Sean Carroll in Preposterous Universe:
We all know stereotypes about people from different countries; but we also recognize that there really are broad cultural differences between people who grow up in different societies. This raises a challenge when most psychological research is performed on a narrow and unrepresentative slice of the world’s population — a subset that has accurately been labeled as WEIRD (Western, Educated, Industrialized, Rich, and Democratic). Joseph Henrich has argued that focusing on this group has led to systematic biases in how we think about human psychology. In his new book, he proposes a surprising theory for how WEIRD people got that way, based on the Church insisting on the elimination of marriage to relatives. It’s an audacious idea that nudges us to rethink how the WEIRD world came to be.