Seeing the Errors You Feel Enhances Locomotor Performance but Not Learning  Ryan T. Roemmich, Andrew W. Long, Amy J. Bastian  Current Biology  Volume 26, Issue 20, Pages 2707-2716 (October 2016) DOI: 10.1016/j.cub.2016.08.012 Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 1 Lab Setup for All Experiments and Visual Display for Experiments 1–3 (A) Participants walked on a split-belt treadmill while viewing visual feedback about their step lengths, or without visual feedback and instead a television show/movie. We recorded participant kinematics (pale blue markers) using three-dimensional motion capture. (B) Example participant kinematics and corresponding visual display for experiments 1–3 with visual feedback (left) and without visual feedback (right). Note that the visual feedback does not indicate real-time foot position, but rather step length (i.e., the distance between ankle markers) at heel-strike. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 2 Experiment 1 Protocol and Results (A) Experiment 1 protocols are shown for the feedback and no feedback groups. The protocols are identical with the exception that the feedback group received visual feedback of their individual step lengths during adaptation while the no feedback group watched a movie instead. (B) Mean ± SE adaptation curves across participants within the feedback (blue) and no feedback (green) groups are shown. The curves are truncated in length to match the participant that took the fewest strides during adaptation. Data points immediately following the adaptation curves show the step length asymmetry during plateau (mean ± SE of the last 30 strides) for each group. (C) Mean deadaptation curves across participants within the feedback (blue) and no feedback (green) groups ± SE are shown. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 3 Experiment 1 Individual Participant and Group Model Fits (A) Dual-rate adaptation model fits are shown for adaptation and deadaptation symmetry change data from each participant in the no feedback group. The data are shown in light green, the fit in dark green, and the perturbation (i.e., 1 for split belts, 0 for tied belts) in red. (B) Dual-rate adaptation model fit to the group mean no feedback data during adaptation and deadaptation. The motor output and adaptation (which overlap) are shown in green, slow process in magenta, fast process in purple, and perturbation in pink. (C) Voluntary correction model fit to the adaptation and deadaptation group mean symmetry change data in the feedback group. The motor output is shown in blue, adaptation in gray, slow process in magenta, fast process in purple, voluntary correction in pink, and perturbation in red. Note that the only difference between the fits on (B) and (C) is the presence of the voluntary correction process that also then changes the motor output. See also Figures S1 and S2. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 4 Experiment 2 Protocol and Results (A) Experiment 2 protocols are shown for the short adapt-feedback and short adapt-no feedback groups. These protocols are identical to those tested in experiment 1 except adaptation is truncated to 1 min. (B) Adaptation predictions from the voluntary correction model based on parameters set in experiment 1 (top) and mean ± SE adaptation curves across participants within the short adapt-feedback (purple) and short adapt-no feedback (dark green) groups (bottom) are shown. Data points immediately following the adaptation curves show the step length asymmetry (mean ± SE) of the last ten strides of adaptation for each group. ∗ indicates a significant difference with p < 0.05. (C) Deadaptation predictions from the voluntary correction model based on parameters set in experiment 1 (top) and mean deadaptation curves across participants within the short adapt-feedback (purple) and no feedback (dark green) groups ±SE (bottom) are shown. See also Figures S3 and S4. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 5 Experiment 3 Protocol and Results (A) Experiment 3 protocols are shown for the short feedback and short feedback-deadapt groups. (B) Adaptation predictions from the voluntary correction model based on parameters set in experiment 1 (top) and mean ± SE adaptation curves across participants within the short feedback group when the feedback was on (cyan) and off (red) as well as the no feedback (green) group from experiment 1 (bottom) are shown. Data points immediately following the adaptation curves show the step length asymmetry (mean ± SE) of the last ten strides for each group. ∗ indicates a significant difference with p < 0.05. (C) Deadaptation predictions from the voluntary correction model based on parameters set in experiment 1 (top) and mean deadaptation curves across participants within the short feedback-deadapt group when the feedback was on (brown) and off (yellow) as well as the no feedback (green) group from experiment 1 (bottom) are shown. See also Figure S5. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 6 Experiment 4 Protocol and Results (A) Experiment 4 protocol is shown for the short video feedback group. (B) Adaptation predictions from the voluntary correction model based on parameters set in experiment 1 (top) and mean ± SE adaptation curves across participants within the short video feedback group when the feedback was on (magenta) and off (dark red) as well as the no feedback (green) group from experiment 1 (bottom) are shown. Data points immediately following the adaptation curves show the step length asymmetry (mean ± SE) of the last ten strides for each group. ∗ indicates a significant difference with p < 0.05. See also Figures S6 and S7 and Table S1. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 7 Experiment 3 Individual Step Lengths and Joint Kinematics (A) Mean ± SE slow and fast step lengths during adaptation in the short feedback group when the feedback was on (slow in dark blue, fast in cyan) and off (slow in dark red, fast in light red). Data points immediately following the adaptation curves show the step length asymmetry (mean ± SE) of the last ten strides for each feedback condition. (B) Mean ± SE ensemble ankle (top), knee (middle), and hip (bottom) angles for the short feedback group averaged over the last five strides when the feedback was on and off. Positive values indicate flexion angles and negative indicate extension. Current Biology 2016 26, 2707-2716DOI: (10.1016/j.cub.2016.08.012) Copyright © 2016 Elsevier Ltd Terms and Conditions