Visual impressions of causality: Effects of manipulating the direction of the target object's motion in a collision event

Stimuli in which a moving object (A) contacts a stationary one (B) and the latter then moves off tend to give rise to visual impressions of causality. In two experiments the angle of Object B's path of motion to that of Object A was manipulated, and in one of these the point of contact of Object A with Object B was also manipulated. The ampliation hypothesis (Michotte, 1963) predicts that the causal impression should be strongest when Object B continues Object A's direction of motion, regardless of point of contact. In fact the causal impression was strongest when the angle of Object B's motion matched the angle that would actually occur for the point of contact in the stimulus. This supports a hypothesis that the causal impression is a product of experience with real object collisions.