An ERP study on whether the P600 can reflect the presence of unexpected phonology.

In this study, we conducted a new approach to determine whether the P600 could reflect the presence of unexpected phonology. In the experiment, the critical Chinese characters in the poems are either original or substituted by homophones or synonyms. The N400 effect is observed only under the homophonic condition. Late positive shifts are revealed under both homophonic and synonymous conditions, but the amplitude under the homophonic condition is smaller than that under the synonymous condition. The observation of the N400 effect under the homophonic condition indicates that semantic processing occurs in Chinese poem comprehension, while the P600 effect elicited under the homophonic condition is a reflection of unfulfilled semantic expectations. The existence of the late positivity under the synonymous condition reveals that P600 can reflect the presence of unexpected phonology. Interestingly, late positivities under the two conditions both consist of two parts. A discussion ensues wherein these two parts of the late positive shift relate, respectively, to monitoring and resolution processes in language comprehension.