Who Did What and When? Using Word- and Clause-Level ERPs to Monitor Working Memory Usage in Reading

ERPs were recorded from 24 undergraduates as they read sentences known to differ in syntactic complexity and working memory requirements, namely Object and Subject Relative sentences. Both the single-word and multiword analyses revealed significant differences due to sentence type, while multiword ERPs also showed that sentence type effects differed for Good and Poor comprehenders. At the single-word level, ERPs to both verbs in Object Relative sentences showed a left anterior negativity between 300 and 500 msec postword-onset relative to those to Subject Relative verbs. At the multiword level, a slow frontal positivity characterized Subject Relative sentences, but was absent for Object Relatives. This slow positivity appears to index ease of processing or integration. and was more robust in Good than in Poor comprehenders.