Figure 11.

Perturbation influence functions for the three button shapes. a, Influence functions computed from the y component of subjects' trajectories in trials with vertical perturbations. b, Influence functions computed from the x component of subjects' trajectories in trials with horizontal perturbations. c, d, Perturbation influence functions derived from the y and x components, respectively, of subjects' trajectories computed from trials containing diagonal perturbations. The dashed curves show the perturbations influence functions predicted from a linear superposition of the perturbation influence functions computed from the trials with vertical and horizontal perturbations (a, b).