Department of Neurology, Vanderbilt University, Nashville TN, USA.
Neuropsychologia. 2013 Mar;51(4):642-55. doi: 10.1016/j.neuropsychologia.2012.12.012. Epub 2012 Dec 31.
The influence of implicit memory representations on explicit recognition may help to explain cases of accurate recognition decisions made with high uncertainty. During a recognition task, implicit memory may enhance the fluency of a test item, biasing decision processes to endorse it as "old". This model may help explain recognition-without-identification, a remarkable phenomenon in which participants make highly accurate recognition decisions despite the inability to identify the test item. The current study investigated whether recognition-without-identification for pictures elicits a similar pattern of neural activity as other types of accurate recognition decisions made with uncertainty. Further, this study also examined whether recognition-without-identification for pictures could be attained by the use of perceptual and conceptual information from memory. To accomplish this, participants studied pictures and then performed a recognition task under difficult viewing conditions while event-related potentials (ERPs) were recorded. Behavioral results showed that recognition was highly accurate even when test items could not be identified, demonstrating recognition-without-identification. The behavioral performance also indicated that recognition-without-identification was mediated by both perceptual and conceptual information, independently of one another. The ERP results showed dramatically different memory related activity during the early 300 to 500ms epoch for identified items that were studied compared to unidentified items that were studied. Similar to previous work highlighting accurate recognition without retrieval awareness, test items that were not identified, but correctly endorsed as "old," elicited a negative posterior old/new effect (i.e., N300). In contrast, test items that were identified and correctly endorsed as "old," elicited the classic positive frontal old/new effect (i.e., FN400). Importantly, both of these effects were elicited under conditions when participants used perceptual information to make recognition decisions. Conceptual information elicited very different ERPs than perceptual information, showing that the informational wealth of pictures can evoke multiple routes to recognition even without awareness of memory retrieval. These results are discussed within the context of current theories regarding the N300 and the FN400.
内隐记忆表征对显式识别的影响有助于解释高不确定性下准确识别决策的情况。在识别任务中，内隐记忆可能会增强测试项目的流畅性，从而使决策过程偏向于将其判断为“旧”。该模型可以帮助解释识别但不识别的现象，即参与者在无法识别测试项目的情况下做出高度准确的识别决策。本研究探讨了图片的识别但不识别是否会引发与其他具有不确定性的准确识别决策类型相似的神经活动模式。此外，本研究还检查了是否可以通过使用记忆中的知觉和概念信息来实现图片的识别但不识别。为此，参与者学习了图片，然后在困难的观看条件下进行识别任务，同时记录事件相关电位（ERP）。行为结果表明，即使无法识别测试项目，识别的准确性也非常高，从而证明了识别但不识别的现象。行为表现还表明，识别但不识别是由知觉和概念信息共同介导的，彼此独立。ERP 结果表明，与识别但不识别的项目相比，在识别且识别为“旧”的项目中，研究中所使用的已识别项目在 300 到 500ms 早期阶段会产生截然不同的与记忆相关的活动。与以前强调在没有检索意识的情况下进行准确识别的工作相似，未被识别但正确判断为“旧”的测试项目会引发负向后新/旧效应（即 N300）。相比之下，已识别且正确判断为“旧”的测试项目会引发经典的正前新/旧效应（即 FN400）。重要的是，这些效应都是在参与者使用知觉信息做出识别决策的条件下引发的。与知觉信息相比，概念信息引发了非常不同的 ERP，表明即使没有记忆检索意识，图片的信息丰富度也可以引发多种识别途径。这些结果是在关于 N300 和 FN400 的当前理论背景下进行讨论的。
