Operant conditioning of wheel-running behavior in rats

Abstract

Rats were trained to run in a running wheel under different schedules of reinforcement and different levels of food deprivation. In Experiment 1, the experimental group was reinforced and maintained with a fixed-ratio 40 or fixed-interval 60 sec schedule. The yoked group was confined to the second wheel and received food pellets at the same time when its master rat was reinforced. The experimental animals learned the wheel-running according to the contingency of reinforcement. The yoked rats ran just after reinforcement. This result suggests that wheel-running of the yoked rats is a schedule-induced behavior. The resistance to extinction was strong and all rats maintained high performance during 5 extinction sessions. In Experiment 2, rats which were less hungry than in Experiment 1, were trained under a fixed-ratio 40 or fixed-interval 60 sec food schedule. They learned wheel-running, and rats under the fixed-interval schedule showed evidence of timing behavior, “scallop”. These results indicated that the wheel-running behavior of rats could be reinforced and maintained by food schedules. However, the high resistance to extinction suggests that there were other sources of reinforcement for the running behavior of rats.