Constant curvature modeling of abstract shape representation.

How abstract shape is perceived and represented poses crucial unsolved problems in human perception and cognition. Recent findings suggest that the visual system may encode contours as sets of connected constant curvature segments. Here we describe a model for how the visual system might recode a se...

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Autores principales: Nicholas Baker, Philip J Kellman
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Publicado: Public Library of Science (PLoS) 2021
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spelling oai:doaj.org-article:229ff4227ad745f2b579081f2cb968872021-12-02T20:18:53ZConstant curvature modeling of abstract shape representation.1932-620310.1371/journal.pone.0254719https://doaj.org/article/229ff4227ad745f2b579081f2cb968872021-01-01T00:00:00Zhttps://doi.org/10.1371/journal.pone.0254719https://doaj.org/toc/1932-6203How abstract shape is perceived and represented poses crucial unsolved problems in human perception and cognition. Recent findings suggest that the visual system may encode contours as sets of connected constant curvature segments. Here we describe a model for how the visual system might recode a set of boundary points into a constant curvature representation. The model includes two free parameters that relate to the degree to which the visual system encodes shapes with high fidelity vs. the importance of simplicity in shape representations. We conducted two experiments to estimate these parameters empirically. Experiment 1 tested the limits of observers' ability to discriminate a contour made up of two constant curvature segments from one made up of a single constant curvature segment. Experiment 2 tested observers' ability to discriminate contours generated from cubic splines (which, mathematically, have no constant curvature segments) from constant curvature approximations of the contours, generated at various levels of precision. Results indicated a clear transition point at which discrimination becomes possible. The results were used to fix the two parameters in our model. In Experiment 3, we tested whether outputs from our parameterized model were predictive of perceptual performance in a shape recognition task. We generated shape pairs that had matched physical similarity but differed in representational similarity (i.e., the number of segments needed to describe the shapes) as assessed by our model. We found that pairs of shapes that were more representationally dissimilar were also easier to discriminate in a forced choice, same/different task. The results of these studies provide evidence for constant curvature shape representation in human visual perception and provide a testable model for how abstract shape descriptions might be encoded.Nicholas BakerPhilip J KellmanPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 16, Iss 8, p e0254719 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Nicholas Baker
Philip J Kellman
Constant curvature modeling of abstract shape representation.
description How abstract shape is perceived and represented poses crucial unsolved problems in human perception and cognition. Recent findings suggest that the visual system may encode contours as sets of connected constant curvature segments. Here we describe a model for how the visual system might recode a set of boundary points into a constant curvature representation. The model includes two free parameters that relate to the degree to which the visual system encodes shapes with high fidelity vs. the importance of simplicity in shape representations. We conducted two experiments to estimate these parameters empirically. Experiment 1 tested the limits of observers' ability to discriminate a contour made up of two constant curvature segments from one made up of a single constant curvature segment. Experiment 2 tested observers' ability to discriminate contours generated from cubic splines (which, mathematically, have no constant curvature segments) from constant curvature approximations of the contours, generated at various levels of precision. Results indicated a clear transition point at which discrimination becomes possible. The results were used to fix the two parameters in our model. In Experiment 3, we tested whether outputs from our parameterized model were predictive of perceptual performance in a shape recognition task. We generated shape pairs that had matched physical similarity but differed in representational similarity (i.e., the number of segments needed to describe the shapes) as assessed by our model. We found that pairs of shapes that were more representationally dissimilar were also easier to discriminate in a forced choice, same/different task. The results of these studies provide evidence for constant curvature shape representation in human visual perception and provide a testable model for how abstract shape descriptions might be encoded.
format article
author Nicholas Baker
Philip J Kellman
author_facet Nicholas Baker
Philip J Kellman
author_sort Nicholas Baker
title Constant curvature modeling of abstract shape representation.
title_short Constant curvature modeling of abstract shape representation.
title_full Constant curvature modeling of abstract shape representation.
title_fullStr Constant curvature modeling of abstract shape representation.
title_full_unstemmed Constant curvature modeling of abstract shape representation.
title_sort constant curvature modeling of abstract shape representation.
publisher Public Library of Science (PLoS)
publishDate 2021
url https://doaj.org/article/229ff4227ad745f2b579081f2cb96887
work_keys_str_mv AT nicholasbaker constantcurvaturemodelingofabstractshaperepresentation
AT philipjkellman constantcurvaturemodelingofabstractshaperepresentation
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