Infant frontal electroencephalogram asymmetry and negative emotional reactivity as predictors of toddlerhood effortful control.

Given the importance of children's self-regulation, relations were examined between two fundamental components of self-regulation, specifically temperamentally based reactivity and regulation. Infant negative emotional reactivity and regulation, measured via frontal electroencephalogram (EEG) asymmetry, were examined as potential precursors to understanding toddlerhood regulation, conceptualized as effortful control. Our longitudinal design allowed for examination of two perspectives on the interplay of reactivity and regulation, namely that (a) early negative affectivity interferes with the development of later regulation and (b) regulation is necessary to modulate negative affectivity and, thus, would buffer the effects of negative affectivity on later regulation. Mother-child dyads participated in a three-wave longitudinal study. Baseline frontal EEG asymmetry was assessed at 10months (T1). Mothers rated children's negative reactivity at both 10 and 24months (T2). Children's effortful control, measured at 30-36months (T3), was a composite score of maternal ratings and observed behavior during a snack delay. Negative affectivity was related to effortful control; however, significant interactions between negative affect and frontal EEG asymmetry were found. Higher levels of negative affectivity at both T1 and T2 were associated with lower levels of effortful control at T3, but only for toddlers who also had right frontal EEG asymmetry. Negative affectivity was not associated with effortful control for the left frontal EEG asymmetry group. Our moderation findings highlight the complex relations of negative affect and frontal EEG asymmetry in understanding children's development of self-regulation, specifically effortful control. The interaction between early reactivity and physiological regulation indicates that both may be important precursors of effortful control.