Abstract
Working memory (WM) contents can guide attention towards matching sensory information in the environment. However, there are mixed findings and theories regarding whether only a single prioritized item or multiple items held in WM can effectively guide attention. The present study aims to precisely examine the dynamics of attentional guidance by WM representations using a novel mouse trajectory analysis. Specifically, a perceptual-matching task was inserted into the maintenance interval of a WM task with the memory set size of 1 or 2. For this perceptual-matching task, a target color was presented at the center of the screen until it was matched on a continuous color-wheel with a mouse-click response. The mouse cursor trajectory was recorded to capture the moment-by-moment influence of WM representations on the perceptual matching process. When a single item was remembered, there was a robust clockwise or counter-clockwise bias, in both reported color and the trial-average mouse trajectory for the perceptual matching task, towards the location of the remembered color on the color-wheel (i.e., attraction bias). When two items were remembered, the same trial-average measures failed to show systematic bias toward either memory color. However, hierarchical Bayesian modeling of the moment-by-moment mouse trajectories revealed two separable central-peaks of trajectory distributions for both memory set sizes. A novel trial-classification method further suggested that the curved mouse trajectories, as a proxy measure of attentional guidance by WM items, are related to the precision of the memory representations. Together, these results support the single-item search template account and highlight the utility of mouse trajectory analyses in hypothesis testing in vision science.