8. Evidence for intentional and referential communication in great apes?

Human speech is frequently accompanied by movements of the arms and hands termed gestures. The majority of these gestures is invented spontaneously and is highly iconic but some gestures are used functionally in ways very similar to speech that is symbolically, referentially, based on intersubjectively learned and shared social conventions. Our closest living relatives, the great apes also use gestures in their natural communication in a variety of contexts such as play, grooming, sex and agonistic encounters. A deep understanding of apes’ gestural signalling might therefore be helpful to get insight into the evolutionary scenario of human communication and cognition. The present chapter investigates the nature of the gestural signalling of the four great apes, bonobos (Pan paniscus), chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus), with a special focus on the following three aspects: (1) the intentionality of gestures, (2) their referential use, and (3) similarities and differences to gestures in prelinguistic or just-linguistic human infants.