Vision and Handwriting
A substantial amount of research evidence indicates that vision plays an important role in the control of handwriting actions. A good example of this role was provided by Smyth and Silvers (1987), who presented evidence showing that a person who is asked to write his or her eyes closed adds extra strokes to some letters, omits strokes from some letters, and duplicates some letters. And if visual feedback is delayed while a person is writing, that person makes many errors, including repeating and adding letters.