Zentall Thomas R, Stagner Jessica P
University of Kentucky.
Learn Motiv. 2011 Aug 1;42(3):245-254. doi: 10.1016/j.lmot.2011.03.002.
Pigeons show a preference for an alternative that provides them with discriminative stimuli (sometimes a stimulus that predicts reinforcement and at other times a stimulus that predicts the absence of reinforcement) over an alternative that provides them with non discriminative stimuli, even if the non discriminative stimulus alternative is associated with 2.5 times as much reinforcement (Stagner & Zentall, 1910). In Experiment 1 we found that the delay to reinforcement associated with the non discriminative stimuli could be reduced by almost one half before the pigeons were indifferent between the two alternatives. In Experiment 2 we tested the hypothesis that the preference for the discriminative stimulus alternative resulted from the fact that, like humans, the pigeons were attracted by the stimulus that consistently predicted reinforcement (the Allais paradox). When the probability of reinforcement associated with the discriminative stimulus that predicted reinforcement was reduced from 100% to 80% the pigeons still showed a strong preference for the discriminative stimulus alternative. Thus, under these conditions, the Allais paradox cannot account for the sub-optimal choice behavior shown by pigeons. Instead we propose that sub-optimal choice results from positive contrast between the low expectation of reinforcement associated with the discriminative stimulus alternative and the much higher obtained reinforcement when the stimulus associated with reinforcement appears. We propose that similar processes can account for sub-optimal gambling behavior by humans.
鸽子对能为它们提供辨别性刺激（有时是预测强化的刺激，有时是预测无强化的刺激）的选择项的偏好超过对能为它们提供非辨别性刺激的选择项，即便非辨别性刺激选择项与多2.5倍的强化相关联（斯塔格纳和曾塔尔，1910年）。在实验1中我们发现，在鸽子对两种选择项无差异偏好之前，与非辨别性刺激相关联的强化延迟几乎可以减少一半。在实验2中，我们检验了这样一个假设，即对辨别性刺激选择项的偏好源于这样一个事实：和人类一样，鸽子会被始终预测强化的刺激所吸引（阿莱悖论）。当与预测强化的辨别性刺激相关联的强化概率从100%降至80%时，鸽子仍然表现出对辨别性刺激选择项的强烈偏好。因此，在这些条件下，阿莱悖论无法解释鸽子表现出的次优选择行为。相反，我们提出，次优选择是由与辨别性刺激选择项相关联的低强化期望和与强化相关的刺激出现时获得的高得多的强化之间的正性对比导致的。我们提出，类似的过程可以解释人类的次优赌博行为。
