Is willpower a limited tank that runs dry the more you use it — or was "ego depletion," one of psychology's most famous findings, basically debunked?

For nearly 20 years, "ego depletion" — the idea that willpower works like a muscle that gets fatigued with use, so resisting one temptation makes you worse at resisting the next — was one of the most cited findings in psychology, based on research by Roy Baumeister. Then the 2010s replication crisis hit psychology hard, and a large multi-lab study specifically designed to replicate ego depletion failed to reproduce the effect. Some researchers now argue willpower isn't a fixed resource at all — what looks like "depletion" might actually be about motivation, beliefs, or simply getting bored. Others argue the original effect is real but smaller and more situational than first claimed, not fully debunked.

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