Affect dynamics of facial EMG during continuous emotional experiences

•Transient zygomatic fluctuations are reliable and track continuous changes in positive emotional experience.•Corrugator activity is aligned with tonic increases in emotional negativity and is inversely coupled with changes in positive affect.•While zygomatic dynamics exhibit affect-related phasic changes, corrugator dynamics are pre-dominated by tonic components.•Corrugator affect dynamics exhibit vast inter-individual variability. Emotional experiences are complex, multi-component processes that unfold over time. Accordingly, it is crucial to understand the temporal dynamics of these constituent components. Here we studied the dynamics of one of the core emotional systems, i.e. facial muscle activity, during continuous emotional experiences, elicited by movies. We found that transient zygomatic fluctuations were narrowly tuned to a positive emotional experience. During a positive but not a negative movie, zygomatic response patterns were consistent across participants, tracked with subjective ratings and co-varied with emotional dynamics. Corrugator activity evidenced a broader affective profile and larger individual variability. It was coordinated with tonic changes in emotional negativity and inversely coupled with transient changes in positive affect. Taken together, our results confirmed previous findings on the affective profiles of facial responses and extended them to temporal dynamics. They further uncovered important differences in temporal response characteristics of zygomatic and corrugator measures.