title: Can chimpanzee infants (Pan troglodytes) form categorical representations in the same manner as human infants (Homo sapiens)?
abstract: We directly compared chimpanzee infants and human infants for categorical representations of three global-like categories (mammals, furniture and vehicles), using the familiarization-novelty preference technique. Neither species received any training during the experiments. We used the time that participants spent looking at the stimulus object while touching it as a measure. During the familiarization phase, participants were presented with four familiarization objects from one of three categories (e.g. mammals). Then, they were tested with a pair of novel objects, one was a familiar-category object and another was a novel-category object (e.g. vehicle) in the test phase. The chimpanzee infants did not show significant habituation, whereas human infants did. However, most important, both species showed significant novelty-preference in the test phase. This indicates that not only human infants, but also chimpanzee infants formed categorical representations of a global-like level. Implications for the shared origins and species-specificity of categorization abilities, and the cognitive operations underlying categorization, are discussed.
authors.affiliation: Department of Psychology, Graduate School of Letters, Kyoto University, Japan. cmurai@bun.kyoto-u.ac.jp
authors.forename: Chizuko
authors.initials: C
authors.lastname: Murai
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kosugi
authors.forename: Masaki
authors.initials: M
authors.lastname: Tomonaga
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tanaka
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Matsuzawa
authors.forename: Shoji
authors.initials: S
authors.lastname: Itakura
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002657:Child Development; D002675:Child, Preschool; D003210:Concept Formation / Q000502:physiology*; D005260:Female; D005556:Form Perception / Q000502:physiology*; D005795:Generalization, Stimulus / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D002679:Pan troglodytes / Q000502:physiology*; D010775:Photic Stimulation; D002666:Psychology, Child; D021641:Recognition, Psychology / Q000502:physiology*