Abstract # 78:

Scheduled for Thursday, June 21, 2012 07:00 PM-09:00 PM: Session 9 (Gardenia) Poster Presentation


THE EFFECT OF REARING AND SELF-DISTRACTING MECHANISMS ON CHIMPANZEES (PAN TROGLODYTES) ABILITY TO DELAY GRATIFICATION

J. A. Schaeffer1, J. L. Russell1 and W. D. Hopkins1,2
1Yerkes National Primate Research Center, Division of Developmental and Cognitive Neuroscience, Atlanta, GA 30329, USA, 2The Neuroscience Institute, Georgia State University, Atlanta, GA 30302
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     Inhibitory control is a crucial component to more advanced executive function in human development. The processes that allow an individual to inhibit behaviors are not thoroughly understood. One’s ability to delay gratification is a crucial component of inhibitory control. The current study examines the ability of 58 captive chimpanzees at the Yerkes National Primate Research Center to inhibit impulsive behavior in order to maximize their reward. Subjects could receive a smaller food reward immediately or delay their gratification to receive a larger reward later. There was a linear relationship between the length of time the subject waited and the amount of food they could receive with longer waiting resulting in larger rewards. Human reared chimpanzees were significantly better at delaying gratification than mother-reared chimpanzees t(57)=2.12, p<.05, particularly as the size of the potential reward increased. We found no sex or age effects. A subset of 15 chimpanzees received additional testing in which the interval of time at which the reward accumulated was gradually increased. Subjects delayed gratification significantly longer to receive a larger food reward when they were given destructible enrichment to distract their attention while the reward accumulated t(14)=-2.79, p<.05. Results indicate that early life factors such as rearing contribute to cognitive control in chimpanzees. Furthermore, consistent with previous findings, chimpanzees in the current study improved performance by utilizing distraction tools.