Document Detail

A Bayesian Observer Replicates Convexity Context Effects in Figure-Ground Perception.
MedLine Citation:
PMID:  22564398     Owner:  NLM     Status:  Publisher    
Peterson and Salvagio (2008) demonstrated convexity context effects in figure-ground perception. Subjects shown displays consisting of unfamiliar alternating convex and concave regions identified the convex regions as foreground objects progressively more frequently as the number of regions increased; this occurred only when the concave regions were homogeneously colored. The origins of these effects have been unclear. Here, we present a two-free-parameter Bayesian observer that replicates convexity context effects. The Bayesian observer incorporates two plausible expectations regarding three-dimensional scenes: (1) objects tend to be convex rather than concave, and (2) backgrounds tend (more than foreground objects) to be homogeneously colored. The Bayesian observer estimates the probability that a depicted scene is three-dimensional, and that the convex regions are figures. It responds stochastically by sampling from its posterior distributions. Like human observers, the Bayesian observer shows convexity context effects only for images with homogeneously colored concave regions. With optimal parameter settings, it performs similarly to the average human subject on the four display types tested. We propose that object convexity and background color homogeneity are environmental regularities exploited by human visual perception; vision achieves figure-ground perception by interpreting ambiguous images in light of these and other expected regularities in natural scenes.
Daniel Goldreich; Mary A Peterson
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-4
Journal Detail:
Title:  Seeing and perceiving     Volume:  -     ISSN:  1878-4755     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-5-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101531524     Medline TA:  Seeing Perceiving     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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