Investigating the effect of cardio-visual synchrony on prosocial behavior towards a social robot

Background: Robots are being designed to alleviate the burden of social isolation and loneliness, particularly among older adults for whom these issues are more widespread. While good intentions underpin these developments, the reality is that many of these robots are abandoned within a short period of time. To encourage the longer-term use and utility of such robots, researchers are exploring ways to increase robot likeability and facilitate attachment. Results from experimental psychology suggest that interpersonal synchrony (the overlap of movement/sensation between two agents) increases the extent to which people like one another. Methods: To investigate the possibility that synchrony could facilitate people’s liking towards a robot, we undertook a between-subjects experiment in which participants interacted with a robot programmed to illuminate at the same rate, or 20% slower, than their heart rate. To quantify the impact of cardio-visual synchrony on prosocial attitudes and behaviors toward this robot, participants completed self-report questionnaires, a gaze-cueing task, and were asked to strike the robot with a mallet. Results: Contrary to pre-registered hypotheses, results revealed no differences in self-reported liking of the robot, gaze cueing effects, or the extent to which participants hesitated to hit the robot between the synchronous and asynchronous groups. Conclusions: The quantitative data described above, as well as qualitative data collected in semi-structured interviews, provided rich insights into people’s behaviours and thoughts when socially engaging with a humanoid social robot, and call into question the use of the broad “Likeability” measurement, and the appropriateness of the ‘hesitance to hit’ paradigm as a measure of attachment to a robotic system.