The project investigates interpersonal neural synchrony during verbal conversations and aims to combine hyperscanning, behavioral analysis, and personalized analytical approaches to better understand successful human communication. During the reporting period, the main scientific effort focused on establishing and implementing the experimental and analytical framework for the first study. A complete hyperscanning protocol was developed and made operational for the study of free verbal conversations in dyads. The protocol integrates EEG, ECG, audio, and video recordings, allowing the simultaneous measurement of neural, physiological, and behavioral dynamics during natural social interaction. Following protocol development, piloting, and implementation, data collection for Study 1 was successfully completed in 40 female stranger dyads participating in free-conversation tasks. In parallel, the project established the corresponding preprocessing and analysis workflow needed to handle multimodal dyadic data. This includes a working software and analysis pipeline for organizing, preprocessing, and preparing EEG, ECG, audio, and video data for integrated analysis. A dataset for Study 1 has therefore been successfully created and is now available for ongoing scientific evaluation. The scientific analyses completed so far have focused primarily on behavioral markers of conversational coordination. In particular, turn-taking measures have been analyzed, providing an initial characterization of interaction dynamics across dyads. Analyses of phonetic convergence are currently in progress, and work is also ongoing on dyad-specific and personalized analytical approaches that are central to the project’s objective of moving beyond group-level descriptions toward more individualized models of interpersonal synchrony. Overall, the main achievement of the reporting period is the successful completion of the first study, including the development of a fully operational hyperscanning protocol, completion of multimodal data collection, establishment of a usable dataset, and implementation of a working analysis workflow. These achievements provide the technical and scientific basis for the next phase of the project, which will extend the work toward the planned causal investigation using multi-person brain stimulation, in line with the original project concept. Due to technical issues related to the synchronization of the tACS devices, this second study has not yet been carried out and is currently in preparation. Overall, the action has delivered one completed scientific study, a multimodal dataset based on 40 dyads, and an operational software and analysis workflow for the study of interpersonal neural and behavioral coordination during conversation. The project has therefore achieved its first major methodological and empirical milestone and created the foundation for the next study, which will investigate the causal modulation of interpersonal synchrony through brain stimulation, as originally envisaged by the project.
