Intentional behavior and intentional communication in young free-ranging orangutans.

The goal of this study was to describe the ontogeny of the manipulation of an animate object (i.e., the mother) by young free-ranging orangutans within the context of food sharing. The food-sharing context is an important one in the development of object manipulation skills and social communication. 5 orangutans, ranging in age from 1 month to 5 years, were videotaped with their biological mothers for 18 hours over the course of 9 months. Systematic coding of the videotapes revealed that even young orangutans, 1-6 months old, used intentional (i.e., goal-directed) behaviors. When young orangutans directed behavior toward the mother in addition to the goal object then maternal responses were positive, resulting in the infant obtaining the food. Intentional communication, evident in gestures and consisting of an abbreviated action directed toward the mother, was found in the 3 oldest orangutans (2 1/2, 3 1/2, and 5 years of age). Cognitive competence and behavioral performance are considered from the developmental perspectives of Piaget and prelinguistic communication. The ability to use a communicative gesture as an intermediate means in the coordination of actions on a social agent with actions on an object is evident in young orangutans.