Sweet delusion. Glucose drinks fail to counteract ego depletion

Initial acts of self-control have repeatedly been shown to reduce individuals' performance on a consecutive self-control task. In addition, sugar containing drinks have been demonstrated to counteract this so-called ego-depletion effect, both when being ingested and when merely being sensed in the oral cavity. However, since the underlying evidence is less compelling than suggested, replications are crucially required. In Experiment 1, 70 participants consumed a drink containing either sugar or a non-caloric sweetener between two administrations of delay-discounting tasks. Experiment 2 (N=115) was designed to unravel the psychological function of oral glucose sensing by manipulating the temporal delay between a glucose mouth rinse and the administration of the consecutive self-control task. Despite applying powerful research designs, no effect of sugar sensing or ingestion on ego depletion could be detected. These findings add to previous challenges of the glucose model of self-control and highlight the need for independent replications.