Event-related responses to pronoun and proper name anaphors in parallel and nonparallel discourse structures.

The present study investigated event-related potential (ERP) effects of pronoun and proper name anaphors in both parallel and nonparallel discourse structures. Thirty-seven students processed 400 semantically different text passages. Each trial consisted of two sentences and a comprehension question. The first sentence introduced a protagonist who was referred to by an anaphoric word in the second sentence. The anaphoric word was either a pronoun or a repetition of the proper name of the protagonist and had either the same or a different syntactic role as its antecedent (subject or object). The sentences were presented word by word as rapid serial visual display. Event-related potentials were recorded from 61 scalp electrodes. In agreement with the parallel function strategy, nonparallel discourse structures required longer decision times and exhibited higher error rates than parallel structures. The ERPs revealed two effects: First, pronoun anaphors evoked a more pronounced negativity than proper name anaphors between 270 and 420 ms latency over the frontal cortex electrodes. Another relative negativity occurred between 510 and 600 ms over the parietal cortex electrodes. Second, anaphors in nonparallel positions were accompanied by a more pronounced negativity over the parietal cortex. These data support the idea that an anaphor in nonparallel position triggers extra processing steps, probably search processes in working memory which integrate currently encountered information with previously activated representations.