Self-Control in Adult Humans: Comparison of Qualitatively Different Reinforcers

Three experiments used 20 adult females in a self-control paradigm to explore why subjects are more impulsive for food reinforcers than for points exchangeable for money. The results suggest that differences found in self-control for food and points exchangeable for money are due, at least in part, to differences in the time of delivery of the reinforcers. Subjects show less self-control for food reinforcers delivered during a session than for points exchangeable for food at the end of a session. Further, subjects′ degree of self-control is similar for points exchangeable for food and for points exchangeable for money. To obtain these results, the present series of experiments employed a new procedure that quickly obtains measures of humans′ sensitivity to variation in reinforcement.