世界知识在句子理解中的整合时程

Hagoort等(2004)应用背离范式发现世界知识和单词意义在句末的整合是同时进行的。本研究将背离信息提前到句首短语中,旨在探讨世界知识在句子阅读过程中被整合的时程特征。实验采用四词句子为材料，其中第二个词（目标词）含有单词意义或世界知识背离信息，记录并比较被试在阅读后三个词时诱发的脑电变化。结果发现：与正确句子比较，无论是单词意义背离还是世界知识背离，背离目标词均引发出经典的N400，二者在峰值时间和始潜时上无显著差异，但世界知识背离信息诱发的N400波幅值相对较小。句中的后继单词不再诱发类似的N400；但到句子结尾，两类含有背离信息句子的句末正常单词又诱发出类似N400的一个负波。结果提示，在句子理解过程中，世界知识的整合与单词意义的整合相似，可能是随着句子理解过程即时进行的，整合的结果不影响后继信息的加工；但到了句末，读者在对整个句子内容作真实性判断时会对先前进行过的整合再进行考察。

The Time Course of World Knowledge Integration in Sentence Comprehension

Using a violation paradigm, Hagoort et al. observed that world knowledge and word meaning are integrated simultaneously at the end of a sentence. The present study was intended to track the time course of integration of world knowledge in sentence comprehension when world knowledge is embedded in a sentence rather than at the sentence end. The materials used were four-word sentences. The second word in the sentences was the target word that could contain information leading to semantic or world knowledge violations. Event-related brain potentials (ERPs) induced by the last three words in each sentence were recorded and compared across three conditions, the word meaning violation condition, the world knowledge violation condition, and the non-violation normal congruence condition. Compared with non-violation congruous sentences, presentation of the target message in world knowledge violation sentences immediately evoked a typical N400. As the sentence unfolded, the subsequent words in the sentence did not produce similar N400 effect except at the sentence end when a negative N400-like component was observed. It is noted that while the N400 evoked by the violation target words showed no obvious hemispheric asymmetry, the one evoked by the ending words showed right hemisphere dominance. Compared with word meaning violation sentences, there were no other ERP waveform differences except that the N400 amplitude was much smaller for world knowledge violation than word meaning violation. The results indicate that world knowledge, similar to word meaning, could be integrated instantly as the sentence unfolds during sentence comprehension and outcome of this integration process does not affect processing of subsequent information. Integrated world knowledge manifested earlier could be reactivated however when the reader reaches the sentence end and makes judgment about the facticity of the whole sentence.