title: Categorization in monkeys and chimpanzees.
abstract: Studies on the classificatory ability of non-human primates are reviewed. The evidence suggests that there are important differences in the degree to which monkeys and chimpanzees detect same/different relations and construct classes that embody these relations. Data on matching to sample performance suggest that monkeys have a limited capacity for abstract representation of identity relations between individual objects. Chimpanzees, by contrast, not only detect similarities and differences between individual objects at a more abstract level than monkeys, but can also perceive same/different relations between pairs of objects. Further evidence for such cognitive differences between monkeys and chimpanzees comes from data on the development of spontaneous classificatory behavior. Monkeys develop first-order classifying. Their spontaneous spatial groupings are restricted to elements from one class. Chimpanzees progress from first-order to elementary second-order classifying. At 5 years of age they are capable of composing two contemporaneous sets in which objects are identical or similar within each set and different between sets.
authors.affiliation: Reparto di Psicologia Comparata, Istituto di Psicologia, C.N.R., Roma, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Spinozzi
mesh_terms: D000818:Animals; D003071:Cognition / Q000502:physiology*; D000882:Haplorhini / Q000502:physiology*; D007858:Learning / Q000502:physiology; D002679:Pan troglodytes / Q000502:physiology*