Referential communication by chimpanzees (Pan troglodytes

Two experiments were conducted to assess the referential function of chimpanzee (Pan troglodytes) gestures to obtain food. The chimpanzees received 1 trial per condition. In Experiment 1 (N 101), in full view of the chimpanzee, a banana was placed on top of 1 of 2 inverted buckets or was hidden underneath 1 of the buckets. In Experiment 2 (N 35), 4 conditions were presented in constant order: (a) no food, no observer; (b) no food, observer present; (c) food present, no observer; and (d) food present, observer present. Gestures and visual orienting were used socially and referentially. The capacity for nonverbal reference may predate the Hominidae–Pongidae split, and the development of nonverbal reference may be independent of human species-specific adaptations for speech. Referential signaling has been historically viewed as being uniquely human (Werner & Kaplan, 1963). Referential signaling, as defined here, means the capacity to direct the attention of an observer to a distal object or entity. In linguistic reference, a symbol represents a concept, and through shared lexicons people can direct the attention of their conversational partners to these conceptual entities. Nonverbal reference, as the term is used i