Williams B A
Department of Psychology, University of California, San Diego, La Jolla 92093-0109.
J Exp Anal Behav. 1993 Jan;59(1):163-72. doi: 10.1901/jeab.1993.59-163.
During one component of a multiple schedule, pigeons were trained on a discrete-trial concurrent variable-interval variable-interval schedule in which one alternative had a high scheduled rate of reinforcement and the other a low scheduled rate of reinforcement. When the choice proportion between the alternatives matched their respective relative reinforcement frequencies, the obtained probabilities of reinforcement (reinforcer per peck) were approximately equal. In alternate components of the multiple schedule, a single response alternative was presented with an intermediate scheduled rate of reinforcement. During probe trials, each alternative of the concurrent schedule was paired with the constant alternative. The stimulus correlated with the high reinforcement rate was preferred over that with the intermediate rate, whereas the stimulus correlated with the intermediate rate of reinforcement was preferred over that correlated with the low rate of reinforcement. Preference on probe tests was thus determined by the scheduled rate of reinforcement. Other subjects were presented all three alternatives individually, but with a distribution of trial frequency and reinforcement probability similar to that produced by the choice patterns of the original subjects. Here, preferences on probe tests were determined by the obtained probabilities of reinforcement. Comparison of the two sets of results indicates that the availability of a choice alternative, even when not responded to, affects the preference for that alternative. The results imply that models of choice that invoke only obtained probability of reinforcement as the controlling variable (e.g., melioration) are inadequate.
在多重时间表的一个组成部分中，鸽子接受了离散试验并发可变间隔-可变间隔时间表的训练，其中一个选择具有高的预定强化率，另一个具有低的预定强化率。当两个选择之间的选择比例与其各自的相对强化频率相匹配时，获得的强化概率（每啄一次的强化物）大致相等。在多重时间表的交替组成部分中，呈现一个单一的反应选择，其具有中等的预定强化率。在探测试验期间，并发时间表的每个选择与恒定选择配对。与高强化率相关的刺激比与中等强化率相关的刺激更受青睐，而与中等强化率相关的刺激比与低强化率相关的刺激更受青睐。因此，探测试验中的偏好由预定强化率决定。其他受试者分别呈现所有三种选择，但试验频率和强化概率的分布与原始受试者的选择模式所产生的相似。在这里，探测试验中的偏好由获得的强化概率决定。两组结果的比较表明，即使没有对选择进行反应，选择的可用性也会影响对该选择的偏好。结果意味着仅将获得的强化概率作为控制变量的选择模型（例如，改善）是不充分的。
