Comments on Cavanagh and Mather (1989): coming up short (and long)
Cavanagh and Mather (1989) reviewed literature concerning the possible distinction between short- and long-range processes in motion perception and concluded that the distinction cannot be supported. Instead, they proposed that motion perception be considered on the basis of detectors for first-order (luminance, color) and second-order (first-order motion, texture, stereo) stimulus attributes. They supported their position with studies of motion based on second-order stimuli. The present paper contends that when experiments permitting the investigation of both processes in the same display are included and when criteria are examined in their totality rather than one-by-one, the original short-range/long-range distinction can be retained. Furthermore, it is argued that the first-order/second-order distinction does not represent a theoretical advancement and that studies of second-order motion can be interpreted in terms of the older distinction. It is concluded that the short-range/long-range distinction is useful and should not be abandoned.
Petersik
J T
JT
Department of Psychology, Ripon College, WI 54971.
D000221:Adaptation, Ocular / Q000502:physiology; D003118:Color Perception / Q000502:physiology; D006801:Humans; D008027:Light; D009039:Motion Perception / Q000502:physiology*; D011601:Psychophysics