Children were observed by Montessori to repeat activities with the materials until they seemed satisfied. She believed the education of the senses is acquired through repetition of an action and that children repeated an exercise because of an inner impulse for perfection. (Boehnlein)

“…at an age when attention flits from one thing to another and cannot be held down...she had been absorbed in concentration such that her ego had withdrawn itself from the reach of any external stimulus…Though such instances of concentration reaching insensibility to the outer world were not usual I noticed a peculiar behaviour that was common to all, and practically the rule in all they did—the special characteristic of child work, which I later called ‘repetition of the exercise.’” (Montessori, Maria, The Secret of Childhood, p. 107) “…an exercise on some external object where the movements of the hands are guided by the mind. And here we find the unfolding of characteristics which plainly come from an inner impulse, the ‘repetition of the exercise.’ and ‘free choice of objects.” (Montessori, Maria, The Secret of Childhood, p. 124) “The phenomenon to be expected from the little child, when he is placed in an environment favourable to his spiritual growth, is this: that suddenly the child will fix his attention upon an object, will use it for the purpose for which it was constructed, and will continue to repeat the same exercise indefinitely.” (Montessori,Maria, The Advanced Montessori Method Volume I, p.119)