Abstract
Although visual working memory (VWM) is often studied in isolation in laboratory research, maintaining and processing of information in VWM tends to occur concurrently with perceptual encoding of new sensory inputs in natural vision. It is unclear how much influence the existing VWM contents have on ongoing perceptual encoding. The present study aims to test the effects of VWM on visual appearance during ongoing perceptual encoding. Participants performed a single-item color change-detection task. A perceptual task was inserted into the maintenance interval of the change-detection task as a secondary task. In the perceptual matching task, a perceptual target color appeared at the center of display until the participants matched its color on a continuous 360 degree color-wheel using mouse clicking. Critically, the perceptual target color was either 40 degree clockwise (CW) or counterclockwise (CCW) from the memory color. The preliminary findings indicated that the perceived color shifted toward (i.e. attraction) the remembered color. First, the circular mean of reported perceptual color and its direction was shifted toward the location of the memory item (e.g. CW or CCW). Second, using an extended Zhang & Luck mixture model with Maximum Likelihood and Hierarchical Bayesian approach, we found a robust attraction effect with minimal effect of guessing and misreport. Third, change detection performance was impaired when the changed color was in the direction of the perceptual color shift. Lastly, mouse trajectory initiated from the display center to the reported color on the color wheel for the perceptual task systemically curved toward the remembered color in VWM. Furthermore, the time-course of the mouse trajectory showed an initial obligatory VWM-based feature guidance and the subsequent redirection of response to the perceptual target. Together, these results support the idea that VWM representations directly interact with ongoing perceptual encoding, leading to distorted perception.