Semantic composition engenders an N400: evidence from Chinese compounds.

This study provides evidence for the role of semantic composition in compound word processing. We examined the online processing of isolated two meaning unit compounds in Chinese, a language that uses compounding to 'disambiguate' meaning. Using auditory presentation, we manipulated the semantic meaning and syntactic category of the two meaning units forming a compound. Event-related brain potential-recordings revealed a significant influence of semantic information, which was reflected in an N400 signature for compounds whose meaning differed from the constituent meanings. This finding suggests that the combination of distinct constituent meanings to form an overall compound meaning consumes processing resources. By contrast, no comparable difference was observed based on syntactic category information. Our findings indicate that combinatory semantic processing at the word level correlates with N400 effects.

The P600 reflects cost of new information in discourse memory.

Discourse processing depends on long-term semantic memory and discourse memory (i.e. the organization and maintenance of a mental model). Using event-related potentials, the information-processing functions of the activities manifested by a centroparietal negativity (N400) and a posterior positivity (P600) were investigated during the processing of inferences. On the basis of findings from semantic priming, it was predicted that the standard N400 signature would modulate differences in the degree of inferential processing (semantic memory). Instead of N400 modulations, however, the two conditions that depended on a more demanding drawing of inferences elicited a P600, indicating that updating the mental model encumbers discourse memory capacity. The results highlight the functional significance of this positivity for discourse updating, and support the view that the P600 reflects distinct language processes.

Effects of (in)transitivity on structure building and agreement.

The present investigation demonstrates that incremental sentence processing is guided by principles of minimal structure building. Event-related potentials (ERPs) to a local number mismatch between an auxiliary and a subsequent noun phrase revealed that the subject preference, a strategy known to be very robust during processing, can be overridden when information about a verb's valency (i.e., the number and type of arguments a verb requires) is available. Using verb-initial sentences, the ERP data revealed a left anterior negativity for the local number mismatch at the noun phrase following the finite verb compared to a locally matching condition in conditions with intransitive verbs, but no effect following conditions with transitive verbs. This indicates that grammar-internal information guides minimal structure formation, such that verbs that require only one argument reveal an immediate mismatch effect, while verbs that require two arguments neglect the subject preference and opt for an alternative interpretation in light of the number mismatch. The study reveals that the decisions made at this point have consequences for the processing of subsequent elements within the sentence. Using coordination constructions (e.g., the dancer and the singer), the study reports additional ERP results at the coordinating conjunction and at the second noun phrase of the coordination, which provide further evidence that verb valency is taken into consideration during incremental parsing and can override local agreement expectations.

Differential effects of saliency: an event-related brain potential study.

We present event-related brain potential evidence from language comprehension that the N400-modulation during noun-phrase integration is a function of the type of referential dependency that is established (identity versus inference) and the saliency (in the following understood as the sum of factors that influence the degree of accessibility of an entity in the mental model) of the information unit that serves as an anchor for the dependency. Identity relations revealed a reduced N400 compared to inferential relations, confirming previous findings. More importantly, the investigation provides novel findings concerning the effect of saliency on noun-phrase integration: identity relations did not reveal a difference in the N400 as a function of the saliency manipulation. In contrast, inferential relations showed a more pronounced N400 with less salient anchors compared to inferential relations that involved a highly salient anchor. Moreover, no difference in N400-amplitude obtained between less salient inference-based entities and new information units. These data suggest that inferential processes are blocked in the absence of a highly accessible anchor. The findings generally indicate that the language system is not only sensitive to the kind of dependency that is established, but also to the saliency of the entity that serves as anchor for the dependency. The data further demonstrate that the processing system is responsive to semantic- and discourse-level information during the interpretation of noun-phrases.

Inferential bridging relations reveal distinct neural mechanisms: evidence from event-related brain potentials.

This study investigates the online comprehension of Determiner Phrases (DPs) as a function of the given-new distinction in two-sentence texts in German and further focuses on DPs whose interpretation depends on inferential information (so-called 'bridging relations'). Previous reaction time studies report an advantage of given over new information. In the present study, this difference is reflected in distinct neural mechanisms: event-related potentials reveal that previously introduced (i.e., given) DPs elicit a reduced N400, while new DPs show an enhanced N400 followed by a P600. Crucially, inferentially bridged DPs, which are hypothesized to share properties with new and given information, first pattern with given DPs (showing an attenuated N400) and then with new DPs (showing an enhanced P600). The data demonstrate that salience relations between DPs and prior context ease DP integration and that additional cost arises from the establishment of independent reference. They further reveal that processing cost associated with the interpretation of bridged DPs results from the anaphoric complexity of introducing an independent referent.

The role of the anterior left hemisphere in real-time sentence comprehension: evidence from split intransitivity.

We investigate Broca's sentence comprehension as an impairment on normal syntactic composition: the slow-syntax hypothesis (SSH). Experiment 1 examines comprehension of object-relative clauses (Wh-movement). Experiment 2 examines comprehension of sentences with unaccusative verbs (NP-movement), which like passives, base-generate their theme-argument in object position. Guided by the SSH, both experiments test the prediction that syntax-dependent effects such as "gap-filling" are observable but in a delayed fashion. Results show that whereas no priming was obtained at the point of the trace, antecedent reactivation emerged 650 and 800 ms after the verb (for Wh- and NP-movement respectively). This shows, contrary to dependency-based generalizations, that Broca's patients are able to successfully implement dependencies, albeit in a protracted manner. Given the localization value provided by Broca's aphasia, this supports the notion that the temporal implementation of syntactic structure formation (i.e., the requirement that it be fast and automatic) depends on the integrity of the anterior left hemisphere.