Abstract
The current study examined transactional associations between maternal internalizing symptoms, infant negative emotionality, and infant resting respiratory sinus arrhythmia (RSA). We used data from the Longitudinal Attention and Temperament Study (N = 217) to examine the associations between maternal internalizing symptoms, infant negative emotionality, and infant resting RSA from 4-months to 18-months using a random-intercepts cross-lagged panel model. We found that mothers with higher average internalizing symptoms have infants with higher levels of resting RSA. However, there were no stable, between-individual differences in infant negative emotionality across time. Additionally, we found significant negative within-dyad cross-lagged associations from maternal internalizing symptoms to subsequent measures of infant negative emotionality, as well as a significant negative cross-lagged association from maternal internalizing symptoms to child resting RSA after 12-months of age. Lastly, we find evidence for infant-directed effects of negative emotionality and resting RSA to maternal internalizing symptoms. Results highlight the complex, bidirectional associations in maternal-infant dyads during the first two years of life, and the importance of considering the co-development of infant reactivity and regulatory processes in the context of maternal internalizing symptoms.