Human-like motion of a humanoid in a shadowing task

Humanoid robots have - by definition - some level of human-likeness in body form. According to previous research in HRI, this leads to a higher expectation of human-like behavior. Nevertheless, human-likeness is not an easy notion to define for motion even in a task as straight forward as real-time motion copying (the shadowing task) as this paper will try to argue. The main hypothesis of this paper is that subjective evaluation of robot´s motion´s human-likeness depends not only on the objective similarity between robot´s motion and human motion but also on the interaction context (e.g, whether or not the human have previously engaged in mutual or back imitation with the robot). Moreover, the paper proposes two features of motion similarity that affect subjective evaluation of human-likeness and accuracy in the shadowing task and shows that human-likeness is a different attribution dimension form both accuracy and humanness (measured using human-nature traits). The paper reports a controlled user study involving 36 participants and 108 HRI sessions to support these claims.