ChimpanSee, ChimpanDo: A Review of the Significance of Social Contagion, and Exploration of Grooming and Play Contagion in Chimpanzees

Abstract

The ability to catch behaviours from others, and share their emotional states, is fundamental to numerous aspects of human social functioning. This state-matching capacity is of great evolutionary importance and is widespread in the primate lineage. Studying which forms of contagion are present in different primate species, and when contagion is most pronounced, can help reveal the fundamental underpinnings and the context-specific facets of these processes, allowing us to understand the nature and significance of social contagion. In chapter 1, I critically review research on mimicry, behavioural contagion and emotional contagion in primates, highlighting which factors are important moderators, and the benefits that contagious processes afford individuals and the group. Research reveals notable difference in trends in positive and negative valenced contexts, although research is limited with regards to positive emotional and behavioural contagion. I emphasise the wide-reaching adaptive benefits of both positive and negative social contagion, and consider social contagion as a basis for social learning, allowing for a unified view of its significance.
In chapter 2, I seek to advance the literature by addressing the research gap of positive social contagion. I conducted an observational study of 47 sanctuary living chimpanzees, to test whether chimpanzees catch grooming and play behaviours from each other, and what predicts this effect. Results reveal the first evidence for the contagion of affiliative behaviours in chimpanzees. The presence of grooming contagion was predicted by social closeness, and was more pronounced in females, whilst play contagion was more pronounced in younger individuals. It is evident that behavioural contagion is not confined to negative contexts, but is widespread and influenced by a multitude of factors, specific to species and behaviour.