Velocity perception and discrimination: relation to temporal mechanisms.
Measurements of three aspects of velocity detection are presented: the upper threshold of motion (UTM), perceived velocity and velocity discrimination. UTM (the highest velocity at which a drifting periodic pattern has the appearance of coherent motion) is reduced by adaptation to a similar drifting pattern of low but not medium or high velocity. The range of adaptation velocities over which the perceived velocity of a test pattern is reduced is quite different, the reduction being greatest at medium adaptation velocities. True velocity discrimination for gratings is possible only at low velocities; at higher velocities other cues (such as temporal frequency) are used. These findings are discussed in relation to current models of motion perception.
Smith
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AT
Department of Psychology, University College Cardiff, Wales.
D000221:Adaptation, Ocular; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology