Faces behind bars: illusory eye movements induced by gratings

  • Benjamin Balas Department of Psychology, Center for Visual and Cognitive Neuroscience, North Dakota State University, Fargo, ND, USA
Keywords: Face perception, eye movements, Footsteps illusion, motion perception, spatial frequency


I describe a novel illusion in which perceived eye movements are induced by moving a vertical grating across a single image of a forward-looking face. By varying properties of the grating, a wide range of illusory eye movements can be generated including nystagmus, a ‘swirling’ motion of the eyes, and vertical scanning/blinking. I suggest that the phenomenon is closely related to the footsteps illusion, but reveals the role that object shape and grating spatial frequency together play in determining the direction of illusory motion that observers perceive. I also discuss the relationship between the current illusion, the footsteps illusion, and Moire pattern animations.


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How to Cite
Balas B. (2021). Faces behind bars: illusory eye movements induced by gratings. Journal of Illusion, 2. https://doi.org/10.47691/joi.v2.8005
Phenomenal reports