You might think that you learn by looking in the mirror and adjusting your movement until it looks the way you want it to appear. However, sensory feedback (including feedback from vision) is simply too slow to help in controlling rapid movements such as dance. It takes at least one fifth of a second to react to a touch on your hand and much longer for similar messages to travel the extra distance from your foot and back again. Visual signals take even longer. It would take around a quarter of a second to look in the mirror and then correct a movement. Visual feedback can help with pinpointing problems when you are practicing, but it is much too slow to control most movements while you are dancing. In addition, responding to slow visual signals can lead to jerky stop–start movement.
(Mary Virginia Wilmerding, Donna Krasnow, International Association for Dance Medicine & Science 著)