SUCCESSIVE INTERRESPONSE TIMES IN FIXED-RATIO AND SECOND-ORDER FIXED-RATIO PERFORMANCE

Three rats were trained on a schedule in which every sixth response produced a timeout of 5 sec minimum duration, and food was delivered at the onset of timeout. Successive interresponse times were measured under these conditions, and also when behavior was maintained by second‐order fixed‐ratio and fixed‐interval schedules. Under the second‐order schedules, each six‐response fixed‐ratio component was followed by a timeout, and occasionally food was delivered at the onset of a timeout. In the fixed‐ratio schedule, the successive interresponse times showed a decrease followed by an increase before food delivery, but this systematic variation in interresponse times was not found when the performance was under second‐order reinforcement. Under both second‐order schedules the latencies of successive components, and the successive interresponse times within each component, showed a decrease as food delivery was approached. 1969 Society for the Experimental Analysis of Behavior