Department of Psychology, The University of Auckland, New Zealand.
J Exp Anal Behav. 2011 Jul;96(1):63-86. doi: 10.1901/jeab.2011.96-63.
It has long been understood that food deliveries may act as signals of future food location, and not only as strengtheners of prefood responding as the law of effect suggests. Recent research has taken this idea further--the main effect of food deliveries, or other "reinforcers", may be signaling rather than strengthening. The present experiment investigated the ability of food deliveries to signal food contingencies across time after food. In Phase 1, the next food delivery was always equally likely to be arranged for a left- or a right-key response. Conditions were arranged such that the next food delivery was likely to occur either sooner on the left (or right) key, or sooner on the just-productive (or not-just-productive) key. In Phase 2, similar contingencies were arranged, but the last-food location was signaled by a red keylight. Preference, measured in 2-s bins across interfood intervals, was jointly controlled by the likely time and location of the next food delivery. In Phase 1, when any food delivery signaled a likely sooner next food delivery on a particular key, postfood preference was strongly toward that key, and moved toward the other key across the interreinforcer interval. In other conditions in which food delivery on the two keys signaled different subsequent contingencies, postfood preference was less extreme, and quickly moved toward indifference. In Phase 2, in all three conditions, initial preference was strongly toward the likely-sooner food key, and moved to the other key across the interfood interval. In both phases, at a more extended level of analysis, sequences of same-key food deliveries caused a small increase in preference for the just-productive key, suggesting the presence of a "reinforcement effect", albeit one that was very small.
长期以来，人们一直认为食物传递可能是未来食物位置的信号，而不仅仅是像效果律所表明的那样作为前置食物反应的增强剂。最近的研究进一步提出了这个观点——食物传递或其他“强化物”的主要作用可能是信号传递而不是增强。本实验研究了食物传递在食物之后跨越时间指示食物可能性的能力。在第 1 阶段，下一次食物传递总是同等可能安排在左或右键响应。条件安排使得下一次食物传递更可能在左（或右）键上更早发生，或者在刚刚产生的（或未产生的）键上更早发生。在第 2 阶段，安排了类似的条件，但最后食物位置由红色钥匙灯信号指示。在食物间隔内以 2 秒为间隔测量的偏好，由下一次食物传递的可能时间和位置共同控制。在第 1 阶段，当任何食物传递信号指示特定键上可能更快的下一次食物传递时，食物后的偏好强烈偏向该键，并在强化剂间隔内移向另一个键。在其他条件下，两个键上的食物传递信号指示不同的后续可能性，食物后的偏好不那么极端，并且迅速趋向于无差异。在第 2 阶段，在所有三种条件下，初始偏好强烈偏向可能更快的食物键，并在食物间隔内移向另一个键。在两个阶段，在更扩展的分析水平上，相同键的食物传递序列导致对刚刚产生的键的偏好略有增加，这表明存在“强化效应”，尽管很小。
