Color–motion asynchrony assessed along the chromatic axes and with luminance variation

Abstract

Color–motion asynchrony was fist reported by Moutoussis and Zeki (Proceedings of the Royal Society B, 264, 393–399, 1997), who showed that a motion direction change needs to precede a color change by approximately 80–120 ms in order for humans to perceive change as synchronous when a visual stimulus changes its direction of motion and color rapidly and repetitively. This phenomenon was investigated with stimuli with a single change of color and a single change of motion. The stimulus was varied along the L/(L+M) axis, along the S/(L+M) axis, or in luminance at a constant chromaticity. The psychophysical task was either a correspondence task or a temporal judgment task. The results showed that all three of the variations in color or luminance produced similar color–motion asynchronies, but the correspondence task consistently showed greater asynchrony (80–110 ms) than did the temporal order judgment task (45–70 ms). The results indicated that color–motion asynchrony is processed at cortical areas after cone-specific chromatic signals and luminance signals are integrated.