Dynamics of mother-infant parasympathetic regulation during face-to-face interaction: The role of maternal emotion dysregulation

Abstract

The dynamics of parent-infant physiology are essential for understanding how biological substrates of emotion regulation are organized during infancy. Although parent-infant physiological processes are dyadic in nature, research is limited in understanding how one person's physiological responses predict one's own and as well as the other person's responses in the subsequent moment. In this study, we examined mother-infant respiratory sinus arrhythmia (RSA) dynamics during the Still-Face Paradigm (SFP) among 106 mothers (M_age = 29.54) and their 7-month-old infants (55 males). Given mothers' role in shaping dyadic interactions with their infant, we also tested how mothers' self-reported emotion dysregulation (measured via the Difficulties in Emotion Regulation Scale) associated with these dynamics. Results showed that both mothers' and infants' RSA tended to return to their respective homeostatic points (i.e., exhibited return strength) during each SFP episode, indicating stability in RSA for mother-infant dyads. Significant shifts in mother and infant RSA return strength were observed across SFP episodes, highlighting the role of contextual demands on each individual's physiological dynamics. Mother-infant RSA dynamics varied as a function of maternal self-reported emotion dysregulation. Specifically, RSA levels of infants with more dysregulated mothers had a weaker tendency to return to homeostasis during the Reunion episode and were less affected by their mothers' RSA during the Still-Face and Reunion episodes of the SFP, suggesting a less effective coregulatory influence. Our findings have implications for the intergenerational transmission of emotion dysregulation via mother-infant physiological dynamics.

Keywords: RSA; co-regulation; dynamic system; emotion regulation; infant; still-face.

FIGURE 1

Illustration of key terminology (reflecting dynamic systems concepts) in the present study. (1) Homeostatic point, (2) return strength, and (3) coupling effect. Infant and mother physiology are illustrated as masses (square boxes) attached to springs (wavy lines). See Table 1 for definitions of these terms and how they translate to the present study’s aims and hypotheses. We acknowledge that the spring analogy is not a perfect representation of our dynamic system model. A spring overshoots and oscillates around the set point, which would require including second order derivatives in the model. Nonetheless, we chose to present the spring analogy because it exemplifies how we conceptualize mother-infant physiological co-regulation.

FIGURE 2

Predicted return strength (2a) and coupling effect (2b) of mother-infant RSA dynamics across three episodes of the still-face paradigm. In Figure 2a, more negative values indicate greater return strength. Asterisks indicate statistically significant changes in return strength between two adjacent episodes.

FIGURE 3

Predicted infant RSA return strength (3a) and mother-to-infant RSA coupling effect (3b) at low and high levels of maternal emotion dysregulation across three episodes of the still-face paradigm. DERS = Difficulties in Emotion Dysregulation Scale. Asterisks indicate statistically significant differences between infants of mothers with high vs. low levels of emotion dysregulation (1 standard deviation above/below the sample average). In Figure 3a, y axis represents b₁₀ in Model 2, which captures the return strength of infant RSA at each SFP episode. More negative values indicate stronger return strength. In Figure 3b, y axis represents b₂₀ in Model 2, which captures the mother-to-infant coupling effects of RSA at each SFP episode.