Compositionality in Primate Gestural Communication and Multicomponent Signal Displays

Abstract

AbstractCompositionality is the ability to combine meaningful elements into new combinations with novel meanings, and it has long been considered one of the main hallmarks of human communication. However, very few studies have addressed the compositional aspects of communication in species other than humans, although a comparative approach is essential to understand the evolutionary origins of human compositionality. We review previous research on compositionality in the gestural communication systems of nonhuman primates, with a special focus on the multicomponent aspects of compositionality. We start by discussing the importance of a comparative approach to study the evolution of human language and then compare the current state of the art on compositionality in the vocal, facial, and gestural communication systems of primates and other species. We further discuss alternative approaches to study compositionality in primates, which may help overcome some of the current methodological limitations in this research area. In particular, we 1) highlight the importance of interdisciplinary tools that facilitate the statistical identification of multicomponent and multimodal combinations of signals, 2) discuss different approaches to infer the meaning of signal combinations, with a special focus on the use of contextual cues and meta-communication, and 3) discuss temporal and intentional aspects of compositionality in primates. Finally, we outline possible lines of research for future studies in this area (e.g., more consistent use of terms across research areas, use of different methodological tools and larger datasets, inclusion of developmental approaches), which might shed light into the evolutionary origins of one of the most crucial properties of human communication.