The facilitative mechanism of social interaction scenarios on second language vocabulary learning: evidence from near-infrared spectroscopy hyper-scanning.

Social interaction has a significant impact on vocabulary learning, but previous studies have examined its unique effects from a single-brain perspective, neglecting the role of inter-brain synchrony. Our study used an fNIRS hyper-scanning method to investigate the neurocognitive effects of social interaction contexts on second language vocabulary learning. A total of 54 bilingual pairs were randomly assigned to interactive or noninteractive conditions and learned words via 9-grid picture matrices. The results revealed higher accuracy in picture selection for interactive learners during the learning phase. During the testing phase, participants in the interactive condition demonstrated significantly higher accuracy than those in the noninteractive condition. Both conditions showed significant inter-brain synchrony (IBS), but interactive learners had greater inter-brain synchrony than noninteractive in the somatosensory association cortex and right supramarginal gyrus. inter-brain synchrony level positively predicted test scores for interactive learners. These results suggest that social interaction can enhance inter-brain synchrony, thereby facilitating second language vocabulary learning.