Pupil dilation predicts individual success in emotion regulation and dietary self-control

Multiple theories have proposed that increasing central arousal through the brains locus coeruleus - norepinephrine system may facilitate cognitive control and memory. However, for emotion research this hypothesis poses a puzzle, because conventionally, successful emotion regulation is associated with a decrease in arousal. Pupil diameter is a proxy to infer upon the central arousal state. We employed an emotion regulation paradigm with a combination of design features that allowed us to dissociate regulation- from stimulus-associated arousal in the pupil diameter time course of healthy adults. A pupil diameter increase during regulation predicted individual differences in emotion regulation success beyond task difficulty. Moreover, the extent of this individual arousal boost predicted performance in another self-control task, dietary health challenges. Participants who harnessed more regulation-associated arousal during emotion regulation were also more successful in choosing healthier foods. These results suggest that a common arousal-based facilitation mechanism may support an individuals self-control across domains.