Abstract
Question: Are working memory representations biased by new visual inputs?
Method: Observers were instructed first to view a random dot motion display (100% coherence) and, then, to remember its direction of motion during a two-second retention interval. While holding that direction of motion in visual working memory, observers viewed second motion display (10%~15% in coherence) and indicated whether it was counter-clock wise or clock wise with respect to a reference line presented at the edge of the display (2AFC task). The difference in motion direction between these two motion displays was independently varied from -20° to +20°. After performing the direction judgment task, observers reported the remembered direction of motion by adjusting a clock needle to the memorized direction. This judgment provided a measure of memory precision, indexed as the difference between the actual direction of the first motion display and the memorized direction.
Result: The remembered direction of motion was systematically biased toward the direction of motion shown during the intervening perceptual-discrimination task.
Discussion: These findings demonstrate that new perceptual inputs affect visual working memory representations. This general experimental paradigm opens avenues to investigate how perception influences working memory representations and, for that matter, how working memory representations influence ongoing perception.