How Dare You, iCub? Robots Face Harsher Judgments than Humans in Social Exclusion

Human beings are naturally predisposed to affiliate with others; due to this inclination, social exclusion is perceived as an unsettling experience. The recent advancements in robotics highlight how robots have started to be considered social agents, raising the necessity to investigate social mechanisms behind Human-Robot Interactions. This study explores whether being excluded by a social robot elicits similar negative outcomes as being excluded by a human. Using an experimental design inspired by the Cyberball Paradigm, we conducted a between-subjects experiment with sixty-two participants, where the humanoid robot iCub and a human confederate excluded the participants. According to the condition, one of the two partially re-included them. Our findings indicate that when the robot excluded participants completely, they experienced more threats to their fundamental needs and judged the robot more negatively compared to the condition where the confederate totally excluded them. Additionally, the analysis suggests that previous encounters with iCub influenced participant strategies during the exclusion. Those who had interacted with the robot before were more likely to prefer the robot when excluded by it and the confederate when excluded by them, possibly reflecting a preference for the excluder. Participants with no prior experience tended to favor the robot in both conditions. Behavioral analyses provided additional details on the dynamics of the interaction, revealing that participants increased their physical distance from the interaction table over rounds, accompanied by a decrease in happy expressions and an increase in sad expressions. This study provides meaningful insights into the behavioral dynamics of robotic exclusion and its perception, gaining awareness of the importance of designing social robots that can recognize and mitigate social exclusion when interacting with humans.