Non-anthropomorphic robots as social entities on a neurophysiological level

The mirror-neuron-system (MNS) is involved in the perception of actions of humans and anthropomorphic robots. The current study investigates whether social interaction with a non-anthropomorphic robot is sufficient for a response of the MNS. Fifty-seven participants observed movements of a vacuum cleaning robot before and after it was handled by its owner. The robot was either humanized, being treated aggressively (n = 30), or it was treated as an object (n = 27). Electroencephalographic mu-activity is used as an index of MNS activity, because both are inversely correlated. Activity within the 8-13 Hz band was measured at central (mu activity) and occipital (alpha-activity) electrodes. Further, the level of aggressiveness displayed by the robot's owner, and the participants' compassion were rated on visual analog scales. Mu-activity showed medium-sized correlations with rated aggressiveness and compassion: The more aggressive the action towards the robot was perceived (r = -.379, p = .004), and the more compassion was felt for the robot (r = -.339, p = .010), the less pronounced mu-activity was at electrode C3 in response to the robot's movement. Thus social interaction with a non-anthropomorphic robot might establish the robot as a social entity and is sufficient to activate the human MNS. (C) 2015 Elsevier Ltd. All rights reserved.