penises vary in size much less than clitorises do, did you know that? It’s true. Why? Because penises have been under direct sexual selection pressure. Clits, not so much.

However. I think – and this is more speculation – I think sexual arousal in general and the clit in particular have been under secondary selection pressure. That is, it’s there anyway, due to the wonders of biological homology (must write post about homology), so evolution’s like, why not see if we can make use of this? I think this might be why the clit, although it is about 1/8th the size of a penis, has something like twice as many nerve endings. Why go to the metabolic expense of developing all those nerve endings unless they serve some purpose?

What is that purpose? Pleasure. IMO.

The hypothesis here is that pleasure rewards a woman for doing things that turn her on, which will in turn potentially result in selecting a good genetic mate, building a supportive social network, etc etc.

Pleasure, NOT ORGASM per se. The available science suggests that high intensity arousal is plenty to change a woman’s biochemistry in the appropriate ways; orgasm is not the target.

Now, it’s not at all speculative to say that, globally, pleasure rewards an organism, which causes the organism to learn. What’s speculative here is my suggestion that a woman’s physiological arousal/arousability has been under selection pressure because it guides her toward adaptive behaviors. The range of potentially adaptive behaviors related to sex and mating is SO VAST among human females that a gigantic range of responsiveness allows women to adapt to any and every set of sociosexual circumstances.

And from there it just gets HIDEOUSLY complicated. I mean shit can go TERRIBLY wrong and be terribly confusing, painful, and maladaptive. Complex systems like women’s sexuality have the potential disadvantage of being wildly disruptable.

Anyway. Before I get on a wacky tangent here, I’ll summarize:

I think women respond genitally to a wide range of stimuli because (1) it helps protect their bodies from damage associated with penetration and (2) the pleasure of arousal, at the physiological level, trains a woman onto behaviors and stimuli that the body interprets as adaptive in the sociosexual context in which a woman is immersed. The range of potential stimuli demands that her body be responsive to nearly anything.

I could do a whole thing about tend and befriend and the potential role of sex in the stress response, but this is already a very long post. We’ll leave it til later, eh?