After seeing a movie that dramatizes nuclear war, they worried more about nuclear war; indeed, they felt that it was more likely to happen. The sheer volatility of people's judgement of the odds--their sense of the odds could be changed by two hours in a movie theater--told you something about the reliability of the mechanism that judged those odds.

Stories people told themselves were biased by the availability of the material used to construct them...what people remember about the past, [Kahneman and Tversky] suggested, is likely to warp their judgement of the future. "We often decide that an outcome is extremely unlikely or impossible, because we are unable to imagine any chain of events that could cause it to occur. The defect, often, is in our imagination.