Original image taken from http://commons.wikimedia.org/wiki/File:Batuku_rhythm.png, modified by Jenny Lu

At the University of Montreal, a team of psychologists led by Jessica Phillips-Silver and Isabelle Peretz reported the first case of “beat deafness,” in which a person cannot follow a beat. This person, a 23-year old man named Mathieu, cannot move in sync with the steady beat of dance music nor distinguish whether the person next to him is moving in sync as well. Although Mathieu can mimic a group of other people who move to the beat, when on his own Mathieu’s movement becomes erratic in the context of the music being played.

What is remarkable is that Mathieu’s hearing and motor functions are normal. The scientists currently conjecture that beat deafness is similar to the more commonly known tone deafness, in that the brain cannot integrate the musical cues that relate to rhythm and beat in time.

In the Science News article that discusses this, a set of two clips under the heading “Offbeat Guy” are shown that demonstrate Mathieu’s beat deafness. It’s really interesting if you play the clips simultaneously—you’ll see the striking irregularity in Mathieu’s rhythm, as he never quite catches the beat of the music. This news makes me wonder how people with a very strong sense of beat—like skilled percussionists, for example—interpret music and language in comparison to those like Mathieu, who may have tonal understanding but no beat recognition at all. Moreover, how much of our aural understanding is devoted to tone in comparison to rhythm and beat?