title: Contour lightness and separation effects in the Ebbinghaus illusion.
abstract: For 48 observers, the central circle of Ebbinghaus figures appeared smaller as the separation between it and the contextual circles increased. Lightness of the contours only affected the illusion when the contextual circles were large and located close to the central circle. An explanation incorporating size contrast and attraction between contours was offered.
authors.affiliation: Department of Psychology, Westminster College, Fulton, MO 65251.
authors.forename: T
authors.initials: T
authors.lastname: Jaeger
authors.forename: K
authors.initials: K
authors.lastname: Grasso
mesh_terms: D015350:Contrast Sensitivity; D005260:Female; D005556:Form Perception; D006801:Humans; D008027:Light; D008297:Male; D009903:Optical Illusions; D012858:Size Perception