Mazur J E
Psychology Department, Southern Connecticut State University, New Haven 06515, USA.
J Exp Anal Behav. 1998 Nov;70(3):253-65. doi: 10.1901/jeab.1998.70-253.
In Experiment 1, pigeons' pecks on a green key led to a 5-s delay with green houselights, and then food was delivered on 20% (or, in other conditions, 50%) of the trials. Pecks on a red key led to an adjusting delay with red houselights, and then food was delivered on every trial. The adjusting delay was used to estimate indifference points: delays at which the two alternatives were chosen about equally often. Varying the presence or absence of green houselights during the delays that preceded possible food deliveries had large effects on choice. In contrast, varying the presence of the green or red houselights in the intertrial intervals had no effects on choice. In Experiment 2, pecks on the green key led to delays of either 5 s or 30 s with green houselights, and then food was delivered on 20% of the trials. Varying the duration of the green houselights on nonreinforced trials had no effect on choice. The results suggest that the green houselights served as a conditioned reinforcer at some times but not at others, depending on whether or not there was a possibility that a primary reinforcer might be delivered. Given this interpretation of what constitutes a conditioned reinforcer, most of the results were consistent with the view that the strength of a conditioned reinforcer is inversely related to its duration.
在实验1中，鸽子啄绿色按键会导致绿灯亮起时出现5秒延迟，然后在20%（或在其他条件下为50%）的试验中给予食物。啄红色按键会导致红灯亮起时出现调整延迟，然后每次试验都给予食物。调整延迟用于估计无差异点：即两种选择被选择的频率大致相等时的延迟。在可能给予食物之前的延迟期间改变绿灯是否亮起对选择有很大影响。相比之下，在试验间隔期间改变绿灯或红灯是否亮起对选择没有影响。在实验2中，啄绿色按键会导致绿灯亮起时出现5秒或30秒的延迟，然后在20%的试验中给予食物。在非强化试验中改变绿灯亮起的持续时间对选择没有影响。结果表明，绿灯有时作为条件强化物，有时则不然，这取决于是否有可能给予初级强化物。基于对构成条件强化物的这种解释，大多数结果与条件强化物的强度与其持续时间成反比的观点一致。
