Motivation, personal beliefs, and limited resources all contribute to self-control

What effects do motivation and beliefs have on self-control? We tested this question using a limited resource paradigm, which generally has found that people show poor self-control after prior exertions of self-control. Recent findings have suggested that motivation and even belief in unlimited willpower can render persons immune to ego depletion. We replicated those findings, but also showed they are limited to cases of mild depletion. When depletion is extensive, the effects of motivation and subjective belief vanished and in one case reversed. After performing only one self-control task, the typical pattern of self-regulation impairment was ameliorated among people who were encouraged to regard willpower as unlimited (Experiment 1) or motivated by task importance (Experiment 2). Those manipulations failed to improve performance among severely depleted persons who had done multiple self-control tasks. These findings integrate ideas of limited resources, motivation, and beliefs in understanding the nature of self-control over time. ► Belief in unlimited willpower only improves mild depletion. ► Enhanced motivation only improves mild depletion. ► Several self-control acts worsen later self-control regardless of lay beliefs. ► Several self-control acts worsen later self-control regardless of motivation.