title: What does visual agnosia tell us about perceptual organization and its relationship to object perception?
abstract: The authors studied 2 patients, S.M. and R.N., to examine perceptual organization and its relationship to object recognition. Both patients had normal, low-level vision and performed simple grouping operations normally but were unable to apprehend a multielement stimulus as a whole. R.N. failed to derive global structure even under optimal stimulus conditions, was less sensitive to grouping by closure, and was more impaired in object recognition than S.M. These findings suggest that perceptual organization involves a multiplicity of processes, some of which are simpler and are instantiated in lower order areas of visual cortex (e.g., collinearity). Other processes are more complex and rely on higher order visual areas (e.g., closure and shape formation). The failure to exploit these latter configural processes adversely affects object recognition.
authors.affiliation: Carnegie Mellon U.
authors.forename: Marlene
authors.identifier: 0000-0002-3814-1015
authors.initials: M
authors.lastname: Behrmann
authors.affiliation: U Haifa.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kimchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000377:Agnosia; D000704:Analysis of Variance; D004192:Discrimination, Psychological; D006801:Humans; D008029:Lighting; D008297:Male; D008960:Models, Psychological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time; D012684:Sensory Thresholds; D013028:Space Perception; D014793:Visual Cortex / Q000502:physiology