Growth and Development of the Babe. Development of Motor Skills

Two major forces—heredity and environment—influence a baby's growth and development Heredity determines the characteristics that babies inherit from their parents through the chromosomes. Environment consists of everything with which a baby comes in contact, including the kind of care the baby receives. Environment especially affects the formation of a baby's personality.

A baby's personality begins to develop soon after birth. The development continues throughout childhood and even throughout life. But most experts believe that a person's very early experiences have an especially strong influence on later personality development For example, infants who never have their needs met when they cry may eventually lie in bed quietly, causing little disturbance. But in time, their emotional, mental, and social growth will fall behind that of other children. Babies who are cared for lovingly—that is, in close and understanding contact with the people who care for them — have the best chances of developing a normal, healthy personality.

Babies differ in the rate and manner of their growth and development For example, many infants begin to crawl at about 9 to 10 months of age. But some begin to crawl earlier and others later. Still other babies learn to walk without ever crawling.

The first month. A baby is considered a newborn for about a month after birth. Newborn babies spend most of their time sleeping.

Characteristics of newborn babies. The average weight for a baby at birth is 7 1/2 pounds (3.4 kilograms). The average length of a newborn is 20 inches (50 centimeters). A newborn baby's head makes up about a fourth of the total body length and is bigger around than the chest The arms are longer than the legs. These proportions change as a child becomes an adult The head, for example, grows less than the rest of the body and makes up about an eighth of an adult's height.

A newborn baby's skull has six soft spots where the bone is not yet completely joined. These areas become completely covered with bone by about the 18th month. The other bones in a baby's body are only partly calcified (hardened with calcium) at birth. These bones calcify gradually throughout childhood.

Most white children have grayish-blue eyes and pink skin at birth. The color of the eyes may change by the fifth or sixth month. This color then becomes permanent. Most black children have brown eyes and relatively light, pinkish skin at birth. The eyes remain brown. The skin begins to darken a few days after birth.

Most of a newborn baby's actions are reflex actions — that is, they are completely automatic. Newborn infants can suck and swallow, move their arms and legs, and cry to make their needs known. When lying in bed, they often curl up in a position like the one they had in the womb. If startled by a loud noise or sudden jolt, they jerk their arms and legs in a reflex action called the startle reflex. For several months, the baby's neck muscles will not be strong enough to hold the head erect A person must therefore be careful to support the head while picking up or holding the baby.

Newborn babies cannot control the movements of their eyes. But they can tell darkness from light and see objects directly in front of them. Newborn babies can also hear, and they quickly learn to recognize their mother's voice.

Feeding and rate of growth. Newborn babies can swallow only liquids. They therefore get their nourishment by sucking milk from their mother's breast or from a bottle. Mothers may begin to nurse their babies — that is, feed them milk at the breast—within a few minutes after birth. In most cases, the breasts do not produce a full supply of milk until several days after birth. But babies need little nourishment during this time. Babies who are not breast-fed are given a special formula that usually is made from cow's milk. This formula resembles mother's milk and is fed from a bottle with a rubber nipple.

Newborn babies can digest less than 2 ounces (60 milliliters) of mother's milk or formula at a time. As a result they must be fed often—in most cases, about every four hours day and night Babies lose weight for a few days after birth because their food intake does not yet meet their needs. But most babies regain the lost weight by about the 10th day after birth. They then begin to gain about 1 ounce (28 grams) a day.

Development of motor skills. These drawings illustrate some of the important motor skills (controlled movements) that babies begin to develop about a month after birth. Before that time, their actions are completely automatic. Each drawing gives the age at which most babies develop the particular skill. But some babies develop the skill earlier and others later

From 1 to 6 months. A baby's growth rate slows after the third month. By the seventh month, the rate will have dropped to about 1/2 ounce (14 grams) a day. At 5 months, most babies weigh about twice what they weighed at birth.

By the second month, babies have begun to develop various motor skills. Motor skills are controlled movements rather than reflex actions. They depend largely on the development of the brain and nerves.

The development of motor skills begins with the head and progresses downward through other parts of the body. Thus, babies learn to move their head and eyes before they can control their arms and legs. By the second month, most infants can turn their head and eyes to follow the movements of people and large objects. By the age of 5 or 6 months, most babies can hold their head erect, grasp objects with their hands, turn themselves over in bed, and sit erect if propped up against something.

Babies first smile and make speech like sounds at 2 to 3 months of age. To develop normal human relationships, children need a feeling of trust and security. Parents help develop such a feeling in a baby if they treat the baby with love and understanding. Yet parents should avoid being overprotective and not give in to a baby's every demand. Children can thus develop a frustration tolerance — that is, the ability to control their feelings when some of their demands are not met.

From 6 to 12 months. Babies achieve a number of "firsts" between 6 and 12 months of age. The first tooth usually appears about the sixth or seventh month. The teeth then continue to grow out at the rate of about one a month until a child has a complete set of 20 primary, or baby, teeth. Most children have all their primary teeth by about 2 1/2 years of age (see Teeth [Kinds of teeth]). After they are about 6 months old, babies learn to pick up small objects and pieces of food by clasping them between the thumb and palm. Most babies sit unsupported for the first time by about 7 months. By about 9 months, they may pull themselves to their feet and stand with support.

At about 6 months of age, most babies develop a degree of independence. Their personality then begins to show itself in various ways. For example, they may want to hold their bottle instead of having it held for them. Gradually, every baby develops characteristic ways of doing things, which differ from the ways other babies do the same things. Such differences in behavior indicate the growth of individuality.

Growth rates for babies. The charts below represent length-forage and weight-forage for boys and girls aged to 36 months. Each colored line represents a percentile rank (P). For example, if a baby's length falls on the 75th percentile (P75), that child is taller than 75 percent of the children in that age group

From 12 to 18 months. Babies learn how to do many things by imitating older people. Their ability to imitate improves after they have reached 1 2 months of age, probably because of a sudden advance in brain and nerve development.

Most infants start to walk with support about the 12th to 13th month. They take their first unaided steps by about 15 months and can run by 18 months. Babies also start to play with blocks, balls, and other objects about the 1 2th month. At first, they may simply throw the objects or put them in their mouth. But by the 1 8th month, many infants have learned, for example, to pile a few blocks on top of one another and to push objects along the floor with their hands.

Most babies can say a few words in addition to "Mama" and "Dada" by the age of 12 months. At 15 months, they may "talk" energetically. But they still know few real words. At 18 months, a child's vocabulary may consist of about 10 to 20 words. Many children can also combine words into phrases at this age.

Babies understand many more words than they use. By 8 or 9 months, most babies respond to the sound of their name. A 1-year-old recognizes the names of a variety of objects and understands "no " and certain other commands. By the age of 15 to 18 months, most babies enjoy listening to simple songs and nursery rhymes. They may also enjoy hearing a story, though the story it-self probably means little to them. Most babies this age like to watch television and look at pictures in books and magazines.

Sometime after 18 months of age, a child may be ready for toilet training — that is, learning to control the bowels and bladder. But the age when such control becomes possible varies greatly among children. Parents should not force toilet training but wait until a child shows readiness for it.