Magnitude of luminance modulation specifies amplitude of perceived movement.
A compelling impression of movement, which is perceptually indistinguishable from a real displacement, can be elicited by patterns containing no spatially displaced elements. An apparent oscillation, w-movement, was generated by a stationary pattern containing a large number of horizontal pairs of spatially adjacent dots modulated in brightness. The observer's task was to adjust the perceived amplitude of the w-motion to match the amplitude of a real oscillation. All of the data can be accounted for by a simple rule: If the relative change in the luminance, W = delta L/L, between two adjacent stationary dots is kept constant, the distance over which these dots appeared to travel in space comprises a fixed fraction of the total distance by which they are separated. The apparent amplitude of the w-motion increases strictly in proportion with luminance contrast, provided that the contrast is represented in the motion-encoding system by a rapidly saturating compressive Weibull transformation. These findings can be explained in terms of bilocal motion encoders comparing two luminance modulations occurring at two different locations.
Allik
J
J
Department of Psychology, University of Tartu, Estoia.
Pulver
A
A
D001288:Attention; D004215:Distance Perception; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D009039:Motion Perception; D009903:Optical Illusions; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics