The extent to which the thought of terrorism freaks us out
How much is our conception of risk warped by the thought of "terrorism?" Consider that there was a study conducted prior to 9/11 in which people were willing to pay more for insurance to protect them from terrorism than from any cause of death:
A further example highlights how making the description of an event very specific can induce people to see it as much more risky. In an investigation of the effects of wording on people's intentions to buy insurance for air travel, researchers found that that people were willing to pay more for a policy that would insure them against "terrorist acts" as opposed to death from "all possible causes." And yet, as must be obvious to the reader, death from terrorist acts is only one of many ways that could lead to death on an airplane. However, because this scenario was made explicit, it became more salient to people thereby increasing their perception of the risk as measured by their willingness to pay an insurance premium.[Citing to Johnson, E. J., Hershey, J., Meszaros, J., & Kunreuther, H. (1993). Framing, probability distortions, and insurance decisions. Journal of Risk and Uncertainty, 7, 35-51.] This study was briefly discussed by Daniel Kahneman while discussing his new book, Thinking, Fast and Slow: In his book, Kahneman suggests that things that are vivid in our minds often have far too much influence over us, compared to equal or greater dangers that are not as vivid. For example, you are far more likely to die of colon cancer as a result of not getting a colonoscopy than to die from an act of terrorism. Yet our national budget priorities are massively skewed to try to achieve zero-tolerance regarding terrorism, which is an impossibility despite the rhetoric of virtually every politician who opens his or her mouth on the topic. It seems that we need to work much harder to make non-vivid dangerous activities more vivid, so that we can rationally prioritize. And certainly, we need to resist the urge to decide budget priorities regarding vivid activities in isolation from all other budgetary needs. I write this assuming, perhaps naively, that the bottom line, the thing for which we are ultimately striving, is the general welfare, including the prevention of needless deaths. To the extent that this is true, when setting public policy we need to work much harder to recognize that a death is a death, regardless of the cause.