An emotion is a psychological state or process that functions in the management of goals. It is typically elicited by evaluating an event as relevant to a goal; it is positive when the goal is advanced, negative when the goal is impeded. The core of an emotion is readiness to act in a certain way (Frijda 1986); it is an urgency, or prioritization, of some goals and plans rather than others. Emotions can interrupt ongoing action; also they prioritize certain kinds of social interaction, prompting, for instance, COOPERATION or conflict.

Starting in the 1950s, however, several influential movements began with cognitive emphases, all stressing function, and all making it clear that emotions typically contribute to rationality instead of being primarily irrational. One result of these movements has been to expand concepts of cognition to include emotion.