Forces exerted against the perturbation in the three experiments.

<p>Top row describes the distribution of target width over the course of trials. In the first experiment (panel A), target width was randomly assigned for the first 66 trials while it was randomly assigned for the first 156 trials in the two other experiments. In the blocked schedules, target width changed every 100 trials in the first experiment with a maximum of 270 trials. In the second (panel B) and third experiments (panel C), target width changed only once after 45 trials. Middle row depicts the average force profiles across all subjects recorded during the perturbation trials for each schedule and each target width separately. In these plots, the forces are represented against the distance from the starting position in order to match the level of perturbation. Shaded area around each curve represents standard error of the mean. The bottom row presents the statistical analysis of the forces recorded at 13 cm in the force profiles in function of target width and schedule. Each column represents a different experiment. Error bars represent the 95% confidence interval.