Processing structure of sentence perception

To extract meaning from a sentence, the listener must combine information from several levels of linguistic analysis. Psycholinguistic research1 has documented a range of processing levels from the phonetic to the semantic, but has not explored the central problem of specifying the interactions between these levels. We have examined three fundamental questions about the processing structure of sentence perception. When, during sentence processing, does information at different levels become available to the listener; what is the time-course of the interactions between these levels; and what is the direction of information flow between them?