Human trajectory formation: Taxonomy of movement based on phase flow topology

Abstract

The notion that a limited number of 'motor primitives' underwrites complex (human) movements is pertinent to various theoretical perspectives on motor control motor control. Consequently, motor primitives have been classified according to different (and often empirically driven) criteria. Departing from the perspective that dynamical systems dynamical systems are unambiguously described in phase space phase space, we propose a movement taxonomy based on phase flow topology topology. We denote qualitative distinct movement classes as normal forms normal forms of movement. The existence of two normal forms of movement governing discrete and rhythmic behavior has been debated repeatedly in the literature. We provide evidence testifying to the existence (and utilization by humans) of both normal forms through a computational analysis and an experimental study involving human participants. We furthermore argue that one other dynamic possibility governing movement likely exists. © 2008 Springer-Verlag Berlin Heidelberg.