Citation

Masson ME, Dodd MD, Enns JT. J. Exp. Psychol. Hum. Percept. Perform. 2009; 35(1): 133-145.

Affiliation

Department of Psychology, University of Victoria.

Copyright

(Copyright © 2009, American Psychological Association)

DOI

10.1037/0096-1523.35.1.133

PMID

19170476

Abstract

The authors describe a new visual illusion first discovered in a natural setting. A cyclist riding beside a pair of sagging chains that connect fence posts appears to move up and down with the chains. In this illusion, a static shape (the chains) affects the perception of a moving shape (the bicycle), and this influence involves assimilation (averaging) rather than opposition (differentiation). These features distinguish the illusion from illusions of motion capture and induced motion. The authors take this bicycle illusion into the laboratory and report 4 findings: Naive viewers experience the illusion when discriminating horizontal from sinusoidal motion of a disc in the context of stationary curved lines; the illusion shifts from motion assimilation to motion opposition as the visual size of the display is increased; the assimilation and opposition illusionsare dissociated by variations in luminance contrast of the stationary lines and the moving disc; and the illusion does not occur when simply comparing two stationary objects at different locations along the curved lines. The bicycle illusion provides a unique opportunity for studying the interactions between shape and motion perception.

Language: en