U Penn, Psychology
An opportunity cost model of self-control and effort
Exerting ‘effort’ or ‘self-control’ is experienced as aversive. From an evolutionary point of view, this is something of a mystery insofar as aversive phenomenology is usually associated with fitness costs or threats, whereas exerting self control seems to be associated with positive outcomes. A leading explanation among psychologists is that there is a resource – the fuel for willpower – that is depleted over time. As this resource is consumed, it becomes phenomenologically harder and harder to resist temptation. However, a growing body of evidence suggests that, as compelling as this explanation might be, there are very good reasons to doubt it. Instead, the phenomenology of effort and the associated sensation of fatigue might more productively be thought of in the context of motivation. The reason that it is difficult to persist on effortful tasks might be due to computations surrounding the possibility of switching to another task that is likely to be psychologically rewarding. That is, engaging in effortful tasks carries the opportunity cost of not engaging in a more pleasurable task. These costs lead to the aversive experiences of effort and fatigue.