| Apparent motion by edge discontinuities. | |
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MedLine Citation:
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PMID: 18773722 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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When the eyes move vertically across a jagged diamond, a local shift (LS) of edge discontinuities and a global shape distortion (GD) (ie expansion/contraction opposite to that expected by the aperture effect) are perceived. These phenomena cannot be accounted for by a local motion signals integration rule based either on the intersection of constraint lines or on the velocity vector summation. The threshold for GD perception and the salience of LS and GD (1 to 10 scale) were measured in two experiments by different methods and displays. In experiment 1 we induced GD through mimicking LS with a kinetic pattern constituted of a set of circular illusory apertures revealing drifting gratings. The point of subjective equality for compression/expansion was reached for gratings the linear extrapolations of which form an angle of 94.4 degrees. In experiment 2 observers followed a dot moving along the vertical elongation axis of a static jagged diamond (with 70 degrees or 90 degrees angles), varying in the shape (triangular, wave, square), frequency, and amplitude of edge discontinuities. GD scores were correlated with LS scores that were inversely related to frequency/amplitude ratios of triangular edge discontinuities. Data are partially accounted for by averaging neighbouring local motion-capture vectors. Results prove that there are strong interrelations between phenomena in which visual motion affects visual localisation and phenomena involving apparent deformation of global shape. |
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Authors:
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Carlo Fantoni; Baingio Pinna |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial |
Journal Detail:
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Title: Perception Volume: 37 ISSN: 0301-0066 ISO Abbreviation: Perception Publication Date: 2008 |
Date Detail:
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Created Date: 2008-09-08 Completed Date: 2008-12-04 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0372307 Medline TA: Perception Country: England |
Other Details:
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Languages: eng Pagination: 973-92 Citation Subset: IM |
Affiliation:
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Department of Psychology, University of Trieste, Trieste, Italy. fantoni@psico.units.it |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Form Perception
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physiology* Humans Motion Perception / physiology* Optical Illusions* Pattern Recognition, Visual Psychophysics |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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