Saturday, October 07, 2006

Adapting Minds: Some Reactions

I just finished reading David Buller's Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature. It is billed as a takedown of Evolutionary Psychology, as practiced by David Buss, Leda Cosmides, John Tooby, Margo Wilson and Martin Daly, and as popularized by Steven Pinker and Robert Wright. Unless the reader is really immersed in these debates, though, it will strike them as much more of an internal feud than an attack on the whole paradigm. Buller accepts contemporary Darwinism and its relevance to human sciences. In fact, the last chapter suggests to me that the only scientific "laws" that apply to people are those derived from biology.

Buller takes on Evolutionary Psychological orthodoxy on four points:

1. According to EP, there are hundreds or thousands of specialized "modules" in the mind, which are adaptations to the Stone Age human environment. According to Buller, the mind itself is an adaptation, but most or all of the "modules" develop from the developmental process of winnowing out brain cells, a process Buller thinks is analogous to selection.

2. EP conceives of male investment in children as a way of improving the male's inclusive fitness by increasing the odds for the male's offspring. Buller thinks the primary reason men invest in children is to get mating opportunities from their mothers, who are evolved to (generally) prefer dads to cads. In other words, for Buller, fatherhood is mating effort, not (ultimately) parenting effort.

3. EP thinks of jealousy, particularly male sexual jealousy, as designed to prevent males investing in unrelated children. Buller thinks it is primarily designed to warn of loss of the relationship/mating opportunities.

4. EP emphasizes male mating preference for young, fertile women and female mating preference for high-status males. Buller emphasizes homogamy (the tendency to want to mate with somebody like you). He says EP empirical results of female preference for high-status males are confounded by the fact that the women surveyed tend to be high-status themselves.

I'm not a psychologist or a biologist, but it is hard for someone with a human mind not to take an interest in these issues. As far as I can see, Buller's 4 points are all susceptible to compromise.

1: Buller does not deny the existence of specialized cognitive abilities, but points out that these could "evolve" during the lifetime of an individual, as opposed to through genetic change in a population. But surely, genetic change could make it easier for the brain to develop some specialized abilities, as opposed to others, and that's all you need.

Buller compares the mind to the immune system. The immune system is general purpose in the sense that it is built to fight pathogens in general, and it learns to fight particular pathogens by developing antibodies. I'm talking out my posterior here, but my understanding is that different genomes are nonetheless better or worse at developing immune systems to fight particular pathogens. Isn't that why Europeans conquered the Americas (better resistance to smallpox than the native population), but not Africa (worse resistance to malaria, etc. than the natives)? So Buller's analogy points to the possibility that general-purpose systems can be genetically biased in favour of specific tasks.

Buller likes Gerald Edelman's idea of neural Darwinism -- that the mind is created by competition between and selection of neurons in a subtractive process. But what is the criterion for selection if it isn't reproduction? Those criteria have to come from somewhere, and ultimately from the genome.

2: One of the principles of ethology that annoys right-thinking people is that male parenting effort is hard to explain. Sperm is cheap, so it would seem that males are always going to maximize their inclusive fitness by seeking out new mating opportunities, rather than changing diapers (or bringing home the bacon for that matter). And few males in the animal world do much child-rearing.

There are at least two possible explanations for male parental invesment: the first, preferred by the theorists Buller refers to as the EP orthodoxy, is that given the greater needs of human child development, there is an inclusive fitness advantage to men in making sure their genetic offspring make it to reproductive age; the second, preferred by Buller, is that women prefer males who give signs of daddying as long-term mates, and so such males have evolved through sexual selection.

Buller's arguments in favour of the sexual selection model seem credible to me. First, he tells us that the mathematical models say daddyhood could never have evolved otherwise. Second, empirical work suggest that men provide resources to children in this order: (1) their genetic children when residing with the genetic mother; (2) their stepchildren when residing with the genetic mother; (3) their genetic children from a past relationship and (4) their setpchildren from a past relationship. The big drop off is between (2) and (3) as people working in child support enforcement are aware.

It seems to me that Buller is mostly right, but there is no reason that inclusive fitenss might not provide a supplemental motive to daddyhood, even if it couldn't generate it by itself.

3: Buller spends a lot of time reinterpreting EP empirical work purporting to show that women care more about emotional infidelity and men about sexual infidelity. He points out that this is what you would expect if men and women both believe that sexual infidelity on a woman's part is more likely to lead to the end of the relationship. Much of what he says will have to result in more finely attuned studies in the future. However, I don't think he gets the real nature of sexual jealousy. If the woman you loved decided to spend the rest of her life in celibate devotion to the Church, like Julia at the end of Brideshead Revisited, then that would be abandonment. You'd be pretty wistful if your regiment was stationed in her old house. But the particular heterosexual male fury created by the idea of the beloved engaging in sex with another man is a different emotion.

4: Buller sounds right to recognize the importance of homogamy, but EP might be right about the deviations from it.

No comments: