Most authors who discuss willpower assume that everyone knows what it is, but our assumptions differ to such an extent that we talk past each other. We agree that willpower is the psychological function that resists temptations – variously known as impulses, addictions, or bad habits; that it operates simultaneously with temptations, without prior commitment; and that use of it is limited by its cost, commonly called effort, as well as by the person's skill at executive functioning. However, accounts are usually not clear about how motivation functions during the application of willpower, or how motivation is related to effort. Some accounts depict willpower as the perceiving or formation of motivational contingencies that outweigh the temptation, and some depict it as a continuous use of mechanisms that interfere with re-weighing the temptation. Some others now suggest that impulse control can bypass motivation altogether, although they refer to this route as habit rather than willpower.

It is argued here that willpower should be recognized as either or both of two distinct functions, which can be called resolve and suppression. Resolve is based on interpretation of a current choice as a test case for a broader set of future choices, which puts at stake more than the outcome of the current choice. Suppression is inhibiting valuation of (modulating) and/or keeping attention from (filtering) immediate alternatives to a current intention. Perception of current choices as test cases for broader outcomes may result in reliable preference for these outcomes, which is experienced as an effortless habit – a successful result of resolve, not an alternative method of self-control. Some possible brain imaging correlates are reviewed.