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Advantage of dichromats over trichromats in discrimination of color‐camouflaged stimuli in nonhuman primates
Author(s) -
Saito Atsuko,
Mikami Akichika,
Kawamura Shoji,
Ueno Yoshikazu,
Hiramatsu Chihiro,
Widayati Kanthi A.,
Suryobroto Bambang,
Teramoto Migaku,
Mori Yusuke,
Nagano Kunitoshi,
Fujita Kazuo,
Kuroshima Hika,
Hasegawa Toshikazu
Publication year - 2005
Publication title -
american journal of primatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 81
eISSN - 1098-2345
pISSN - 0275-2565
DOI - 10.1002/ajp.20197
Subject(s) - trichromacy , color vision , biology , stimulus (psychology) , primate , color discrimination , zoology , psychology , artificial intelligence , neuroscience , cognitive psychology , computer science
Due to a middle‐ to long‐wavelength‐sensitive (M/LWS) cone opsin polymorphism, there is considerable phenotypic variation in the color vision of New World monkeys. Many females have trichromatic vision, whereas some females and all males have dichromatic vision. The selective pressures that maintain this polymorphism are unclear. In the present study we compared the performance of dichromats and trichromats in a discrimination task. We examined tri‐ and dichromatic individuals of two species: brown capuchin monkeys ( Cebus apella ) and long‐tailed macaques ( Macaca fascicularis ). We also examined one protanomalous chimpanzee ( Pan troglodytes ). The subjects' task was to discriminate a circular pattern from other patterns in which textural elements differed in orientation and thickness from the background. After they were trained with stimuli of a single color, the subjects were presented with color‐camouflaged stimuli with a green/red mosaic overlaid onto the pattern. The dichromatic monkeys and the protanomalous chimpanzee selected the correct stimulus under camouflaged conditions at rates significantly above chance levels, while the trichromats did not. These findings demonstrate that dichromatic nonhuman primates possess a superior visual ability to discriminate color‐camouflaged stimuli, and that such an ability may confer selective advantages with respect to the detection of cryptic foods and/or predators. Am. J. Primatol. 67:425–436, 2005. © 2005 Wiley‐Liss, Inc.