I was giving some lectures in the last week or so on Judgment and Heuristics, and devoted a lot of time to the availability heuristic and salience. It is worth thinking about this in the context of terror alerts about potential Mumbai-style attacks in Europe. I am going to give the people who issue these types of alerts the benefit of the doubt and assume that there is a good reason for doing them e.g. to allow people to make their own choice, to raise general alertness about threats to aid prevention and so on (William Easterly is less willing to give the benefit of the doubt). But it does raise the strong possibility that people will start worrying about things that will affect them with very low probabilities and over which they do not have much control. Furthermore, there is a huge imbalance in the airtime devoted to making people afraid of things compared to the airtime devoted to getting people to set things in their proper context e.g. there are terrorist threats in operation in Europe but you are far more likely statistically to be killed in a car accident.
Given the probabilities involved for any individual in dying in a terrorist attack while travelling to Continental Europe, my response to the class was that if they intended cancelling an upcoming trip to France or Germany then I suggested that we lock the doors and I will call up for supplies and we will barracade ourselves in the lecture theatre because the relative safety of staying there for the rest of the term compared to braving the roads home everyday is far greater than the relative safety of staying in Ireland for a few days compared to taking your trip. It is easier to imagine dying in a terrorist attack than dying in a car crash and it occupies more of our mind when we are recalling risk. It is not at all inconsistent to feel moral outrage about terrorist attacks and seek that they be prevented and/or the perpetrators pursued. It is inconsistent with a rational worldview to overestimate your exposure to risk and to allow this to influence your decisions. Part of living in the modern world is overcoming fears of salient but low probability and non-catastrophic risk and getting on with life and making decisions based on more core values. Given the huge asymmetric costs faced by public officials from not revealing information about risk, it may ultimately have to be up to us as individuals to learn how to filter out things that lead to wrong decisions and a life based on fear.