Fig. 10.

Measures of variability and stability in state space in experiment 2. A and B: arm trajectories on day 1 and day 4 of an exemplary subject form the self-paced group. C and D: arm trajectories on day 1 and day 4 of an exemplary subject form the discrete group. E: standard deviations at the Poincaré section STD-PM across 6 days of practice. F: Floquet multiplier across 6 days of practice. The 2 groups improve across the 6 days, and they differ in performance measures. The variability (Bodfish et al. 2000) and stability measures show the same pattern as in experiment 1.