AbstractThe provision of feedback with complex information beyond the correct answer, i.e., elaborated feedback, can powerfully shape learning outcomes such as transfer. However, an understanding of neurocognitive mechanisms that support elaborated feedback during instructor-learner interactions remains elusive. Here, a two-person interactive design is used during simultaneous recording of functional near-infrared spectroscopy (fNIRS) signals from adult instructor-learner dyads. Instructors either provided elaborated feedback (i.e., correct answer and an example) or simple feedback (i.e., correct answer only) to learners during a concept learning task. Our results showed that elaborated feedback produced comparable levels of retention to simple feedback, however, transfer was significantly enhanced by elaboration. We also noted significant instructor-learner neural synchronization in frontoparietal regions during the provision of elaborated feedback, especially when examples were provided. Further, interpersonal neural synchronization in the parietal cortex successfully predicted the transfer of knowledge to novel contexts. This prediction was retained for both learner-delayed and learner-preceding neural synchronization, supporting the interpretation that deeper-level representations of knowledge, such as abstract structure and personal interpretation, may promote the transfer of learning. These findings point toward interpersonal neural synchronization as a key neurocognitive mechanism that supports learning transfer effects, and may have important implications for real-world learning and pedagogical efficacy.Educational Impact and Implications StatementFeedback provides the information regarding the gap between what is achieved and what is aimed to be achieved, and thus plays a critical role in any learning processes. In real-world settings, feedback is oftentimes provided and received during social interactions, and contains complex information beyond the correct answer, that is elaborated feedback. This study sought to investigate neurocognitive mechanisms that support elaborated feedback during instructor-learner interactions using fNIRS hyperscanning. It was revealed that providing learners with elaborated feedback enhanced the transfer of knowledge to novel contexts relative to simple feedback. Instructor-learner neural synchronization was detected in frontoparietal regions during the provision of elaborated feedback, especially for examples. Parietal instructor-learner neural synchronization predicted the transfer. This study provides a novel lens, i.e., interpersonal neural synchronization, for people to understand more about how elaborated feedback takes effects on learning transfer, and may have critical implications for real-world learning and pedagogical efficacy.