Multiple theories have proposed that increasing central arousal through the brain’s locus coeruleus—norepinephrine system may facilitate cognitive control and memory. However, the role of the arousal system in emotion regulation is less well understood. 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 emotional arousal in the pupil diameter time course of 34 healthy adults. Pupil diameter increase during regulation predicted individual differences in emotion regulation success beyond task difficulty.
Fig: Self-regulation tasks and behaviour. (a) Emotion reappraisal success. On the 9-point SAM scale, the panel shows the mean emotion ratings for each block (negative view, negative reappraise, neutral view, positive reappraise, and positive view blocks). The black solid line indicates the group mean and the box its standard error. Each grey dot represents the mean ratings from one participant. Participants successfully reappraised both negative and positive images, shifting their feelings in both cases towards a neutral state. (b) Emotion reappraisal task. Participants saw positive, neutral and negative stimuli from the International Affective Picture System (IAPS). For display purposes, we replaced the IAPS stimuli by unrelated landscape photos here. In each block, participants either viewed the images without changing their emotional response (“view”) or reappraised the scene to render their feelings more neutral (“reappraise”). To allow the pupil to adapt to brightness and contrast, a phase-scrambled version of the stimulus was displayed for 1 s before the image was revealed. Participants then viewed or reappraised the scene for 7 s before they rated their current feeling on a Self-Assessment-Manikin (SAM) scale. A jittered inter trial interval of 1–5 s separated the trials. (c) Dietary health challenge task. Participants made 100 choices indicating whether they wanted to eat the displayed food at the end of the study. A phase-scrambled adaptation stimulus was presented for 1 s before the food image was revealed and participants had 3 s to decide by pressing the left or right button for selecting the answers “yes” or “no”. A white frame highlighted the answer for 0.1 s when it was logged. Trials were separated by a 2–6 s (jittered) inter-trial interval.
Moreover, the extent of this individual regulatory 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 individual’s self-control across domains.
Maier, S.U., Grueschow, M. Pupil dilation predicts individual self-regulation success across domains. Sci Rep 11, 14342 (2021). https://doi.org/10.1038/s41598-021-93121-y