title: Influence of stimuli size on color discrimination in capuchin monkeys.
abstract: Large-field trichromacy is a general feature of protanope and deuteranope humans, provided that the stimuli size extends to an 8 degrees visual angle. In this study we compared the performance of five male and three female tufted capuchin monkeys (Cebus apella) in discriminating pairs of Munsell color papers. Human subjects were also studied in two-choice discrimination tests, using the same stimuli and apparatus employed for the monkeys. The results show that although the dichromatic humans showed improved discrimination with larger versions of the stimuli, the dichromatic monkeys exhibited the same performance for both stimuli sizes. Thus, Cebus apella apparently do not present large-field trichromacy-at least for the conditions in the present experiments.
authors.affiliation: Laboratory of Neurosciences and Behavior and Primate Center, University of Brasilia, Brasil. ursula@unb.br
authors.forename: Ursula R
authors.initials: UR
authors.lastname: Gomes
authors.forename: Daniel M A
authors.initials: DM
authors.lastname: Pessoa
authors.forename: Elisa
authors.initials: E
authors.lastname: Suganuma
authors.forename: Carlos
authors.initials: C
authors.lastname: Tomaz
authors.forename: Valdir F
authors.initials: VF
authors.lastname: Pessoa
mesh_terms: D000328:Adult; D000818:Animals; D002428:Cebus / Q000502:physiology*; D003118:Color Perception; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012858:Size Perception