Constancy of target velocity as a critical factor in the emergence of auditory and visual representational momentum

Representational momentum refers to the tendency to displace the judged final position of a moving auditory or visual target as being too far forward along the path of motion. This phenomenon was investigated here by comparing apparent displacements in final position with constant or with irregularly varying target velocities. Final positions of auditory or visual targets, moving along the horizontal plane, were indicated by manual pointing. In both modalities, we found a significantly smaller displacement magnitude with varying velocities compared to constant velocity. The reduction in displacement occurred irrespective of whether or not the participants pursued the visual targets with their eyes. These findings indicate that the emergence of representational momentum critically depends on the constancy of target velocity. The results are compatible with a model in which changes in the motion signal can override the extrapolation mechanism that usually causes the forward displacement of representational momentum.