Ego depletion, and the replication that could not find it. · published 7 September 2026
The 1998 ego depletion study found the radish group gave up sooner and launched the idea that willpower is a finite fuel tank — but when 23 labs ran one pre-agreed protocol on over 2,000 people in 2016, the pooled effect came out near zero, and a second large pre-registered test in 2021 found it very small or absent; the likeliest reason the original literature looked so solid is that studies finding the effect got published and those that didn’t mostly didn’t, and the glucose spin-off — that a sweet drink restores self-control — has fared worse still, though Baumeister disputes the replication’s choice of task and that argument is still live.
These are the working notes, unedited. Everything the video
states as fact comes from here, and nothing else may be stated as fact.
The sections on limits and on what the finding does not show are
part of the brief, not an afterthought — see
the method.
The original claim: Roy Baumeister and colleagues, “Ego Depletion: Is the Active Self a Limited Resource?” (Journal of Personality and Social Psychology, 1998). Participants who had to resist eating chocolate biscuits, and instead ate radishes, later gave up sooner on an unsolvable puzzle than participants who had not had to resist anything.
The interpretation: self-control draws on a limited resource that depletes with use, like a muscle tiring. It became one of the most cited ideas in psychology, and produced a large literature — including work suggesting the resource was literally glucose, and that a sugary drink could restore it.
What happened next
Hagger and colleagues ran a pre-registered multi-laboratory replication published in Perspectives on Psychological Science in 2016. Twenty-three laboratories, over two thousand participants, one agreed protocol chosen in advance and approved by proponents of the effect. The pooled estimate came out close to zero.
A second large-scale attempt, Vohs and colleagues (Psychological Science, 2021), ran a further pre-registered multi-site test with a different task and also found the effect very small or absent.
Publication bias is the likeliest explanation for the original literature. The effect appeared robust because studies that found it were published and studies that did not were mostly not, so a meta-analysis of the published record measured what got printed rather than what was true.
The glucose version has fared worse still. The idea that self-control is limited by blood sugar, and restorable by a sweet drink, does not survive scrutiny — the brain’s glucose consumption does not vary nearly enough to support it, and the drink experiments have not replicated reliably.
What this does not show
That self-control does not exist, or that fatigue is imaginary. People do perform worse when tired, bored, or unmotivated, and that is not in dispute. What is in dispute is the specific claim that exerting self-control drains a finite reserve that then impairs unrelated tasks.
Baumeister has not accepted the null result and has contested the replication’s choice of task. That disagreement is live and should be described as such rather than as a settled defeat.