A Perceptually Driven Dynamical Model of Bimanual Rhythmic Movement (and Phase Perception)

Abstract

Rhythmic bimanual movement has been a paradigm system in the study of perception–action. In perception–action, movement generates information that is then used in turn to guide the movement. The result is complex behavior emerging from relatively simple dynamical organization. Nonlinear dynamics has been used to describe the organization, but the models thus far have not much featured the role of information so that the information has not been investigated. Therefore, we propose a new perceptually driven dynamical model. We first review our perceptual judgment studies of coordinated rhythmic movements. We then describe a perceptually driven model of single and coupled oscillators. Finally, we explore the implications for investigation of information. The main variable in the study of coordination of human rhythmic movements is relative phase, that is, the relative position of two oscillating limbs within an oscillatory cycle. For people without special skills (e.g., jazz drumming), the cardinal phenomena in bimanual coordination are (a) at preferred frequency, only two relative phases are stably produced, at 0° and 180° (preferred frequency is about 1 Hz); (b) other relative phases can be produced on average when people follow metronomes, but the movements exhibit large amounts of phase variability; and (c) as frequency is increased beyond preferred, phase variability of 180° increases and movement switches to 0° when frequency reaches about 3 to 4 Hz. With the switch, phase variability drops. These phenomena were produced by the Haken–Kelso–Bunz (HKB; Haken, Kelso, & Bunz, 1985) model shown in Figure 1. The potential function in this model represents the energy required to maintain a given phase. The HKB simply assumes this function.