Smith J B, McKearney J W
Psychopharmacology (Berl). 1977 Jul 18;53(2):151-7. doi: 10.1007/BF00426485.
Keypecking in one group of pigeons was maintained under schedules in which food was presented only when a specified number of responses was followed by a 30-s pause without a response. d-Amphetamine and pentobarbital increased low rates of responding (and, thus, decreased food presentation) only after initial injections or when, during drug sessions, responses during the 30-s period did not reset the period. When responses during the pause-interval postponed food delivery, the rate-increasing effects of both drugs diminished over succeeding administrations. Thus, immediate effects of response consequences were as influential as the actual presence of a drug in determining the reproducibility of the behavioral effects of that drug. In a second experiment, keypecking in another group of pigeons was maintained under a 10-min fixed-interval schedule of food presentation but suppressed by a 100-response fixed-ratio schedule of shock delivery (punishment). d-Amphetamine and pentobarbital increased low rates of punished responding when shock delivery was eliminated during drug sessions. Pentobarbital, but not d-amphetamine, also increased punished responding when shock delivery was present. Rate-increasing effects of these drugs were determined by not only predrug patterns of responding but also effects of reinforcers and punishers that occurred during exposure to the drug.
在一组鸽子中，啄击行为是按照这样的程序维持的：只有当特定次数的反应之后紧接着出现30秒无反应的停顿，才会给予食物。只有在初次注射后，或者在药物作用期间，当30秒内的反应没有重置该时间段时，右旋苯丙胺和戊巴比妥才会提高低反应率（从而减少食物供应）。当停顿间隔期间的反应推迟了食物递送时，两种药物的促反应率作用在后续给药过程中都会减弱。因此，在决定药物行为效应的可重复性方面，反应结果的即时效应与药物的实际存在一样具有影响力。在第二个实验中，另一组鸽子的啄击行为是按照10分钟的食物呈现固定间隔程序维持的，但会被100次反应的固定比率电击程序（惩罚）所抑制。当在药物作用期间取消电击时，右旋苯丙胺和戊巴比妥会提高受惩罚反应的低比率。当存在电击时，戊巴比妥（而非右旋苯丙胺）也会增加受惩罚反应。这些药物的促反应率作用不仅取决于给药前的反应模式，还取决于在接触药物期间强化物和惩罚物的作用。
