How Can Robot's Gaze Ratio and Body Direction Show an Awareness of Priority to the People With Whom it is Interacting?

When a person interacts with others who require different levels of authority, his/her gaze ratio and body direction for each person are different, e.g., a salesperson who turns to and looks at a very important person (VIP) more attentively than a member of that VIP's staff. In this study, we investigate the effects of gaze ratios and body directions with which social robots demonstrate an awareness of authority when they are simultaneously interacting with multiple persons. We develop a gaze-controller system for a social robot and experimentally investigate the effects of the gaze ratio and the body direction (priority oriented: body direction turns to a target and non-priority oriented: body direction does not turn to a target) when the robot salesperson is describing items to two persons who are playing different roles: a VIP and a follower (e.g., member of a VIP's staff). Our experiment results show that different advantages of gaze ratio and body direction demonstrate an awareness of priority. In the priority-oriented condition, participants more highly evaluated the gaze at 100:0 ratio between VIPs and followers. But, in the non-priority-oriented condition, the participants more highly evaluated the gaze ratios at 80:20 or 90:10. These results contribute to a gaze behavior design for social robots that interact with multiple persons who require different levels of priority.