Geoffrey Miller's The Mating Mind impressed me. It was clearly intended for a general audience, and so light on the really detailed evidence, but Miller showed an awareness not shared by the other evolutionary psychologists I've looked at to recognize when his data wasn't all that and be cautious with his speculations. His speculations were nonetheless fascinating and in many cases plausible.
In particular, I am attracted to his theory that humans might have evolved ethical behavior as a mating display. Altruism obviously involves taking on costs for no apparent benefit, and it is less often noted that the same is true of punishment in most instances. One of the depressing aspects of this theory, but also one of my reasons for finding it extremely plausible, is that it accounts for why people generally devote so little effort to making sure their generosity and punishments are directed at the most appropriate targets. If we punish people to show off our surplus power, and perhaps our commitment to the community, we're going to want to punish unpopular people (harming popular people will have negative effects which would undermine the benefits of the display), but punishing people who are actually guilty, or whose behavior is likely to be usefully influenced by the punishment, would hardly matter at all. That is a pretty good description of how people target their punishments.
Of course, I also take this as further evidence for utilitarianism. The objections which are always considered so problematic for utilitarianism involve cases where utilitarianism gives answers that feel wrong. If Miller's right about where our ethical feelings come from, my own inclination to think people shouldn't be putting so much faith in their unanalyzed feelings seems even more justified.
The question, given Miller's data, is whether ethical behavior, or more specifically costly displays (helping, altruism, etc.), evolved for mating purposes, or were co-opted for those purposes. Nothing he's produced so far implies that there is an evolutionary relationship between the existence of ethical behavior and mating, but he has shown that impressing potential mates does affect ethical behavior. I suppose a more plausible hypothesis is that we developed certain helping behaviors (especially reciprocal altruism), and these were then co-opted as mating displays.
Posted by: Chris | July 08, 2007 at 06:48 PM
Of course this is the sort of thing which requires more research, as Miller admits. But I don't really see that you're proposing a rival hypothesis here (though perhaps this shows that I was being unclear in my post). The mating display theory is intended to account for why our ethical behavior is so prominent, and often seemingly completely counter-productive in terms of individual survival and reproductive success. Of course, species do not invent mating displays; traits which become mating displays will often have developed to some more limited extent for some other reason, before they started being evaluated as attractive to mating partners and so continuing to evolve to be more prominent and to match the evolving tastes of the evaluators. It's certainly likely that reciprocal altruism played some role in the process, though there are other obvious candidates as well. Kindness toward kin and cautious hostility toward non-kin are of obvious adaptive benefit, and if those practices came to be attractive to mating partners, they could also have grown and mutated into something quite different under the influence of sexual selection. Probably both, and many other things as well, played roles in the story. Evolution always involves many complicated factors, and I did not intend to imply otherwise, and neither does Miller imply otherwise.
Posted by: Aaron Boyden | July 09, 2007 at 07:28 AM