Color and luminance in the perception of 1- and 2-dimensional motion.
An isoluminant color grating usually appears to move more slowly than a luminance grating that has the same physical speed. Yet a grating defined by both color and luminance is seen as perceptually unified and moving at a single intermediate speed. In experiments measuring perceived speed and direction, it was found that color- and luminance-based motion signals are combined differently in the perception of 1-D motion than they are in the perception of 2-D motion. Adding color to a moving 1-D luminance pattern, a grating, slows its perceived speed. Adding color to a moving 2-D luminance pattern, a plaid made of orthogonal gratings, leaves its perceived speed unchanged. Analogous results occur for the perception of the direction of 2-D motion. The visual system appears to discount color when analyzing the motion of luminance-bearing 2-D patterns. This strategy has adaptive advantages, making the sensing of object motion more veridical without sacrificing the ability to see motion at isoluminance.
Farell
B
B
Institute for Sensory Research, Syracuse University, NY 13244-5290, USA. bart_farell@isr.syr.edu
D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity; D003867:Depth Perception / Q000502:physiology; D006801:Humans; D008029:Lighting; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011601:Psychophysics; D013053:Spectrophotometry; D013997:Time Factors