Perception of Emotional Relationships by Observing Body Expressions between Multiple Robots

Emotional expressions are essential in augmenting a robot’s expression. Many robots with limited facial expression freedom, such as the Nao robot, can effectively express emotions using body movement. Previous studies have used a single robot and evaluated its expression. Multiple robots expressing emotion in their interactions may have a greater impact than robots expressing emotion only when interacting with humans. The relationships between these robots should allow them to develop more diverse modes of expression. However, it is unclear how people perceive relationships by observing robots’ emotional expressions. In this study, we applied every combination of four characteristic body emotion expressions (Sadness, Fear, Pride, and Happiness) based on Russell’s circumplex model to robots. Furthermore, we investigated how the relationships were evaluated in an online video-based experiment. The results show that the relationships between the two robots are influenced by each robot’s body emotional movement and can be interpreted using the valence-arousal model.