INTERACTIONS BETWEEN SENTENCE CONTEXT AND WORD-FREQUENCY IN EVENT-RELATED BRAIN POTENTIALS

Event-related brain potentials (ERPs) were recorded as subjects silently read a set of unrelated sentences. The ERP responses elicited by open-class words were sorted according word frequency and the ordinal position of the eliciting word within its sentence. We observed a strong inverse correlation between sentence position and the amplitude of the N400 component of the ERP. In addition, we found that less frequent words were associated with larger N400s than were more frequent words, but only if theeliciting words occurred early in their respective sentences. We take this interaction between sentence position and word frequency as evidence that frequency does not play a mandatory role in wordrecognition, but can besuperseded by the contextual constraint provided by a sentence. © 1990 Psychonomic Society, Inc.