Humans Perform Social Movements in Response to Social Robot Movements: Motor Intention in Human-Robot Interaction

In an experimental study of humans reactions to social motor intention (SMI) in a humanoid robot, we showed that SMI cause the emergence of social interaction between human and robot. We investigated whether people would respond differently to a humanoid robot depending on the kinematic profile of its movement. A robot placed a block on a table in front of a human subject in three different ways. We designed the robot’s arm and upper body movements to manifest the human kinematic profile of either a non-social motor intention or a social motor intention. In the control condition the robot performed an irregular (given the set-up) movements. Once the robot had finished its task, the task of the human was to place another block on top of the first one. We distinguished
between social and non-social responses to the robot’s behavior based in gaze behavior and kinematic profile of the human’s arm movement during the task. Our results show that the behavior of the human can be modulated by the kinematics of a robot’s motor action. In several cases the participants reciprocated movements displaying social motor intention with movements with a similar kind of kinematics, attempting to make eye contact during the task. This shows that HRI can emerge implicitly by sensorimotor processing and suggests that implementing a mechanism for social-motor intention in social robots designed to interact spontaneously would be useful.