Figure 1: Representative data from a healthy young subject (age 23): A) Sample trials of CoM displacements under different FOE conditions. B) Net heading correction at the end of the walking trial. Each point indicates the magnitude of reoriention in the physical world at the end of the trial (when the FOE was rotated 40° for perturbation conditions). Data are plotted sequentially in the order of data collection, grouped by perturbation condition. C) Heading error, i.e. the degrees (virtually) off from the midline of the room at the end of the trial.