I thought of the selective advantage of the clitoris in heterosexual intercourse. Lubrication of the vagina is as important as a precondition to successful intercourse as erection of the penis. Thus, it enhances intercourse for the woman to have an orgasm _before_ intercourse for lubrication. Thereby, clitoral orgasm, _outside of direct intercourse_, enhanced intercourse and would be selected for.
Your data on orgasms from clitoral manipulation thereby becomes data supporting direct selection, not spandrel-like trait.
Miles Jackson: You're not getting the completely arbitrary linkages that are possible on the human genome. Spandrels are not just "side effects" that can be easily and clearly be linked to adaptive traits; they can be functionally distinct and completely unrelated. And again, you're ignoring the data: female orgasm is far more likely without intercourse than with it!
^^^^^^ CB: But you are presuming the arbitrary linkage in this case. So, you are presuming what has to be demonstrated. You haven't shown an arbitrary link. That's what is being debated.
As I have said several times on this thread in response to your second point, that there are orgasms, even more orgasms, otherwise than by intercourse doesn't undermine the fact that there _are_ orgasms associated with intercourse. Those times there are orgasms with intercourse would make intercourse more desirable , and thereby probably increase amount of intercourse, and thereby give advantage in differential fertility.
Spandrels-like traits do not have functions. Otherwise, they are not spandrel-like. They are "arch-like",from the achitectural analogy, and would function
You only pay attention to some of the data; and your interpretation of that data is not the only possible interpretation.
^^^^^^
I would agree with this completely if in fact heterosexual intercourse was a very common way for women to have orgasms. Given the fact that study after study has demonstrated that it is not, I'm compelled to disagree with you.
^^^^^ CB: Also, looking at the studies posted here, it is not accurate to say that intercourse is not a common way to have orgasms. To say that they have orgasms by masturbation more is not the same thing as saying that having orgasms by intercourse is "uncommon". They are common enough that women would seek intercourse in order to have an orgasm.
Also, upon further reconsideration of the data, even the women who don't have orgasms a majority of the time in intercourse don't say they never have orgasms during intercourse. ONLY 16% of women never have orgasms during intercourse. Thus 84% women are capable of having orgasms during intercourse. Since an overwhelming majority of women are _capable_ of orgasm during intercourse, then the data presented are even stronger supporting a selection argument.
Then there's the difference in social orders between today and 200,000 years ago. Modern alienation , male supremacy are sexually repressive phenomena.
^^^^^^
>CB: Isn't masturbation a spandrel-like trait with respect to fertilizing
function of the penis ? What do you want to bet that men have orgasms a
higher percentage of the time masturbating than in intercourse ? Would you
say the ability to have penis-orgasm in intercourse is a spandrel-like trait
> in relation to penis-masturbation? No.
Miles: What's sauce for the goose here isn't sauce for the gander. False analogy.
^^^^^ CB: Why ?
^^^^
> My thought in response was why wouldn't both the clitoris and the penis be
selected for ? Or ,afterall, since the original, fetal organ that both
males and females have is the clitoris, not the penis, why not speculate
that the penis is spandrel-like trait to the clitoris, which was the trait
naturally selected for ?
Once more, if this were so, most women would easily achieve orgasm during intercourse, as men do. Given the data, your sociobiological just-so story is dubious.
^^^^^ CB: No, not necessarily. Many women do easily achieve orgasm during intercourse. Most can. This is data supporting selection for the trait. Your idealist wish is dubious thereby.
Actually, yours is much more a "just so" story than mine. Basically, you say the clitoris and female orgasm "just happened" with no cause. It's literally, "just so". Discussion of "arbitrary (and capricious) links" is "just so" per se. It is saying "this just happened ; it had no cause."
^^^^^^
>CB: Why bend over backwards to look for a way to find that the clitoris and
> vaginal orgasm are not adaptive traits ?
Miles:Why bend over backwards--ignoring the relevant data!--to assume that they must be adaptive?
^^^^^ CB: The relevant data supports it as an adaptive trait (see discussion above). There is a huge minority of women who do achieve orgasm from intercourse most of the time , even according to your studies. Then there are those who achieve it much of the time if not most. ONLY 16% say they never have orgasms during intercourse. Your data don't support your inference.
Not only that you ignore the other facts and data here. The data you ignore are that clitoral manipulation lubricates the vagina, clitoral orgasms "turn on" the recipient, a state of readiness for intercourse. Manipulation of the clitoris, and other actions which arouse the woman have an affinity with intercourse, are not "alienated" from it as you suggest. You assume that women in the studies cited who have orgasms from clitoral manipulation don't have that in association with intercourse. But that may not be true. Thereby, much of the data on clitoral oragasm would _support_ the notion of selection for clitoris and orgasm. In other words, the data you cite support an opposite interpretation from yours, when one thinks about sex holistically instead of all chopped up. The idea that no or few men have sense enough to "do" foreplay is an exaggeration.
^^^^^^^
The real lesson of Darwin, as I mentioned in a recent post, is not that all traits in a species are products of natural selection; it is that many traits persist and change in a species for reasons that have nothing to do with evolution!
Miles
^^^^ CB: Well, that's not the lesson of _Darwin_, though there is some truth in it, though a bit overstated by you. A main update lesson of Darwin is that traits closely related to sexual intercourse are most likely to involve selection.
What "reasons" besides spandrel-like , are you talking about ? You overstate Gould and other experts' claims for the exceptions to natural selection as the main mechanism of change.
As to persistence of traits, vestiges, this cuts against your argument here. That orgasm may occur more outside of intercourse now may be partially the vestigial persistence of a trait beyond its original function. The time when orgasms probably enhanced fertility in a fitness struggle is hundreds of thousands of years past.