The filling-in illusion and moving visual phantoms.

A new visual illusion, filling-in illusion, is reported and compared to the moving visual phantoms of Tynan and Sekuler (1975). 169 unrelated, unpaid, volunteer subjects were recruited from students and faculty and classified as filling-in positive--able to perceive the illusion, or filling-in negative--unable to perceive it. Other investigations examined the effects of light levels, moving vs static test figures, and black-and-white vs shaded figures. A polaroid study suggests a central rather than retinal location of the illusory effect. Filling-in is a contour completion effect, as are moving visual phantoms. Although a number of differences between the two phenomena exist, it is suggested that they may be due to different aspects of a common mechanism.