Abstract

Recent research has shown that chimpanzee (Pan troglodytes) societies rely heavily on the use of gestures to convey information and maintain social cohesion. To date there had only been one non-continuous longitudinal study of gesture use, which still leaves the question, "How do gestures change as infants develop into juveniles?" Data was collected in a longitudinal study documenting gesture use across contexts for infant, 1 to 5 years of age, and adult chimpanzees living in a social group at the Kyoto University Primate Research Institute (KUPRI) in Japan. Descriptions of all manual gestures and the contexts in which they occurred were recorded. Here we report on: 1) the gestures and contexts used, 2) how gesture use and contexts change over time, 3) the extent to which the gesture ‘touch’ is used flexibly, 4) if there is a difference in the use of the gesture by adult vs. infant chimpanzees, 5) whether there was a hand bias when using the gesture ‘touch’, 6) if adult and infant chimpanzees showed similar biases, 7) the content of gesture sequences, and 8) how gesture sequences change over time. The results from the subsequent studies show that while new gestures and contexts are acquired through the years other more infantile gestures are simultaneously lost, some gestures can be used flexibly in multiple contexts while others are context specific and bound by context. While some gestures were used flexibly, only the gesture ‘touch’ was found in a vast number of contexts. When further analysing the gesture ‘touch’ for hand bias, only right hand preferences had been found for a few contexts; and these contexts differed for the adults and infants. And lastly, the number of gestures, contexts, and number and lengths of the gesture sequences used decreased over time suggesting that, over time, the infants become more efficient communicators, which lends support to the theory of ontogenetic ritualization. These data are the first glimpse into the ways in which gestural communication develops in young chimpanzees and illustrates the importance of contextualized meaning in understanding flexibility in the gesture use of great apes. A better understanding of the developmental process that underlies chimpanzee communication can lead to a better understanding of the development of human communication.

Additional Notes

Supervisor: Kim Bard

Course: Master of Philosophy - MPhil

Date Deposited: 2017-05-09

URI/permalink: https://library.port.ac.uk/dissert/dis12873.html