| Anisotropies in judging the direction of moving natural scenes. | |
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MedLine Citation:
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PMID: 20884500 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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Although visual systems are optimized to deal with the natural visual environment, our understanding of human motion perception is in large part based on the use of artificial stimuli. Here, we assessed observers' ability to estimate the direction of translating natural images and fractals by having them adjust the orientation of a subsequently viewed line. A system of interleaved staircases, driven by observers' direction estimates, ensured that stimuli were presented near one of 16 reference directions. The resulting error distributions (i.e., the differences between reported and true directions) reveal several anisotropies in global motion processing. First, observers' estimates are biased away from cardinal directions (reference repulsion). Second, the standard deviations of estimates show an "oblique effect" being ∼45% lower around cardinal directions. Third, errors around cardinal directions are more likely (∼22%) to approach zero than would be consistent with Gaussian-distributed errors, suggesting that motion processing minimizes the number as well as magnitude of errors. Fourth, errors are similar for natural scenes and fractals, indicating that observers do not use top-down information to improve performance. Finally, adaptation to unidirectional motion modifies observers' bias by amplifying existing repulsion (e.g., around cardinal directions). This bias change can improve direction discrimination but is not due to a reduction in variability. |
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Authors:
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Steven C Dakin; Deborah Apthorp; David Alais |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-09-03 |
Journal Detail:
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Title: Journal of vision Volume: 10 ISSN: 1534-7362 ISO Abbreviation: J Vis Publication Date: 2010 |
Date Detail:
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Created Date: 2010-10-04 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101147197 Medline TA: J Vis Country: United States |
Other Details:
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Languages: eng Pagination: 5 Citation Subset: IM |
Affiliation:
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Institute of Ophthalmology, University College London, London, UK. s.dakin@ucl.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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| Grant Support | |
ID/Acronym/Agency:
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//Wellcome Trust |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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