Abstract # 103:

Scheduled for Friday, June 21, 2013 10:45 AM-11:00 AM: Session 11 (San Geronimo Ballroom B) Oral Presentation


J. L. Russell1,2, S. Bogart1,2, J. P. Taglialatela1,3 and W. D. Hopkins1,2
1Yerkes National Primate Research Center, 954 Gatewood Rd., Atlanta, Georgia 30329, USA, 2Neuroscience Institute, Georgia State University, 3Department of Biology and Physics, Kennesaw State University
     The evolutionary origin of language is the subject of debate with researchers arguing for exclusively gestural or vocal origins. Here we quantified the use of multimodal signaling during gestural communication in chimpanzees. Gesture events (GE) were collected from a group of 15 chimpanzees (3 males, 12 females). Eight hundred seventy seven gesture events were recorded (18 - 166 GEs / individual). GEs were categorized as Ritualized Gestures (RG) and Non-specific Gestures (NG) and whether or not they included a concomitant communicative signal (CCS). We hypothesized that RGs such as food begs and threat gestures were more likely to include a CCS than NGs such as gentle touches and claps because they presumably convey more meaning and are used in specific contexts. For each subject, the number of observed GEs in each category was divided by that individual’s total number of GEs to calculate a proportion RGs and NGs with and without CCS. Paired sample t-test revealed no significant difference in the proportion of NGs that included a CCS compared to those that did not. However, the proportion of RGs that included a CCS was significantly higher than those without, t(14)=4.14, p<.01 . Our data support a multimodal origin of human language where manual gestures were under common control with other signal types and coevolved in a common hominid ancestor.