We employ a scenario-sentence-verification paradigm to inves-tigate the role of scenario-given alternatives for the process-ing of affirmative and negative sentences. We show that forboth affirmative and negative sentences the N400 amplitude islarger if the context model provides multiple alternatives fora true sentence continuation relative to the case when it pro-vides only a unique referent. Additionally, we observe a latepositivity effect for negative relative to affirmative sentences,independent of the context model.