title: Categorization influences illusory conjunctions.
abstract: Illusory conjunctions (ICs) provide evidence for a binding problem that must be resolved in vision. Objects that are perceptually grouped are more likely to have their features erroneously conjoined. We examined whether semantic grouping, determined by category membership (letter vs. number), also influences illusory conjunction rates. Participants were instructed to detect an "L" or a "7" among briefly presented character strings and to report its color. Despite high shape discrimination accuracy, participants often made color conjunction errors, reporting instead the color of a distractor character, "O". This distractor could be ambiguously interpreted as a letter or a number. The status of the "O" was determined by other noncolored flanker characters, which were either letters or numbers. When both the target and flankers were of the same category, participants made more ICs than when the target and flankers were of different categories. This finding demonstrates that alphanumeric categorization can precede and subsequently influence binding.
authors.affiliation: Department of Psychology, University of California, Berkeley, CA 94720-1650, USA. esterman@uclink.berkeley.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Esterman
authors.forename: William
authors.initials: W
authors.lastname: Prinzmetal
authors.forename: Lynn
authors.initials: L
authors.lastname: Robertson
mesh_terms: D000328:Adult; D005403:Fixation, Ocular; D006801:Humans; D009903:Optical Illusions; D011930:Reaction Time; D014796:Visual Perception