Genes and Culture

The NY Times today has a piece on the interaction of genes and culture. Since the author is Nicholas Wade, the author of a very silly recent book on the evolution of religion, it is not surprising that this article is far from deep:

As with any other species, human populations are shaped by the usual forces of natural selection, like famine, disease or climate. A new force is now coming into focus. It is one with a surprising implication — that for the last 20,000 years or so, people have inadvertently been shaping their own evolution.

The force is human culture, broadly defined as any learned behavior, including technology. The evidence of its activity is the more surprising because culture has long seemed to play just the opposite role. Biologists have seen it as a shield that protects people from the full force of other selective pressures, since clothes and shelter dull the bite of cold and farming helps build surpluses to ride out famine.

Because of this buffering action, culture was thought to have blunted the rate of human evolution, or even brought it to a halt, in the distant past. Many biologists are now seeing the role of culture in a quite different light.

Although it does shield people from other forces, culture itself seems to be a powerful force of natural selection.

I don't see how this could be controversial, and it strikes me as rather obvious. Evolution is generally seen as an interaction between the genes and the environment within which the organism lives. The environment within which people live is largely constructed by human culture. Therefore, their cultures are going to interact with their genes. What could be simpler? The notion that culture somehow prevents evolution is a silly backward projection from our own era, because farming societies from the neolithic to the 18th century had higher death rates than hunter-gathering societies. And since it is generally held that environmental change causes the rate of evolution to increase, the very rapid rate of change in the human environment over the past 20,000 years ought to have led to an increase in the rate of our evolution. People point to the spread of adult lactose tolerance as one clear indication of culture-driven evolution, but a much more important factor has been resistance to epidemic disease, something practically unknown among hunter-gathers.