A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect.
Level 1 - systematic review of randomized trials
Preregistered multi-laboratory replication and meta-analysis across 36 testing sites.
PubMed 34520296 · doi:10.1177/0956797621989733
What was done
A preregistered multi-laboratory project across 36 laboratories (N = 3,531) tested the size and robustness of the ego-depletion effect using a paradigmatic replication approach. Each laboratory implemented one of two procedures designed to manipulate self-control and subsequently measured performance on a self-control task.
What was found
Confirmatory tests showed a nonsignificant effect (d = 0.06). Confirmatory Bayesian meta-analyses with an informed prior (δ = 0.30, SD = 0.15) showed data were 4 times more likely under the null hypothesis than the alternative hypothesis. In exploratory analyses of the full sample without exclusion criteria, a statistically significant effect was found (d = 0.08), with Bayesian analyses indicating data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests indicated larger effects for participants reporting more fatigue, with no moderation by trait self-control, willpower beliefs, or action orientation.
Why it matters
This large, preregistered multi-site effort provides robust evidence that standard laboratory ego-depletion paradigms produce negligible effect sizes that do not reliably differ from zero.
Limits
The abstract does not specify the exact tasks used for self-control manipulation and measurement, the participant demographics, or the nature of the preregistered exclusion criteria.