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

Eye-gaze synchrony-the temporal coordination of eye movements between individuals-has been widely studied in dyadic interactions, but its operationalization remains inconsistent and its extension to multi-person settings is methodologically challenging. This proof-of-concept study examines whether eye-gaze synchrony can be captured in a single triadic interaction using mobile eye tracking and proposes a reproducible workflow for doing so. Three participants wore Tobii Pro Glasses 3 during a 7-min spontaneous face-to-face conversation. Independent recordings were synchronized via a router-based setup, and gaze points were re-expressed within a common two-dimensional reference frame anchored by a fiducial marker. To illustrate how different operationalizations can be applied in this context, we compared an event-based approach quantifying discrete occurrences of mutual gaze and joint attention with an index-based approach assessing temporal alignment of gaze signals via Surrogate Synchrony methods. The two approaches yielded different descriptive patterns, suggesting that they may emphasize different features of gaze coordination in this interaction. These results support the technical feasibility of capturing gaze coordination in triadic interactions using mobile eye tracking and underscore the importance of carefully considering how synchrony is operationalized. The proposed workflow provides a foundation that future studies can evaluate and extend across interactions and contexts.