“It is obvious that a knowledge of these sensitive periods will have a profound effect on the way we teach – especially on what we shall teach at any given age. We must place as the basis of all instruction the fact that a child can understand different things at different ages…. The important thing is to present at any epoch those aspects of the subjects taught which correspond to it. Hence we must see to it that the child’s environment should be furnished with those things which correspond to the needs and special capacities of each successive period.”
Maria Montessori and others. Ed. E.M.Standing. No year given, but a recent re-publishing of the 2nd edition published in 1965. 56.