Participants read a series of news articles, each containing a target event followed by 2 causes. To study the ease with which readers update their mental representation as they proceed through the text, the certainty of the first cause was manipulated: It was presented as either a certain explanation of the subsequent target event or as a suspected explanation. In a control condition, no first cause was presented. After a backgrounding section, a critical sentence introduced a second, definitive cause. In Experiment 1, reading times for the critical sentence were the slowest when the first cause was presented as certain. Reading times were also longer in the suspected condition than in the no-cause condition. Because recall protocols collected in Experiment 2 revealed the readers' tendency to encode the suspected cause one half of the time as certain, the hypothetical status of the first cause was stressed in the suspected condition in Experiment 3. Again, reading times increased when a second cause was introduced in both conditions (i.e., suspected and certain), and varied as a function of the certainty of the first cause. These results highlight that as long as a cause has been invoked earlier in the news articles, the updating process needs extra processing time to incorporate a new cause; this extra time is necessary independent of the certainty of the information that has to be replaced. (Contains 4 tables.)