This article concerns a class of experimental manipulations that require people to generate explanations or imagine scenarios. A review of studies using such manipulations indicates that people who explain or imagine a possibility then express greater confidence in the truth of that possibility. It is argued that this effect results from the approach people take in the explanation or imagination task: They temporarily assume that the hypothesis is true and assess how plausibly it can account for the relevant evidence. From this view, any task that requires that a hypothesis be treated as if it were true is sufficient to increase confidence in the truth of that hypothesis. Such tasks cause increased confidence in the hypothesis at the expens...