Abstract:
Three experiments were conducted which examined rats' preference for response-dependent versus response-independent reinforcement. Experiment 1 investigated the effects of administering different amounts of prior training with response-dependent and response-independent schedules of reinforcement. Preference was measured by the amount of time allocated to each schedule during a subsequent test in which both schedules were concurrently available. Experiment 2 replicated Experiment 1 with the exception that preference was tested under conditions of extinction. In Experiment 1 there was a direct relationship between the relative amount of response-dependent training given and the relative amount of time allocated to the right (response-dependent) side of the chamber. Experiment 2 showed that time allocation was unaffected by prior training, but that rate of responding on the first day of testing was directly related to the amount of prior response-dependent training.
Experiment 3 examined the effects of varying the rate of response-independent reinforcement on the allocation of time between the two concurrently available schedules. It was found that the ratio of time allocated to the response-independent schedule to time allocated to the response-dependent schedule matched the ratio of the number of reinforcements obtained from the two schedules. The allocation of time was unaffected by the asymmetrical response requirements.
The results of the three experiments are discussed in relation to the phenomenon of contrafreeloading. Considered together, the results support the position that the extent to which an animal exhibits contrafreeloading (preference for response-dependent reinforcement) is determined by the amount of prior training given with each reinforcement source and the rate of reinforcement associated with each source during testing.
