Dynamics of frontal alpha asymmetry in mother-infant dyads: Insights from the Still Face Paradigm.

The parent-infant dynamic has a foundational role in emotion regulation development. Electroencephalography (EEG) hyperscanning from mother-infant dyads can provide an unprecedented window into inter-brain dynamics during the parent-infant exchange. This potential depends on the feasibility of hyperscanning with dyads in emotionally taxing contexts. We sought to demonstrate feasibility of hyperscanning from 10 mother-infant dyads during the Still Face Procedure (SFP). We measured frontal alpha asymmetry (FAA) to elucidate ongoing regulatory dynamics and considered maternal caregiving quality as a window into dyads' history. Results showed dyads exhibited a rightward shift in FAA over the course of SFP, indicating growing negative emotionality and desire to withdraw. Results also showed growing variability in FAA for infants over the course of SFP, indicating less active emotional control as stress ensued. Variability was especially low for mothers during periods when asked to be emotionally unavailable, suggesting active control to match the task demands. Dyads with a more responsive mother exhibited higher (more left) FAA relative to dyads with a less responsive mother, which might reflect a more positive emotional experience overall. We raise important methodological and theoretical questions that hyperscanning during SFP can address, such as the developmental origins of trait-like self-regulatory dispositions.