Interplay of synchronized music

Rhythmic activities are ubiquitous in nature. Synchronization of rhythmic patterns can be found in interacting inanimate systems where the mechanism of the coupling can usually be identified and understood; it is also commonly observed in living systems where the mechanisms of the interaction are less apparent, and sometimes even mysterious. To characterize the statistical properties—and to develop a simple mathematical model—of these couplings can shed some light on an important class of phenomena of interacting living systems. In PNAS, Hennig (1) examines the cross-correlation of tempo time series: that is, the time intervals between successive musical beats, between two people playing rhythmic music in synchrony. Hennig finds long-range (power-law decayed) cross-correlation between the two synchronized tempo sequences. To simulate the observed phenomenon, Hennig proposes a simple mathematical model that might also be helpful in providing some insights into other synchronization processes in nature. It is expected that there should be coupling in the tempo time series of musical rhythms when two people are playing the music together. The significance of Hennig’s work is the special kind of correlation that appears between two individuals playing music together. To appreciate this discovery, let us first consider the …