Symmetry perception and affective responses: A combined EEG/EMG study

► Previous work has suggested emotional responses to symmetry are not spontaneous. ► We recorded EEG and EMG activity from the smiling muscle (Zygomaticus Major, ZM). ► We found a spontaneous emotional reaction in terms of ZM activation. ► Symmetry produced early ERP modulations, and 10-14 Hz desynchronization. ► There were novel ERP differences between reflectional and rotational symmetry.