Everyone is interested in people's perceptions of risks—and of why people are afraid. This paper identifies a new source of excessive and unjustified fear. Probability neglect can be found in many areas, from environmental protection to the war on terrorism; so it's a general phenomenon of possible interest in many fields.

I think it gives a name to a phenomenon that others have studied, but perhaps hadn't often been categorized as a general problem before—and certainly hadn't been analyzed or studied in the context of politics and law.

The question is: why do people sometimes fear risks that are unlikely to come to fruition? The answer is that when our emotions are engaged, we sometimes focus on the worst case, and pay little attention to the probability that the event will actually occur. This phenomenon is documented with previous studies and with some data of my own. For the first time, the problem is connected with problems in policy and law. Sometimes government regulates problems that do not deserve a great deal of attention; "probability neglect" is one reason.

I've studied environmental law, and the law relating to risk, for many years, and I've also collaborated with psychologists and behavioral economists, and this seemed like a new way toward understanding both human cognition and social policy.

Cass R. Sunstein
Karl N. Llewellyn Distinguished Service Professor of Jurisprudence
Law School, Department of Political Science and the College
University of Chicago Law School
Chicago, IL, USA