Impacts of Robot Head Gaze on Robot-to-Human Handovers

In this paper, we investigate the use of a robot’s gaze to improve the timing and subjective experience of face-to-face robot-to-human handovers. Based on observations of human gaze behaviors during face-to-face human–human handovers, we implement various gaze behaviors on a PR2 humanoid robot. We conducted two consecutive robot-to-human handover studies. Results show that when the robot continually gazes at a projected handover position while handing over an object, the human receivers reach for the object significantly earlier than when the robot looks down, away from the handover location; further, when the robot continually gazes at the receiver’s face instead of the handover position, the receivers reach for the object even earlier. When the robot—instead of continually gazing at a location—transitions its gaze from the handover position to the receivers’ face, or vice versa, the receivers’ reach time did not improve; however, the receivers perceive these gaze transitions to better communicate handover timing than continual gazes. Finally, the receivers perceive the robot to be more likeable and anthropomorphic when it looks at their face than when it does not. Findings from our studies indicate that robot’s use of gaze can help improve both fluency and subjective experience of the robot-to-human handover interactions.