This research project is evaluating the capacity for numerical competence of non-human primates. The research focuses on the ability of adolescent and adult chimpanzees to acquire number- related abilities, including counting, number comprehension, and the symbolic representation of quantities. Drs. Boysen and Berntson already have documented the acquisition of counting by chimpanzees, as well as the ability to manipulate number symbols through implicit counting strategies. Additional studies of the use of fractions for labelling portions of foods and other objects will be completed with two young-adult animals. Fraction concepts will be tested using novel objects and the introduction of a novel fraction. To test receptive number comprehension, the chimpanzees are shown an Arabic numeral and then must construct an array of the same number from a collection of objects. This is a high-level counting skill, and preliminary tests indicate success unprecedented in animal research. This research is adding greatly to our understanding of the information-processing capacities of non-human primates for symbol use, and the similarities and differences in representational abilities between humans and apes. The demonstration of such abilities in a species that shares our primate heritage will make important contributions towards characterizing the possible evolution of cognition in our early hominid ancestry. These studies may also yield significant teaching and training strategies for the acquisition of complex numerical skills, which could be applied in a variety of settings and for a range of compromised human populations, including learning-disabled, autistic, and developmentally-delayed children.
