Empathy-related individual differences in brain responses to robot and human pain

Introduction Robots are increasingly implemented across diverse social contexts. Empathy is one construct that has gained focus in human-robot interaction (HRI) research. While previous studies have demonstrated neural activation for explicit depictions of robot pain, this work has primarily used a limited range of human and robot stimuli, and it is less clear how humans perceive a broader range of faces. Methods The current study examined the neural correlates of human empathy for robot pain using functional Near-Infrared Spectroscopy (fNIRS) and a diverse range of human and robot face stimuli. In Study 1, we conducted an online survey with N = 63 adults to identify and validate photo stimuli of subtle depictions of robot pain. In Study 2, N = 39 adults completed an fNIRS task in which they viewed and rated human and robot photos in a painful touch and neutral conditions. Results In Study 1, results found that the painful touch condition stimuli successfully elicited the intended emotion. In Study 2, there were no significant differences in brain responses to human pain in comparison to robot pain, though results demonstrated behavioral sensitivity to both the touch and face conditions. Neuroimaging analyses also suggest that individual differences in self-oriented empathy is linked to neural activation for human and robot pain. Discussion The current work contributes our understanding of the role of individual differences in self-rated empathy in shaping neural responses to robot pain and highlights the importance of tailoring HRI to the emotional and empathetic responses of users. We did not find evidence for significant differences in neural responses to human pain stimuli in comparison to robot pain stimuli, despite significant differences in behavioral pain ratings. This suggests a discrepancy between brain and behavior necessitating further inquiry.