Our cultural groups draw pretty tight boundaries around themselves and can absorb genetic immigrants without absorbing their cultures

From Genes mix faster than stories: Folk tales' 'DNA' shows that people would sooner have sex with strangers than tell their fables by Philip Ball

An interesting investigation.

This folk tale has hundreds of variants, and it has been passed on across Europe for centuries. But how similar your version is to mine depends not just on how far apart we live but also on how ethnically and linguistically different our cultures are, according to a new study.

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.”

My initial reaction is that the research is a methodological leap but that the metaphorical insight is likely right.

“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.”

I suspect that the conclusion is right - we mix genetically much more easily than we do culturally. Put in different terms, this would suggest that the policy preoccupation with the physical aspects of race are a red herring. Yes, it is necessary to prohibit discrimination, segregation, red-lining, etc. But those are the easy things to do. It might take longer, but people end up mixing of their own accord. What is much harder, as this research suggests, is to create the circumstances that facilitate cultural assimilation. There are all sorts of philosophical issues with that as a goal but it seems that that is the really challenging issue.