Urbain C, Poling A, Millam J, Thompson T
J Exp Anal Behav. 1978 May;29(3):385-92. doi: 10.1901/jeab.1978.29-385.
Sixteen rats were initially exposed for 50 sessions to either a fixed-ratio 40 or an interresponse-time-greater-than-11-second food reinforcement schedule, then shifted to a fixed-interval 15-second food reinforcement schedule. Animals with fixed-ratio 40 histories lever pressed at much higher rates under the fixed-interval schedule than did animals with inter-response-time-greater-than-11-second histories. This difference persisted across 93 sessions of fixed-interval exposure. The effects of d=amphetamine were assessed after 15 and 59 sessions of fixed-interval exposure. On both occasions, the low-rate responding of animals with interresponse-time-greater-than-11-second histories was typically increased by all doses of the drug, while the high-rate responding of animals with fixed-ratio 40 histories was typically decreased by all doses of the drug. These results suggest that control response rate under the fixed-interval schedule, which may be affected by a history of responding under another schedule, is the primary determinant of the relative effects of d-amphetamine.
16只大鼠最初接受50次实验，分别采用固定比率40或反应间隔时间大于11秒的食物强化程序，然后转换为固定间隔15秒的食物强化程序。有固定比率40实验经历的动物在固定间隔程序下的杠杆按压频率比有反应间隔时间大于11秒实验经历的动物高得多。这种差异在93次固定间隔实验中持续存在。在固定间隔实验15次和59次后评估了右旋苯丙胺的效果。在这两种情况下，所有剂量的药物通常都会增加有反应间隔时间大于11秒实验经历的动物的低频率反应，而所有剂量的药物通常都会降低有固定比率40实验经历的动物的高频率反应。这些结果表明，固定间隔程序下的控制反应率可能受另一种程序下反应经历的影响，是右旋苯丙胺相对效果的主要决定因素。
