Real-time mother–infant bio-behavioral synchrony and infant socioemotional functioning over the first year

From a bio-behavioral framework, mother–infant physiological and behavioral synchrony are dynamic processes that unfold in a time-locked manner during face-to-face interactions, and dyadic physiology and behavior may influence each other in real time. No prior study, however, has investigated these bidirectional relations between physiological and behavioral synchrony in a time-lagged manner. Furthermore, despite the rapid development across domains during infancy, there is a lack of longitudinal studies on developmental changes and long-term implications of mother–infant physiological dynamics over the first year of life. To address these gaps, I used data from 102 mothers and their infants (45 girls) during the still-face paradigm at 3, 6, and 9 months of age. From video recordings of mother–infant interaction during the play and reunion episodes, infant and maternal behaviors (i.e., facial expressions, vocalizations, and directions of gaze) were coded by separate teams and then aggregated into the dyadic matching of positive engagement states across 1-s intervals. Using two-level models and indices of maternal and infant parasympathetic response (i.e., changes in respiratory sinus arrhythmia [RSA]), I examined contemporaneous and lagged (i.e., behavior-lead and physiology-lead) relations between RSA synchrony and matching of positive engagement states on a second-by-second timescale. I also explored these real-time relations across (a) time points, (b) emotional contexts (the play and reunion episodes), and (c) expressive modalities (shared positive facial affect and mutual gaze). Further, to investigate the contributions of RSA synchrony to infant socioemotional functioning, I assessed infant (a) behavioral stress recovery as the proportion of social engagement with the mother during the reunion episode and (b) physiological stress recovery as RSA increases from the still-face to the reunion episode, at 3, 6, and 9 months, and (c) parent reports of infant behavioral problems at 12 months. Using random intercept and traditional cross-lagged panel models, I examined the extent to which RSA synchrony predicted concurrent and subsequent infant behavioral and physiological stress recovery, as well as behavioral problems at the end of the first year. Physiology-lead relations emerged at 6 and 9 months, such that more positive (less negative) RSA synchrony in a given second predicted higher levels of matching in infant and maternal positive engagement states in the next second. At 9 months, divergent RSA synchrony patterns were observed across emotional contexts. RSA synchrony was negative during the reunion and tended to be positive during the play episode. These findings suggest that mother–infant physiological synchrony provides real-time support for more positive social dynamics, and mother–infant dynamics become more coherent across systems and more flexible to social context over the first year. Limited support emerged with respect to the implications of RSA synchrony for infant socioemotional functioning. More positive RSA synchrony during the reunion episode at 6 months predicted increased infant social engagement during the reunion at 9 months, suggesting that adaptive physiological co-regulation in a stressful context may facilitate the development of infant stress regulation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Human Dvlpmt & Family Studies

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Hu, Yannan

Contributors dc:contributor

• McElwain, Nancy L.
• Bost, Kelly Freeman
• Tu, Kelly M.
• Berry, Daniel

• Mother–infant Real-time Dynamics
• Physiological Synchrony
• Behavioral Synchrony
• Respiratory Sinus Arrhythmia

Statement dc:rights

• Copyright 2023 Yannan Hu

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/120384

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F120384