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The features that control discrimination of an isodipole texture pair.

TitleThe features that control discrimination of an isodipole texture pair.
Publication TypeJournal Article
Year of Publication2019
AuthorsGroulx K, Chubb C, Victor JD, Conte MM
JournalVision Res
Date Published2019 05
KeywordsContrast Sensitivity, Discriminant Analysis, Discrimination, Psychological, Female, Form Perception, Humans, Male, Pattern Recognition, Visual

Visual features such as edges and corners are carried by high-order statistics. Previous analysis of discrimination of isodipole textures, which isolate specific high-order statistics, demonstrates visual sensitivity to these statistics but stops short of analyzing the underlying computations. Here we use a new texture centroid paradigm to probe these computations. We focus on two canonical isodipole textures, the even and odd textures: any 2 × 2 block of even (odd) texture contains an even (odd) number of black (and white) checks. Each stimulus comprised a spatially random array of black-and-white texture-disks (background = mean gray) that varied in their fourth-order statistics. In the Even (Odd) condition, disks varied along the continuum between random coinflip texture and pure (highly structured) even (odd) target texture. The task was to mouse-click the centroid of the disk array, weighting each disk location by the target structure level of the disk-texture (ranging from 0 for coinflip to 1 for even or odd). For each of block-sizes S=2×2, 2 × 3, 2 × 4 and 3 × 3, a linear model was used to estimate the weight exerted on the subject's responses by the differently patterned blocks of size S. Only the results with 2 × 4 and 3 × 3 blocks were consistent with the data. In the Even condition, homogeneous blocks exerted the most weight; in the odd condition, block-pattern symmetry was important. These findings show that visual mechanisms sensitive to four-point correlations do not compute evenness or oddness per se, but rather are activated selectively by features whose frequency varies across isodipole textures.

Alternate JournalVision Res.
PubMed ID30885878
PubMed Central IDPMC6658094
Grant ListR01 EY007977 / EY / NEI NIH HHS / United States

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