Does willpower run down like a battery? The story of "ego depletion"

The famous experiment with radishes and cookies (1998), the large replications with thousands of participants that did not find the effect and what we know about self-control today

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Translated from the Albanian original by the editors. Shqip

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Illustration: a drop that does not run out, a symbol of the question whether willpower is depleted
Original illustration by the lexoshpejt editors. Not a historical photograph or object.
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In 1998 the psychologist Roy Baumeister and his colleagues published an experiment that became famous. Students were brought into a room that smelled of freshly baked chocolate-chip cookies. Some were allowed to eat the cookies; others were asked to resist and eat only radishes. Then all of them tried to solve a puzzle that, unknown to them, was unsolvable.

The students who had resisted the cookies gave up on the puzzle sooner. The interpretation: self-control had been used up, like a tired muscle or a battery. This idea was called "ego depletion".

A highly influential idea

In the years that followed, hundreds of studies reported similar effects. The idea spread into books and advice: "do not make important decisions when you are tired", "willpower is limited". Some studies even suggested that a sugary drink could refill willpower.

The replications

However, some researchers began to have doubts. In 2016 a project coordinated by Martin Hagger and colleagues tested the effect in 23 laboratories at once, with over 2,000 participants and a pre-registered plan. The effect was almost zero. Another large replication, led by Kathleen Vohs, one of the theory's supporters, with hundreds more participants in dozens of laboratories, found in 2021 a very small effect, close to zero. The idea about sugar was also seriously questioned.

Fatigue exists. But the idea that every act of self-control automatically drains a hidden reservoir has no strong support.

The role of beliefs

An interesting finding came from Veronika Job, Carol Dweck and Gregory Walton in 2010. They found that the fatigue effect appeared mainly in people who believed willpower is limited. Those who believed that effort does not deplete willpower did not show the same drop. This suggests that the way we think about willpower may influence the way we behave.

What you can do

  1. Do not use "I have no willpower left" as an automatic excuse. Often, after a short break or a change of task, you can carry on.
  2. Take real tiredness seriously: lack of sleep, hunger and prolonged stress really do affect decisions.
  3. Change the environment instead of relying only on resistance. People with high self-control often simply avoid temptation.
  4. Remember why you are doing it. Motivation and meaning seem to matter more than a "reserve" of willpower.

Sources and further reading

  1. Baumeister, R. F., Bratslavsky, E., Muraven, M. & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74(5), 1252–1265. PubMed
  2. Hagger, M. S., Chatzisarantis, N. L. D. et al. (2016). A multilab preregistered replication of the ego-depletion effect. Perspectives on Psychological Science, 11(4), 546–573. PubMed
  3. Vohs, K. D., Schmeichel, B. J. et al. (2021). A multisite preregistered paradigmatic test of the ego-depletion effect. Psychological Science, 32(10), 1566–1581. PubMed
  4. Job, V., Dweck, C. S. & Walton, G. M. (2010). Ego depletion—Is it all in your head? Implicit theories about willpower affect self-regulation. Psychological Science, 21(11), 1686–1693. PubMed

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