Mental extrapolation and representational momentum for complex implied motions.

A sequence of static displays implying consistent motions of a pattern induces distortions in memory for the last-observed appearance of the pattern. These memory distortions suggest that there is an internal analogue to physical momentum called representational momentum. Two experiments are reported comparing performance on tasks in which observers must remember the final display with those in which they are instructed to extrapolate the implied motions out to the next step in the sequence. In each experiment, the memory shifts were highly correlated with the actual rates at which the implied motions were extrapolated. In addition, the memory shifts were larger when the mental extrapolations occurred along the same directions of implied motion each time. These findings suggest that the memory shifts depend both on the rate at which the mental extrapolations are performed and on how consistently they are performed.