Language acquisition in early childhood occurs through dynamic social interactions, both within familial settings for infants and toddlers and in classroom environments for school-aged children. fNIRS hyperscanning—the monitoring of brain activity in two or more people simultaneously to measure their inter-brain coherence (IBC)—enables researchers to quantify social interaction. Increased IBC can arise both from neural entrainment to shared external cues (e.g., auditory, visual input) as well as by the interplay between self- and other-reference during interaction. We conducted fNIRS hyperscanning studies to uncover the neural mechanisms underlying how young children learn child-directed speech and figurative language conveyed through speech in naturalistic settings. We find how parent-child and peer interactions facilitate language learning outcomes among young children through increased IBC, which was beyond mere presence and neural entrainment. Our research bridges developmental psychology and multi-person neuroscience, offering implications for both family-based and pedagogical approaches to language education.
Zhou et al. (2025) studied this question.