汉字单字词识别的N400

目的　探讨单词识别过程中事件相关电位N40 0成分的心理学意义。方法　在长 ( 60 0ms)与短 ( 2 0 0ms)两种刺激呈现间隔 (SOA)、3种语境 (相关、中性和无关 )条件下 ,进行词汇抉择作业 ,通过对反应时间 (RT)和事件相关电位 (ERP)的检测 ,观察目标词词汇抉择的语义启动效应 (RT效应和N40 0波幅效应 )。结果　长SOA时 ,RT实验有语义促进效应 (相关语境RT较中性语境短 )和抑制效应 (无关语境RT较中性语境长 ) ,而ERP实验只有N40 0波幅抑制效应 ;短SOA时 ,RT实验只有语义促进效应 ,而ERP实验无任何N40 0波幅效应。结论　结果表明 ,N40 0反映了词汇后水平的整合加工 ,而不反映词汇水平的词汇提取加工。

The N400 in the process of recognizing Chinese monosyllabic words

Objective To discuss the psychological meaning of the N400 in the word recognition.Methods The semantic priming effects, including response time(RT) effect and N400 effect, were investigated in this paper by means of measuring RT and event related potentials(ERP) in the lexical decision for target words. These words were in conditions of three contexts (related, neutral and unrelated) and two stimulus onset asynchronies (SOA:600 ms and 200 ms).Results In the condition of 600 ms SOA, the RT experiment showed that the RT for unrelated targets was longer than that for neutral targets (inhibitory effect) which was longer than that for related targets (facilitation effect), and the ERP experiment showed that the N400 amplitudes in the unrelated targets was larger than those in the related and neutral targets. And in the condition of 200 ms SOA, there was only a RT facilitation effect in the RT experiment and no N400 amplitude effects in the ERP experiment.Conclusions These results indicated that the N400 only reflects the postlexical integration process and does not reflect the lexical access process.