Münster 1997 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 19: Poster II

DY 19.18: Poster

Donnerstag, 20. März 1997, 09:30–12:30, Z

Nonlinear phenomena in rhythmic hand movements — •Ralf Engbert — Institut für Theoretische Physik und Astrophysik, Universität Potsdam, Postfach 601553, D-14415 Potsdam

In cognitive psychology the study of rhythmic hand movements is used as a paradigm for the study of movement control. Polyrhythms are interesting to investigate because of their conflicting phase relationships between the two hands. Time series from related experiments are typically short and noisy. The application of symbolic dynamics as a method of nonlinear time series analysis yields new insights into the dynamics of hand movements. In particular, we show the occurrence of phase transitions within the performance of a 3:4 polyrhythm under experimental manipulation of the tempo of performance.

These qualitative changes are well explained by a nonlinear dynamical model which is discrete in time. The model is based on two coupled rhythm generators, where the coupling constants and the strength of the correction mechanism are the control parameters. Furthermore, the model essentially incorporates a finite time delay for the feedback control.