Professor Plucky: Expressive body movement in human–robot musical ensembles

When people play music together, they move their bodies, and that movement plays an important role in the activity of group music making. In contrast, when robots play music with people, the robots are usually stiff and mechanical in their movement. In general, it is not well understood how the movement of such robots affects how people interact with them, or how the robot movement should be designed in order to promote certain features of interaction. As an initial exploration into these questions, we built a prototype guitar plucking robot that plucks the strings with either a) kinetic plucking mechanisms that are designed to have visually appealing movement, or b) control plucking mechanisms that do not visually move. In a pilot study we found that when guitarists play with the robot, they move their hands more and look at the robot more when it uses the kinetic mechanisms as opposed to the control ones. However, they do not report preferring the kinetic mechanisms. These preliminary findings suggest some very clear hypotheses for future followup studies.