Shimon is an interactive robotic marimba player that can improvise both music and choreography in real-time to the melody of a human pianist.
Playing an instrument does not make you a musician. To become a musician you need to listen, analyze, improvise, and interact through the sound you produce and your body language.
With this in mind, Hoffman et al. explore robotic musicianship. Unlike robots that simply perform a sequence of notes, Shimon’s performances are composed of a sequence of gestures that may or may not produce sound. Using gestures as the building blocks of musical expression is particularly appropriate for robotic musicianship, and nicely fits with our embodied view of human-robot interaction.
The robot is able to improvise by following basic aspects of standard Jazz joint improvisation and can anticipate gestures to easily synchronize with duet partners. Building on this, the human and robot could perform three types of interactions. In the first interaction, the robot and human played two distinct musical phrases, where the second phrase is a commentary on the first phrase. The second interaction was centered around the choreographic aspect of movement with the notes appearing as a “side-effect” of the performance. The third interaction was a rhythmic phrase-matching improvisation.
Using this improvisation system, the pair performed full-length performances of nearly 7 minutes in front of live public audiences and more than 70’000 online viewers.
After the live performances, additional experiments were conducted to investigate the importance of physical embodiment and visual contact in Robotic Musicianship. Results show that synchronization between the robot and musician can be aided by visual contact when the tempo is uncertain and slow. In addition, the audience perceives Shimon as playing better, more like a human, as more responsive, and even more inspired when compared to a “computer musician”. Shimon was also rated as better synchronized, more coherent, communicating, and coordinated; and the human as more inspired and more responsive.
In the future, Hoffman et al. hope to further explore robot musicianship by giving Shimon a socially expressive robot head, vision and new gestures.