| Abstract: | In previous studies of delayed reinforcement, response rate has been found to vary inversely with the response-reinforcer interval. However, in all of these studies the independent variable, response-reinforcer time, was confounded with the number of reinforcers presented in a fixed period of time (reinforcer frequency). In the present study, the frequency of available reinforcers was held constant, while temporal separation between response and reinforcer was independently manipulated. A repeating time cycle, T, was divided into two alternating time periods, tD and tΔ. The first response in tD was reinforced at the end of the prevailing T cycle and extinction prevailed in tΔ. Two placements for tD were defined, an early tD placement in which tD precedes tΔ and a late tD placement in which tD follows tΔ. The duration of the early and late tD was systematically decreased from 30 seconds (i.e., tD = T) to 0.1 second. Manipulation of tD placement and duration controlled the temporal separation between response and reinforcement, but it did not affect the frequency of programmed reinforcers, which was 1/T. The results show that early and late tD placements of equal duration have similar overall effects upon response rate, reinforcer frequency, responses per reinforcer, and obtained response-reinforcer temporal separation. A stepwise regression analysis using log response rate as the dependent variable showed that the obtained delay was a significant first-step variable for six of eight subjects, with obtained reinforcer frequency significant for the remaining two subjects. |
