Inter-brain synchrony in mother-child dyads during cooperation: An fNIRS hyperscanning study.

Coordinated brain activity between individuals, or inter-brain synchrony, has been shown to increase during cooperation and correlate with cooperation success. However, few studies have examined parent-child inter-brain synchrony and whether it is associated with meaningful aspects of the parent-child relationship. Here, we measured inter-brain synchrony in the right prefrontal (PFC) and temporal cortices in mother-child dyads while they engaged in a cooperative and independent task. We tested whether inter-brain synchrony in mother-child dyads (1) increases during cooperation, (2) differs in mother-son versus mother-daughter dyads, and (3) is related to cooperation performance and the attachment relationship. Overall inter-brain synchrony in the right hemisphere, and the right dorsolateral and frontopolar PFC in particular, was higher during cooperation. Mother-son dyads showed less inter-brain synchrony during the independent task and a stronger increase in synchrony in response to cooperation than mother-daughter dyads. Lastly, we did not find strong evidence for links between inter-brain synchrony and child attachment. Mother-child cooperation may increase overall inter-brain synchrony, although differently for mother-son versus mother-daughter dyads. More research is needed to better understand the potential role of overall inter-brain synchrony in mother-child cooperation, and the potential link between inter-brain synchrony and attachment.