ABSTRACT
This chapter discusses some schedules of reinforcement. The schedule delivers a reinforcer immediately after an operant response, but only if at least a specified interval has elapsed since any preceding response. In this way, a differential reinforcement of low rates of responding is achieved, the schedule being abbreviated as differential reinforcement of low rate (DRL). The DRL schedule may be further refined by setting a maximum delay between a reinforced response and the preceding response, as well as the minimum time requirement. Animals trained on fixed ratio schedules are usually exposed to small ratios, which are then gradually increased. Low consistent rates of responding have been observed with many different animals exposed to DRL schedules, both with and without limited hold requirements. The effects of prior food-deprivation on DRL responding have been investigated, but, on the whole, established patterns of behaviour are quite resistant to disruption by changes in motivation.
