Informative use of "not" is N400-blind.

While sentence processing is generally a highly incremental and predictive process, negation seems to present an exception to this generalization. Two-step models of negation processing claim that predicate negation is computed only after the meaning of the core proposition has been computed. Several ERP studies eliciting the N400 (an index of semantic integration or lexical expectation) have found a "negation-blind" pattern of N400 results, suggesting that the negation has not been integrated into the overall sentence meaning by the time the critical word for the N400 is encountered. Recent research, however, showed that the N400 was sensitive to the negation-modulated truth value of the sentence when negation was pragmatically licensed. We investigate the possibility that negation-blind N400 is due to under-informativeness of stimuli in past experiments. We found that ERPs to simple class-exclusion statements ("A hammer is not a bird") still exhibit negation blindness, even when negation is presented in a more meaningful context. The current findings provide new support for late/non-incremental interpretation of negation even when negation is pragmatically licensed.