WEIRD is Joseph Henrich’s acronym for the psychological profile of societies that are Western, Educated, Industrialised, Rich, and Democratic — a slice of humanity that supplies the overwhelming majority of participants in behavioural-science studies whose findings are then generalised as human nature. Henrich, professor of human evolutionary biology at Harvard, coined the term about a decade before popularising it, to flag how statistically unusual this population actually is.
Compared with most of the world, WEIRD people tend toward impersonal trust (cooperating readily with strangers rather than leaning on tight kin networks), individualism (defining themselves through personal traits and self-enhancement rather than relationships), and analytical thinking — sorting people and objects into fixed categories rather than reading them through relationship and context. Henrich traces these traits to the medieval Catholic Church’s bans on cousin marriage and polygamy and its promotion of individual inheritance, which broke up extended kin groups into small nuclear families and, over centuries, seeded more individualistic, rule-based cognition. He notes that cultural adaptation to new institutions can take “decades, or even longer.”
The term also travels as a joke on itself: Western Entitled Individualistic Reductive Deluded (GTDF) — a reminder that what gets studied as universal psychology is often a narrow, parochial cultural formation.
Also see Individualism and The Rice Theory