Plowright C M, Shettleworth S J
University of Toronto, Toronto Ontario, Canada M5S 1A1.
Behav Processes. 1990 Jun;21(2-3):157-78. doi: 10.1016/0376-6357(90)90022-8.
Pigeons (Columba livia) were confronted with a problem in choice known as the two-armed bandit (TAB): two concurrent discrete trials random-ratio schedules in which the good side changes randomly from day to day. In the first experiment a substantial proportion of the birds' choices were contrary to those predicted by immediate maximization. Under a variety of parameter settings the pigeons chose the bad side more often than expected by immediate maximization. The hypothesis was advanced that shifting, that is, the tendency to avoid the most recently visited location, was responsible for limiting the number of choices on the good side of the TAB. Experiments 2-4 examined this hypothesis. The first of these experiments compared the accuracy on win-shift vs win-stay trials, and lose-shift vs lose-stay. When the response keys were at opposite sides of the operant chamber (keys-far), as in the first TAB experiment, there was a significant tendency to shift. This tendency was not present when the keys were close together (keys-close), in Experiment 3. Experiment 4 compared TAB performance in the original keys-far situation with that in the keys-close chamber. The proportion of choices on the good side of the TAB increased faster and attained a higher level for the keys-close group, and the proportion of choices which were shifts from one side to the other was smaller. A higher proportion of individual choices in the keys-close condition could be accounted for by immediate maximization.
鸽子（家鸽）面临一个被称为双臂强盗问题（TAB）的选择难题：两种并发的离散试验随机比率时间表，其中好的一边每天随机变化。在第一个实验中，很大一部分鸽子的选择与即时最大化预测的选择相反。在各种参数设置下，鸽子选择坏的一边的频率比即时最大化预期的要高。提出的假设是，转换，即避免最近访问过的位置的倾向，是限制在TAB好的一边选择数量的原因。实验2至4检验了这一假设。这些实验中的第一个比较了赢后转换与赢后停留试验，以及输后转换与输后停留试验的准确性。当反应键位于操作箱的相对两侧（键距远）时，如在第一个TAB实验中，有显著的转换倾向。在实验3中，当键靠得很近（键距近）时，这种倾向不存在。实验4比较了在原始键距远的情况下与键距近的操作箱中的TAB表现。对于键距近的组，在TAB好的一边的选择比例增加得更快且达到更高水平，并且从一边转换到另一边的选择比例更小。在键距近的条件下，更高比例的个体选择可以用即时最大化来解释。
