Visual categorization of natural and abstract items in forest monkeys and humans

A preference for novelty paradigm was used to investigate whether mangabeys (Lophocebus albigena), an arboreal non-human primate species, were able to discriminate and to categorize different visual stimuli belonging to natur al (food items) and abstract (non-food items) categories. In a comparative perspective human subjects were tested with the same procedure and the same stimuli. Two out of four mangabeys and three out of the four humans showed significant preference for novelty when comparing food versus non-food ite ms. Hence they discriminated between these two sets of items. The two manga beys and one non-adult human subject sorted the food items in one category, showing no preference for novelty when comparing known and unknown food-it ems and different Views of the same food items. In contrast the two adult h uman subjects who showed preference for novelty in the between-category, di d not show preference for novelty when comparing known and unknown food-ite ms but did show such a preference when comparing different views of the sam e food items. Compared to human performances, the results suggest that mang abeys are able to form at least a perceptual category of natural, ecologica lly relevant stimuli. (C) 2001 Elsevier Science B.V. All rights reserved.