Abstract
Theories of choice and behavioural change are generally based on the premise that actors seek to maximise rewards and minimise costs. This premise, however, is rarely supported by empirical research. In this paper, the authors propose an alternative principle: that choices tend to be made so as to equalise a function of costs across available alternatives. They demonstrate the effectiveness of this general principle in three binary-choice settings involving noncontingent and contingent reward probabilities for positive reinforcement and positive punishment situations, and in two framing situations. This study suggests that relatively simple principles may explain a wide variety of human choice behaviours. (A)