Department of Psychology, Tufts University, 490 Boston Avenue, Medford, MA 02155, USA.
J Cogn Neurosci. 2011 May;23(5):1230-46. doi: 10.1162/jocn.2010.21452. Epub 2010 Feb 22.
This study examined neural activity associated with establishing causal relationships across sentences during on-line comprehension. ERPs were measured while participants read and judged the relatedness of three-sentence scenarios in which the final sentence was highly causally related, intermediately related, and causally unrelated to its context. Lexico-semantic co-occurrence was matched across the three conditions using a Latent Semantic Analysis. Critical words in causally unrelated scenarios evoked a larger N400 than words in both highly causally related and intermediately related scenarios, regardless of whether they appeared before or at the sentence-final position. At midline sites, the N400 to intermediately related sentence-final words was attenuated to the same degree as to highly causally related words, but otherwise the N400 to intermediately related words fell in between that evoked by highly causally related and intermediately related words. No modulation of the late positivity/P600 component was observed across conditions. These results indicate that both simple and complex causal inferences can influence the earliest stages of semantically processing an incoming word. Further, they suggest that causal coherence, at the situation level, can influence incremental word-by-word discourse comprehension, even when semantic relationships between individual words are matched.
本研究考察了在线理解过程中建立句子间因果关系时的神经活动。参与者阅读三句场景的句子，并判断最后一句与上下文具有高度因果关系、中等程度因果关系和无因果关系，在此过程中测量了 ERPs。使用潜在语义分析在三种条件下匹配词汇语义共现。在因果关系不相关的情况下，关键单词引发的 N400 大于高度因果关系和中等程度因果关系的情况下的 N400，无论它们出现在句子的最后位置之前还是之后。在中线部位，与高度因果关系的单词相比，与中等程度因果关系的句子最后一个单词的 N400 衰减到相同程度，但与中等程度因果关系的单词相比，N400 与高度因果关系的单词之间的差异较小。在各种条件下都没有观察到晚期正/ P600 成分的调制。这些结果表明，简单和复杂的因果推断都可以影响语义处理传入单词的最早阶段。此外，它们表明，即使单个单词之间的语义关系相匹配，情境层面的因果连贯性也可以影响逐字逐句的话语理解。
