Robot humor: How self-irony and Schadenfreude influence people's rating of robot likability

Humor in robotics is a promising, though not yet significantly researched topic. We performed a user study exploring two different kinds of laughter. In our study, participants observed a robot-robot interaction where an iCat and a NAO robot exhibited different laughing behavior. While NAO laughed at itself (self-irony), the iCat laughed at NAO (Schadenfreude1). Our participants watched four turns of the same robot-robot interaction, with either NAO or the iCat laughing, both robots laughing, or no robot laughing (baseline). After each turn we asked the participants to rate both robots' likability individually. Our results show that the participants liked a robot with a positively attributed form of humor significantly more than its gloating robotic interaction partner. However, likability ratings showed a trend to approach each other when either robot laughed or when both robots laughed together. Both, the higher likability ratings for a robot showing positively attributed humor and the decreasing difference in likability ratings when both robots laugh together, provide proof of the positive effect of humor. While participants' age did not affect likability ratings, there was a significant interaction effect between participants' gender and robot type. Female participants rated the iCat more likable, while male participants liked NAO better. In addition, more neurotic people liked the self-ironic robot more when no robot laughed and more open people like the robot showing Schadenfreude more when both robots laughed.