Document Detail


The time it takes to detect changes in speed and direction of visual motion.
MedLine Citation:
PMID:  12120628     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We studied the ability of human observers to detect abrupt changes in velocity of motion of a random dot pattern. The pattern moved horizontally for 0.9 s at velocity V0, then changed to V1 either in speed, or in direction for a time T and returned to the initial motion. The threshold duration for detection of the change was measured for initial speeds of 2, 4, 8 and 16 deg/s. The time to detect a velocity reversal was equal to that for detection of an increase in speed by a factor of three. The time to detect an abrupt cessation of motion was equal to the time for detection of an increase in speed by a factor of two. The time to detect a direction change, the speed being constant, decreased gradually with increasing angle between V0 and V1 from 12 to 180 degrees and with increasing V0; the detection time was a function of (V1-V0) almost independent of the value of V0. This finding supports the hypothesis of Dzhafarov et al. (Percept Psychophys 1993;54:373-750), that the visual system effectively reduces the detection of velocity changes (from V0 to V1) to the presumably more simple detection of a motion onset, from 0 to (V1-V0). The characteristics of the detection process in the cases of uni- and two-dimensional velocity changes are discussed.
Authors:
J Hohnsbein; S Mateeff
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  38     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1998 Sep 
Date Detail:
Created Date:  2002-07-15     Completed Date:  2002-08-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  2569-73     Citation Subset:  IM    
Affiliation:
Institut für Arbeitsphysiologie, Universität Dortmund, Ardeystr. 67, D-44139 Dortmund, Germany. hohnsbein@arb-phys.uni-dortmund.de
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Humans
Motion Perception / physiology*
Psychophysics
Time Factors

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


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