Using a Social Robot to Promote Interaction Among Older Adults at a Day Center in Japan: a Pilot Study Based on Sociograms

Abstract This pilot study examines whether the introduction of a social robot can enhance social interaction among older adults attending a day care center in Japan. A quasi-experimental within-subject design with repeated measures was implemented across four group sessions held over one month: one baseline ses-sion without the robot and three sessions with the robot. Using structured observation, sociomatrices, and sociograms, the study analyzed human-human, human-robot, and human-robot-human interaction episodes during guided group activities. Network indicators such as in-degree, out-degree, mean degree, close-ness, betweenness centrality, and authority were compared across sessions to assess changes in relational structure. Brief descriptive interpretation was also complemented by field notes and post-session user evaluations. The baseline ses-sion showed a low-density network with a small active core and several peripheral participants. After the robot was introduced, the volume of exchanges increased and the networks became more cohesive, with higher mean degree values and shorter relational distances. Overall, the findings suggest that the robot func-tioned not only as an object of direct interaction but also as a mediator that stimulated human-robot-human dynamics and helped activate less connected members of the group. Despite these promising results, the study should be inter-preted cautiously due to its pilot nature, small sample, and single-site design. The findings support the potential of social robots as facilitators of group engage-ment in adult day care settings and highlight the usefulness of social network analysis for examining interactional change in gerontechnology research.