Weatherly J N, McMurry A S, Melville C L
Department of Psychology, McNeese State University, Lake Charles, LA 70609-1895, USA.
Behav Processes. 1999 Jun;46(2):121-9. doi: 10.1016/s0376-6357(99)00031-5.
In the present study, rats' wheel running was reinforced when they responded at different food deprivations. In experiment 1, fourths of a wheel turn were reinforced on a variable interval (VI) 15- or 60-s schedule during 50-min sessions. Subjects responded at 75, 85 or 95% of their free-feeding body weights, across conditions. Within-session decreases in responding were steepest at subjects' 75% weights for the VI 60-s schedule, but were similar at different weights for the VI 15-s schedule. In experiment 2, subjects responded on a VI 60-s schedule at 75 or 95% of their free-feeding body weights. Reinforcer size was one or four food pellets. Steeper within-session decreases in responding were observed at subjects' 75% weight than at their 95% weight, with no effect of reinforcer amount. The present results cannot disconfirm either leading theory for within-session changes because the terms involved (i.e. habituation and satiation) are not adequately defined. However, the present results seem to pose problems for both explanations.
在本研究中，当大鼠在不同程度的食物剥夺状态下做出反应时，其转轮行为会得到强化。在实验1中，在50分钟的实验时段内，以可变间隔（VI）15秒或60秒的时间表对四分之一圈的转轮行为进行强化。在不同条件下，实验对象的体重维持在自由进食体重的75%、85%或95%。在VI 60秒的时间表中，实验对象体重为75%时，实验时段内反应的下降最为陡峭，但在VI 15秒的时间表中，不同体重下的反应下降情况相似。在实验2中，实验对象以VI 60秒的时间表做出反应，体重为自由进食体重的75%或95%。强化物的大小为1颗或4颗食物颗粒。实验对象体重为75%时，实验时段内反应的下降比体重为95%时更为陡峭，强化物数量没有影响。由于所涉及的术语（即习惯化和饱腹感）没有得到充分定义，目前的结果无法否定关于实验时段内变化的任何一种主导理论。然而，目前的结果似乎给这两种解释都带来了问题。
