Physiological Signatures of Emotional Processing via Pupil Diameter, Galvanic Skin Response, and Gaze Behavior: A...

This pilot study investigated the effects of emotional images on gaze behavior, pupil diameter, and galvanic skin response (GSR). After measuring trait anxiety, 37 healthy adults were shown images (disgust, fear, happiness, sadness, or neutral) from the International Affective Picture System for 4 s each while recording eye tracking and physiological responses.

Recorded data included total fixation duration, average fixation duration, fixation count, first fixation duration, mean pupil diameter during fixation, and average GSR.

Compared to images depicting happiness, those depicting fear were associated with longer average fixation duration, fewer fixations, and larger pupil diameters. Compared with neutral images, those showing happiness were associated with larger pupil diameters. No significant differences in GSR were observed across emotion categories. Regarding anxiety levels, fear-inducing images tended to be associated with fewer fixations and larger pupil diameters across all anxiety groups. In moderate- and high-anxiety groups, there was a tendency for longer fixation duration compared to images evoking happiness.

Overall, these preliminary findings suggest that while individuals tend to fixate on fear images less often than on happiness images, they fixate for longer on them, which may cause pupil dilation. However, no significant response was observed depending on the level of trait anxiety. Further research using a larger sample size is needed to confirm these initial observations.