The updating process is crucial to the development of a situation model. The process may be either an online or a delayed process. These 2 opposite assumptions led us to investigate the time course and quality of the updating process. We assumed that the updating process is sensitive to readers' prior knowledge and to the task that participants have to perform. We compared the data obtained with 2 tasks that both assessed the integration of the same information: a probe task inserted during the comprehension of the text and an inference judgment task presented after the text comprehension. Our results demonstrated that all readers can update their situation model online, but the delayed integration of new incoming information requires a high level of prior knowledge of the situation described. Moreover, the online updating is enhanced when participants complete a task that strengthens the model that initially is built. The implications for this new view of the updating process are discussed within current theories of text comprehension.