基于不可识别模糊字词仍能诱发N400的词汇加工理论假设,以某大学学生为被试,延迟同一字判断为任务,利用脑电技术记录不同模糊程度靶字的认知过程,来探讨N400出现的条件,以阐明N400反映的是词汇加工,还是词汇后加工。实验结果表明:与轻度、可识别模糊汉字一样,高度、不可识别模糊汉字仍然可以诱发N400,N400语义启动效应反映了词汇加工过程。
The popular mechanisms of N400 component of the event - related brain potential (ERP) proposed to explain that the N400s are the automatic spreading activation and lexical analytic process,which are in contrast to the equally popular postlexical mechanisms that are conscious and attentional. The present study examined the contrast theories or mechanisms,and used the ERP methodology to investigate electrophysiological correlates of cognitive representations underlying N400 priming effect for highly blurred and consciously unidentifiable Chinese character targets. In this study,three-character items were presented in succession in each trial of a delayed character-matching task,representing intact prime,blurred target,and intact probe stimulus,respectively. Two variables,priming and blurring,were manipulated with a 2 × 2 factorial within-subjects design in the experiment,and ended up with four treatment conditions,which were primed slightly blurred,primed highly blurred,unprimed slightly blurred,and unprimed highly blurred conditions. During a delayed character-matching task,the subjects were asked to press a key on keyboard if the target and the probe,which followed the target,were the same character in identity,and press another one if not. Sixteen native Chinese undergraduate or graduate students participated in the experiment and were instructed to make a yes / no distinction in the task,and the data of four participants were given up because of abnormal data. The ERPs of blurred Chinese characters (the targets) were recorded while participants performed a delayed character - matching task. Behavioral data showed interactions between priming and blurredness: the priming effects on accuracy rate and reaction time were more significant for highly blurred targets than for slightly blurred targets. The repeated-measures of ANOVAs on the mean amplitude with factors of blurring (slightly blurred,highly blurred) ,priming (primed,unprimed) ,and electrode site revealed significant main effects of blur