Latent profiles of infant negative affect and respiratory sinus arrhythmia during the still‐face paradigm: The role of maternal sensitivity

We examined if there were profiles of infants' behavioural and physiological responses during the still‐face and if these profiles were predicted by maternal sensitivity. Participants included 230 mothers (40.4% non‐white) and their 2‐month‐old infants (48.7% female). Three profiles were identified: continually increasing negative affect and decreasing respiratory sinus arrhythmia (RSA) (17.39%); modest, classic still‐face effect for negative affect and RSA (64.35%); high negative affect, late decreasing RSA (18.26%). Infants of highly sensitive mothers were more likely to be in the modest, classic still‐face effect for negative affect and RSA profile than in the continually increasing negative affect and decreasing RSA and the high negative affect, late decreasing RSA profiles. Additionally, infants of mothers who were high in maternal sensitivity were more likely to be in the continually increasing negative affect and decreasing RSA profile compared to the high negative affect, late decreasing RSA profile. The findings demonstrate heterogeneity in infant responses and that maternal sensitivity is an important predictor of children's behavioural and physiological responses to stressors.