Abstract
Memory for the final location of a moving target is often displaced forward in the direction of target motion, and this has been referred to as representational momentum. In many experiments on representational momentum, participants are presented with a probe after the target vanishes and then judge whether that probe is at the same location where the target vanished or at a different location. The experiments reported here examined whether manipulation of the actual or believed a priori probability that a same response would be correct influenced the magnitude of displacement. In Experiment 1, a same response was correct on 10, 30, 50, 70, or 90 percent of the trials, but observers were not instructed regarding these probabilities. In Experiment 2, a same response was correct on 11 percent of the trials, but different groups of participants were instructed a same response would be correct on 10, 30, 50, 70, or 90 percent of the trials. Probabilities of a same response to different probe positions, weighted mean estimates of the magnitude of representational momentum, hit rate and false alarm rates, and d' and Beta are reported. Representational momentum occurred in all conditions but was not influenced by changes in actual or instructed a priori probabilities that a same response would be correct. Changes in actual a priori probabilities that a same response would be correct decreased d' and produced a trend for more positive Beta, and changes in instructed a priori probabilities that a same response would be correct did not influence d' but increased Beta. Overall, there might be shifts in both sensitivity and criterion as a function of actual or instructed changes in the a priori probability that a same response would be correct, but these shifts are not sufficiently large to significantly influence representational momentum.