Abstract # 4345 Poster # 81:

Scheduled for Thursday, June 21, 2012 07:00 PM-09:00 PM: Session 9 (Gardenia) Poster Presentation


OBJECT CATEGORIZATION BY PRIMATES: IS ‘SHAPE’ AS INFORMATIVE FOR MONKEYS AS IT IS FOR HUMANS?

K. D. Hughes1,2, C. Litovsky1, A. M. Barnard1 and J. F. Cantlon1
1Brain and Cognitive Science, University of Rochester, Box 270268, Meliora Hall, Rochester, NY 14627, USA, 2Department of Anthropology, Yale University
line
     Of the many features available to recognize and categorize objects, one feature, shape, may have a special role. A so-called shape bias in categorizing objects is known in human children and may support rapid learning of new objects in their early years. Whether non-human primates also benefit from the shape bias is unknown. Tthe shape bias may be a product of kind representations, or natural categories of objects based on experience in the absence of language, and in this case, primates may exhibit a shape bias. Alternatively, the shape bias may be a product of language learning, so that the bias would only be found in humans. To investigate, we tested whether rhesus macaques (Macaca mulatta) would demonstrate a shape bias. Two monkeys were trained on a match-to-sample object categorization task using a touch screen. To assess the shape-bias effect, probe trials tested whether monkeys would classify a sample with a color, material or shape match, all other features controlled. Above chance performance on non-probe trials indicated that macaques understood the task (one sample t-test, both subjects p < 0.001), however, we did not find a significant tendency to classify objects according to shape in probe trials. This supports the interpretation that such object categorization rules may be specific to humans.