What's in a pause: Event-related potential analysis of temporal disruptions in written and spoken sentences

Two experiments examined the effects of disrupting the temporal patterns that develop during sentence reading and listening. Sentences were presented either visually, one word at a time (Experiment 1) or as natural speech (Experiment 2). Half of the sentences were familiar (proverbs or idioms) while the other half were constructed anew for these experiments. Within half the sentences, there was an unexpected 600-ms delay between the final two words. In both modalities, the amplitude of the N400 component of the event-related brain potential (ERP) to sentence final words was larger for unfamiliar than familiar sentences. The results in the two modalities differed, however, in that a Contingent Negative Variation (CNV) developed during the delay interval in the visual modality, whereas in the auditory modality the delay was marked by an emitted potential. The present results show that temporal patterns are processed differently in natural speech and in reading words presented one at a time in the center of a computer screen. (C) 1997 Elsevier Science B.V.