Negation and the N400: investigating temporal aspects of negation integration using semantic and world-knowledge violations

Negation comprehension is a time-consuming, resource demanding process. This study investigates whether additional time to process the negation operator eases negation integration. In Experiment 1 we analysed N400 amplitude in sentences of the following types: correct sentences (Zebras are (not) stripy), world-knowledge violation sentences (Ladybirds are (not) stripy) and semantically violated sentences (Thoughts are (not) stripy). In Experiment 2, the negation was pre-pended to the actual sentence using an introductory statement (It is (not) true that ladybirds are stripy) to provide additional processing time to deal with the negation operator. Crucially, in both experiments the N400 amplitude was larger for semantic and world-knowledge violations than correct sentences irrespective of the negation operator. Taken together, our study suggests that allowing additional time to process the negation operator alone – before encountering the information that completes the negated proposition – has no beneficial influence on on-line negation integration as reflected in the N400.