Tough Choices Weaken Willpower
Self-control requires a measurable expenditure of mental energy, reserves of which are not inexhaustible.
Test-subjects were asked to stifle or exaggerate their emotions while watching a disturbing video. Their physical stamina was tested before and after with a handgrip.
In another study, hungry participants were asked to resist chocolate and freshly baked cookies before working on difficult puzzles.
In all cases, participants who exercised self-control were less effective on the second task. Resisting temptation consumed an important resource, which was then less available to help the person persist in the face of failure.
Sleep may be one way that individuals can replenish self-control. Most forms of self-regulation failure escalate over the course of the day, becoming more likely and more frequent the longer the person has been deprived of sleep. Positive emotional experience may also help replace self-control energy.