, Volume 12, Issue 1, pp 77-85

Movement aftereffects contingent on color, intensity, and pattern


We have found contingent movement aftereffects (CMAEs) lasting several days, contingent upon the color, intensity, and stripe width of moving patterns. Ss adapted for 10 min to a patterned disk rotating clockwise under red light, alternating every 10 sec with counterclockwise under green light. When stopped, the disk then appeared to rotate counterclockwise under red light and clockwise under green light. The effect lasted only a second or two, reappearing each time the field’s color was changed. But it increased in strength over the first 1/2 hand was still present 1 or 2 days later. Color transposition effects were found: after adaptation to red-clockwise (long wavelength) alternating with green-counterclockwise (short wavelength), a stationary yellow (long wavelength) test field appeared to rotate counterclockwise and a blue (short wavelength) field appeared to rotate clockwise. Relative, not absolute, color of the test triggered the CMAE. Similar CMAEs and transposition effects were produced by pairing direction of movement with intensity, with width of moving stripes and with orientation of a stationary grating projected onto a rotating patterned disk.

The authors thank Pamela Vaughan for her assistance in conducting the experiments, Brian Rogers for his helpful comments and discussion, and Tania Morley for drawing Fig.1. They gratefully acknowledge support from the Science Research Council under Grant B/SR/4836. Also. the authors recently learned that O. Favreau, V. Emerson, and M. C. Corballis have independently found effects very similar to their own. to be published shortly in Science. They are grateful to these authors for making them aware of their results before publication.