Grouped results from Experiment 3. Two metrics are used to compare performance. Error bars denote standard error. Data are from one cohort of subjects (N = 11). (A) Comparison of within-subject factors of visual feedback condition (red bars), tactile feedback condition (green bars), and trial phase (grey bars). Within-subjects ANOVA revealed significant main effects of visual feedback condition and tactile feedback condition, but not phase, indicated by stars. For detailed statistics see text. (B) Comparison of subjects' performance as a function of feedback condition: (left to right) no feedback; vibrotactile feedback only; visual feedback only; both visual and tactile feedback. The two bars per condition indicate performance in the first (left) and second (right) phases of training. Subjects performed significantly worse in the absence of either source of feedback.