Friday, January 12, 2007
Has it been almost a month since I originally posted this topic? Where does the time go?
This post was originally going to be a response to the comments in my earlier post, Why my forefathers became Breast Men, but it got so long that I decided to make it a another feature post.
Anyway, I agree that on the surface it appears that intercourse without reproduction would not be evolutionarily beneficial. The unspoken assumption I made in my earlier argument is that the scenario I present is valid only for a species that considers future effects of their actions (and is likely somehow tied to societal ethos) but this is still stated unclearly.
Evolution isn't just about reproductive success. If that were true, selection would favour impregnating as many females as possible. (Don't get me wrong, the urge to go through the actions required for impregnating as many females as possible is a common male urge, thus it has been selected for at some point) Evolution weighs the fitness functions of the various strategies based on reproduction and survival of resulting offspring to their own reproduction. It is unlikely that we are the result of a single reproductive strategy, and much more likely that we are the result of many reasonable ones. (Think along the lines of the Nash equilibrium)
Lets say for arguments sake that all males aged 15 and up have an urge to go out and copulate. The urge is probably present in most sexually mature mammals. In humans, however, if these same men believed their action would result in pregancy every single time, only a small percentage would actually perform the full act of reproduction. This is because every young boy/adult wants to fuck, but they don't want to make babies every time they do so. They would probably take matters into their own hands, or have non-vaginal relations. (Compare this with the dominant factor for whether or not a criminal will commit a crime - their expectation of being caught. If they believe they will be caught with 100% certainty, they don't do the crime) The urge comes from natural selection, and almost certainly is still selected for (i.e. people who don't want to have sex don't have as many children, on average), but thinking humans who believe there is a good chance at impregnating a woman and does not want to suffer any related social consequences will give pause. This is why birth control has been invented!
I am saying that for early non-technological non-permanently-swollen-breast humans, a pregnant woman (and her swollen breasts as indicator) was the most obvious and trustworthy method of birth control.
However, evolution is essentially a reproductive arms race. The moment a mutation occurred where a woman had permanently swollen breasts regardless of pregnant status, she would be knocked up faster than you can say "$250, same as in town". The mutated genes would swiftly spread through the entire genome. (and if the timing of the mutation was right, it might have been in an incredibly small population) The permanently swollen breasts would be an indicator of "safe to have sex with, no children GUARANTEED!", but being a false indicator, it would result in more pregancies than otherwise would have happened. This is what gives it a selective advantage.
Eventually we learned the trick and could intellectually ignore the genetic disinformation campaign (the selection for a false indicator) but we still like titties, boobs, breasts, Jessica Alba nude, or whatever you want to call them because now it's built in. We intellectually lost the use of swollen breasts as consequence free sex indicators (i.e. we know that just because you look good in a tight sweater, it has nothing to do with your current odds of new impregnation), but the selected preference is still there. Jessica Alba is still a tight little slice of all right pie as far as I'm concerned. I'd make the double backed beast with her in a second, but I do not intellectually want to produce children with her (although I'm sure they would be very nice). I mean, shit, just look at her, she jangles the hormonal nerves of men worldwide.
Remember, we are the only primate that has this sexually mature female breast feature/mutation. (I wonder about the extinct hominids. Can we tell anything about them from their fossils or art?)
An animal will fuck to its hearts content. It's an animal responding to urges. We are also animals responding to urges, but we also see long term consequences related to our short term actions and can sometimes override them. Natural selection is notorius for optimizing to take advantage of whatever small advantage is available. If there was a situation where men were having lots of sex with women under the premise that there would be no children, soon enough there would be a mutuation selected to exploit that, producing children. (Just wait for the engorged vagina dissolving latex mutation! :-)
At this point, I was going to go off on a tangent about societal ethos (variant from society to society!) and how they play a role in our reproductive lives. They are also selected for and tied into this, but the long winded rant smelled more like a different post for the future. Here's a teaser: The reproductive ethics (amongst other things) of societies are also selected for naturally. If a societal rule is being naturally selected for, there is some advantage conferred by moving the individual-level selection to a group-level selection. (A good book to read on this topic is Darwin's Cathedral, which discusses this in the context of natural selection of religions in society, but is still relevant to the topic at hand)
Burton MacKenZie http://www.burtonmackenzie.com/