Marching to your own beat: self-entrainment as a missing link between rhythm perception and synchronization

In the study of auditory rhythm perception, a key question is the relationship between the perception of a beat and moving to the beat. The most obvious way to observe an individual’s perceived beat is to ask them to move along with it (e.g., tap a finger on the beat). But this type of observation affects the observed percept: experiment shows that rhythm perception is altered in several ways during movement, even if that movement is as minimal as a finger tap. In particular, rhythmic movement seems to give perceptual “momentum” to a beat percept, helping it continue and making it robust to input perturbations and complexity. Here, we argue that this phenomenon can be elegantly accounted for by assuming that our perception of a periodic beat is partly entrained by the sensory feedback from our own movement. We show that this under-studied aspect of human rhythm provides a parsimonious explanation for a range of experimental results in healthy and disordered populations; that it poses challenges to existing models of rhythm production and entrainment; and that it may be a key to understanding the role of the cerebellum in sensorimotor synchronization and the observation of synchronization differences in autism.