According to a widely shared view, experience plays only a limited role in children's acquisition of the capacity to pass the false belief test: at most, it facilitates or attunes the development of mindreading abilities from infancy to early childhood. Against the facilitation—and also the maturation—hypothesis, I report empirical data attesting that children and even adults never come to understand false beliefs when deprived of proper social and linguistic interaction. In contrast to the attunement hypothesis, I argue that alleged mindreading abilities in infancy differ significantly from those required to pass the false belief test at age four. I conclude that children's success in the false belief test reflects the acquisition of a novel psychological competence, and argue that social experience in the form of conversation about mental states teaches children to exploit belief reports to predict intelligent behaviour, and induces their acquisition of a capacity to recognize and track others' beliefs across contexts.