The establishment of reference is essential to language comprehension. The goal of this study was to examine listeners' sensitivity to referential ambiguity as a function of individual variation in attention, working memory capacity, and verbal ability. Participants listened to stories in which two entities were introduced that were either very similar (e.g., two oaks) or less similar (e.g., one oak and one elm). The manipulation rendered an anaphor in a subsequent sentence (e.g., oak) ambiguous or unambiguous. EEG was recorded as listeners comprehended the story, after which participants completed tasks to assess working memory, verbal ability, and the ability to use context in task performance. Power in the alpha and theta frequency bands when listeners received critical information about the discourse entities (e.g., oaks) was used to index attention and the involvement of the working memory system in processing the entities. These measures were then used to predict an ERP component that is sensitive to referential ambiguity, the Nref, which was recorded when listeners received the anaphor. Nref amplitude at the anaphor was predicted by alpha power during the earlier critical sentence: Individuals with increased alpha power in ambiguous compared with unambiguous stories were less sensitive to the anaphor's ambiguity. Verbal ability was also predictive of greater sensitivity to referential ambiguity. Finally, increased theta power in the ambiguous compared with unambiguous condition was associated with higher working-memory span. These results highlight the role of attention and working memory in referential processing during listening comprehension.

Previous research suggests that bilingual comprehenders access lexical representations of words in both languages nonselectively. However, it is unclear whether global language suppression plays a role in guiding attention to target language representations during ongoing lexico-semantic processing. To help clarify this issue, this study examined the relative timing of language membership and meaning activation during visual word recognition. Spanish–English bilinguals performed simultaneous semantic and language membership classification tasks on single words during EEG recording. Go/no-go ERP latencies provided evidence that language membership information was accessed before semantic information. Furthermore, N400 frequency effects indicated that the depth of processing of words in the nontarget language was reduced compared to the target language. These results suggest that the bilingual brain can rapidly identify the language to which a word belongs and subsequently use this information to selectively modulate the degree of processing in each language accordingly.

We present results from a study demonstrating that high- and low-span listeners show qualitatively different brain responses when comprehending simple active sentences. Participants listened to naturally produced sentences in three conditions in which the plausibility of thematic relations was manipulated, for instance: The dog(1)/The poet(2)/The box(3) is biting the mailman. Event-related potentials were recorded to the first noun, the verb, and the second noun in all three conditions. In (2), the thematic relations between the words in the sentence are less expected given our world knowledge, and this resulted in an N400 effect of semantic processing difficulty to the second noun for both high- and low-span subjects. In (3), the inanimate first noun cannot be the agent of the verb. Only high-span subjects showed an effect of animacy on the sentence-initial nouns, evident from a larger anterior negative shift to inanimate than animate nouns. Furthermore, to the thematically violated verbs (3), low-span subjects showed an N400, whereas high-span subjects generated a P600. We suggest that this P600 effect to the thematically violated verb may be related to processing costs resulting from a conflict between the provisional thematic roles assigned as a function of the inanimate sentence-initial noun, and the actual (animate) agent required by the verb. We further argue that low-span subjects lag behind those with high span in their use of animacy, but not real-world knowledge in the on-line computation of thematic roles in spoken language comprehension.

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.

One of the core aspects of human sentence processing is the ability to detect errors and to recover from erroneous analysis through revision of ambiguous sentences and repair of ungrammatical sentences. In the present study, we used event-related potentials (ERPs) to help identify the nature of these processes by directly comparing ERPs to complex ambiguous sentence structures with and without grammatical violations, and to simpler unambiguous sentence structures with and without grammatical violations. In ambiguous sentences, preference of syntactic analysis was manipulated such that in one condition, the structures agreed with the preferred analysis, and in another condition, a nonpreferred but syntactically correct analysis (garden path) was imposed. Nonpreferred ambiguous structures require revision, whereas ungrammatical structures require repair. We found that distinct ERPs reflected different characteristics of syntactic processing. Specifically, our results are consistent with the idea that a positivity with a posterior distribution across the scalp (posterior P600) is an index of syntactic processing difficulty, including repair and revision, and that a frontally distributed positivity (frontal P600) is related to ambiguity resolution and/ or to an increase in discourse level complexity.