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Contrast affects flicker and speed perception differentlyWe have previously shown that contrast affects speed perception, with lower-contrast, drifting gratings perceived as moving slower. In a recent study, we examined the implications of this result on models of speed perception that use the amplitude of the response of linear spatio-temporal filters to determine speed. In this study, we investigate whether the contrast dependence of speed can be understood within the context of models in which speed estimation is made using the temporal frequency of the response of linear spatio-temporal filters. We measured the effect of contrast on flicker perception and found that contrast manipulations produce opposite effects on perceived drift rate and perceived flicker rate, i.e., reducing contrast increases the apparent temporal frequency of counterphase modulated gratings. This finding argues that, if a temporal frequency-based algorithm underlies speed perception, either flicker and speed perception must not be based on the output of the same mechanism or contrast effects on perceived spatial frequency reconcile the disparate effects observed for perceived temporal frequency and speed.
Document ID
20040172966
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Thompson, P.
(University of York U.K)
Stone, L. S.
Date Acquired
August 22, 2013
Publication Date
May 1, 1997
Publication Information
Publication: Vision research
Volume: 37
Issue: 10
ISSN: 0042-6989
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Neuroscience

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