Effects of erring behavior in a human-robot joint musical task on adopting intentional stance toward the iCub robot

In this study, we examined whether the likelihood of attributing intentionality to robots is influenced by the human-likeness of errors during HRI. To this end, we designed an experimental protocol in which users performed a melody in a joint task with the iCub robot. We programmed the iCub robot to make an error in 60% of the repetitions. For half of the users, in the erroneous trials, the robot displayed a human-like error, i.e. switched one element of the melody by pressing the wrong key. For the other half of users, the robot erred mechanically, i.e., it interrupted to play the melody and moved back and forth between two keys in an "endless"loop. Before and after the joint musical task, we administered the InStance Test to evaluate the likelihood of treating the robot as an intentional agent. Results showed that mechanical errors during HRI reduced intentionality attribution toward the robot.