Self-Control Relies on Glucose as a Limited Energy Source: Willpower Is More Than a Metaphor

Department of Psychology, Florida State University, Tallahassee, FL 32306-1270, USA.
Journal of Personality and Social Psychology (Impact Factor: 5.08). 03/2007; 92(2):325-36. DOI: 10.1037/0022-3514.92.2.325
Source: PubMed


The present work suggests that self-control relies on glucose as a limited energy source. Laboratory tests of self-control (i.e., the Stroop task, thought suppression, emotion regulation, attention control) and of social behaviors (i.e., helping behavior, coping with thoughts of death, stifling prejudice during an interracial interaction) showed that (a) acts of self-control reduced blood glucose levels, (b) low levels of blood glucose after an initial self-control task predicted poor performance on a subsequent self-control task, and (c) initial acts of self-control impaired performance on subsequent self-control tasks, but consuming a glucose drink eliminated these impairments. Self-control requires a certain amount of glucose to operate unimpaired. A single act of self-control causes glucose to drop below optimal levels, thereby impairing subsequent attempts at self-control.

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Available from: Lauren Brewer, Apr 22, 2015
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    • "The model does not specify the nature of the mechanism underlying the ego depletion effect. Glucose was offered as a candidate for the resource that was being depleted, potentially providing a more mechanistic account (Gailliot et al., 2007). However, this explanation has subsequently been shown to be a poor one (see Beedie & Lane, 2012; Molden et al., 2012; Kurzban, 2010a). "
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    • "ion " ; Hagger , Wood , & Stiff , 2010 ; Baumeister & Heatherton , 1996 ) . To account for these findings , it is thought that self - control draws from a somewhat global , limited resource and that ex - hausting it reduces the amount ( or allocation ) of avail - able self - control resources to be deployed in the near future ( Baumeister , 2014 ; Gailliot et al . , 2007 ; Baumeister & Heatherton , 1996 ) . An alternative theory explains the decrement in self - control as a decrease in participants ' motivational state during the second task ( Inzlicht , Schmeichel , & Macrae , 2014 ) . Our results argue against the motivational account , as we found no pre - to - post changes in participants ' motivati"
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    • "That resource is largely assumed to be blood glucose. However, direct measurement of blood sugar levels (Fairclough and Houston, 2004; Gailliot et al., 2007) and metabolic rate (Huang et al., 2012) during cognitively demanding tasks show effects that are too small to account for the detrimental effects on performance that occur during a hypoglycemic state. We suggest that this apparent contradiction can be explained by accounting for the energy storage and buffer mechanism provided by astrocytic glycogen (c.f. "
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