ABSTRACT
In this chapter we aim to identify collective variables (or order parameters) and their dynamics (stability, loss of stability, hysteresis . . .) for perceptionaction patterns. To do so we extend earlier results on phase transitions in human bimanual coordination to a perception-action task, synchronizing or syncopating finger flexion with an auditory metronome whose frequency is varied in steps (.25 Hz) over a wide range (1.0 Hz to 3.5 Hz). The chief idea is to study the metronome-hand relation as an example of a pattern forming system. Relative phase between hand and metronome proves to be an adequate collective variable that characterizes empirically observed patterns. A theoretical model using the concepts of synergetics and dynamic pattern theory reproduces all observed patterns, among which are frequency locking and phase locking, phase transitions, and loss of entrainment (relative coordination). The general implications of these results are discussed and new predictions proposed.
