Solving the problem of double negation is not impossible: electrophysiological evidence for the cohesive function of sentential negation

In natural languages, two negating elements that cancel each other out (as in not impossible) are logically equivalent to the non-negated word form (in this case, possible). It has been proposed that the function of sentential double negation is to create coherence between sentences containing opposing information. Thus, not impossible is functionally different from possible. The present ERP study tested this hypothesis in Dutch. Native speakers read sentences in which evoked negative expectations are cancelled by a second sentence including either a double negation or the corresponding non-negated word form. Results showed that non-negated word forms, such as possible, elicited a larger N400 effect than double negations, such as not impossible. We suggest that canceling out a negative expectation by a double negation compared to the non-negated word form, makes it easier for the reader to integrate the two sentences semantically and connect them to the present discourse. © 2016 Informa UK Limited, trading as Taylor & Francis Group.