关键词: 双加工理论, FN400, LPC, 熟悉性, 回想

Abstract: Two cognitive processes contribute to memory recognition, namely recollection and familiarity. The Dual process theory supposed that recognition can be decomposed into two distinct processes that reflect the separate mnemonic mechanisms of familiarity and recollection. Previous electrophysiology researches commonly believed FN400 and LPC index to familiarity and recollection, respectively. The FN400 is more negative for new than old stimuli over front-centrally, between 300-500 ms, which has been associated with familiarity. The LPC is a later positive old/new difference maximal over centroparietal channels between 500-800 ms post-stimulus, which has been associated with recollection. The FN400 similarly to the N400 in timing and response pattern, however, some studies have proven that there are functional differences between the FN400 and N400. In the previous researches, the measurement of familiarity was mainly done by a recognition test, which was a measurement of explicit memory, ignoring the influence of implicit memory on recognition. There was a great overlap between familiarity and conceptual priming in the experimental operation. Therefore, the FN400 may also be the result of the co-occurrence of conceptual priming and familiarity. Therefore, to eliminate the interference of conceptual priming on FN400, the researchers used meaningless materials to separate familiar processing. It should be noted, however, that some researchers have recently posited that FN400 is an index of the interaction of conceptual priming and familiarity, and the specific role of the two in the production of FN400, remains to be further explored. In addition to the intense discussion on the significance of FN400, some researchers also believe that the LPC is related to familiarity. It is generally believed that only recollection supports source information retrieval, but studies have proven that familiarity is also beneficial to remember source information, which indicates that recollection and familiarity processing may be included in source information retrieval at the same time, hence LPC may be a mixed indicator of both. However, the recent research provided new insight into the precise functional utility of the LPC and recollection, they successfully replicated existing within-participant modulations of the magnitude of the LPC with recollection during old/new recognition, Remember/Know/Guess and source memory task in two large samples of healthy young adults. Critically, however, they also suggested that variation in the magnitude of the LPC doesn’t index memory performance as expected. The limitations in prior ERP studies of recognition memory are driven by the restrictions in the recording setup. In another research, there was no LPC when investigating neural correlates of remembering in more naturalistic settings. This indicates that the specific index of FN400 and LPC still needs debate, and the influence of factors, other than familiarity and recollection, should be fully considered when using FN400 and LPC as evidence of the dual process theory. There are three questions to issue in the future. Firstly, it is necessary to further clarify the preconditions for conceptual priming and familiarity to influence FN400 or not. Second, we must clarify the index of LPC while improving ecological validity and controlling extraneous variables. Third, further explore the interaction between familiarity and recollection in the recognition process.

Key words: dual process theory, NF400, LPC, familiarity, recollection