Effects of bodily mood expression of a robotic teacher on students

Abstract

This paper reports our investigation into the effects of bodily mood expression of a humanoid robot in a scenario close to real life. To this end, we used the NAO robot to perform as a lecturer in a university class. To display either a positive or a negative mood, we modulated 41 co-verbal gestures by adjusting behavior parameters that control spatial extent and motion dynamics, without modifying gesture function. Unique in this study is that (a) the robot gave an actual lecture to real students, (b) the interaction is one-to-many and relatively long (30 min), and (c) mood modulation was applied to a large set of behaviors. The robot presented the same lecture either in a positive or a negative mood to two audiences (between subjects). Although statistical analysis does not show that participants consciously recognized the robot mood, the results do show that participants in the positive mood condition rated their own arousal significantly higher than in the negative condition. Further, video annotation showed increased valence and arousal of the audience in the positive condition. Finally, participants' ratings of the lecturing quality and the gesture quality of the robot are higher in the positive condition, demonstrating the importance of robot mood expression in a one-to-many interaction setting.