Evolving Risk Perceptions About Near-Miss Terrorist Events

After disasters such as the attacks of September 11, 2001, the public experiences a heightened response that naturally returns to some lower level of concern. We demonstrate that this pattern of heightened response followed by a decline as time passes also occurs for terrorist events that are near misses. Data from a field study and two experimental lab studies show that people's perceptions of the risk of similar category events and their perception that the near-miss attempt was close to being a successful terrorist attack decline over time. Moreover, the decline in the perception of how close the near miss was to being a successful terrorist attack partially explains the decline in the perception of the risk of future similar category events. We also show that the perceived risk for terrorism in general decays more slowly than for a specific category event, and is reactivated by additional terrorist attempts. Finally, we show that people rely on reference points to provide the context for near-miss terrorism events, and without reference points assessing perceptions of risk and perceptions of how close an event was to having a truly bad outcome are difficult. The reliance on reference points for context can result in different people evaluating the same event differently depending on that person's information about prior terrorist attempts. Our contributions provide guidance to organizations such as the U.S. Department of Homeland Security for encouraging stakeholders to make rational decisions on the basis of the nature, scale, and scope of the attack that balance recovery with continued vigilance. We also provide information to other intelligence agencies who need to consider their own individuals' personal biases that may arise when repeatedly examining terrorist near misses.