Does Evolution Explain Why Some People Are Mean to Strangers? Yes, according to some researchers in an article published on the Smithsonian website. If it's published by Smithsonian, it must be right? Right?
Rob Dunn writes in: The Culture of Being Rude.
Recently a group of biologists has offered a theory that they say explains, if not tube socks, then nearly everything else. In a series of high-profile papers, Corey Fincher and Randy Thornhill, both at the University of New Mexico, and Mark Schaller and Damian Murray of the University of British Columbia argue that one factor, disease, ultimately determines much of who we are and how we behave.Dunn expresses some skepticism using appropriate language but he goes on to describe "data" (correlations, actually) that supports the idea. The tone of the article is quite supportive of the idea that evolution is behind this behavior.
Their theory is simple. Where diseases are common, individuals are mean to strangers. Strangers may carry new diseases and so one would do best to avoid them. When people avoid strangers—those outside the tribe—communication among tribes breaks down. That breakdown allows peoples, through time, to become more different.
Differences accumulate until in places with more diseases, for example Nigeria or Brazil, there are more cultures and languages. Sweden, for example, has few diseases and only 15 languages; Ghana, which is a similar size, has many diseases and 89 languages. Cultural diversity is, in this view, a consequence of disease.
Then Fincher and colleagues go even further. Where people are more xenophobic and cultures more differentiated from one another, wars are more likely. Democratic governments are less likely because the tribe or group comes first; the nation and individuals in other tribes within the nation come second. And finally, poverty becomes nearly inevitable as a consequence of poor governance, hostility between groups, and the factor that triggered this cascade in the first place—disease.
Evolution absolutely requires genes and alleles. There no evidence to suggest that we have an allele that encourages us to avoid diseased strangers. It could be entirely cultural based on the fact that we have a large brain that's capable of reasoning.
Keep this in mind next time I'm mean to you. It may not be my genes that are making me do it. It may just be my brain and my life experience telling me that I should behave that way!
[Hat Tip: a skeptical John Hawks]