Three experiments examined development of perceptual causality in 3- to 9-year-olds. Findings indicated that participants of all ages assigned contact events (A moves toward B, which moves upon contact) to the physical domain and non-contact events (B moves before contact) to the psychological domain. Participants chose causality more often for events without delay than with delay at the closest point; these events became more distinct over the preschool range. (Author/KB)