Investigating the effects of distance and number interference in processing subject-verb dependencies: an ERP study.

Event-related potentials (ERPs) were used to investigate whether the processing of subject-verb dependencies is influenced by (1) the linear distance between the subject and the verb and (2) the presence of an intervening noun phrase with interfering number features. Linear distance did not affect integration and diagnosis or revision processes at the verb, as indexed by early negative and P600 components. This is in accordance with hierarchy-based models of reanalysis, but is problematic for distance-based integration models. However, tracking of the subject features is affected by linear factors: more judgment errors were made in the long compared to the short condition. Furthermore, the presence of a plural object between the singular subject and the verb led to more judgment errors, and an enhanced positivity around 250 ms for the grammatical verbs. This suggests that linear factors affect feature tracking, but not integration processes following feature retrieval or repair processes following the detection of a mismatch.