Wednesday, July 08, 2009

Evolutionary psychology: Why it is on the way out, with last year's magazines

Sharon Begley's critical look at evolutionary psychology in a recent edition of Newsweek is a must-read for anyone interested in the field. She is hardly the first, but the first to have so wide a non-professional audience for a rational, science-based evaluation of the topic. Many of us have regaled ourselves over the years with the distinct pop-culture sound - more lark than lab, more salon than science.

We have learned so much from evolutionary psychology:

- Rape today can be explained because rape was once adaptive and rapists had more kids, so we carry rape genes. (The guys who didn't rape just didn't leave enough kids.) Then some ignorant scientist decided to pull in data from his many years' observation of one of the few remaining groups of people who live much as all humans lived 100 000 years ago. He did not observe rapes, but ran some numbers on the probabilities, based on the lifestyle, and discovered that rape was quite unlikely to be adaptive. Unless a fine collection of spears in one's back is adaptive ...

Begley observes that one hindrance to a scientific assessment of evolutionary psychology has been the moral outrage it provoked. Moral outrage enables the purveyor of silly or pernicious ideas to don the mantle of science, invoke Galileo, and delay the day of reckoning.

But it seems to have stretched as far as it can go because, behind all the posturing, some were counting.

For example (these from Begley's article, and don't let my summary stop you from reading it):

- Is it true that men are genetically adapted to prefer women with a waist to hip ratio of 0.7? That depends on what other qualities are important. Could Barbie work 10 hours a day under a hot sun?

- Are men programmed to neglect or kill their stepchildren? Many such claims relied on social work data gathered for other purposes, and often poorly or prejudicially gathered. Also, and this is a point Mario Beauregard and I made in The Spiritual Brain, the term "stepfather" can sometimes be used very loosely, and one need not assume that the man even intends to stay long.

- The brave warrior gets the girls? Not necessarily. An analysis of the family histories of 95 Amazon warriors showed that women avoid the "badass" guy, who is typically a disaster as a husband, and may trigger a counterraid that gets his family killed.

Begley notes that a growing new approach, behavioral ecology, makes much more sense than evolutionary psychology (BE). BE posits that evolution created the core of human nature as variability and flexibility - the ability to adapt behavior to the environment quickly - and that there is no universal human nature.

I have qualms with this approach, because I think that some features of human nature are universal, other things being equal. The desire for approval comes readily to mind. What there isn't are modules in the brain, created by selfish genes, that can be accounted for by the ways in which the behaviour was adaptive in the Pleistocene era..

But qualms aside, it is nice to see the subject finally leave the salon and get back to the lab.