In The Absorbent Mind, Dr. Montessori wrote, "The most important period of life is not the age of university studies, but the first one, the period from birth to the age of six. For that is the time when man's intelligence itself, his greatest implement is being formed. But not only his intelligence; the full totality of his psychic powers ... at no other age has the child greater need of intelligent help, and any obstacle that impedes his creative work will lessen the chance he has of achieving perfection."
Modern psychological studies based on controlled research have confirmed these theories of Dr. Montessori. After analyzing thousands of studies, Dr. Benjamin S. Bloom of the University of Chicago, wrote in Stability and Change in Human Characteristics, "From conception to age four, the individual develops 50% of his mature intelligence; from ages four to eight he develops another 30% ... this would suggest the very rapid growth of intelligence in the early years and the possible great influence of the early environment on this development. "
Like Dr. Montessori, Dr. Bloom believes "That the environment will have maximum impact on a specific trait during that trait's period of most rapid growth." As an extreme example, a starvation diet would not affect the height of an 18 year-old, but could severely retard the growth of a one year-old baby. Since 80% of the child's mental development takes place before she is eight years old, the importance of favorable conditions during these years can hardly be over emphasized.