Abstract # 174:

Scheduled for Friday, August 19, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

Evidence of Planning for a Tool Modification by Chimpanzees (Pan troglodytes)

A. E. Bania, S. Harris, H. R. Kinsley and S. T. Boysen
The Ohio State University, Department of Psychology, 1885 Neil Avenue, 242 Townshend Hall, Columbus, OH 43210-1222, USA
     Nine chimpanzees (Pan troglodytes) were tested to assess their ability to use the appropriate tool to obtain a food reward from two different apparatus. In its deconstructed form, the tool functioned as a probe that was appropriate for the first apparatus. In its constructed form, the tool functioned as a hook that was appropriate for the second apparatus. Each subject was administered four trials with each apparatus type. The type of the tool they received was randomized, and counter-balanced between both forms. All sessions were videotaped for later analyses. Results demonstrated that adult and juvenile chimpanzees (n = 7) were successful with both tool types (binomial: N = 28, P < 0.0001) using a one-tailed test. The two infant chimpanzees performed near chance (9/16, 56% correct responses). Offline video analyses revealed that tool modification followed by an attempt at solution by the adults and juveniles was typically correct on the first try (binomial: N = 28, P < 0.002) using a one-tailed test. Neither infant was successful in correctly modifying the tool on the first try during any of the eight trials. The chimpanzees’ ability to consistently choose the correct tool prior to use suggests foresight, planning, and likely includes a sophisticated understanding of causality.