In an ERP experiment we investigated how the recruitment and integration of world knowledge information relate to the integration of information within a current discourse context. Participants were presented with short discourse contexts which were followed by a sentence that contained a critical word that was correct or incorrect based on general world knowledge and the supporting discourse context, or was more or less acceptable based on the combination of general world knowledge and the specific local discourse context. Relative to the critical word in the correct world knowledge sentences following a neutral discourse, all other critical words elicited an N400 effect that began at about 300 ms after word onset. However, the magnitude of the N400 effect varied in a way that suggests an interaction between world knowledge and discourse context. The results indicate that both world knowledge and discourse context have an effect on sentence interpretation, but neither overrides the other.
IntroductionAlmost everyday we read or listen to new information. Listening to the news, speaking with a family member or coworker, overhearing a conversation or watching a television show will likely all involve encountering some new information, such as an anecdote of something that happened that day. Deriving the meaning of each of these utterances involves, at the least, retrieving the meanings of the individual words and facts about the world and combining them in a way that is licensed by the grammar and the prior discourse context. However, we sometimes hear new facts that may or may not be congruent with what we already know, for example, when speaking with a friend (e.g., Mary says to Bob, "John can't make it to the party", when Bob thought John was coming to the party) or watching a television show (e.g., "The pigs are flying low today, eh", John Cleese, 1969 in Monty Python's Flying Circus). When this occurs, do we initially just incorporate the current discourse for understanding the sentence or do we also integrate our world knowledge, creating a conflict? The purpose of the current study is to investigate how the recruitment and integration of world knowledge information relate to the integration of information within a current discourse context. When the discourse information does not fit with our previous world knowledge, is the default world knowledge overwritten? Models of language comprehension disagree on how and when discourse information and world knowledge are