Department of Psychology, University of Illinois, Urbana-Champaign, USA; Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, USA; Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University Nijmegen, The Netherlands.
Department of Psychology, University of Illinois, Urbana-Champaign, USA; Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, USA; Program in Neuroscience, University of Illinois, Urbana-Champaign, USA.
Cortex. 2018 Apr;101:16-30. doi: 10.1016/j.cortex.2017.12.018. Epub 2018 Jan 2.
Stimulus processing in language and beyond is shaped by context, with predictability having a particularly well-attested influence on the rapid processes that unfold during the presentation of a word. But does predictability also have downstream consequences for the quality of the constructed representations? On the one hand, the ease of processing predictable words might free up time or cognitive resources, allowing for relatively thorough processing of the input. On the other hand, predictability might allow the system to run in a top-down "verification mode", at the expense of thorough stimulus processing. This electroencephalogram (EEG) study manipulated word predictability, which reduced N400 amplitude and inter-trial phase clustering (ITPC), and then probed the fate of the (un)predictable words in memory by presenting them again. More thorough processing of predictable words should increase repetition effects, whereas less thorough processing should decrease them. Repetition was reflected in N400 decreases, late positive complex (LPC) enhancements, and late alpha/beta band power decreases. Critically, prior predictability tended to reduce the repetition effect on the N400, suggesting less priming, and eliminated the repetition effect on the LPC, suggesting a lack of episodic recollection. These findings converge on a top-down verification account, on which the brain processes more predictable input less thoroughly. More generally, the results demonstrate that predictability has multifaceted downstream consequences beyond processing in the moment.
语言及其他领域的刺激处理受语境影响，可预测性对在呈现单词时展开的快速过程有特别充分的影响。但是，可预测性是否也会对构建的表示质量产生下游影响？一方面，处理可预测单词的容易程度可能会释放时间或认知资源，从而允许对输入进行相对彻底的处理。另一方面，可预测性可能允许系统以自上而下的“验证模式”运行，以牺牲对刺激的彻底处理为代价。这项脑电图（EEG）研究操纵了单词的可预测性，从而降低了 N400 幅度和试验间相位聚类（ITPC），然后通过再次呈现这些单词来探测记忆中（不可预测）单词的命运。对可预测单词进行更彻底的处理应该会增加重复效应，而对其进行不彻底的处理则会降低重复效应。重复反映在 N400 的减少、晚期正复合（LPC）的增强以及晚期 alpha/β波段功率的降低。关键是，先前的可预测性往往会降低 N400 上的重复效应，表明启动作用较小，并且消除了 LPC 上的重复效应，表明缺乏情节记忆。这些发现都集中在自上而下的验证解释上，即大脑对更可预测的输入进行的处理不够彻底。更一般地，这些结果表明，可预测性在当下处理之外具有多方面的下游影响。
