The following is a summary of “Revisiting the color-motion asynchrony,” published in the January 2023 issue of Ophthalmology by Huang, et al.
When two changes occur concurrently, people experience color-motion asynchrony (CMA), an illusion in which they notice a change in color before a change in motion direction. This phenomenon could mean that in the visual system, color is processed before motion. Due to conflicting results and methodological flaws in earlier research, the very existence of CMA was under doubt.
For a study, researchers revisited CMA using two tasks: the temporal order judgment (TOJ) task in experiment 2 and the motion and color correspondence tasks in experiment 1 and respectively. The relative timing of color and direction changes varied across trials, but colored dots went in one direction and changed color/direction at some point. Participants in the correspondence exercise were asked whether the direction/color of dots with a certain direction/color remained longer before or after the change. Participants in the TOJ task indicated whether the color change or the change in motion direction happened first.
Results showed that in either the motion correspondence task or the color correspondence test, participants saw changes in color earlier than changes in motion direction, with the former showing a larger asynchrony. Although participants in the TOJ task did not vary in psychophysical measurements, they responded more quickly when the change in color came before (as opposed to after) the change in direction. When the color changed before (as opposed to after) the change in direction, Drift-Diffusion Modeling (DDM) indicated a lower decision threshold, indicating less caution was taken in judgment when the color changed sooner.
The findings supported the validity of CMA in various tasks and suggested that response times might be examined in conventional psychophysical research.
Reference: jov.arvojournals.org/article.aspx?articleid=2785275