A dynamical systems approach to manual tracking performance

Manual Cracking performance was investigated from the perspective of dynami cal systems theory. The authors manipulated the type of visual display, the control system dynamics, and the frequency of the sinusoidal input signal to examine couplings with various phases between the visual signal and cont rol movements. Analyses of the system output amplitude ratio and relative p hase showed that participants (N = 24) performed poorly with 90 degrees rel ative phase coupling. All the couplings became less stable as the movement frequency increased. The authors developed an adaptive oscillator model wit h linear damping to describe the coupled system consisting of the human per former, the visual display, and the control system dynamics. A. geometric a ccount of the stability of performance at different relative phases is also presented.