"A teacher said a word rapidly in passing, and on return saw it had been written with moveable letters. For these mites of four, once was enough, though a child of seven requires much repetition before he grasps the word correctly. All this was due to that special period of sensitivity; the mind was like soft wax, susceptible at this age to impressions which could not be taken in at a later stage, when this special malleability would have disappeared."

- Dr. Marie Montessori, Education for a New World, Clio Montessori Series,1996, p. 5