Being watched by a humanoid robot and a human: Effects on affect-related psychophysiological responses

Eye contact with a humanoid robot has been shown to evoke similar affect and affiliation related psychophysiological responses as eye contact with another human. In this pre-registered study, we investigated whether these effects are dependent on the experience of being "watched". Psychophysiological responses (SCR, zygomatic and corrugator facial EMG, frontal EEG asymmetry) to a humanoid robot's or a human model's direct vs. averted gaze were measured while manipulating the participants' belief of whether the robot/human model could see them or not. The results showed greater autonomic arousal responses and facial responses related to positive affect both to the robot's and the human model's direct vs. averted gaze, regardless of the belief condition. The belief condition influenced the overall magnitude of these responses to both stimulus models, however, to a lesser extent for the robot than for the human model. For the frontal EEG asymmetry, the effect of gaze direction was non-significant in both belief conditions. The results lend further support for the importance of eye contact in human-robot interaction and provide insights into people's implicit attributions of humanoid robots' mental capacities.