Patterning of Behavior in a Concurrent Variable-Interval Schedule as a Function of the Changeover Delay
Altmeyer, Bernd K.
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The problem. The present study was conducted to determine the temporal placement of licking in a concurrent schedule of reinforcement and to see how various changeover delays affect the temporal placement of licking. Procedure. Rats were trained to press a lever for food. Food was made available by two independent reinforcement schedules, separated by a changeover delay. The changeover delay was varied over a range of 0 to 8 seconds. A drinking tube was freely available in the experimental chamber. Numerical data were obtained on the frequency of lever pressing, lick episodes, and their temporal patterning. Findings. Changeover response rates showed a systematic change in accordance with the length of the changeover delay. Response rates showed a systematic change only for animals which were exposed to signalled changeover delays. These animals tended to engage in licking following the delivery of a pellet, whereas animals exposed to unsignalled changeover delays tended to engage in licking following foodlever presses. Licking never occurred during the changeover delay. Changeover responses were maintained when their only effect was a possible delay of the reinforcement in a simple variable interval schedule. Conclusion. A changeover delay is not a necessary condition to obtain matching. The length and the type of changeover delay does affect the patterning of behavior. The increase in overall response rates with longer changeover delays, the occurrence of changeover responses in a simple variable interval schedule, and the absence of licking during the changeover delay indicate that the changeover delay is a period of high probability of reinforcement which maintains high rates of behavlor. Recommendations. It was recommended that a broad range of changeover delays be examined in terms of their effect on the rate and temporal patterning of both the foodlever responses and the changeover responses.
35 leaves. Advisor: Larry A. Alferink.