Discrimination of luminance and chromaticity differences by dichromatic and trichromatic monkeys.
Dichromatic and trichromatic representatives from two genera of platyrrhine monkeys that show widespread color vision polymorphism (Saguinus--tamarins, Saimiri--squirrel monkeys) were tested for their abilities to make increment-threshold and flicker discriminations based on luminance and chromaticity differences. The details of these tests were arranged to attempt to emphasize the relative contributions to visual behavior of non-opponent and spectrally-opponent neural mechanisms. The results indicate that dichromatic and trichromatic monkeys differ only trivially on tests where performance is based on the contributions of non-opponent mechanisms, that the contribution of spectrally opponent mechanisms to the "brightness signal" is very similar in trichromatic and dichromatic monkeys, and that in increment-threshold discriminations where there are both chromaticity and luminance cues some test wavelengths yield superior performance for trichromats while others appear to favor the dichromat.
Jacobs
G H
GH
Department of Psychology, University of California, Santa Barbara 93106.
D000818:Animals; D003118:Color Perception / Q000502:physiology*; D003117:Color Vision Defects / Q000503:physiopathology; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D005425:Flicker Fusion / Q000502:physiology; D008027:Light; D008297:Male; D010786:Photoreceptor Cells / Q000502:physiology; D012452:Saguinus; D012453:Saimiri; D012684:Sensory Thresholds / Q000502:physiology; D013053:Spectrophotometry