Abstract

Discrimination of colors and brightness was studied with instrumental learning paradigm in monkeys (Macaque rhesus) and fish (Carpio Cyprinus L.). The confusion matrices composed of percentage of instrumental responses were treated by principal components analysis. The spherical structure of perceptual color and brightness spaces revealed in both animals was similar to those in humans with normal color vision. In concordance with spherical model the eigenvectors constituting these spaces correspond to neuronal channels that encode differences between stimuli in color and brightness.