Born to dance but beat deaf: a new form of congenital amusia.

Humans move to the beat of music. Despite the ubiquity and early emergence of this response, some individuals report being unable to feel the beat in music. We report a sample of people without special training, all of whom were proficient at perceiving and producing the musical beat with the exception of one case ("Mathieu"). Motion capture and psychophysical tests revealed that people synchronized full-body motion to music and detected when a model dancer was not in time with the music. In contrast, Mathieu failed to period- and phase-lock his movement to the beat of most music pieces, and failed to detect most asynchronies of the model dancer. Mathieu's near-normal synchronization with a metronome suggests that the deficit concerns beat finding in the context of music. These results point to time as having a distinct neurobiological origin from pitch in music processing.