This Robot is Sociable: Close-up on the Gestures and Measured Motion of a Human Responding to a Proactive Robot

During an unannounced encounter, we study the appreciation of the robot's sociable character (measured via the answers to a questionnaire) and the motion (arm and head movement frequency and smoothness using IMU sensors) of two humans interacting with a proactive humanoid, knowing that the experiment involves twenty pairs of participants. We also investigate the dependencies between the participants' response to the robot's non-verbal actions and their perception of its sociability. Our results show that the more the humans find the robot sociable, the more they tend to respond to its engaging gestures and the higher is the frequency of their arm motion and the smoothness of their head motion when interacting with it. Therefore, these results show that measurable physical movements might be significant indicators to investigate a social robot's sociable character from the human partner's point of view, as well as to possibly infer the human tendency to interact with it. More generally, the sociable trait attributed to an assistive robot operating in a public or in a private environment, seems to be one of the keys to the success of human-robot interactions.