Color classification by chimpanzees (Pan troglodytes) in a matching-to-sample task.

We investigated chimpanzees' color classification using a matching-to-sample procedure. One of the two subjects had learned symbolic color names through long-term training, while the other had received less training and had a limited understanding of color names. The results showed similar distributions of classified colors in a color space, irrespective of the subjects' differential color-naming experience. However, the chimpanzee with little color-naming experience showed less stable classifications. These results suggest common features of color classification in chimpanzees, as well as the influence of color experience and/or the learning of color names on the stability of classification of colors.