Representational momentum and event course anticipation in the perception of implied periodical motions.

After viewing an object in an implied rotation, subjects' short-term visual memory for the object's position is distorted in the direction of rotation. Previous accounts of this representational momentum effect have emphasized the analogy to physical momentum. This study provides a more general perspective: Position memory is influenced by anticipatory processes related to the future event course. In Experiment 1, subjects are presented with an implied periodical event in which a rectangle rotates back and forth. When a direction change in the implied rotation can be anticipated, memory distortion size drops back to zero. Experiment 2 rejects an alternative explanation for the findings of Experiment 1 in terms of enhanced position memory caused by repeated presentations of the memory pattern orientation within the same trial. In Experiment 3, the periods of the implied event are marked by changes in velocity rather than direction. The anticipation of a sudden velocity increase leads to a larger memory shift. We conclude that the perceptual system anticipates the event course on the basis of a representation of the higher order event structure rather than the local motion characteristics.