Iversen I H
Department of Psychology, University of North Florida, Jacksonville 32216.
J Exp Anal Behav. 1993 Jul;60(1):219-38. doi: 10.1901/jeab.1993.60-219.
In three experiments, access to wheel running was contingent on lever pressing. In each experiment, the duration of access to running was reduced gradually to 4, 5, or 6 s, and the schedule parameters were expanded gradually. The sessions lasted 2 hr. In Experiment 1, a fixed-ratio 20 schedule controlled a typical break-and-run pattern of lever pressing that was maintained throughout the session for 3 rats. In Experiment 2, a fixed-interval schedule of 6 min maintained lever pressing throughout the session for 3 rats, and for 1 rat, the rate of lever pressing was positively accelerated between reinforcements. In Experiment 3, a variable-ratio schedule of 20 or 35 was in effect and maintained lever pressing at a very stable pace throughout the session for 2 of 3 rats; for 1 rat, lever pressing was maintained at an irregular rate. When the session duration was extended to successive 24-hr periods, with food and water accessible in Experiment 3, lever pressing settled into a periodic pattern occurring at a high rate at approximately the same time each day. In each experiment, the rats that developed the highest local rates of running during wheel access also maintained the most stable and highest rates of lever pressing.
在三个实验中，能否使用跑步轮取决于是否按压杠杆。在每个实验中，跑步的使用时长逐渐减少至4秒、5秒或6秒，且程序参数逐渐扩大。实验时段持续2小时。在实验1中，固定比率为20的程序控制着一种典型的按压杠杆的间歇-连续模式，3只大鼠在整个实验时段内都保持这种模式。在实验2中，6分钟的固定间隔程序使3只大鼠在整个实验时段内都保持按压杠杆，对于1只大鼠，在两次强化之间按压杠杆的速率呈正加速。在实验3中，20或35的可变比率程序有效，3只大鼠中有2只在整个实验时段内以非常稳定的速度保持按压杠杆；对于1只大鼠，按压杠杆的速率不规则。当实验时段延长至连续的24小时期间，且在实验3中可获取食物和水时，按压杠杆形成了一种周期性模式，每天大约在同一时间以高频率出现。在每个实验中，如果大鼠在使用跑步轮期间的局部跑步速率最高，那么它们也能保持最稳定和最高的按压杠杆速率。
