School of Psychology, and Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, Australia.
School of Medicine/Division of Psychology, University of Tasmania, Australia.
Neurobiol Learn Mem. 2020 Oct;174:107285. doi: 10.1016/j.nlm.2020.107285. Epub 2020 Jul 31.
Research has shown that a single presentation of the conditioned stimulus prior to extinction training can diminish conditioned responses. However, replication has proven difficult and appears to be limited by boundary conditions. Here we tested the boundary condition of memory strength by comparing the effect of reinforcement rate to assess its role in post-retrieval extinction. Eighty university students had undergone a three-day fear conditioning experiment in which two partial reinforcement schedules (40%, 80%) were applied. The findings indicated that both low and high partial reinforcement groups did not demonstrate recovery of conditioned responses after post-retrieval extinction. In contrast, both groups demonstrated significant recovery to standard extinction with significantly greater recovery in the 80% group relative to the 40% group. Additionally, we found that greater physiological arousal during memory retrieval significantly predicted recovery of fear at test phase. We conclude that when compared to a lower partial reinforcement schedule, a higher partial reinforcement resulted in the formation of a stronger memory as indicated by greater physiological arousal during memory reactivation and recovery of conditioned responses after standard extinction, but that it does not function as a boundary condition of post-retrieval extinction. These data are significant because it is the first study to investigate the effect of varying partial reinforcement schedules on fear recovery and add to the body of literature that continue to identify sources of failure in the application of post-retrieval extinction.
研究表明，在消退训练之前单次呈现条件刺激可以减少条件反应。然而，复制已经证明是困难的，并且似乎受到边界条件的限制。在这里，我们通过比较强化率的影响来检验记忆强度的边界条件，以评估其在检索后消退中的作用。八十名大学生参加了为期三天的恐惧条件反射实验，其中应用了两种部分强化计划（40%、80%）。结果表明，低和高部分强化组在检索后消退后都没有表现出条件反应的恢复。相比之下，两组在标准消退后都表现出明显的恢复，80%组的恢复明显大于 40%组。此外，我们发现记忆检索期间更大的生理唤醒显著预测了测试阶段恐惧的恢复。我们得出结论，与较低的部分强化计划相比，较高的部分强化导致更强的记忆形成，这表现为记忆重新激活期间更大的生理唤醒和标准消退后条件反应的恢复。但是，它不能作为检索后消退的边界条件。这些数据很重要，因为这是第一项研究不同部分强化计划对恐惧恢复的影响的研究，并为继续确定检索后消退应用失败的来源的文献增添了内容。
