BEHAVIOR OF HUMANS IN VARIABLE-INTERVAL SCHEDULES OF REINFORCEMENT

During Phase I, Human subjects pressed a button for monetary reinforcement in 5 variable-interval schedules, each of which specified a different frequency of reinforcement. The rate of responding was an increasing, negatively accelerated function of reinforcement frequency; the data conformed closely to Herrnstein''s equation. During Phase II, the same 5 schedules were in operation, but in addition a concurrent variable-interval schedule (B) was introduced, responses on which were always reinforced at the same frequency. Response rate in component A increased while response rate in B decreased, as a function of the reinforcement frequency in A. Relative response rates in the 2 component schedules matched the relative frequencies of reinforcement. Comparing the absolute response rates in A during Phase I and Phase II, introduction of the concurrent schedule did not affect the value of the theoretical maximum response rate, but did increase the value of the reinforcement frequency needed to obtain any particular submaximal response rate.