Cross-modal transfer in the chimpanzee

Abstract

TASKS of cross-modal performance assess the capacity to recognise stimulus-objects with one of the senses when they have previously been experienced only with another. In a number of recent publications^1–3, it has been shown that apes succeed at such tasks, in marked contrast to the negative or weak effects previously found for monkeys. The training procedures used with the apes were, however, new¹, and had not been tried with monkeys, so that it remained possible that monkeys would perform as well as apes with these procedures^4–5. Monkeys have been shown capable of cross-modal performance in two different methods of training (ref. 6, and M. J. Jarvis and G. Ettlinger, unpublished) one of which was designed to follow the principles used successfully with apes. We here describe the performance of three chimpanzees on cross-modal tasks of a kind which have in the past not yielded positive results with monkeys: our findings with the chimpanzees are unclear, or at least not certainly positive.