Context, not sequence order, affects the meaning of bonobo (Pan paniscus) gestures

In most languages, individual words can be ambiguous between several different meanings, but through syntax and context the intended meaning of an ambiguous word usually becomes apparent. Many great ape gestures also have ambiguous meanings, which poses the problem of how individuals can interpret the signaller’s intended meaning in specific instances. We tested the effects of sequence compositionality and situational context (including behavioural and interpersonal contexts) in wild bonobos (Pan paniscus) at Wamba, DRCongo. We found no effect on a gesture’s meaning from its presence and position in sequence. However, two aspects of situational context did affect meaning: behaviour of the signaller immediately prior to gesturing, and relative age/sex of signaller and recipient. The intended meaning of ambiguous gestures was almost completely disambiguated by means of these aspects of context. Our findings suggest that the use of contextual information to interpret ambiguous signals predates the uniquely-human lineage and is not specific to language.