Distinct neural correlates for pragmatic and semantic meaning processing: an event-related potential investigation of scalar implicature processing using picture-sentence verification.

The present study examines the brain-level representation and composition of meaning in scalar quantifiers (e.g., some), which have both a semantic meaning (at least one) and a pragmatic meaning (not all). We adopted a picture-sentence verification design to examine event-related potential (ERP) effects of reading infelicitous quantifiers for which the semantic meaning was correct with respect to the context but the pragmatic meaning was not, compared to quantifiers for which the semantic meaning was inconsistent with the context and no additional pragmatic meaning is available. In the first experiment, only pragmatically inconsistent quantifiers, not semantically inconsistent quantifiers, elicited a sustained posterior negative component. This late negativity contrasts with the N400 effect typically elicited by nouns that are incongruent with their context, suggesting that the recognition of scalar implicature errors elicits a qualitatively different ERP signature than the recognition of lexico-semantic errors. We hypothesize that the sustained negativity reflects cancellation of the pragmatic inference and retrieval of the semantic meaning. In our second experiment, we found that the process of re-interpreting the quantifier was independent from lexico-semantic processing: the N400 elicited by lexico-semantic violations was not modulated by the presence of a pragmatic inconsistency. These findings suggest that inferential pragmatic aspects of meaning are processed using different mechanisms than lexical or combinatorial semantic aspects of meaning, that inferential pragmatic meaning can be realized rapidly, and that the computation of meaning involves continuous negotiation between different aspects of meaning.