Abstract
Motion repulsion is a visual illusion in which perceived directions of the two sets of superimposed coherently moving dots are shifted away from each other than their physical directions. This illusion is thought to occur due to mutual inhibition of two pools of neurons representing different motion directions. We investigated competition between two mental representations by using the motion repulsion as a model system. Subjects were asked to remember direction of two random dot motion displays presented in sequence and then reported both of them. Similar to motion repulsion observed in perception, remembered motion directions were shifted away from their physical inputs. More importantly, the repulsion magnitude of an item was greater when it was retrieved following memory retrieval of the other item than when it was retrieved first. This suggests that earlier retrieval exerted greater inhibition on the item being held in short-term memory. Control experiments ruled out alternative hypotheses, such that neither reduced cognitive resources for maintaining short-term memory during memory retrieval nor continued interactions between short-term memory representations could explain distortion in short-term memory. Instead, our results indicate that reactivated representations during memory retrieval inhibit competing representations still being held in short-term memory. Our finding suggests that inhibition is a common feature of memory retrieval for both short- and long-term memory.
Meeting abstract presented at VSS 2015