Wednesday, February 20, 2013

Culture is More Conservative Than Genes

One of the tacit assumptions behind the academic resistance to evolutionary explanations of human behavior is that culture is easier to change than genes.  According to this assumption, if behavior X is largely or wholly determined by culture then we can change it merely by reeducating people and by modifying institutions.  These are presumed to be relatively easy.  By contrast, to the degree that behavior X is influence by genetic heritage, it will be intractable. 
I have long suspected that the opposite might be the case.  Genetic influences are often highly responsive to environmental information.  Figuring out how and why men are genetically more disposed toward physical aggression might give us some valuable clues as to how to deal with male aggression.  On the other hand, culture can be fiercely resistant to change.  Cultural patterns, or memes, may offer fewer levers for reform to pull and culture may develop precisely to resist both natural and artificial challenges. 
Some evidence that I am right comes from a recent article in Nature. 
If folk tales simply spread by diffusion, like ink blots in paper, one would expect to see smooth gradients in these variations as a function of distance. Instead, researchers found that language differences between cultures create significant barriers to that diffusion.
These barriers are stronger than those for the exchange of genes — a message that might be crudely expressed as: “I’ll sleep with you, but I prefer my stories to yours.”
This suggests that culture is precisely resistant to the kind of diffusion that levels the genetic playing field across human populations. 
In the study, a team of researchers in Australia and New Zealand used the statistical tools of population genetics to investigate variations in ‘The kind and the unkind girls’ across 31 European populations, such as Armenian, Scottish, Basque and Icelandic groups.
“The geographic gradients we found are similar in scale to what we see in genetics, suggesting that there may be parallel processes responsible for mixing genetic and cultural information,” says lead author Quentin Atkinson, who studies human evolution at the University of Auckland in New Zealand.
“But the mechanisms aren’t identical,” Atkinson adds. “The effect of ethnolinguistic boundaries is much stronger for the folk tales than for genes.” This fits with recent studies looking at other aspects of culture, such as song2. “Our findings support predictions that cultural variation should be more pronounced between groups than genetic variation,” says Atkinson.
“This supports the view that our cultures act almost like distinct biological species,” says Mark Pagel, an evolutionary biologist at the University of Reading, UK, who specializes in cultural transmission. “Our cultural groups draw pretty tight boundaries around themselves and can absorb genetic immigrants without absorbing their cultures.”
The implications of this may be the reverse of the common assumptions.  Genetic diffusion is, let us say, promiscuous.  It is the basis of a general equality in innate human capacities.  Culture, by contrast, creates some of the enormous differences that we observe between different populations and nations. 
It may be the case that any hope for human progress depends largely on the degree to which human behavior is influenced by biology rather than by culture.  This is the opposite of what nearly everyone seems to believe. 

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