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Proceedings Paper • Open Access

Adaptation and perceptual norms
Author(s): Michael A. Webster; Maiko Yasuda; Sara Haber; Deanne Leonard; Nicole Ballardini

Paper Abstract

We used adaptation to examine the relationship between perceptual norms--the stimuli observers describe as psychologically neutral, and response norms--the stimulus levels that leave visual sensitivity in a neutral or balanced state. Adapting to stimuli on opposite sides of a neutral point (e.g. redder or greener than white) biases appearance in opposite ways. Thus the adapting stimulus can be titrated to find the unique adapting level that does not bias appearance. We compared these response norms to subjectively defined neutral points both within the same observer (at different retinal eccentricities) and between observers. These comparisons were made for visual judgments of color, image focus, and human faces, stimuli that are very different and may depend on very different levels of processing, yet which share the property that for each there is a well defined and perceptually salient norm. In each case the adaptation aftereffects were consistent with an underlying sensitivity basis for the perceptual norm. Specifically, response norms were similar to and thus covaried with the perceptual norm, and under common adaptation differences between subjectively defined norms were reduced. These results are consistent with models of norm-based codes and suggest that these codes underlie an important link between visual coding and visual experience.

Paper Details

Date Published: 16 February 2007
PDF: 11 pages
Proc. SPIE 6492, Human Vision and Electronic Imaging XII, 64921S (16 February 2007); doi: 10.1117/12.730399
Show Author Affiliations
Michael A. Webster, Univ. of Nevada/Reno (United States)
Maiko Yasuda, Univ. of Nevada/Reno (United States)
Sara Haber, Univ. of Nevada/Reno (United States)
Deanne Leonard, Univ. of Nevada/Reno (United States)
Nicole Ballardini, Univ. of Nevada/Reno (United States)

Published in SPIE Proceedings Vol. 6492:
Human Vision and Electronic Imaging XII
Bernice E. Rogowitz; Thrasyvoulos N. Pappas; Scott J. Daly, Editor(s)

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