title: Joseph Delboeuf on visual illusions: a historical sketch.
abstract: The Delboeuf illusion consists in a change in the perceived (judged) size of one circle in the presence of another concentric circle. This illusion was presented and analyzed for the first time in 1865 and not, as stated by numerous investigators, in 1892 or 1893. This misconception reflects profound misreadings of Delboeuf's works. The present study examines the three Delboeuf articles on visual illusions (1865a, 1865b, 1892) and analyzes the author's data in the light of results obtained to date on concentric circle illusions.
authors.affiliation: Université de Paris V (René Descartes) et EPHE, Laboratorie de Psychologie Expérimentale, CNRS-URA 316, Centre Henri-Piéron, Paris, France.
authors.forename: R B
authors.initials: RB
authors.lastname: Evans
mesh_terms: D005602:France; D049672:History, 19th Century; D006801:Humans; D007088:Illusions / Q000266:history*; D011584:Psychology / Q000266:history; D014796:Visual Perception