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The weirdest people in the world?

Why this mattered

Henrich, Heine, and Norenzayan’s paper mattered because it made a methodological problem look like a theoretical one. Before 2010, the reliance on undergraduate and other Western samples was often treated as a convenience limitation: imperfect, but not necessarily fatal to claims about “human” cognition, motivation, morality, or social behavior. The paper reframed that habit as a source of systematic distortion. By assembling evidence across perception, fairness, cooperation, reasoning, selfhood, moral judgment, and IQ heritability, it argued that WEIRD populations were not merely under-diverse samples but often statistical outliers. That shifted the burden of proof: universality could no longer be assumed from a narrow population base.

The paradigm shift was not just “use more diverse samples.” It was the claim that human psychology itself had to be studied comparatively, with cultural, institutional, ecological, and developmental variation treated as data rather than noise. After this paper, it became newly possible to criticize broad behavioral claims at the level of sampling architecture, not just experimental design. It helped legitimize large-scale cross-cultural replication, field experiments outside university settings, and collaborations with anthropology, cultural psychology, economics, and evolutionary social science. It also gave researchers a compact vocabulary, “WEIRD,” for naming a structural bias that had previously been diffuse and easy to ignore.

Its influence is visible in later work on the replication crisis, global behavioral science, cultural evolution, moral psychology, and cross-cultural experimental economics. The paper did not solve the representativeness problem, and many fields still rely heavily on convenient samples, but it changed what counted as an adequate claim about human nature. Subsequent breakthroughs increasingly depended on that change: broader sampling, explicit tests of cultural moderation, and greater caution about treating psychological effects found in rich democratic societies as species-level facts.

Abstract

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 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 challenges.

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