A Multi-Site Preregistered Paradigmatic Test of the Ego Depletion Effect

Abstract

We conducted a preregistered, multi-laboratory project (k = 36; N = 3531) to assess the size and robustness of ego depletion effects using a novel replication method, termed the paradigmatic replication approach. Laboratories implemented one of two procedures that intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a non-significant result, d = 0.06. Confirmatory Bayesian meta-analyses using an informed prior hypothesis (δ = 0.30; SD = 0.15) found the data were four times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring preregistered exclusion criteria; see supplemental online materials) found a statistically significant effect (d = 0.08), with data about equally likely under the null and informed prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants reporting more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation.

Again, No Evidence for or Against the Existence of Ego Depletion: Opinion on “A Multi-Site Preregistered Paradigmatic Test of the Ego Depletion Effect”

“…Given the concerns about the internal consistencies of cognitive estimation tests, the items of these tests may even measure different constructs (Scarpina et al, 2015). Vohs et al (2021) did not report the internal consistency of the CET in their study, which is typically rather low [e.g., Cronbach's α = 0.60 in Schultz and Ryan (2019)]. Taken together, in our opinion, the CET is neither a reliable nor a valid measure of selfcontrol.…”

“…In previous research (Schmeichel et al, 2003), it was claimed that each CET question can be appropriately answered by reasoning and consideration of related knowledge-or more precisely via fluid cognitive processing, which is enabled by the central executive of the working memory system [see also Shallice and Evans (1978)]. Based on the CET performance, Vohs et al (2021) did not observe any evidence of the ego depletion effect. This makes sense to us as we cannot see that the CET measures self-control or any other executive functioning that should be impaired by recent self-control demands.…”

“…In their recently published multi-site project, Vohs et al (2021) made another attempt to assess the size and robustness of ego depletion effects. For this reason, the authors also adopted the sequential two-task paradigm in a study with more than 3,500 participants from 36 laboratories.…”

“…The CET requires participants to guess the answers to a series of 20 questions (19 questions in the Vohs et al study) that have unclear answers, meaning that participants needed to generate novel responses (e.g., "How many seeds are there in a watermelon?, " "What is the age of the oldest living person in the United States?, " "How long does it take to iron a shirt?, " and "How long does it take for fresh milk to go sour in the refrigerator?"). According to Vohs et al (2021), the CET requires self-control because the answers cannot be determined algorithmically or with declarative knowledge. This is an overly succinct rationale from which it does not logically follow that the CET does require self-control.…”

“…In Vohs et al's study, estimations that were within the 25-75th percentile interval of this norm sample received two points, answers within the 5-24th or the 76-95th percentiles received one point, and answers outside these intervals received zero points. How arbitrary this scoring system is, becomes even more apparent given the fact that in another ego depletion study, the participants within the 90% response range (rather than in the 95% response range; Vohs et al, 2021) of the norm sample were awarded one point (Schmeichel et al, 2003). From all this, it follows that, at best, the CET can identify the (maybe clinically relevant) tendency to give more or less untypical estimations, whereby the reasons for such deviations are unknown.…”