Human behavioural responses to robot head gaze during robot-to-human handovers

A robot that can fluently hand over objects to people can be useful in many applications. In an effort to develop a fluent robot-to-human handover system, this work investigates people´s behavioural responses to a robot that hands over objects to them while using different types of gaze cues. In our previous work, we found empirical evidence that the use of a robot´s head gaze can affect a person´s timing of reaching towards the offered object. In this paper, we investigate this effect further by exploring the manner in which human´s reaching and gaze behaviours are affected by a robot´s head gaze. We conducted a video-based investigation of 97 naïve participants´ behavioural responses to robot-to-human handovers. Through a frame-by-frame analysis, we recorded a detailed timeline of the robot´s and human´s gaze and reaching behaviours. Results confirm the finding from our previous study that the robot´s head gaze can significantly impact the timing of human receiver´s reaching behaviour during handovers. In addition, our results demonstrate that the robot´s head gaze affects human´s gaze behaviour during handovers, and this effect explains some unexpected findings in our previous work.