Evolutionary approaches to the emotions have traditionally focused on a subset of emotions that are shared with other species, characterized by distinct signals, and designed to solve a few key adaptive problems. By contrast, an evolutionary psychological approach (a) broadens the range of adaptive problems emotions have evolved to solve, (b) includes emotions that lack distinctive signals and are unique to humans, and (c) synthesizes an evolutionary approach with an information-processing perspective. On this view, emotions are superordinate mechanisms that evolved (...) to coordinate the activity of other programs in the solution of adaptive problems. We illustrate the heuristic value of this approach by furnishing novel hypotheses for disgust and sexual arousal and highlighting unexplored areas of research. (shrink)

Behavioral scientists routinely publish broad claims about human psychology and behavior in the world's top journals based on samples drawn entirely from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Researchers – often implicitly – assume that either there is little variation across human populations, or that these “standard subjects” are as representative of the species as any other population. Are these assumptions justified? Here, our review of the comparative database from across the behavioral sciences suggests both that there is (...) substantial variability in experimental results across populations and that WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers. The domains reviewed include visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ. The findings suggest that members of WEIRD societies, including young children, are among the least representative populations one could find for generalizing about humans. Many of these findings involve domains that are associated with fundamental aspects of psychology, motivation, and behavior – hence, there are no obviousa priorigrounds for claiming that a particular behavioral phenomenon is universal based on sampling from a single subpopulation. Overall, these empirical patterns suggests that we need to be less cavalier in addressing questions ofhumannature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity. We close by proposing ways to structurally re-organize the behavioral sciences to best tackle these challenges. (shrink)

In the target article, we presented the hypothesis that parasite-stress variation was a causal factor in the variation of in-group assortative sociality, cross-nationally and across the United States, which we indexed with variables that measured different aspects of the strength of family ties and religiosity. We presented evidence supportive of our hypothesis in the form of analyses that controlled for variation in freedom, wealth resources, and wealth inequality across nations and the states of the USA. Here, we respond to criticisms (...) from commentators and attempt to clarify and expand the parasite-stress theory of sociality used to fuel our research presented in the target article. (shrink)