title: Speed perception is affected by the Ebbinghaus-Titchener illusion.
abstract: We examined whether the apparent extent of motion affects speed perception. On the first presentation of each trial, a light dot travelled horizontally across a central circle of one of the Ebbinghaus configurations (with either small or large inducing elements). On the second presentation, observers adjusted the speed of a dot moving within the central circle alone so as to match the speed perceived in the first presentation. For all stimulus speeds (1.3, 2.1, and 5.5 deg s-1), the matched speed with small inducing circles was systematically less than that with large inducing circles. The findings indicate that the perceived speed depends on the apparent extent of motion: the larger the apparent size of a frame, the slower the apparent speed. These results are consistent with the predictions of transposition effects in visual motion.
authors.affiliation: Institut für Medizinische Psychologie und Verhaltensneurobiologie, MEG-Zentrum, Eberhard-Karls-Universität Tübingen, Gartenstrasse 29, D 72074 Tübingen, Germany. marina.pavlova@uni-tuebingen.de
authors.forename: M
authors.initials: M
authors.lastname: Pavlova
authors.forename: A
authors.initials: A
authors.lastname: Sokolov
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009903:Optical Illusions; D012858:Size Perception / Q000502:physiology