Document Detail


Ideal observer for discrimination of the global direction of dynamic random-dot stimuli.
MedLine Citation:
PMID:  8478742     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Random-dot cinematograms in which each dot's successive movements are randomly drawn from a Gaussian distribution of directions can produce a percept of global coherent motion in a single direction. Discrimination of global direction was measured for various exposure durations, stimulus areas, and dot densities and bandwidths of the distribution of directions. Increasing the duration produced a greater improvement in performance than did increasing either the area or the density. Performance decreased as the distribution bandwidth increased. An ideal-observer model was developed, and the absolute efficiency for human direction discrimination was evaluated. Efficiencies were highest at large distribution bandwidths, with average efficiencies reaching 35%. A local-global noise model of direction discrimination, based on the ideal-observer model, containing a spatial and temporal integration limit as well as internal noise, was found to fit the human data well. The utility of ideal-observer analyses for psychophysical tasks and the interpretation of efficiencies is discussed.
Authors:
S N Watamaniuk
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of the Optical Society of America. A, Optics and image science     Volume:  10     ISSN:  0740-3232     ISO Abbreviation:  J Opt Soc Am A     Publication Date:  1993 Jan 
Date Detail:
Created Date:  1993-05-24     Completed Date:  1993-05-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8402086     Medline TA:  J Opt Soc Am A     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  16-28     Citation Subset:  IM; S    
Affiliation:
Department of Psychology, Northwestern University, Evanston, Illinois 60208.
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MeSH Terms
Descriptor/Qualifier:
Discriminant Analysis
Humans
Mathematics
Models, Biological
Motion Perception / physiology*
Photic Stimulation
Random Allocation

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