Connecting primate gesture to the evolutionary roots of language: A systematic review

• Published in: American journal of primatology Vol. 83; no. 9; pp. e23313 - n/a
• Main Authors: Rodrigues, Evelina D., Santos, António J., Veppo, Flávia, Pereira, Joana, Hobaiter, Catherine
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc 01.09.2021
• Subjects: Communication; Domains; Evolution; gestures; Humans; Language; language evolution; Natural use; nonhuman primates; Ontogeny; Precursors; Primates; Psychology; Roots; Species; Species diversity; Systematic review
• ISSN: 0275-2565; 1098-2345
• DOI: 10.1002/ajp.23313

Comparative psychology provides important contributions to our understanding of the origins of human language. The presence of common features in human and nonhuman primate communication can be used to suggest the evolutionary trajectories of potential precursors to language. However, to do so effectively, our findings must be comparable across diverse species. This systematic review describes the current landscape of data available from studies of gestural communication in human and nonhuman primates that make an explicit connection to language evolution. We found a similar number of studies on human and nonhuman primates, but that very few studies included data from more than one species. As a result, evolutionary inferences remain restricted to comparison across studies. We identify areas of focus, bias, and apparent gaps within the field. Different domains have been studied in human and nonhuman primates, with relatively few nonhuman primate studies of ontogeny and relatively few human studies of gesture form. Diversity in focus, methods, and socio‐ecological context fill important gaps and provide nuanced understanding, but only where the source of any difference between studies is transparent. Many studies provide some definition for their use of gesture; but definitions of gesture, and in particular, criteria for intentional use, are absent in the majority of human studies. We find systematic differences between human and nonhuman primate studies in the research scope, incorporation of other modalities, research setting, and study design. We highlight eight particular areas in a call to action through which we can strengthen our ability to investigate gestural communication's contribution within the evolutionary roots of human language. Research Highlights Gesture has been studied to a similar extent in human and nonhuman primates, but different research domains have been prioritized: for example, gestural ontogeny in humans and forms and repertoires in nonhuman primates. Very few studies include >1 species, thus, investigation of similarities and distinctions across primate taxa is almost entirely dependent on comparison across studies, but methodologies were highly varied and definitions not always transparent. There is substantial scope for future research including (i) explicit testing of evolutionary hypotheses in our empirical work; (ii) data from diverse species, social groups, and environments, (iii) natural use of gesture forms in humans and gesture ontogeny in nonhuman primates. Primate species are represented in the review. The area represents the number of studies in the review including that species. Nonhuman primates (on the left) include great apes (chimpanzees, bonobos, gorillas, and orang‐utans), and Afro‐Eurasian monkeys (macaques, baboons, and mandrills).