Predictability and human stress: Toward a clarification of evidence and theory

This chapter introduces predictability and human stress and the notion of predictability. Two nonoverlapping classes of predictability are defined in the chapter: knowing the conditions under which the event will occur (contingency predictability) and knowing what the event will be like (what-kind-of-event predictability). The interaction of the two classes of predictability and their controllability is discussed in the chapter. The chapter describes the five major existing theories of predictability and human stress—namely, information seeking, preparatory response, preparatory set, uncontrollability, and safety signal. To specify the conditions under which predictability has stress-reducing effects and when it does not, four new hypotheses (the blunting hypothesis, the analytic hypothesis, the script hypothesis, and the arousal hypothesis) that attempt to organize the sweep of data are considered in the chapter. Humans generally prefer predictable over unpredictable aversive events. There is one exception, however—that is, when individuals can distract themselves from danger-related information, they prefer unpredictable aversive events.