Mother-Child Synchrony and Behavioral Problems in Chinese Children: A Preliminary fNIRS-Hyperscanning Study

Parent-child synchrony, defined as the coordination of biological and behavioral processes during social interactions, serves as a critical predictor of children's psychological health and behavioral outcomes. Although recent research has examined its neurobiological underpinnings, the longitudinal relationship between mother-child synchrony and preadolescent behavioral problems in China remains underexplored.

This longitudinal study followed mother-child dyads at ages 7, 9, and 11, focusing on the trajectory of children's behavioral problems. At age 7, functional near-infrared spectroscopy was employed during a mother-child drawing task to measure neural synchrony. Neural synchrony was assessed using wavelet transform coherence to capture both timealigned and time-lagged dynamics during naturalistic mother-child interaction. Group-level analyses linked these neural patterns to behavioral synchrony and developmental outcomes using regression models and exploratory structural equation modeling.

Results revealed that time-lagged neural synchrony, involving the mother's temporoparietal junction and the child's dorsolateral prefrontal cortex, was significantly associated with the predominant form of temporally sequential behavioral synchrony. Furthermore, mother-led child-following behavioral synchrony and 13-s time-lagged neural synchrony were linked to fewer externalizing problems in children.

Main findings reveal that specific patterns of time-lagged mother-child neural synchrony, particularly when the mother leads and the child follows, are associated with reduced externalizing behavioral problems in children. These findings provide preliminary evidence regarding neurocognitive processes relevant to children's social-emotional development from middle childhood to preadolescence. These findings are consistent with emerging literature indicating that delayed but structured interbrain dynamics may contribute to co-regulated emotional development. However, the current evidence remains preliminary and warrants further validation using multimodal synchrony measures and larger longitudinal cohorts to establish causal pathways.