Hemispheric differences and similarities in comprehending more and less predictable sentences.

With a growing literature demonstrating the predictive nature of language processing, the current study examines contributions of the brain's two hemispheres in processing more and less probable sentence continuations. Specifically, we use the ERP method in conjunction with the visual half-field paradigm to test for hemispheric utilization of sentential constraint to (pre-)activate lexical information and resolve meaning. Taking advantage of the N400's semantic sensitivities, we find support for both hemispheres exhibiting remarkably similar involvement, across a range of message level constraint, in meaning construction. In contrast, hemispheric ERP patterns at a later processing stage differed, as reflected in an anterior post-N400 positivity (PNP) to constraint violations for words presented to the right but not left visual field (indicating a left hemisphere processing bias). We show here that hemispheric involvement in predictive sentence comprehension varies at different stages of word processing, and we examine these patterns' (in)consistencies with findings from the hemi-field and central visual presentation literature.