Fig. 7.

A measure of forces recorded at the interaction point between subjects and robot as a function of time into an after-effect. Each line is an average change in the interaction force during after-effects (n = 5) to targets at 270° and 225° for the first 80 movements in a given force field with respect to those recorded from the same group of subjects in the baseline conditions. This representation of the interaction force is the same as the measure shown in Figure3D–F, with the difference that time is explicitly represented and the sign of the force is positive for a counter-clockwise vector and negative otherwise. Line 1represents mean ± 95% confidence interval of the force produced by naive subjects that learned field B₁.Line 7 represents mean ± 95% confidence interval for naive subjects that learned field B₂.Lines 2–6 are the forces produced by subjects that were learning B₂ at 5 min, 30 min, 2.5 hr, 5.5 hr, or 24 hr after learningB₁, respectively.