Self-Control & Delay of Gratification

Self-Control and Delay of Gratification: Directed by Dr. Michael Beran, this research program focuses on the self-control behavior of nonhuman primates. Here, we use delay of gratification tasks in which animals can obtain a more preferred or larger rewards by waiting to make a response whereas they obtain a smaller or lesser preferred rewards if they make that response. In the most recent studies, we have used a technique in which food items accumulate as long as an animal inhibits consumption of those items. Thus, the longer the animal waits to eat the food items that are accessible, the more food items it can acquire. This rather simple technique has provided compelling evidence that chimpanzees show excellent delay of gratification (sometimes for periods in excess of 20 minutes with very highly preferred food accumulating in front of them). Even rhesus monkeys, traditionally viewed as a highly impulsive species, show some success with this task, and recent projects with a new apparatus, the rotating tray task, has shown that capuchin monkeys with very poor delay of gratification skills can improve when given that task. We also have examined the relation between attention allocation either to the food items or to other available stimuli and delay maintenance (continued inhibition of the impulsive response). For children, attention to the reward is highly detrimental to delay maintenance, but this appears not to be true for chimpanzees. In some cases, attention to the food items may even facilitate greater delay maintenance, and so we continue to probe this relation as well as other aspects of self-control in these species. For example, we have shown that chimpanzees will use self-distraction to help aid delay of gratification. 
This research is supported by the National Institute of Child Health and Human Development (HD-060563).