title: Illusory rotation of a spoked wheel.
abstract: A disk was divided into 16 stationary sectors of different grey levels that stepped around clockwise. When thin stationary spokes of constant mid-grey separated the sectors, the spokes showed robust and striking counterclockwise apparent motion, and when stopped, they gave a brisk clockwise motion aftereffect. The spokes had to match the grey of some of the sectors. We attribute these effects to small displacements across the thickness of the spokes that stimulated hard-wired motion detectors.
authors.affiliation: Department of Psychology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0109, USA; email:  sanstis@ucsd.edu.
authors.forename: Stuart
authors.initials: S
authors.lastname: Anstis
authors.forename: Brian
authors.initials: B
authors.lastname: Rogers
keywords: apparent motion temporal resolution; illusions; motion perception