Effects of the Changeover Delay on Interchangeover Responding in Concurrent Schedules of Reinforcement

Abstract

The problem. In concurrent schedules of reinforcement, the use of a changeover delay has been assumed to be necessary in order to reduce superstitious alternation, separate the components in time, and thus insure independence between components. The purpose of this study was to look at responding between changeovers and to see whether superstitious alternation does indeed occur. Procedure. During daily sessions, four male rats were exposed to a concurrent variable-interval schedule on which changeover delays of different values were superimposed. Food-lever responses intervening between changeovers and changeover responses were measured and recorded. Findings. When a changeover delay was used, total changeover responses decreased, and number of interchangeover responses and overall responding increased. This effect was found to be more pronounced with higher changeover delay values. A high percentage of changeover responses occurring without an intervening food-lever response was observed, especially when a changeover delay was introduced. Conclusions. No evidence of superstitious alternation was found, Therefore, it was concluded that the use of a changeover delay to eliminate such a pattern was not justified. The increase in interchangeover responses and percentage of changeover responding was argued to be due to the possible discriminative stimulus and conditioned reinforcing function as the changeover delay. Recommendations. It was suggested that further attention be paid ta the role and effect of the changeover delay, especially in terms of simple alternation, a pattern that seems to be more dominant than superstitious alternation,