THE FOLLOWING SCHEDULE OF REINFORCEMENT AS A FUNDAMENTAL DETERMINANT OF STEADY STATE CONTRAST IN MULTIPLE SCHEDULES

Two experiments investigated whether steady‐state interactions in multiple schedules depend exclusively on the following schedule of reinforcement. Experiment 1 used a four‐component multiple schedule in which two components were associated with the same constant schedule of reinforcement, and where rate of reinforcement was varied in the component that followed one of these. Contrast effects were reliable only in the component that preceded the point of reinforcement variation, although some contrast did occur otherwise. In those instances where contrast other than the following‐schedule effect did occur, it was accounted for by the effect of the preceding schedule, an effect for which there were consistent individual differences among subjects, and which varied with component duration. Experiment 2 used a three‐component schedule, in which reinforcement rate was varied in the middle component. The results were consistent with Experiment 1, as the following‐schedule effect was the only consistent effect that occurred, although an effect of the preceding schedule did occur for some subjects under some conditions, and was especially evident early in training. The conclusion from both experiments is that there is no general effect of relative rate of reinforcement apart from the sum of the effects of the preceding and following schedules, and that the following‐schedule effect is the fundamental cause of steady‐state interactions.