In Experiment 1, Japanese children (4-, 5-, 7-, and 10-year-olds (n = 78)) and adults (n = 36), answered questions about the possibility of psychogenic bodily reactions, i.e., bodily outcomes with origins in the mind. The 4- and 5-year-old preschoolers typically denied that bodily conditions could originate in mental states. Developmentally, recognition of psychogenic bodily reactions appeared between ages 8 and 11. Experiment 2 showed that these findings did not depend on whether reactions were positive or negative. The preschoolers had some difficulty in assuming not only negative but also positive psychogenic bodily reactions. In Experiment 3, 5-, 6-, 8-, and 11-year-old children (n = 70) and adults (n = 18) were asked to explain why physical/psychological states would lead to bodily outcomes. Adults relied on mechanical causation for physically induced bodily reactions, while for psychogenic reactions they often referred to vitalistic concepts. In contrast, young children sometimes referred to vitalistic concepts for physically induced reactions, but seldom did so for psychogenic reactions. Vitalistic causality appears to change from causality based on only the body, to a framework that applies not only bodily but also to mental phenomena. (Contains 4 tables.)