Abstract # 157:

Scheduled for Sunday, September 20, 2009 06:30 PM-09:00 PM: Session 14 (Mission Bay Ballroom CDE) Poster Presentation


B. J. Kelly1 and M. A. Novak1,2
1University of Massachusetts, Neuroscience and Behavior Graduate Program, Tobin Hall, Amherst, MA 01003, USA, 2Psychology Department, University of Massachusetts, Tobin Hall, Amherst, MA 01003, USA

Three-year-old children (Homo sapiens), but not 2-1/2-year-old children solve scale-model tasks (finding a toy in a room after seeing a replica of the toy hidden in a small model). Interestingly, 2-1/2-year-old children solve model tasks when the model and actual room are the same size. Research with nonhuman primates has demonstrated that chimpanzees (Pan troglodytes), like 3-year-old children, can solve model tasks; however, most monkeys fail to find a hidden object on a full-scale apparatus after seeing it hidden on a scale model. This study explored whether monkeys (M. mulatta), like 2-1/2-year-old children, could solve a model task when the apparatus and its referent were the same size (1:1 ratio). Adult monkeys [n=4] watched as a familiar rubber ball was hidden behind one of four doors on an apparatus. A second identically-sized apparatus was then presented and the monkeys searched for a replica of the ball. The mean proportion of correct first searches was compared to the expected mean [0.25]. As a group, monkeys found the ball significantly more than chance [Mean=0.546, t(3)=3.79, p<0.05] and individually three monkeys solved the task [Binomial probabilities, p<0.05]. This is the first study to test comprehension of a 1:1 scale-model task in nonhuman primates. The data support the conclusion that as with 2-1/2-year-old children, decreasing the size difference between a model and its referent increases the subject’s ability to mentally represent space using 3-dimensional stimuli.