Summary
WEIRD stands for Western, Educated, Industrialised, Rich and Democratic. Joseph Henrich, professor of human evolutionary biology at Harvard, coined the acronym with colleagues as “a kind of consciousness-raising device”: psychology had drawn its findings largely from Western students, who turned out to be “psychologically unusual”.
Compared with most of the world, WEIRD people lean towards trusting strangers, individualism and analytic thinking – sorting people and objects into categories instead of reading relationships and context. Henrich traces this to the early medieval Church’s rules against cousin marriage and polygamy, which broke kin groups into nuclear families. Psychology and institutions, he argues, then went on shaping each other.
Rationale
Henrich documents a loop Part 1 describes: arrangements “continually reproduce the dispositions that sustain them”. His case is marriage and inheritance rules remaking how people think, over centuries.