Catching Spheres, Chasing Colors: How Tracking Load Affects Color Perception in Visualizations

Abstract

Color is a key encoding channel in visualization, yet it is often interpreted under divided attention rather than in isolation. In a controlled dual-task study, 36 participants performed multiple object tracking (MOT) while detecting color changes along the lightness, chroma, and hue dimensions of OKLCH. Static sensitivity was estimated with a 4AFC 2-down 1-up staircase, and dynamic thresholds were then measured under low and high tracking load. Results show a clear trade-off between tracking accuracy and color detection, with systematic differences across color dimensions and base hues. Lightness is most vulnerable to load, hue remains comparatively robust, blue hue changes are consistently less detectable than red and green, and red chroma retains relatively high salience under dynamic conditions. These findings show that perceptual thresholds in visualization depend on task context and motivate more attention-aware color design for dynamic interfaces.