Landon Jason, Davison Michael, Elliffe Douglas
Department of Psychology, The University of Auckland, New Zealand.
J Exp Anal Behav. 2003 May;79(3):351-65. doi: 10.1901/jeab.2003.79-351.
Five pigeons were trained on pairs of concurrent variable-interval schedules in a switching-key procedure. The arranged overall rate of reinforcement was constant in all conditions, and the reinforcer-magnitude ratios obtained from the two alternatives were varied over five levels. Each condition remained in effect for 65 sessions and the last 50 sessions of data from each condition were analyzed. At a molar level of analysis, preference was described well by a version of the generalized matching law, consistent with previous reports. More local analyses showed that recently obtained reinforcers had small measurable effects on current preference, with the most recently obtained reinforcer having a substantially larger effect. Larger reinforcers resulted in larger and longer preference pulses, and a small preference was maintained for the larger-magnitude alternative even after long inter-reinforcer intervals. These results are consistent with the notion that the variables controlling choice have both short- and long-term effects. Moreover, they suggest that control by reinforcer magnitude is exerted in a manner similar to control by reinforcer frequency. Lower sensitivities when reinforcer magnitude is varied are likely to be due to equal frequencies of different sized preference pulses, whereas higher sensitivities when reinforcer rates are varied might result from changes in the frequencies of different sized preference pulses.
五只鸽子在一种切换键程序中接受了成对的并发可变间隔时间表的训练。在所有条件下，安排的总体强化速率是恒定的，并且从两种选择中获得的强化物大小比率在五个水平上变化。每个条件持续65个实验期，并对每个条件下最后50个实验期的数据进行分析。在宏观分析水平上，偏好可以用广义匹配定律的一个版本很好地描述，这与之前的报告一致。更细致的分析表明，最近获得的强化物对当前偏好有微小的可测量影响，其中最近获得的强化物影响显著更大。更大的强化物导致更大、持续时间更长的偏好脉冲，并且即使在强化物间隔时间很长之后，对更大大小的选择仍保持着小的偏好。这些结果与控制选择的变量具有短期和长期影响的观点一致。此外，它们表明强化物大小的控制方式与强化物频率的控制方式相似。当强化物大小变化时较低的敏感性可能是由于不同大小偏好脉冲的频率相等，而当强化物速率变化时较高的敏感性可能是由于不同大小偏好脉冲频率的变化。
