Observational learning of tool-use by young chimpanzees
At the time of publication, Maryann Davis was not yet affiliated with the University of Massachusetts Medical School.
In the current study two groups of young chimpanzees (4–6 and 8–9 years old) were given a T-bar and a food item that could only be reached by using the T-bar. Experimental subjects were given the opportunity to observe an adult using the stick as a tool to obtain the food; control subjects were exposed to the adult but were given no demonstration. Subjects in the older group did not learn to use the tool. Subjects in the younger group who were exposed to the demonstrator learned to use the stick as a tool much more readily than those who were not. None of the subjects demonstrated an ability to imitatively copy the demonstrator's precise behavioral strategies. More than simple stimulus enhancement was involved, however, since both groups manipulated the T-bar, but only experimental subjects used it in its function as a tool. Our findings complement naturalistic observations in suggesting that chimpanzee tool-use is in some sense «culturally transmitted» — though perhaps not in the same sense as social-conventional behaviors for which precise copying of conspecifics is crucial.
M. Tomasello, Maryann Davis, L. Camak, and K. Bard. "Observational learning of tool-use by young chimpanzees" Human Evolution 2.2 (1987).
Available at: http://works.bepress.com/maryann_davis/4