Using the hard, Randy, and Rittler test to evaluate color vision in Capuchin ( Cebus libidinosus )

• Published in: International journal of primatology 2012-12, Vol.33 (6), p.1467-1476
• Main Authors: Altavini, Tiago Siebert, Henriques, Leonardo Dutra, Bonci, Daniela Maria Oliveira, Nagy, Balázs Vince, Ventura, Dora Fix, Pessoa, Valdir Filgueiras
• Format: Article
• Language: English
• Subjects: Biological anthropology; Colour; Primate behaviour; Primates; Primatology; Visual culture
• ISSN: 0164-0291
• DOI: 10.1007/s10764-012-9638-8

The identification of color vision types in primates is fundamental to understanding the evolution and biological function of color perception. The Hard, Randy, and Rittler (HRR) pseudoisochromatic test categorizes human color vision types successfully. Here we provide an experimental setup to employ HRR in a nonhuman primate, the capuchin ( Cebus libidinosus ), a platyrrhine with polymorphic color vision. The HRR test consists of plates with a matrix composed of gray circles that vary in size and brightness. Differently colored circles form a geometric shape (X, O, or *D) that is discriminated visually from the gray background pattern. The ability to identify these shapes determines the type of dyschromatopsy (deficiency in color vision). We tested six capuchins in their own cages under natural sunlight. The subjects chose between two HRR plates in each trial: one with the gray pattern only and the other with a colored shape, presented on the left or right side at random. We presented the test 40 times and calculated the 95_% confidence limits for chance performance based on the binomial test. We also genotyped all subjects for exons 3 and 5 of the X-linked opsin genes. The HRR test diagnosed two subjects as protan dichromats (missing or defective L-cone), three as deutan dichromats (missing or defective M-cone), and one female as trichromat. Genetic analysis supported the behavioral data for all subjects. These findings show that the HRR test can be applied to diagnose color vision in nonhuman primates. Reprinted by permission of Springer