The process of understanding has been widely shown to be more complex when sentences are presented in a negative form, such as “A robin is not a tree,” compared to their affirmative counterparts, regardless of context. Two eye-tracking experiments compared affirmative and negative sentences in both an informative context, “Due to its high addiction, heroin is not very safe,” and an uninformative one, “The heart’s functioning is not very superficial.” In Experiment 1, participants read sentences while their eye movements were tracked. The results showed that eye fixations on the target word (e.g., "safe") lasted longer for negative sentences than for affirmative ones in the uninformative context, but only for true sentences. This difference disappeared in the informative context, supporting the theory that context facilitates the processing of negation. We also tested whether this finding was due to predictability. In Experiment 2, we equalized predictability across both contexts. Participants listened to the sentences while two target words were displayed on the screen (e.g., “Safe/Dangerous” or “Superficial/Important”), and their eye movements were tracked. We will discuss those results in relation to the main theories of comprehension.