The development of gestural communication in great apes

Abstract

Great apes deploy gestural signals in goal-directed and flexible ways across a wide range of social contexts. Despite growing evidence for profound effects of developmental experience on social cognition, socio-ecological factors shaping gesture use are still poorly understood, particularly in apes living in their natural environment. After discussing current ambiguities in terminology and methods, we review recent work implementing a longitudinal and/or cross-sectional approach in great ape gesture acquisition (phylogenetic and ontogenetic origins) and development (ontogenetic trajectories). To understand whether and to what extent the socio-ecological environment influences gestural communication, it is essential to distinguish between the gestural repertoire and gesture usage, which represent different levels of analysis. While the majority of the apes’ gestural repertoire seems to be innate, accumulating evidence shows that the communicative usage of these signals is substantially affected by interactional experiences throughout ontogeny. Nevertheless, since great ape communication is intrinsically multimodal, future developmental research on gesture should incorporate other modes of communication. Great apes navigate their differentiated social relationships by means of a large and flexible repertoire of gestures. However, gestural ontogeny is still poorly understood, particularly in primates living in their natural environment. We first discuss how the different usages of the term ‘gesture’ have led to a number of apparently disparate views, but highlight that these perspectives each provide their own contribution and may be reconciled by considering them as different levels of explanation. We then review recent studies on the various individual and social factors shaping the gestural use in great apes throughout development, highlighting the impact of socio-ecological factors. While the majority of the apes’ gestural repertoire seems to be innate, the communicative usage of these signals is substantially affected by interactional experiences throughout ontogeny. Given that ape gestural signals are inherently multimodal and are then often combined with other communicative signals, a broad multimodal perspective on gesture is important in order to gain a thorough understanding of the developmental processes underlying great ape communication.