title: The Bitter Truth About Sugar and Willpower: The Limited Evidential Value of the Glucose Model of Ego Depletion.
abstract: The idea behind ego depletion is that willpower draws on a limited mental resource, so that engaging in an act of self-control impairs self-control in subsequent tasks. To present ego depletion as more than a convenient metaphor, some researchers have proposed that glucose is the limited resource that becomes depleted with self-control. However, there have been theoretical challenges to the proposed glucose mechanism, and the experiments that have tested it have found mixed results. We used a new meta-analytic tool, p-curve analysis, to examine the reliability of the evidence from these experiments. We found that the effect sizes reported in this literature are possibly influenced by publication or reporting bias and that, even within studies yielding significant results, the evidential value of this research is weak. In light of these results, and pending further evidence, researchers and policymakers should refrain from drawing any conclusions about the role of glucose in self-control.
authors.affiliation: Department of Primary Care and Public Health Sciences, King's College London.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Vadillo
authors.affiliation: Department of Philosophy, King's College London.
authors.forename: Natalie
authors.initials: N
authors.lastname: Gold
authors.affiliation: Biological and Experimental Psychology Group, School of Biological and Chemical Sciences, Queen Mary University of London m.osman@qmul.ac.uk.
authors.forename: Magda
authors.initials: M
authors.lastname: Osman
mesh_terms: D004532:Ego; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007389:Internal-External Control; D015203:Reproducibility of Results; D000068356:Self-Control / Q000523:psychology*; D000073893:Sugars / Q000600:supply & distribution*
chemical_list: D000073893:Sugars; D005947:Glucose
keywords: ego depletion; glucose; meta-analysis; open data; p-curve; self-control