The weirdest people in the world

Behavioral scientists routinely publish broad claims about human psychology, cognition, and behavior in the world’s top journals based on samples drawn entirely from highly educated segments of Western 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. Are these assumptions justified? Here, our review of the comparative database from across the human behavioral sciences suggests both that there is substantial variability in experimental results across population and that standard 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 (holistic vs. analytic), self‐concepts and related motivations, and the heritability of IQ. The comparative findings suggest that members of Western, educated, industrialized, rich, and democratic 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, or behavior – hence, there are no obvious a priori grounds 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 of human nature 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 scientific challenges. Weird People 28 Nov 2008 Draft 08 In the tropical forests of New Guinea the Etoro believe that for a boy to achieve manhood he must ingest the semen of his elders. This is accomplished through ritualized rites of passage that require all young male initiates to fellate a senior member (Herdt 1984, Kelley 1980). In contrast, the nearby Kaluli maintain that male initiation is only properly done by ritually delivering the semen through the initiate’s anus, not his mouth. The Etoro revile these Kaluli practices, finding them disgusting. To become a man in these societies, and eventually take a wife, every boy must undergo these ritual initiations. Such in‐depth studies of “exotic” societies, historically the province of anthropology, are extremely important for understanding human behavioral variation. However, this paper is not about these peoples. It’s about another exotic group: people from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. In particular, it’s about the Western, and more specifically American, undergraduates who form the bulk of the experimental database in the experimental branches of psychology, cognitive science, and economics, as well as allied fields (we label this aggregate of fields the “behavioral sciences”). Given that scientific knowledge about human psychology is largely based on findings from this population, we ask how representative these typical subjects are in light of the currently available comparative database. How justified are researchers, in asserting, or—as if often the case—of implicitly assuming, a species‐level generality of their experimental findings? Are these WEIRD people representative of our species? Here, we review the evidence regarding how WEIRD people compare with those from other populations. To pursue this we constructed our empirical review by looking first for studies that involved large‐scale comparative experimentation of important psychological or behavioral variables. Although such comparative studies are highly informative, they are rather rare, especially when compared to the frequency of species‐generalizing claims. When such studies were absent we have relied on large assembles of studies comparing 2 or 3 populations, and, when available, relevant meta‐analyses. Of course, researchers do not implicitly assume universality with everything they study. Some phenomena are a priori expected to vary across individuals, and by extension, societies, such as personal values, emotional expressiveness, and personality traits. Indeed, the goal of much research on such topics is to identify the ways that people and societies differ from one another on these. A number of large‐scale research projects have sought to map out the world on dimensions such as values (G. Hofstede 2001, Inglehart, Basanez, & Moreno 1998, S. H. Schwartz & Bilsky 1990), personality traits, (e.g., McCrae, Terraciano, & Project 2005, Schmitt, Allik, McCrae, Benet‐Martinez, & al. 2007), and levels of happiness, (e.g., Diener, Diener, & Diener 1995). The present review does not address those phenomena assessed by individual difference measures for which the guiding assumption in the research is variability among