Perceptual organization across retinal eccentricity.
Item
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Title
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Perceptual organization across retinal eccentricity.
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Identifier
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AAI3310614
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identifier
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3310614
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Creator
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Tannazzo, Teresa M.
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Contributor
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Adviser: Daniel D. Kurylo
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Date
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2008
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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, Experimental
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Abstract
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Across all levels of visual processing, from retinal to extra-striate cortex, central visual areas are allocated more cells for processing than peripheral visual areas, producing a reduction in a variety of perceptual capacities for increased eccentricity. This effect has not been explored for perceptual organization. An examination was made here of perceptual organization of stimuli oriented across retinal positions. Four stimulus features were tested across five retinal eccentricities ranging from 0 to 60 degrees. The stimulus features tested were luminance, motion, orientation, and proximity. The size and spacing of stimulus elements were also manipulated. Participants viewed visual patterns that could be perceptually organized into either vertical or horizontal lines. Threshold measurements were obtained through psychophysical techniques while participants fixated different points eccentric to the stimulus. For all stimulus features, no differences existed in thresholds obtained from eccentricities between 0 and 23 degrees. Beyond 23 degrees eccentricity, the features showed different patterns of decline in perceptual capacities. Results do not correspond to cortical magnification factors, found for many other perceptual functions. Results also do not correspond to homogeneous sensitivity, or binocular/monocular distinctions. Instead, perceptual organization follows a unique pattern of functional decline across eccentricity, varying relative to the stimulus feature upon which perceptual organization is based.
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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.
