Document Detail


Interaction between complex motion patterns in the perception of shape.
MedLine Citation:
PMID:  18068751     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated how different types of complex motion patterns interact in the perception of shape. We used global dot-motion stimuli which consisted of two superimposed groups of dots; one group of dots moved along an ellipsoidal trajectory (target pattern), while the other group of dots was divided into quadrants with dots in alternating sectors moving in radial expanding and radial contracting directions (background pattern). In the first experiment, observers judged whether the major axis of an ellipsoidal motion pattern oriented at 45 degrees or -45 degrees from vertical lay to the right or to the left of a central vertical line. Ellipsoids with different aspect ratios, which controlled both the tilt (left or right of vertical) and the extent of ellipsoidal curvature, were presented to observers using method of constant stimuli. The appearance of the ellipsoidal target pattern was distorted in the presence of background motion. The aspect ratio of the target at which observers perceived the figure to be circular was approximately 0.86 (an aspect ratio of 1.0 indicates a circle), with the pattern's major axis lying in the two sectors that contained contracting motion. This finding may constitute evidence that background motion distorts the perception of space, resulting in a distorted target pattern. However, the distortion effect is limited to conditions for which the speed of the target pattern and background pattern was slow and high contrast, and for when dots forming the target and background patterns were of the same luminance polarity.
Authors:
Wang On Li; Sieu K Khuu; Anthony Hayes
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  48     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2008-02-04     Completed Date:  2008-04-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  167-78     Citation Subset:  IM    
Affiliation:
Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China. liwangon@gmail.com
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MeSH Terms
Descriptor/Qualifier:
Form Perception*
Humans
Motion Perception*
Pattern Recognition, Visual
Photic Stimulation / methods
Psychometrics
Psychophysics

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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