Lost in Transmission: Contextual Variation in Chimpanzee Pant Hoots and its Implications for Referential Communication in Primates

Abstract

Pant hoots are the species-typical 'loud' call used by chimpanzees to communicate over long distances. Some previous studies have explored the possibility that there are acoustically distinct subtypes of pant hoots that communicate to distant listeners different information abou the caller's behaviour or ecological and social circumstances. As listerners are presumably able to elicit information about the caller's circumstance through the acoustic propoerties of the received call, chimpanzee pant hoots have variously been labeled "referential" in quality because theya ppear to share some of the symbolic properties of human language. However, results of previous studies to date have been either conflicting or inconclusive in establishing the existence of referential vocalizations in chimpanzees, and many of the interpreations of the functional similarities between chimpanzee calls and langugage have been based on preconceptions about chimpanzee cognition. These preconceptions are rooted largeley in phylogenetic assumptions; that is, because chimpanzees are closely reatled to humans there is a tendency to evaluate their cognitive abilities by the extent to which humans possess those abiltities. This talk will present data from an extensive acoustic analysis of chimpanzee pant hoots from the Budongo Forest, Uganda that I undertook to help resolve some of the issues raised above. I will offer an interpreation of the data that is consistent with an ecological, rather than phylogenetic approachy to explaining the functional significance of pant hoots. I will also discuss the relevance of this work to my current research program that is being established with New World primates.