Cohen S L
Department of Psychology, Bloomsburg University, Pennsylvania 17815.
J Exp Anal Behav. 1991 Sep;56(2):289-302. doi: 10.1901/jeab.1991.56-289.
Three pigeons were studied under a multiple schedule in which pecks in each component were reinforced according to a variable-interval 120-s second-order schedule with fixed-interval 60-s units. In the first component of the multiple schedule, the completion of a fixed interval produced either food or a 4-s change in key color plus houselight illumination. In the second component an identical schedule was in effect, but the stimulus was a 0.3-s change in key color. Both long and short brief stimuli were not paired with food presentations in Conditions 1 and 3 and were paired with food in Condition 2. There were no consistent differences in response patterns under paired and nonpaired brief-stimulus conditions when the stimulus was a 4-s change in key color accompanied by houselight illumination. However, pairing the 0.3-s key-color change with food presentations resulted in higher indices of curvature and lower response rates in the early segments of the fixed interval than when the stimulus was not paired with food presentations. Low doses of d-amphetamine (0.3 and 1 mg/kg) produced small and inconsistent increases in overall response rates, and higher doses (3 and 10 mg/kg) decreased overall response rates. d-Amphetamine altered response patterns within fixed intervals by decreasing the indices of curvature and increasing response rates in the early segments of the fixed interval. Response rates and patterns under paired and nonpaired brief-stimulus conditions were not differentially affected by d-amphetamine. Thus, evidence for the enhancement of the conditioned reinforcement effects of psychomotor stimulant drugs was not found with the second-order schedules used in the present study.
对三只鸽子进行了多重强化程序实验，在该程序中，每个成分中的啄击行为按照可变间隔120秒的二阶强化程序进行强化，其中每个单位的固定间隔为60秒。在多重强化程序的第一个成分中，固定间隔的结束会产生食物奖励，或者按键颜色有4秒的变化并伴有饲养箱灯光亮起。在第二个成分中，实施相同的强化程序，但刺激是按键颜色有0.3秒的变化。在条件1和条件3中，长时和短时的短暂刺激都不与食物呈现配对，而在条件2中则与食物配对。当刺激是按键颜色有4秒的变化并伴有饲养箱灯光亮起时，在配对和非配对短暂刺激条件下，反应模式没有一致的差异。然而，将0.3秒的按键颜色变化与食物呈现配对时，与刺激不与食物呈现配对相比，在固定间隔的早期阶段，曲率指数更高，反应率更低。低剂量的右旋苯丙胺（0.3和1毫克/千克）使总体反应率有小幅且不一致的增加，而高剂量（3和10毫克/千克）则降低了总体反应率。右旋苯丙胺通过降低曲率指数并增加固定间隔早期阶段的反应率，改变了固定间隔内的反应模式。右旋苯丙胺对配对和非配对短暂刺激条件下的反应率和反应模式没有差异影响。因此，在本研究使用的二阶强化程序中，未发现精神运动兴奋剂药物增强条件性强化作用的证据。
