Stimulus uncertainty affects velocity discrimination.

Y Chen; H E Bedell; L J Frishman; D M Levi

doi:10.1016/s0042-6989(97)00282-4

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Stimulus uncertainty affects velocity discrimination.

Y Chen·H E Bedell·L J Frishman·D M Levi

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Abstract

Velocity discrimination thresholds were determined for 1 c/deg drifting gratings when uncertainty about the reference velocity was introduced by interleaving stimuli with different reference velocities from trial to trial. When drifting gratings with reference velocities spanning 4 octaves (1-16 deg/sec) were mixed randomly within a series of trials, the velocity discrimination threshold for a 4 deg/sec stimulus increased by more than a factor of 3. The threshold elevation decreased as the range of interleaved velocities was reduced from 4 to approx. 0.75 octaves, below which velocity interleaving had little effect. In contrast, when gratings that spanned a 4-octave range in spatial frequency were interleaved on successive trials, velocity discrimination for 4 deg/sec was essentially unaffected. Our results indicate that the psychophysical mechanisms underlying velocity discrimination are not spatial-frequency specific, but are turned to the velocity or speed of the stimulus.

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Discrimination, Psychological Humans Motion Perception Pattern Recognition, Visual Psychophysics Sensory Thresholds Time Factors Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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Y Chen, H E Bedell, L J Frishman, D M Levi. 1998. Stimulus uncertainty affects velocity discrimination.. https://doi.org/10.1016/s0042-6989(97)00282-4

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