Abstract # 65:

Scheduled for Saturday, September 19, 2009 06:30 PM-09:00 PM: Session 5 (Mission Bay Ballroom CDE) Poster Presentation


THE GESTURAL SEQUENCES OF CHIMPANZEES (PAN TROGLODYTES) FROM 1 TO 5 YEARS OF AGE

V. Maguire-Herring and K. A. Bard
Centre for the Study of Emotion, Department of Psychology, University of Portsmouth, King Henry Building, Portsmouth PO1 2DY, USA
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Chimpanzee (Pan troglodytes) societies rely heavily on the use of gestures to convey information and maintain social cohesion. Few studies focus on the development of gestural communication with longitudinal investigations. Our goal was to analyze gesture sequences of chimpanzees to determine how content changed over time, i.e., from the ages of 1 to 5 years. Each gesture sequence (the initiator, receiver, type of manual gesture, and context) was recorded from videotaped observations of 3 mother-reared chimpanzees housed in a social group at the Kyoto University Primate Research Institute (KUPRI) in Japan [860 minutes per subject]. There were a total of 568 gestural sequences observed; the largest proportion were used by 1-year-olds [33%] a decline occurred from 2 to 4 years [21% by 2-year-olds, 20% by 3-year-olds, 15% by 4-year-olds], and the smallest proportion used by 5-year-olds [11%]. The average number of gestures per sequence ranged from 3.9 [at 5 years] to 4.6 [at 2 years]. The results suggest that young chimpanzees, at least in captive conditions, become more efficient communicators over the first 5 years of life, as the numbers of gestures and gesture sequences declined each year. The gestural development hypothesis of ontogenetic ritualization is supported.