Ego Depletion

Roy Baumeister's theory that self-control draws on a limited mental resource — 'ego' — which becomes depleted with use, causing subsequent self-control failures.

The strength model of self-control: like a muscle, self-control uses a limited resource. After exerting self-control (resisting radishes, suppressing emotions), the resource is temporarily depleted, making subsequent self-control harder. The glucose hypothesis: blood glucose is the physical resource underlying willpower. Widely replicated in the 2000s. Significant public impact (books on willpower). Then: the replication crisis. Large pre-registered replications failed to find the effect; the glucose hypothesis was undermined. The most prominent casualty of the replication crisis in social psychology.