Play-solicitation gestures in chimpanzees in the wild: flexible adjustment to social circumstances and individual matrices.

Marlen Fröhlich,Roman M Wittig,Simone Pika

doi:10.1098/rsos.160278

Abstract

Social play is a frequent behaviour in great apes and involves sophisticated forms of communicative exchange. While it is well established that great apes test and practise the majority of their gestural signals during play interactions, the influence of demographic factors and kin relationships between the interactants on the form and variability of gestures are relatively little understood. We thus carried out the first systematic study on the exchange of play-soliciting gestures in two chimpanzee (Pan troglodytes) communities of different subspecies. We examined the influence of age, sex and kin relationships of the play partners on gestural play solicitations, including object-associated and self-handicapping gestures. Our results demonstrated that the usage of (i) audible and visual gestures increased significantly with infant age, (ii) tactile gestures differed between the sexes, and (iii) audible and visual gestures were higher in interactions with conspecifics than with mothers. Object-associated and self-handicapping gestures were frequently used to initiate play with same-aged and younger play partners, respectively. Our study thus strengthens the view that gestures are mutually constructed communicative means, which are flexibly adjusted to social circumstances and individual matrices of interactants.

Highlights

Humans’ unique creativity and innovation skills have been suggested to be longer-term outcomes and benefits of playfulness [1].2016 The Authors
We examined the influence of age, sex and kin relationships of the play partners on gestural play solicitations, including object-associated and self-handicapping gestures
Our results demonstrated that the usage of (i) audible and visual gestures increased significantly with infant age, (ii) tactile gestures differed between the sexes, and (iii) audible and visual gestures were higher in interactions with conspecifics than with mothers

Summary

Introduction

Humans’ unique creativity and innovation skills have been suggested to be longer-term outcomes and benefits of playfulness [1].2016 The Authors. The high impact of play on evolutionary and ontogenetic development has further been emphasized 2 by studies on humans’ closest living relatives, the non-human primates (hereafter primates), showing that investments in play can take ontogenetic priority over growth with persisting consequences for life history [2]. Play behaviour consists of solitary and social play [6] and often involves the use of objects [7]. Chimpanzees of the Kanyawara community in Uganda have been observed to engage in stick-carrying behaviour [14], which has been suggested to represent a rudimentary variant of doll play observed in human children. Lonsdorf et al [15] highlighted the role of play in chimpanzee infancy, showing that solitary and social play comprise about one-third of an infant’s observation time at particular developmental stages

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