I’ve been greatly enjoying an interesting video lecture series by Robert Sapolsky on the biological origins of behavior. (10 years ago, my nights were spent banging strippers and snorting crystal meth off their boobs, now I enjoy video lecture series.)

In a segment I watched recently, Sapolsky described some interesting behavior on the parts of gorillas (or baboons, or some other kind of ape.) These apes live in a kind of harem culture where there’s one boss ape and he gets to have sex with all the chicks, while the other apes have to go jerk off in the forest. However, every couple years or so, a younger, tougher ape, will dethrone the top ape, and then this new ape gets all the women. And what does he do then? He kills all the infants sired by the previous ape. Why? Because these infants are nursing, and as a result, their mothers can’t get pregnant. If this ape seeks to pass on his genes, he needs to make sure that the apes he rapes (hey — that’s poetry!) can be impregnated. Thus his behavior — infanticide — is programmed by the demands of natural selection (e.g. apes that kill the babies of nursing mothers and then have sex with them will pass on their genes, the ones that don’t, won’t.)

That kind of explains the genetic programming, but I’m curious what the ape is actually thinking. It seems unlikely he’s thinking, “nursing mothers can’t get pregnant, so I better kill off their babies.” (I’m not sure I was even aware that nursing mothers can’t get pregnant until watching the video, and I’m a pretty smart ape.) But I also doubt he’s just filled with some robotic urge like “must… kill… infants…” Natural selection may explain the behavior, but how does the ape experience the behavior?

And this raises the rather obvious question: To what degree are we humans subject to these biological urges? Let’s say you find that your wife is sleeping with you. You get pissed off, maybe you kill her (paging OJ Simpson.) You might say your anger is justified, but why? So she slept around… who cares? Are you merely sensing a biological directive and then confabulating a rationale for your behavior? And if humans do that, are apes essentially doing the same thing in their heads — coming up with an excuse to kill the kids? (“These babies are ugly!”)