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Summary: The First Three Years

The word gene is a shorthand term for a group of DNA sequences that guide the synthesis of a biological product such as a protein. In the nucleus of the cell, genes are gathered into chromosomes, each consisting of a strand of DNA six feet long, curled and folded into a character­istic shape.

Each chromosome contains about 20,000 active genes. Fifty percent of a person's genes come from the mother and fifty percent from the father, but grandparents can contribute more or less than twenty-five percent.

The heritability index is based on mea­suring a trait in identical twins and dizy­gotic (fraternal) twins. A higher heritability index indicates identical twins are more similar than dizygotic twins for that trait.

Even behaviors clearly not linked to genes (like TV watching) have a high heritability index. A high heritability index does not indicate a trait is somehow coded into a person's DNA; it means a trait is related to parts of the organism, such as brain structures, that might be influenced by genetics.

A newborn arrives with built-in reflexes aiding survival. These include the gag reflex, sucking reflex, rooting reflex, and grasp reflex. Babies have differences in temperament that are already apparent in hospital nurseries days after birth.

People naturally communicate with newborns by moving in synchronization with them, speaking in a distinctive tone of voice, and making clicking sounds. Newborns are also sensitive to the odor and sounds of the mother.

Babies are able to hear external sounds while in the womb, and a 1980s study showed they could recognize sounds they heard often. A word from the mother triggers a distinctive evoked response in a baby's brain.

Babies benefit from touch, which releases a distinctive brain chemical (ODC) promoting growth. Premature babies who must stay in incubators are now massaged every day.

Newborns have cognitive capabilities that are precursors or early versions of the talents developed later in childhood. They can point with their fingers. They can judge approximate numbers of objects.

Babies can usually recover from adverse circumstances during the first year of life. However, evidence indicates that the time from age 1 to 3 is critically important. By the age of 3 children already differ in overall competence, and the children who excel at age 3 continue to excel at age 6 and later.

The first three years of life are important for child development. Burton White's book The First Three Years recom­mended letting 1 to 3 year olds roam freely in a child-proofed home, using adults as consultants when needed, and of course receiving love in abundance.

Write to Dr. Dewey at

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