跨视听通道的相继错误记忆效应

The DIM Effect of False Recognition During Visual and Auditory Modalities

本研究以12名大学生为被试采用DRM范式,考察了视觉与听觉通道在编码阶段的错误记忆ERP效应,以从更深层面认识错误记忆的内在加工机制。研究结果表明,在编码阶段,在300-500ms及500-700ms的时间窗视觉通道均存在相继错误记忆效应(DIM),但DIM效应出现的时间及头皮分布不同,这不仅说明视觉通道与听觉通道在编码阶段具有不同的脑机制,而且表明DIM效应与学习项目的语义加工有着密切的关系。

One of the great puzzles in false memory is the effect of modality, which was firstly reported and defined by Smith and Hunt in 1998, namely, there is a lower false recognition of critical lures following visual presentation than following auditory presentation. Though the effect of study modality in false memory was explored in many written recall tests and visual recognition tests by means of the Deese-Roediger-McDermott （DRM） paradigm, only few studies explored the neurophysiological correlates of the encoding phase in false memory using ERP techniques and their results were mixed. Urbach, Windmann, Payne and Kutas （2005）argued that item-specific encoding difference was a neural precursor of false memory, while Geng et al. （2007） suggested that the increased active semantic associative processing or a gist representation was established for those items that elicited later false memory. The present study investigated the neural activity associated with cognitive processes underlying the encoding phase following visual presentation and auditory presentation by means of ERP techniques to further get into the eleetrophysiological processes of the modality effect in false memory. The experiment was conducted with 12 undergraduate students as the subjects and 80 DRM lists as the stimuli. The participants studied 5 blocks （8 DRM lists in each block and 7 associated items in each DRM list） both in visual modality and in auditory modality, immediately followed by 5 visual old/new recognition tests respectively. The ERP recorded during the encoding phase were computed according to whether the corresponding lure was or was not recognized later. The results showed that the effects of DIM （Difference in subsequent Illusory Memory） in visual modality during the encoding phase were different from those in auditory modality, namely, the DIM effect was found in visual modality at 300-500ms and 500-700ms and the DIM effect in auditory modality was found only at 200-400ms. The difference between visual and auditory modality suggested that the semantic associative processing or a gist representation was important to those items that elicited later false memory, which con- firmed the findings of Geng et al （2007）.