Do Apes Ape?
MICHAEL TOMASELLO Department of Psychology and Yerkes Primate Center Emory University Atlanta, Georgia 30322
In 1990, Visalberghi and Fragaszy asked the question: "Do monkeys ape"? After a review of the pertinent research literature, they answered in the negative. In this chapter I would like to ask the similar question: "Do apes ape"? Although many researchers assume that the answer to this question is more positive, there are two complicating factors. First, there are many different ways to ape. Beginning with Thorpe ( 1956), a number of theorists have demonstrated that the same behavioral outcome may result from very different processes of learning and social learning (e.g., Galef, 1988, 1992; Whiten & Ham, 1992). This potential ambiguity in what it means to "ape" thus makes the current question less than totally straightforward, and it means that a certain amount of theoretical work must be done before the relevant research literature may be usefully examined.
The second complicating factor is that research on the social learning of apes comes from three very different sources: (1) observational studies of apes in their natural habitats in which it has been discovered that there are population differences of behavior within the same species. These studies have the virtue of ecological validity, but their lack of experimental control means that they are of limited usefulness in determining with any precision the learning processes that are responsible for the observed population differences. (2) experimental studies of apes in captivity. These studies have the required experimental controls, but they investigate animals who, because they have been raised and tested in artificial circumstances, may or may not be representative of their conspecifics in the wild. (3) observational and experimental studies of apes that have been raised and/or trained