Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
School of Psychology, Shannxi Normal University, Xi'an, China.
PLoS One. 2013 Dec 2;8(12):e79734. doi: 10.1371/journal.pone.0079734. eCollection 2013.
This study investigated whether semantic integration in discourse context could be influenced by topic structure using event-related brain potentials. Participants read discourses in which the last sentence contained a critical word that was either congruent or incongruent with the topic established in the first sentence. The intervening sentences between the first and the last sentence of the discourse either maintained or shifted the original topic. Results showed that incongruent words in topic-maintained discourses elicited an N400 effect that was broadly distributed over the scalp while those in topic-shifted discourses elicited an N400 effect that was lateralized to the right hemisphere and localized over central and posterior areas. Moreover, a late positivity effect was only elicited by incongruent words in topic-shifted discourses, but not in topic-maintained discourses. This suggests an important role for discourse structure in semantic integration, such that compared with topic-maintained discourses, the complexity of discourse structure in topic-shifted condition reduces the initial stage of semantic integration and enhances the later stage in which a mental representation is updated.
本研究采用事件相关脑电位技术考察了语篇语境中的语义整合是否会受到话题结构的影响。参与者阅读了一些语篇，语篇的最后一句话包含一个关键的词，这个词与第一句话中建立的话题要么一致，要么不一致。在语篇的第一句话和最后一句话之间的句子既可以保持原来的话题，也可以转换话题。结果表明，在保持话题的语篇中，不一致的词会引起广泛分布在头皮上的 N400 效应，而在转换话题的语篇中，不一致的词会引起偏向右侧半球的 N400 效应，并集中在中央和后区。此外，只有在转换话题的语篇中，不一致的词才会引起晚正电位效应，而在保持话题的语篇中则不会。这表明语篇结构在语义整合中起着重要的作用，与保持话题的语篇相比，转换话题的语篇结构的复杂性降低了语义整合的初始阶段，增强了更新心理表征的后期阶段。
