The models of internal self-control that have recently been proposed by behavioral economists do not depict motivational interaction that occurs while temptation is present. Those models that include willpower at all either envision a faculty with a motivation (“strength”) different from the motives that are weighed in the marketplace of choice, or rely on incompatible goals among diverse brain centers. Both assumptions are questionable, but these models’ biggest problem is that they do not let resolutions withstand re-examination while being challenged (...) by impulsive alternatives. The economists’ models all attempt to make a single equilibrium preference predictable from a person’s prior incentives. This was the original purpose of these models’ hyperboloid (“β–δ”) delay discount functions, which have been widely justified by the assumption that a person’s intertemporal inconsistency (impulsiveness) can be accounted for by the arousal of appetite for visceral rewards. Although arousal is clearly a factor in some cases of intertemporal inconsistency, it cannot be blamed for others, and furthermore does not necessarily imply hyperboloid discounting. The inadequacy of β–δ functions is particularly evident in models of internal self-control. I have reviewed several of these models, and have argued for a return to pure hyperbolic discount function as originally proposed, the relatively high tails of which can motivate a recursive process of self-prediction and thereby the formation of self-enforcing intertemporal contracts. Such a process does not require a separately motivated faculty of will, or incompatible goals among brain centers; but it also does not permit the prediction of unique preferences from prior incentives. (shrink)

There is a simple view of motivation on which desires are like pain-killers; they come in different strengths, and their strength determines their efficacy. That is, the stronger a desire the greater its motivational force and, when two desires conflict, the stronger one “wins out” over the weaker. This view makes it puzzling how anyone could ever exhibit “strength of will” and act on the weaker desire, even when it is a desire for something more highly valued than what is (...) more strongly desired. When the will, as the agent of reason, enters the fray, an explanation of what a person is motivated enough to do must reckon not only with competing desires and their motivational forces, but also with the will’s capacity to be affected by different ones in ways not proportional to their force. However, this complication sheds little light, for if the will must bestow its stamp of approval on a desire before the desire leads to action, then, it would seem, motivational force should be measured by strength of effect on the will. And if that’s the way to measure motivational force, then, since by that measure one always acts on the desire that affects one’s will most, there is no problem of strength of will after all. But the problem seems real, however inapt the label. (shrink)