The N400 is an event-related potential (ERP) that reflects the processing of semantics in the brain. When reading sentences, the N400 amplitude is modulated by both the cloze probability of the sentence and the association strength between individual words. When contradicted in strongly constraining sentences, that is, the beginning of the sentence builds a strong expectation of the final word; the cloze probability overrules the effect of association strength. We evidence that this is also the case for non-constraining sentences, such as the ones with low to moderate cloze probabilities. Our results give the evidences that if the sentence generates even weak to moderate expectations about the final word, word association plays almost no role in the processing of this word.