Audience effects in sooty mangabeys

The ability to take others into account during communication is an important feature of human language. Although, there is evidence of the audience effects in several animal taxa, it is not known for most species if signallers consider the social consequences of communicating. In apes, there is evidence that individuals are able to adjust signal production depending on the attention state of the receiver, but it is currently unknown whether this is restricted to some contexts or generally present during communication. A related question is if the ability to take the attention of others into account is a general feature of primate cognition or present just in some species. Sooty mangabeys (Cercocebus atys) are forest dwelling monkeys that live in groups of around 100 individuals with a stable linear dominance hierarchy. The focus of this thesis is on how sooty mangabeys employ communication signals in the presence of different audiences, particularly how communication is used in resolving social conflict, discovering food, and dealing with predators. I was interested in whether and how sooty mangabeys showed signs of awareness of their audiences in each of these situations and how this impacted their communicative behaviour. My results suggest that audience composition always plays a role, sometimes just by the number of individuals and others because of the presence of socially important members. The evidence I presented supports a gradual view, that features and components of human language are already present deep in the evolutionary tree of primates and most have therefore evolved early. Finally, all the patterns I have described are not in line with a notion of animal calls as hardwired or reflexive responses to specific stimuli, but appear to involve considerable amounts of social cognition, allowing individuals to make assessments of both ecological and social variables in ways that meet criteria of intentional signalling.

Dissertation committee:
Prof Klaus ZUBERBÜHLER, University of Neuchatel, thesis director
Prof Steven Paul MORAN, University of Neuchatel
Prof Robert SEYFARTH, University of Pennsylvania

Defended on the 19th of April, 2023

No de thèse : 3221