Imitation learning and co-presence learning influence the acquisition of word formation rules: A fNIRS hyperscanning...

Imitation learning and co-presence learning are common forms of social learning. However, the effects of these two types of learning on acquiring word formation rules have gone relatively underexplored, particularly in the context of adult social learning. The current study uses functional near-infrared spectroscopy (fNIRS) hyperscanning techniques to record the cognitive neural mechanisms of acquiring word formation rules during imitation learning and co-presence learning among dyads of 120 healthy adults. The experiment was a 2 (word learning type: within-subjects, easy word formation rules vs. difficult word formation rules) × 2 (social learning type: between-subjects, imitation learning vs. co-presence learning) mixed design. We used FDR correction to control for false positive rates. Co-presence learning enhanced interbrain synchronization and representation similarity among co-learners in the left middle frontal gyrus. In contrast, imitation learning increased interbrain synchronization in the right superior frontal gyrus, with Granger causality analysis indicating a unidirectional flow of neural activity from the imitator to the demonstrator. These findings suggest that there are distinct neural mechanisms underlying imitation learning and co-presence learning.