| dc.description.abstract | The role of glucose in self-control has been under heated debate. Recent studies have suggested that both swishing and ingesting glucose can improve self-control, casting doubt on the idea that reduced self-control results from depleted blood glucose levels. However, no studies have directly compared the effects of rinsing and ingesting glucose on self-control. Furthermore, despite a multitude of behavioral evidence that glucose restores self-control, the mechanisms behind this restoration effect remain unknown. In two studies examining the effects of glucose on self-control, participants received one of three beverages that contained either glucose or aspartame. Two of the beverages were identical glucose solutions, but one group ingested it and the other group rinsed their mouths with the liquid and spit it out.
In the first study participants completed a task that did or did not require the use of self-control before being asked to drink or swish the beverage. Participants then completed a series of tasks to assess self-control, emotional responding, and future discounting. Among participants who exerted self-control, both swishing and ingesting glucose solutions improved subsequent self-control performance. Furthermore, swishing glucose increased self-reported arousal to all images and reduced discounting of future rewards.
The design for Study 2 was nearly identical to Study 1, except that all participants exerted self-control on the initial task, the tasks were counterbalanced in a different order, and participants no longer rated their subjective reactions to the emotional images. Instead, electroencephalography was used to assess emotional processing as well as various cognitive processes occurring before and after responses on the dependent measure of self-control. Both glucose conditions caused lower emotional processing for all image types, contrasting with Study 1. No effects of drinking glucose were found for self-control or future discounting, due in part to insufficient sample size. Emotional reactions were linked to self-control performance. Furthermore, blood glucose levels were related to action monitoring processes following self-control failure, despite not predicting self-control performance in either study. These results include some of the first direct evidence of processes affected by glucose following self-control exertion and provide a glimpse into the underlying mechanisms behind self-control restoration. | en |
