Four bonobos, seven gorillas, and six orangutans were presented with two small rectangular boards on a platform. One of the boards had a piece of food under it so that it acquired an inclined orientation whereas the other remained flat on the platform. Subjects preferentially selected the inclined board. In another experiment, subjects were…

Comments on Gauvain's discussion, in this issue, of the development of thinking from a sociocultural perspective, expanding her analysis by comparing research on apes who have developed in natural habitats with apes raised by humans in something resembling a human culture. Argues that the study of nonhuman primates can contribute to the emerging…