Abstract # 127:

Scheduled for Sunday, September 14, 2014 03:15 PM-03:30 PM: Session 20 (Henry Oliver) Oral Presentation


D. Proctor, S. Calcutt and F. B. de Waal
Emory University, Yerkes National Primate Research Center, 2409 Taylor Lane, Lawrenceville, GA 30043, USA
     Humans increase their gambling, or risk taking behavior, in the presence of others. There are several potential explanations for this behavior, including wishing to be perceived as a winner and to increasing one's reputation. In order to understand the evolutionary roots of this behavior, we assessed how a social context may influence chimpanzees (Pan troglodytes) in a gambling style task. We predicted that, like humans, chimpanzees would increase their preference for an option with potential, but unpredictable, large payoffs when with a social partner relative to their performance alone. In a modified form of the primate gambling task (Proctor et al., 2014), chimpanzees chose to deposit a token in one of two buckets. One option, the more variable bucket, had the potential for both large gains and zero outcomes, while the consistent option always had a low value reward. Chimpanzees (N=7) were tested both alone and with a social partner. Chimpanzees, as a group, did not increase their preference for the more variable option in the presence of a social partner (p >0.05). However, at the individual level, some chimpanzees did show changes in their preferences, although not always in the predicted direction, making generalizations about their preferences challenging. Our findings suggest that the presence of others does alter chimpanzee’s choices in a gambling task, although not necessarily in the same way as in humans.