Capturing eye gaze synchrony in a triadic interaction: A proof-of-concept study

Eye gaze synchrony, the temporal coordination of eye gaze between individuals, is a key feature of social engagement and interpersonal bonding. Whereas dyadic eye gaze synchrony has been widely studied, its operationalization remains inconsistent, and methods extending beyond dyads are scarce. This proof-of-concept study introduces a reproducible pipeline for capturing eye gaze synchrony in a triadic interaction using mobile eye tracking. Three participants each wore Tobii Pro Glasses 3 during a 7-minute naturalistic conversation. Independent recordings were synchronized via a router-based setup, and gaze points were spatially aligned within a shared coordinate system anchored by a fiducial marker. We compared two analytical frameworks: a correlation-based approach using Surrogate Synchrony methods (SUSY and its multivariate extension mv-SUSY) to quantify temporal alignment of gaze, and an event-based approach assessing occurrences of mutual gaze and joint attention. The study demonstrated the feasibility of analyzing eye gaze synchrony among multiple participants. Results indicated that correlation-based and event-based measures capture distinct but complementary aspects of triadic coordination. This work provides a foundation for reproducible quantitative analyses of gaze coordination in complex social settings.