Synthese (2012) 189:173–183

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). 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.