Mother attachment boosts child-adult brain synchrony in toddlers

In a study published on arXiv, Ruxin Su and colleagues from Shanghai Jiao Tong University, Peking University, and other institutions explored how internalized attachment representations shape real-time brain synchronization between children and adults. Using a novel Remote Partner-Belief Manipulation paradigm, they studied 40 trios of 3-4-year-old children, their mothers, and a female stranger. Children engaged in a cooperative game believing their remote partner was either their mother or the stranger, while EEG was recorded from both child and adult. The actual partner was always a stranger, isolating the effect of belief.

The results revealed that when children believed they were cooperating with their mother, interbrain synchrony in the theta band (4-8 Hz) increased significantly, regardless of the actual partner. This effect was localized to the child's right temporoparietal junction (P4 channel), a region linked to social cognition and attachment. Moreover, the strength of this synchrony correlated with the child's attachment security (as measured by standard assessments) and with faster response times when the mother was believed to be the partner. The findings establish that attachment representations act as an endogenous, top-down driver of neural coupling, independent of external cues. This provides a neurocognitive mechanism for how early attachment bonds influence social interaction and suggests that symbolic activation of attachment figures may buffer stress during separation.