Abstract # 181:

Scheduled for Friday, August 18, 2006 07:00 PM-09:00 PM: Session 17 (Regency West 1/3 ) Poster Presentation

Self-control in chimpanzees (Pan troglodytes) is not mediated by experimenter presence or reward source visibility

M. Beran and T. Evans
Georgia State University, Language Research Center, 3401 Panthersville Road, Decatur, GA 30034, USA
     Self-control often is studied in the laboratory by assessing individuals’ willingness to forego a small immediate reward to obtain a large delayed reward. Previous research in our laboratory has demonstrated that chimpanzees can delay gratification for as long as 3 minutes as an experimenter transfers preferred food items from a transparent container to a bowl placed in front of the subject. In the present study, we examined the influence of the visibility of the food source, as well as the presence of the experimenter, on 4 chimpanzees’ self-control in this paradigm. In Experiment, 1 an experimenter transferred 15 preferred food items between a distant opaque container and a bowl placed in front of the subject. In Experiment 2, we tested the chimpanzees with an automated system that (in the absence of the experimenter) transferred up to 36 highly preferred food items from a universal food dispenser to a container located inside the subject’s enclosure. A final experiment, designed to test the limits of the chimpanzees’ self-control with the automated paradigm indicated that individuals could delay gratification for 6 to 11 min in order to obtain all 36 reward items. In all experiments, the chimpanzees delayed gratification as they had in the previous study, indicating that source visibility and experimenter presence does not mediate self-control in this paradigm.