Neural mechanisms of sentence comprehension based on predictive processes and decision certainty: Electrophysiological evidence from non-canonical linearizations in a flexible word order language.

The specificity or generality of language-related event-related brain potentials (ERPs) has been a point of continuing debate in the cognitive neuroscience of language. The present study measured ERPs to (preferred) subject-before-object (SO) and (dispreferred) object-before-subject (OS) word orders in German while manipulating morphosyntactic and semantic cues to correct sentence interpretation. We presented sentence pairs as connected speech (context and target sentences) and examined ERPs at the position of the first argument (noun phrase) in the target sentence. At this position, word order was determinable by either (a) case marking (morphosyntactic cue); (b) animacy (semantic cue); or (c) the preceding context sentence (local ambiguity; contextual cue). Following each sentence pair, participants judged the acceptability of the second sentence in the context of the first and performed a probe word recognition task. Results showed a biphasic N400-P600 pattern at the first noun phrase in the OS conditions irrespectively of which cues (syntactic or semantic) were available to the parser for disambiguation. N400 latency varied as a function of temporal cue availability and P600 amplitude increased for unambiguous object-initial conditions even though these were rated acceptable in the judgment task. These findings support an interpretation of ERP components in terms of general cognitive mechanisms such as predictive processes (N400) and decision certainty (P600 as an instance of the P300) rather than a domain-specific view of a semantic N400 and a syntactic P600.