An amplification of feedback from facial muscles strengthened sympathetic activations to emotional facial cues.

The facial feedback hypothesis suggests that feedback from cutaneous and muscular afferents influences our emotions during the control of facial expressions. Enhancing facial expressiveness produces an increase in autonomic arousal and self-reported emotional experience, whereas limiting facial expression attenuates these responses. The present study investigated differences in autonomic responses during imitated versus observed facial expressions. Thus, we obtained the facial electromyogram (EMG) of the corrugator muscle, and measured the skin conductance response (SCR) and pupil size (PS) of participants while they were either imitating or simply observing emotional expressions of anger. We found that participants produced significantly greater responses across all three measures (EMG, SCR, and PS) during active imitation than during passive observation. These results show that amplified feedback from facial muscles during imitation strengthens sympathetic activation in response to negative emotional cues. Our findings suggest that manipulations of muscular feedback could be used to modulate the bodily expression of emotion, including autonomic responses to the emotional cues.