INTENTIONAL COMMUNICATION BY CHIMPANZEES - A CROSS-SECTIONAL STUDY OFTHE USE OF REFERENTIAL GESTURES

This study describes the use of referential gestures with concomitant gaze orienting behavior to both distal food objects and communicative interactants by 115 chimpanzees, ranging from 3 to 56 years of age. Ga ze alternation between a banana and an experimenter was significantly associated with vocal and gestural communication. Pointing was the mos t common gesture elicited; 47 subjects pointed with the whole hand, wh ereas 6 subjects pointed with index fingers. Thus, communicative point ing is commonly used by laboratory chimpanzees, without explicit train ing to point, language training, or home rearing. Juveniles exhibited striking decrements in their propensity to communicate with adult male experimenters compared with older chimpanzees. Significantly fewer mo ther-reared chimpanzees exhibited gaze alternation compared with nurse ry-reared chimpanzees.