The subpopulation that Henrich and colleagues found to be overrepresented are entirely WEIRD (Western, Educated, Industrialized, Rich, and Democratic) societies. While it’s bad enough that WEIRD American undergraduates are serving as our model for human behavior, what their paper goes on to document should be of concern to all behavioral and cognitive researchers (particularly those whose work focuses on human evolutionary explanations).
When these affluent American and non-Western populations are compared there are important differences in domains as seemingly unrelated as visual perception, fairness, cooperation, spatial reasoning, moral reasoning, reasoning styles, and even the heritability of IQ. In all cases American undergraduates didn’t simply differ, they differed substantially. Nevertheless, they form the basis of most researchers’ assumptions about human nature even though, as Henrich and colleagues conclude, “this particular subpopulation is highly unrepresentative of the species.”