Emotional expressions with minimal facial muscle actions. Report 1: Cues and targets

摘要

We tested the hypothesis that a still-face person keeping direct gaze can express an emotion. The prospective study involved healthy volunteers as senders (n = 100). Four pictures of the face of a participant who tried to express certain emotion by gaze were obtained (Neutral - Angry - Sad - Happy). Twenty blinded judges judged the ability to express the emotions. We used the pupil/canthal tilt index for analysis of pupil dilatation. The pictures with emotions (n = 300) presented perfectly expressed emotions - 207 (69%), flawed expressions - 38 (12.66%), and lack of expression or inability to express an emotion - 55 (18.33%). The pupil/tilt index was: neutral gaze - 0.18, angry gaze - 0.21, sad gaze - 0.2, and happy gaze - 0.19. Majority of senders express an emotion by gaze very good. The facial expression of an emotion can be adequately achieved with only minimal muscular involvement when the gaze is the main component of such expression. An "emotional gaze" during a still-face or static face situation may be a result of the combined slight activity of small intraorbital muscles and broader involvement of sympathetic and parasympathetic reactions.