Sidman's (2000) theory of stimulus equivalence states that all positive elements in a reinforcement contingency enter an equivalence class. The theory also states that if an element from an equivalence class conflicts with a reinforcement contingency, the conflicting element will “drop out” of the class. Minster et al. (2006) found evidence that a conflicting reinforcer does not drop out of an equivalence class. To explain their results, they proposed that the reinforcer enters the class via pairing after conditional relations have been established, and when there is a conflict between the class and the contingencies, conditionally related elements that have a longer history in the class and that were brought in via reinforcement will exert stronger control. In the current study, stimulus-reinforcer relations were established before conditional relations to assess the role of developmental order of stimulus relations on conditional-discrimination performance. The results replicate the findings of Minster et al. (2006) but suggest that developmental order may not be an important factor contributing to maintained accuracy on baseline conditional relations. An interpretation of “dropping out” in terms of differentiated subclasses is discussed. The relevance of the results to the phenomenon known as the differential outcomes effect is also discussed.

中文翻译：

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意外事件冲突的元素是否会从等价类中删除？重新检验 Sidman (2000) 的理论

Sidman (2000) 的刺激等价理论指出，强化意外事件中的所有积极元素都进入等价类。该理论还指出，如果等价类中的元素与强化意外事件发生冲突，则冲突元素将从该类中“退出”。明斯特等人。（2006）发现有证据表明冲突的强化物不会从等价类中退出。为了解释他们的结果，他们提出，在条件关系建立后，强化物通过配对进入类，当类与偶然事件之间发生冲突时，类中历史较长的条件相关元素被带入类中。通过强化会发挥更强的控制力。在当前的研究中，在条件关系之前建立刺激-强化关系，以评估刺激关系的发展顺序对条件歧视表现的作用。结果重复了 Minster 等人的发现。（2006）但表明发展顺序可能不是有助于维持基线条件关系准确性的重要因素。讨论了根据差异化子类对“退出”的解释。还讨论了结果与差异结果效应现象的相关性。（2006）但表明发展顺序可能不是有助于维持基线条件关系准确性的重要因素。讨论了根据差异化子类对“退出”的解释。还讨论了结果与差异结果效应现象的相关性。（2006）但表明发展顺序可能不是有助于维持基线条件关系准确性的重要因素。讨论了根据差异化子类对“退出”的解释。还讨论了结果与差异结果效应现象的相关性。