The Effect of Action on Perception is Really the Effect of Information on Memory
36.55, Sunday, May 12, 2:45 - 6:45 pm, Vista Ballroom
Bruce Bridgeman1, Sabine Blaesi1; 1Department of Psychology, University of California, Santa Cruz
Tossing a marble into a hole changes memory of the holes size; it seems larger if the toss was successful than if it was unsuccessful. This has been attributed to the effect of action on subsequent perception or memory. We ask what the action provides: Is it feedback from the motor act or only the information provided by the action that alters memory of hole size? We find that perceived difficulty alone changes remembered goal characteristics, with no changes in the stimuli or the task. Observers are given a marble, shown a hole, and told that the throwing task is difficult, that 90% of participants fail, or that it is easy, that 90% of participants succeed. The hole is then covered and its size is judged. Those who were told that the task is easy judge the hole to be significantly larger than it is, while those told that the task is difficult make judgements not significantly different from the veridical size of the hole. Size is given as a choice among seven previously memorized alternatives. When the observers subsequently attempt to throw the marble into the hole, their success rate does not depend on their choice or what they were told about the difficulty of the task, showing that their size estimate affects memory but not action. Our task shares several characteristics with other tasks used to test the effects of action on perception, such as golf putting or football punting: the target of the action is exocentric, accuracy is assessed spatially, and there is a ballistic component to the action. Our measure differs because target size is judged while fixating visually on the target, without manipulating another object for comparison.