Five experiments used ERPs and eye tracking to determine the interplay of word-level and discourse-level information during sentence processing. Subjects read sentences that were locally congruent but whose congruence with discourse context was manipulated. Furthermore, critical words in the local sentence were preceded by a prime word that was associated or not. Violations of discourse congruence had early and lingering effects on ERP and eye-tracking measures. This indicates that discourse representations have a rapid effect on lexical semantic processing even in locally congruous texts. In contrast, effects of association were more malleable: Very early effects of associative priming were only robust when the discourse context was absent or not cohesive. Together these results suggest that the global discourse model quickly influences lexical processing in sentences, and that spreading activation from associative priming does not contribute to natural reading in discourse contexts.

Effects of word repetition are extremely robust, but can these effects be modulated by discourse context? We examined this in an ERP experiment that tested coreferential processing (when two expressions refer to the same person) with repeated names. ERPs were measured to repeated names and pronoun controls in two conditions: (1) In the prominent condition the repeated name or pronoun coreferred with the subject of the preceding sentence and was therefore prominent in the preceding discourse (e.g., "John went to the store after John/he."); (2) in the nonprominent condition the repeated name or pronoun coreferred with a name that was embedded in a conjoined noun phrase, and was therefore nonprominent (e.g., "John and Mary went to the store after John/he."). Relative to the prominent condition, the nonprominent condition always contained two extra words (e.g., "and Mary"), and the repetition lag was therefore smaller in the prominent condition. Typically, effects of repetition are larger with smaller lags. Nevertheless, the amplitude of the N400 was reduced to a coreferentially repeated name when the antecedent was nonprominent as compared to when it was prominent. No such difference was observed for the pronoun controls. Because the N400 effect reflects difficulties in lexical integration, this shows that the difficulty of achieving coreference with a name increased with the prominence of the referent. This finding is the reverse of repetition lag effects on N400 previously found with word lists, and shows that language context can override general memory mechanisms.

The use of repeated expressions to establish coreference allows an investigation of the relationship between basic processes of word recognition and higher level language processes that involve the integration of information into a discourse model. In two experiments on reading, we used eye tracking and event-related potentials to examine whether repeated expressions that are coreferential within a local discourse context show the kind of repetition priming that is shown in lists of words. In both experiments, the effects of lexical repetition were modulated by the effects of local discourse context that arose from manipulations of the linguistic prominence of the antecedent of a coreferentially repeated name. These results are interpreted within the context of discourse prominence theory, which suggests that processes of coreferential interpretation interact with basic mechanisms of memory integration during the construction of a model of discourse.

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