Schultz Douglas H, Balderston Nicholas L, Geiger Jennifer A, Helmstetter Fred J
Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Behav Neurosci. 2013 Jun;127(3):357-68. doi: 10.1037/a0032742.
The nature of the relationship between explicit and implicit learning is a topic of considerable debate. To investigate this relationship we conducted two experiments on postconditioning revaluation of the unconditional stimulus (UCS) in human fear conditioning. In Experiment 1, the intensity of the UCS was decreased after acquisition for one group (devaluation) and held constant for another group (control). A subsequent test revealed that even though both groups exhibited similar levels of UCS expectancy, the devaluation group had significantly smaller conditional skin conductance responses. The devaluation effect was not explained by differences in the explicit estimates of UCS probability or explicit knowledge that the UCS intensity had changed. In Experiment 2, the value of the UCS was increased after acquisition for one group (inflation) and held constant for another group (control). Test performance revealed that UCS inflation did not alter expectancy ratings, but the inflation group exhibited larger learned skin conductance responses than the control group. The inflation effect was not explained by differences in the explicit estimates of UCS probability or explicit knowledge that the UCS intensity had changed. The SCR revaluation effect was not dependent on explicit memory processes in either experiment. In both experiments we found differences on an implicit measure of learning in the absence of changes in explicit measures. Together, the differences observed between expectancy measures and skin conductance support the idea that these responses might reflect different types of memory formed during the same training procedure and be supported by separate neural systems.
外显学习与内隐学习之间关系的本质是一个备受争议的话题。为了探究这种关系，我们针对人类恐惧条件反射中无条件刺激（UCS）的条件作用后重新评估进行了两项实验。在实验1中，一组在习得后降低了UCS的强度（贬值组），另一组则保持不变（对照组）。随后的测试表明，尽管两组对UCS的预期水平相似，但贬值组的条件性皮肤电导反应显著更小。贬值效应无法通过对UCS概率的外显估计差异或对UCS强度已改变的外显知识来解释。在实验2中，一组在习得后提高了UCS的价值（增值组），另一组保持不变（对照组）。测试结果显示，UCS增值并未改变预期评分，但增值组比对照组表现出更大的习得性皮肤电导反应。增值效应无法通过对UCS概率的外显估计差异或对UCS强度已改变的外显知识来解释。在两个实验中，皮肤电导重新评估效应均不依赖于外显记忆过程。在两个实验中，我们都发现在外显测量没有变化的情况下，内隐学习测量存在差异。总之，预期测量与皮肤电导之间观察到的差异支持了这样一种观点，即这些反应可能反映了在相同训练过程中形成的不同类型的记忆，并由不同的神经系统支持。
