Naïve impetus and Michotte's "tool effect": evidence from representational momentum.

Displacement in the remembered position of targets in displays based on Michotte's (1951/1991) tool effect paradigm was examined. Targets in tool effect displays exhibited less forward displacement than did otherwise identical targets presented in isolation; the decrease in forward displacement was not dependent upon the motion of a visible intermediary, but was dependent upon a visible intermediary contacting both the launcher and the target. The data were consistent with naïve impetus theory and the hypothesis that decreases in forward displacement of targets in tool effect displays resulted from the intermediary transferring perceived impetus of the launcher to the target and a dissipation of that impetus with subsequent target motion. Possible connections between displacement, impetus, and the perception of causality are discussed.