The targets of terrorist attacks are multiple and diverse. This fact constitutes an advantage for terrorists, because it is one facet of the uncertainty on which they capitalize—where and when will an attack occur and what kind of attack will it be? Some targets of terrorist attacks are human beings themselves, for example, assassinations, the bombing of large human assemblies, and biological and chemical poisoning and contamination. Others do not attack humans at all but aim to disrupt some vital economic or institutional functioning, for example, disruption of financial institutions or computer networks. No matter what the attack, however, there is always a human response to it. In this chapter we summarize much of what is known about these responses from research in the behavioral and social sciences.
