Traditional scientific views of rationality are couched in economic terms; choosing an option that does not maximize expectancy is irrational. The construct has been extended metaphorically so that the term “irrational” now describes any decision deemed foolish by the evaluator. For everyday decisions that do not involve money, a decision maker’s utilities are generally not known to an onlooker. Therefore, the pejorative label may be applied inappropriately because the evaluation is distorted by incorrect assessment of the decision maker’s goals. We (...) tie this linguistic confusion to the predominance of gambling studies within decision making research. For noneconomic decisions, we propose an alternative definition, one inspired by a theory of everyday decisions. We label a decision irrational if is inconsistent with a policy previously established by the decision maker. The hierarchical structure of everyday decisions, along with the descriptive multiattribute utility model, are core elements in the theory presented by Weiss et al. (2010 Theory and Decision, 68, 101–114). The theory holds that fast changing considerations are a crucial element in the evaluation of decision options. The momentary salience attached to a consequence can change with current, often fleeting circumstances. An option that would usually be rejected can quickly become too tempting to resist. Most people exhibit this kind of irrationality, violating a personal policy, some of the time—and they are not necessarily foolish to do so. (shrink)

We propose a descriptive version of the classical multi-attribute utility model; to that end, we add a new parameter, momentary salience, to the customary formulation. The addition of this parameter allows the theory to accommodate changes in the decision maker’s mood and circumstances, as the saliencies of anticipated consequences are driven by concerns of the moment. By allowing for the number of consequences given attention at the moment of decision to vary, the new model mutes the criticism that SEU models (...) call for an omniscient decision maker. Use of the model is illustrated with a large-scale longitudinal study showing that adolescent smokers have higher utility for smoking than nonsmokers. We also propose to use the model hierarchically to describe everyday decisions that people deal with repeatedly. Big decisions, which set policy, guide a host of nested little decisions, which in turn lead to action. For a little decision, one of the options will be consistent with the policy, and will inherit its high utility. Accordingly, most little decisions will be made quickly and will follow the policy. However, people do sometimes decide to violate their own policies, and we describe how these lapses can lead to collapse of the policy. (shrink)