The flash-lag effect during illusory chopstick rotation.
In the 'flash-lag' effect, a static object that is briefly flashed next to a moving object appears to lag behind the moving object. A flash was put up next to an intersection that appeared to be moving clockwise along a circular path but was actually moving counterclockwise [the chopstick illusion; Anstis, 1990, in AI and the Eye Eds A Blake, T Troscianko (London: John Wiley) pp 105 117; 2003, in Levels of Perception Eds L Harris, M Jenkin (New York: Springer) pp 90 93]. As a result, the flash appeared displaced clockwise. This was appropriate to the physical, not the subjective, direction of rotation, and it suggests that the flash-lag illusion occurs early in the visual system, before motion signals are parsed into moving objects.
Anstis
Stuart
S
Department of Psychology, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093-0109, USA. sanstis@ucsd.edu
D005403:Fixation, Ocular; D006801:Humans; D008027:Light; D009039:Motion Perception; D009903:Optical Illusions; D009904:Optical Rotation; D009949:Orientation; D010469:Perceptual Distortion; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011930:Reaction Time