Amount awarded: $10,000

Project Narrative: Inter-brain networks (IBNs) are a methodological measure of brain synchrony between multiple interacting people. Although they figure prominently in social neuroscience, the many ways IBNs can be constructed and used to account for diverse phenomena obscure how they carry out their explanatory role. This project brings together experts from neuroscience and philosophy of science to determine how IBNs actually explain and what claims they can bear.

Project Summary: Hyperscanning, or the simultaneous neuroimaging of two or more interacting individuals, is at the methodological vanguard of social neuroscience (Montague et al., 2002; Schilbach and Redcay, 2025). Its central product is the inter-brain network (IBN): a methodological construct describing the synchrony between interacting brains (Czeszumski et al., 2020). IBNs are the field's primary explanans, appearing in accounts of social interaction in domains ranging from social psychology and developmental psychiatry (Reindl et al., 2018; Leong and Schilbach, 2019; Speer et al., 2024; Li et al., 2025) to educational psychology (Dikker et al., 2017; Bevilacqua et al., 2019).

However, the exact way in which IBNs are supposed to explain this wide range of phenomena remains unclear. Studies differ not only in imaging modality, measurement thresholds, and connectivity metrics, but also in how IBNs are interpreted: as a mere correlation among neural measurements (Burgess, 2013; Holroyd, 2022), as a form of brain-to-brain coupling (Hasson et al., 2012), or as a representation of the shared dynamics of joint activity (Hasson and Frith, 2016). There is no consensus on whether IBNs form one explanatory kind or many, what explanatory level they target, or whether they function as measurements of neural similarity or full-blown representations of target phenomena. Without answers, individual hyperscanning explanations cannot be evaluated, let alone compared across studies. Despite a fast-growing empirical literature, no work in the philosophy of science addresses the IBN directly.

This project supplies the missing account. It convenes three communities that rarely interact together: the hyperscanners who build IBNs, the network neuroscientists who can situate them among brain-network measures, and the philosophers of neuroscience who can clarify their explanatory status. A three-day workshop of ten invited contributors anchors the effort, framed against the first philosophy-of-science treatment of the IBN drafted and circulated in advance of the event by the project participants. The workshop will culminate in an open-access edited volume, with a framing chapter establishing shared questions and vocabulary and a concluding chapter co-authored across the three communities. We will also trace how hyperscanning results propagate into clinical, educational, and policy guidance, and a public-facing companion essay will carry the findings beyond academia.