Interpersonal neural synchrony in joint music-making and conversation: toward an integrative Marr-level account.

Joint music-making and conversation are two fundamental forms of human interaction. A growing number of hyperscanning studies have examined interpersonal neural synchrony (INS) in music and language separately, yet few have sought to connect findings across these domains within a unified theoretical framework. Recent reviews have highlighted the need for approaches that move beyond isolated reports of brain regions or oscillatory patterns. This article responds to that need by applying David Marr's tripartite framework-computational, algorithmic, and implementational-to hyperscanning findings from dyadic musical and conversational interaction. Rather than presupposing strict equivalence between domains, the review examines whether music and conversation involve partially overlapping coordination problems, cognitive processes, and neural dynamics. The article introduces INS as an implementational-level measure indexing interpersonal coordination, situates it within the broader rise of hyperscanning in social neuroscience, and discusses methodological caveats specific to the field, including reverse inference, sensor-to-region mapping, and the distinction between intra-individual and genuinely interaction-specific processes. It then synthesizes evidence from musical interaction studies, including dynamic synchrony, task manipulations, and sensorimotor coupling, alongside thematically organized findings from conversational interaction. Overlapping neural networks and oscillatory patterns are compared across domains and interpreted through Marr's framework in terms of the coordination problems they may address, the processes they may instantiate, and their neural realization, while carefully considering the limitations associated with reverse inference. The review concludes by outlining future directions and testable hypotheses concerning role asymmetry, mutual adaptation, stimulus-driven versus interaction-specific synchrony, and dynamic network reconfiguration.