Tracking within-category colors is easier: Color categories modulate location processing in a dynamic visual task.

The categorical perception (CP) of color describes the phenomenon that colors across categories (e.g., blue and green) are more discriminable than within-category colors (e.g., green) even when the perceptual distance is controlled. While most studies are conducted in a static visual scene, the current study investigated the effect of color categories when tracking multiple colored objects within two experiments. The targets or distractors were either from the same color category or from two different categories, and the perceptual distance was controlled across all conditions. We found that location tracking was facilitated when the targets or the distractors shared the same color category in the tracking task, which required location tracking and color memorization at the same time, compared with when they were from two different categories (Experiment 1). By contrast, when location tracking was the sole demand and no explicit color processing was required, the target CP effects, but not the distractor CP effects, persisted (Experiment 2). We conclude that color categories can dynamically modulate preattention visual processing when color working memory is involved, but that attention is necessary to produce CP effects when color is irrelevant to the task.