Infants’ cortisol reactivity and infant–mother cortisol synchrony in urban Chinese families: The role of maternal control strategy

Maternal control strategy refers to a mother’s practices used to impel, inhibit, guide, or shape their children’s behaviors during mother-child interaction. The present study examined control strategies used by Chinese urban mothers and how they associated with infants’ cortisol trajectory and infant-mother cortisol synchrony during a separation task. Participants were 115 infant-mother dyads. Maternal control strategy was assessed during mother-infant free-play when the infants were 6 months (T1) and 1 year (T2) old. Salivary cortisol samples were collected from both infants and mothers during a stress-inducing task at T2. The results indicated that mothers most frequently adopted the moderate power control strategy, at both T1 and T2. T1 maternal low control strategy significantly predicted infants’ cortisol response curve, namely infants of mothers who predominantly adopted a low power control strategy had a more dynamic reactivity and recovery in their cortisol response to the separation task. Positive cortisol synchrony was observed between mothers and infants during the separation stress condition. In addition, T2 maternal high power control strategy accounted for inter-individual variations in infant-mother cortisol synchrony, such that mothers who predominantly adopted a high power control strategy exhibited a heightened level of cortisol synchrony with their infants. Our findings suggest that targeted training in maternal control strategies could help mothers calibrate their infants’ adrenocortical regulation.