Recent evolution in Newsweek

I very much appreciate that Newsweek has started including a regular opinion column on science, written by Sharon Begley. I don’t always like it, but it places science properly as a regular feature. And it certainly beats Jonathan Alter.

In the most recent issue, Begley reviews some of the pieces in last year’s annual Brockman volume, What Have You Changed Your Mind About?: Today’s Leading Minds Rethink Everything, now out in paperback. The theme of Begley’s article is that scientists need to be willing to change their minds. Even in this volume, she finds few that really represent reversals, more common being shifts of opinion:

Many of the changes of mind are just changes of opinion or an evolution of values. One contributor, a past supporter of manned spaceflight, now thinks it's pointless, while another no longer has moral objections to cognitive enhancement through drugs. An anthropologist is now uncomfortable with cultural relativism (as in, study the Inca practice of human sacrifice non-judgmentally). Other changes of mind have to do with busted predictions, such as that computer intelligence would soon rival humans'.

Well, it’s not that interesting to read an essay that begins like, “I used to think that we would never sequence the Neandertal genome, but facts have compelled me to change my mind.” OK, there’s a certain entertainment value there. But changing your mind in the face of mere facts just doesn’t have the “man versus self” quality of great literature.

Unless, of course, the conflict is applied to man’s understanding of self. Begley finds that the most interesting reversals have resulted from our work on recent human evolution:

The most fascinating backpedaling is by scientists who have long pushed evolutionary psychology. This field holds that we all carry genes that led to reproductive success in the Stone Age, and that as a result men are genetically driven to be promiscuous and women to be coy, that men have a biological disposition to rape and to kill mates who cheat on them, and that every human behavior is "adaptive"that is, helpful to reproduction. But as Harvard biologist Marc Hauser now concedes, evidence is "sorely missing" that language, morals and many other human behaviors exist because they help us mate and reproduce. And Steven Pinker, one of evo-psych's most prominent popularizers, now admits that many human genes are changing more quickly than anyone imagined. If genes that affect brain function and therefore behavior are also evolving quickly, then we do not have the Stone Age brains that evo-psych supposes, and the field "may have to reconsider the simplifying assumption that biological evolution was pretty much over" 50,000 years ago, Pinker says.

Well, the assumption that humans stopped changing in the Pleistocene was always obviously false. You won’t find many people who will admit to making that assumption, but there it is anyway, strewn through their works. It made a useful assumption for some people, in that they could examine so-called universals instead of more messy variations. But those variations are proving to be the most interesting frontier of behavioral science. Some of them have been under strong selection, perhaps showing the adaptive reactions of minds to new social and cultural systems of the Holocene.

I tend to think that the “Stone Age Mind” metaphor exists for two purposes. First, it jibes with the Darwinian idea that evolution leads to imperfect results. Rather than having the minds of angels, humans have minds that are saddled with various equivalents of the vermiform appendix – useful once, but not yet fully discarded.

The second purpose was to insulate “evolutionary psychology” from the Gouldian criticism drawn by its progenitor, sociobiology. If behavioral evolution occurred long ago, in the dim Pleistocene, then surely humans today are all fully identical in their behavioral capacities.

Why that would be true for the mind, when it is false for more mundane functions like oxygen transport is not obvious. But it clearly was a useful fiction for some – not Pinker, who always emphasized the possible importance of human genetic diversity. So maybe he didn’t really change his mind, either.