During smooth pursuit eye movement, observers often misperceive velocity. Pursued stimuli appear slower (AubertFleishl phenomenon [1, 2]), stationary objects appear to move (Filehne illusion [3]), the perceived direction of moving objects is distorted (trajectory misperception [4]), and selfmotion veers away from its true path (e.g., the slalom illusion [5]). Each illusion demonstrates that eye...