Generative aspects of manipulation in tufted capuchin monkeys (Cebus apella).

Evaluating the cognitive and ontogenetic bases of tool use in primates requires comparative data on the generative nature of manipulation, including the frequency and variety of combinations of actions and objects. Thirty-one tufted capuchins (Cebus apella) of 3 age groups devoted significant proportions of time to interaction with objects and substrates. Activity that combined an object with a substrate occurred often; activities that combined 2 portable objects were less frequent. Predictions drawn from neo-Piagetian theory of an ontogenetic link between combinatorial behaviors and the onset of tool use were not supported. The frequency and generative nature of capuchins' manipulative activity, particularly acts combining objects and substrates, could account for their proclivity to use tools. The use of tools by capuchins need not involve the representational abilities proposed by neo-Piagetian theory.