When the Beat Goes Off: Mutually Interacting Complex Systems

When: Thursday, June 13, 2013 at 1:30 pm
Where: DA 5th fl
Speaker: Dr. Holger Hennig
Organization: Postdoctoral Research Fellow, Harvard university, Visiting Scholar, University of Bremen, Germany
Sponsor: CCNR

Although human musical performances represent one of the most valuable achievements of mankind, the best musicians perform imperfectly. Musical rhythms are not entirely accurate and thus inevitably deviate from the ideal beat pattern. It will be shown that long-range correlations are a natural companion of complex human rhythmic performances [1]. Moreover, listeners strongly prefer long-range fluctuations in musical rhythms [2]. Thus, the favorable fluctuation type for humanizing interbeat intervals coincides with the one inherent in human musical performances. In the second part of the talk we ask, how two musicians interact when playing musical rhythms together. Iwill show that the interbeat intervals generically exhibit scale-free (power law) cross-correlations on time scales up to several minutes [3]. A model is presented providing a physiologically meaningful explanation for the occurrence of scale-free cross-correlations in mutually interacting complex systems. While the results have lead to applications in audio engineering, the statistics observed contribute to the understanding of the foundations of interval timing on the neural networks level, and of cases where interval timing is disrupted (Huntington’s disease).

[1] HH, R. Fleischmann, A. Fredebohm, Y. Hagmayer, A. Witt, J. Nagler, F. Theis and T. Geisel, PLoS ONE, 6, e26457 (2011)

[2] HH, R. Fleischmann, and T. Geisel, Physics Today 65, 64-65 (2012)

[3] HH, to be submitted (2013)