title: Primates do not spontaneously use shape properties for object individuation: a competence or a performance problem?
abstract: Several recent studies have documented that non-human primates can individuate objects according to property and/or kind information in much the same way as human infants do from around one year of age when they begin to acquire language. Some studies suggest, however, that only some properties are used for the individuation of food items: color, but not shape. The present study investigated whether these findings reveal a true competence problem with shape properties in the food domain or whether they merely reveal a performance problem (e.g., lack of attention to shapes). We tested 25 great apes (chimpanzees, bonobos and gorillas) in two food individuation tasks. We manipulated subjects' experience with differences in color and shape properties of food items. Results indicated (i) that all subjects, regardless of their prior experience, solved the color-based object individuation task and (ii) that only the group with previous experience with different shape properties succeeded in the shape-based individuation task. Great apes can thus be primed to take shape into account for individuating food objects, and this results clearly speaks in favor of a performance (rather than a competence) problem in using shape for object individuation of food items.
authors.affiliation: Institute of Cognitive Neurology and Dementia Research, Otto-Von-Guericke Universität Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany. natacha.mendes@med.ovgu.de
authors.forename: Natacha
authors.initials: N
authors.lastname: Mendes
authors.forename: Hannes
authors.initials: H
authors.lastname: Rakoczy
authors.forename: Josep
authors.initials: J
authors.lastname: Call
mesh_terms: D000367:Age Factors; D000818:Animals; D001288:Attention; D003118:Color Perception; D005247:Feeding Behavior / Q000523:psychology; D005260:Female; D005502:Food; D005556:Form Perception; D006071:Gorilla gorilla / Q000502:physiology / Q000523:psychology; D008297:Male; D019974:Pan paniscus / Q000502:physiology / Q000523:psychology; D002679:Pan troglodytes / Q000502:physiology / Q000523:psychology; D021641:Recognition, Psychology