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English

Don't believe that “willpower is like a muscle that runs out after a while”

  • High value
  • Evidence A
  • Saves time
  • Free
  • Takes minutes
  • No willpower

In plain words

The popular claim is: do one thing that takes self-control first, and you will then be more likely to slip afterward, so you should ration your willpower. 23 labs with 2141 people repeated the experiment with the same protocol, and the result was almost zero. Stop explaining yourself with “I've used up my willpower today,” and don't spend money on courses that teach you to save up willpower.

Cost

Free. The only thing to change is a way of putting things.

What you get

A multi-lab preregistered replication, with 23 labs and 2141 participants in all, redid the sequential-task paradigm using the standardized protocol of Sripada and colleagues: first a task that uses up self-control, then a second task that needs self-control. The pooled result showed that the ego depletion effect was very small, and the 95% confidence interval included 0 (d = 0.04, 95% CI −0.07 to 0.15). The authors used this to discuss whether the model of “self-control as a limited resource” still holds. Another replication with a protocol also registered in advance, 36 labs and 3531 people, had an effect size of d = 0.06, likewise too small to count.

Notes

What is being ruled out is the model that “self-control is a resource that gets used up,” not the idea that people get tired. Too little sleep and working too long at a stretch do make people less effective, but that is a separate matter, handled by the sleep and working-hours items in §3. What randomized trials do support is changing your environment and changing how you write things down; see §4.10 (move what you don't want to touch farther away) and §4.1 (write it as “at what time, where, and when this happens, do that”). Fixing what you wear and what you eat is still worth doing, because it costs almost nothing. What it saves is those few minutes and a few rounds of agonizing, not willpower, so don't expect it to make your judgment better in the afternoon. The other items in this section count money; this one counts time and energy, and the two are not converted into each other.

Evidence grade
A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.
Sources
  1. Hagger MS, Chatzisarantis NLD, Alberts H, et al. (2016). A Multilab Preregistered Replication of the Ego-Depletion Effect. Perspectives on Psychological Science, 11(4), 546–573. https://doi.org/10.1177/1745691616652873
  2. Vohs et al. (2021). A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect. Psychological Science. https://doi.org/10.1177/0956797621989733

Translated from the Chinese original. Original book, section 6, tip 25. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer