Behaviour 2019
Pragmatic inference in wild vervet monkeys
Adwait Deshpande1,2, Klaus Zuberbühler1,2,3. 1Comparative Cognition, University of Neuchâtel, Neuchatel, Neuchatel, Switzerland; 2Inkawu Vervet Project, Mawana Game Reserve, Vryheid, Kwazulu Natal, South Africa; 3School of Psychology and Neuroscience, University of St Andrews, St Andrews, Scotland, United Kingdom

In human language, meaning resides in individual signals, syntactic combinations and contextual use, which has led to a distinction between lexical, compositional and pragmatic meaning. While there is good evidence for the first two processes in animal communication, pragmatic meaning has not yet been investigated systematically. Male vervet monkeys produce the same alarm calls during encounters with terrestrial predators and neighbouring groups, suggesting that recipients must take the context into account to respond in an adaptive way. We empirically tested this hypothesis by playing male alarm calls during intergroup encounters or during neutral situations. We found that subjects responded in context-appropriate ways to the alarm calls, with significant differences in startle responses, vigilance behaviour and gazes towards the presumed caller. We concluded that non-human primates could derive meaning pragmatically, a capability that may be more widespread in animal communication.