DIFFERENTIATION OF PERCEPTUAL CLOSURE: IMPLICATIONS FOR RIGHT HEMISPHERE FUNCTIONING.
Item
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Title
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DIFFERENTIATION OF PERCEPTUAL CLOSURE: IMPLICATIONS FOR RIGHT HEMISPHERE FUNCTIONING.
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Identifier
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AAI8112375
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identifier
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8112375
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Creator
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WASSERSTEIN, JEANETTE.
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Contributor
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Dr. Jeffrey Rosen
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Date
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1981
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology
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Abstract
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Level of functioning on perceptual closure tasks has been associated with degree of right hemisphere integrity. Closure ability has been assessed by different Gestalt Completion Tests (GCTs). Users of these instruments have assumed that a unitary process, common to each test, underlies identification of pictures despite the fact that (1) considerable ambiguity exists in the Gestalt literature on the meaning of 'closure', and (2) the degree of interrelationship among the several GCTs has yet to be determined.;The tacit assumption of a unitary process was subjected to empirical analysis in the first experiment of this study. A collection of GCTs and Milner facial recognition stimuli (another test of right hemisphere visual-perceptual processing) were group administered to normal subjects (N = 70). Findings demonstrated that traditional Street figures as well as competing versions of GCTs, although partially overlapping, could not be defined by a unitary set of characteristics. Further, facial memory and whatever was measured by these closure tasks appeared to be separate functions.;A second experiment with unilaterally focal brain-lesioned subjects (N = 23) isolated a subset of closure items which were maximally sensitive to RH pathology and shared a common underlying perceptual process, as defined by a concurrent measure. These findings indicated that the ability to appreciate subjective contour illusions characterizes the right hemisphere capacity required by GCTs. Further, the dissociation between two right hemisphere sensitive visual-perceptual tasks implied by the first experiment was corroborated, and related to the visual discrimination rather than the memory aspect of the original facial memory task. Case-by-case analysis suggested the existence of site-by-task specificity and reciprocal interactions within the right hemisphere for those dissociated processes. Finally, left brain-damaged subjects were found to perform better than normals on several dimensions of the closure tests. Findings are discussed in relation to (1) underlying right hemisphere spatial abilities, particularly depth perception, (2) differentiated structural organization of the right hemisphere and (3) interference models of inter/intrahemispheric interactions.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Psychology
