Toward a better understanding of the communication cues involved in a human-robot object transfer

Handing-over objects to humans (or taking objects from them) is a key capability for a service robot. Humans are efficient and natural while performing this action and the purpose of the studies on this topic is to bring human-robot handovers to an acceptable, efficient and natural level. This paper deals with the cues that allow to make a handover look as natural as possible, and more precisely we focus on where the robot should look while performing it. In this context we propose a user study, involving 33 volunteers, who judged video sequences where they see either a human or a robot giving them an object. They were presented with different sequences where the agents (robot or human) have different gaze behaviours, and were asked to give their feeling about the sequence naturalness. In addition to this subjective measure, the volunteers were equipped with an eye tracker which enabled us to have more accurate objective measures.