THE DEVELOPMENTAL STAGES
THE FIRST MONTH
Touch. A newborn infant can already interpret some of his body sensations and respond with built-in reflex movements. His sense of touch has been operating fairly well for several months in the womb. If you gently touch his cheek, it is likely he will turn his head toward your hand. This reflex is an adaptive reaction that nature designed to help infants find a meal. Although these innate reactions are automatic, the sensations must be integrated for the reflex to occur in a meaningful and purposeful way.
The sensations from a wet diaper make the infant uncomfortable, while the touch of his mother’s hand is comforting. However, the child cannot tell very well where he is being touched, because his brain cannot differentiate one spot from another. At this age, touch sensations are more important as a source of emotional satisfaction. The touching between an infant and his mother is essential for brain development and the development of the mother-child bond.
During his first month, a baby will automatically grasp any object that touches the palm of his hand. This reflex is designed to help the child hand onto something so that he doesn’t fall. Because the newborn does not have the ability to open or extend his fingers, his hands often remain curled into loose fists for the first few months of life.
Gravity and movement. The newborn also shows responses to the sensations of gravity and movement that come from his inner ears. If you hold him in your arms and suddenly lower him a foot or so, he will show alarm and his arms and legs may move outward as though to grasp something. The messages from his inner ears tell him that he is falling and that he better try to do something to protect himself. This clinging or flexion movement of the entire body is the first total-body motor pattern
When the one-month-old child is held up with his head resting on his parent’s shoulder, he will intermittently try to lift up his head. This happens because the pull of gravity stimulates the part of the brain that, in turn, activates the neck muscles that raise the head. Over the next few weeks, this adaptive response will develop so that the baby can lift his head while lying on his stomach. The same neural mechanism holds an adult’s head upright without deliberate effort. At one month, however, it is still immature and the infant’s head wobbles and needs support.
Every mother quickly learns that carrying or rocking a child brings him comfort and usually quiets him. The sensations of gentle body movement tend to organize the brain, and this is why the image of a cradle brings back so many fond memories. In addition to calming the baby, carrying and rocking provide
sensations that are essential building blocks for other sensations and for self-determined body movements. Although you cannot actually see this happening in the brain, you can easily see that your child wants to be carried and rocked. Sensations that make a child happy tend to be integrating.
Muscle and joint sensations. The average one-month-old child will adjust his body to fit nicely into the arms and body of the person holding him. He senses how to do this through his muscles and joints. Later on his muscles and joints will tell him how to use a knife and fork and how to climb a jungle gym. The child must practice and organize many, many movements to develop adult skills. In his first few months, therefore, the infant makes many movements that appear random and haphazard, and then later on become well organized. Then lying on his back he thrusts his arms and legs out playfully. On his stomach he makes alternating crawling motions. These movements occur because the sensations from his muscles and joints and inner ears stimulate his nervous system to produce movements. Meanwhile the child’s inner drive helps him to organize these sensations and movements.
Muscle and joint sensations also tell the brain when the head is turned to one side. This activates a reaction known as the tonic neck reflex, which makes the arm on that side tend to extend or straighten while the other arm tends to bend at the elbow. During the first few weeks of life, this reflex plays a major role in determining arm movements; and so the infant lying on his back often looks toward his extended arm while his other arm is bent. Although the tonic neck reflex influences the muscle tone in our arms for our entire life, its influence should become negligible by the sixth year. In children with poor sensory integration, the reflex is often overactive.
Sight. The one-month-old infant’s sense of sight is not very well organized, although he does recognize his mother’s face and other significant objects. His focus is vague and he cannot differentiate complex shapes or color contrasts. He can sense danger in movement or in touch, but not from sight. His first step in developing vision is to learn to follow a moving object or person with his eyes and then his head. This adaptive response requires sensations from the muscles surrounding the eyes and in the neck, in conjunction with gravity and movement sensations from the inner ears. Notice how an infant becomes alert and happy when he sees movement in people or animals or toys, and can practice his ability to follow them with his eyes.
Sound. The one-month-old child will respond to the sound of a rattle or bell, and also to the human voice, although he cannot understand what these sounds mean. He may turn his head or smile. Simply responding to sounds is the first building block in the development of speech. He also makes small throaty sounds. The muscular contractions in the throat that cause these sounds also produce sensations that help to develop speech areas of the brain.
Smell and taste. Another sense that is probably well organized at birth is the sense of smell. It may play and important role during the first month of life. The sense of smell is not further developed and refined in the older child in the way that sight and hearing are. The infant can also taste well. Sucking is the adaptive response that comes from taste and smell, and the infant usually has the reflex when he is born.
So at one month, the infant has already performed a considerable number of adaptive responses to sensations, particularly to the sensations from his own body and from gravity. Many of these responses are built into his nervous system before birth, so that they would be turned on by the sensations of gravity and movement and touch. Without the integration that occurs in this simple sensory-motor activity, adequate development would be impossible later on in life.
THE SECOND AND THIRD MONTHS
The eyes and neck. The infant’s motor functions develop from head to toe. The eyes and neck are the first body parts he learns to control. Keeping the head and eyes stable is a fundamental ability that has very important survival value. Visual perception involves more than just looking at something; in addition, the eyes must hold a steady image of the object and the neck must keep the head steady, otherwise the object would appear to blur and flutter, like a photograph taken by a camera that is not held steady. For this, the brain must integrate three types of sensation: one, the gravity and movement sensations from the inner ears; two, the sensations from the eye muscles; and three, the muscle sensations from the neck. The brain puts these three types of sensation together to know how to hold the eyes and neck steady.
As the infant scans the room and looks at people and objects, his brain is busy working to integrate the sensations from his inner ears, eye muscles, and neck muscles. Through this integrative process, he learns to “take a clear picture” of his environment even when his head or even his whole body is moving. This development will continue for several years and is a vital building block for learning to read. It also helps the child learn balance and overall body movement.
Rising up. When you think of how consistent and powerful gravity is, you realize how much inner drive the child must have to rise to a standing position in just one year. After he learns to hold his head up with his neck muscles, the infant uses the muscles in his upper back and arms to lift his chest off the floor. This development occurs in the prone position (lying face downward). The infant’s urge to lift his chest comes mainly from the sensations of gravity, which stimulate the b4ain to contract the muscles in the upper back. The child also learns to sit up-right with his head balanced if you support his lower back. Some challenge is necessary for any learning. Supporting his entire back eliminates the challenge, while giving no support to the lower back makes the challenge too great for the child at this age.
Grasping. The three-month-old infant’s hands are open most of the time. He reaches for objects and people but lacks the eye-hand coordination necessary to make his reach accurate. As he integrates body sensations with what he sees, he finds out how to aim properly.
When he grabs, he does not use his thumb and forefinger; instead he holds the objects with his three other fingers and the palm of his hand. He grasps a rattle in this simple way, and his sense of touch sends messages to his brain that help him to hold onto the object. At this age, grasping is still an automatic reaction to the touch sensations in the palm of his hand, and he cannot voluntarily release his hold on the rattle. Over the next few months he will integrat3 these touch sensations with the sensations from the muscles and joints in his hands and gradually develop a more efficient pincer motion with his thumb and fingers.
THE FOURTH TO SIXTH MONTHS
The arms and hands. Now the baby makes big movements, such as banging a spoon against a table, and experiences the thrill of having an impact on the physical world. This very simple emotional satisfaction is a building block toward the more mature emotions that develop later on.
He now begins to touch and look at his hands, and thereby develop an awareness of where his hands are in space. He needs touch and muscle and joint sensations along with vision to learn to use his hand accurately in conjunction with what he sees. He has to coordinate the parts of his brain that “see” with those parts that “feel” the hand and arm. He begins to use his thumb and forefinger, but his grip lacks precision. He is apt to reach with one hand more often than with both together since he can now control his urge to reach.
One of the most important developments of this age occur when the child spontaneously brings his hands together in front of his body so that they touch each other. This is the beginning of coordination between the two sides of the body. Another step in this development occurs a few months later when he holds a toy in each hand and bangs them together. These actions require an important type of sensory integration that must develop long before the child can know his right and left.
By his sixth month, the child’s wrist rotates so he can turn his hand and manipulate objects and play in many new ways. Most of the movements in the first six months were automatic, but now the infant begins to do things that he must plan. Each new play activity involves more of this “motor planning” and more sensory integration. He can also sit alone for a short time without losing his balance. The automatic muscular reactions that keep him upright are guided by the sensations of gravity, movement, and sight. If these sensations are not well integrated, the infant will have difficulty sitting or may not even try to sit.
The airplane position. At about six months, the infant’s nervous system becomes particularly sensitive to the pull of gravity on his head while he is lying on his stomach. This sensitivity produces a strong urge to raise the head, upper back arms, and legs all at the same time. The baby balances his whole body on his stomach, and looks a little bit like an airplane. This is referred to as the prone extension posture. This position is a vital step in developing the muscles that are used for rolling over, standing up, and walking. Older children who cannot hold this position often have problems integrating gravity and movement sensations.
The joy of being moved. The six-month-old-child also likes to be rocked, held up, swung in the air, turned over, and moved about. These are among the most satisfying experiences of infancy. The joy comes from experiencing stronger gravity and movement sensations, which the child can now integrate. If the movements are too rough or the child cannot integrate the sensations, they will disorganize his nervous system and cause him to cry.
THE SIXTH TO EIGHTH MONTHS
Locomotion. One of the most important aspects of development during this period is locomotion, or movement from one place to another. Locomotion greatly increases the number of things and places the infant can explore. Crawling and creeping on hands and knees contribute many sensations to be integrated and also give the child a concept of himself as an independent being.
First he must get himself into the prone position, on his stomach. A reflex known as the “neck righting reflex,” which has been active since birth, helps him turn over from his back to his stomach. This is the same reflex that enables a cat to land on his feet even when he is dropped with his back down and feet up. The sensations that activate this reflex come from gravity and the muscles and joints of the neck. These sensations activate the neck righting reflex for much of the time at this age, and so the normal infant tends to spend a lot of time lying on his stomach.
Spatial perception. Locomotion gives the child knowledge about space and the distance between himself and objects in the environment. It is not enough merely to see things to judge distance; the brain must also “feel” the nature of distance through the sensations of body movement. As he crawls and creeps from one place to another, he learns the physical structure of space, and this helps him to understand what he sees. Good distance judgment also helps the child to know how large things are. If the child at this age has difficulty integrating the sensations of crawling and creeping, he may later on have trouble judging distance and size.
The fingers and eyes. The child can now use his thumb and forefinger in a scissors or pincer action to pick up small objects or pull a string. He can also poke his forefinger in a hole. The sensations of touch, and those from his muscles and joints, provide the basic information and guides these movements. For fine hand motions, however, he needs precise information from his eyes. He must have fine control over his eye muscles to direct his eyes precisely to the place he needs to see. To develop precise eye control, the child must already have the simple eye control that developed as he lay on his stomach and raised his head, crawled, and crept about in his environment.
Motor planning. At this age, the child begins to plan his hand movements well enough to ring a bell or put simple things together and take them apart. Movements must be planned inside the brain to complete a sequence of actions in the proper order. Sensations from the body provide the information necessary for planning movements.
This is also the age when the child begins to look for an object that has been covered up or dropped out of sight. By touching and moving around objects, he learns that they still exist even when he cannot see them. This is the beginning of the mental ability to visualize objects.
Babbling. The eight-month-old child listens to sounds well enough to hear details. He recognizes familiar words and knows that some sounds mean one thing and others mean something else. He may repeat simple syllables such as “ma” and “da”, although this is not really speech. Babbling sends sensations from the jaw joint, muscles, and skin of the mouth to the brain. As the brain integrates more and more of these sensations, it learns how to form more complex sounds. If the child has difficulty with babbling, he may have trouble learning to speak.
THE NINTH TO TWELFTH MONTHS
This is the time for major changes in the way the child relates to the earth and the space around his body. He creeps for longer distances and explores more places in his environment. This stimulates his nervous system with many sensations from the muscles that hold up his head and body and the bones that support his weight, and also from the pull of gravity. These sensations help him coordinate the two sides of his body, learn how to motor plan, and develop visual perception. He spends a lot of time just looking at things and figuring out what they are. The more different things he experiences as he roams about, the more practice he gets in integrating sensations and forming adaptive responses to those sensations.
Play. Watch a child banging things together, pulling them off a table, throwing them about, and so on, and try to see the importance of what he is doing and sensing. Very often one of his hands reaches across to the other side of his body. These motions develop his ability to cross the midline, a very important ability that is sometimes poor in children with sensory integrative dysfunctions. Every time he puts something together or takes it apart, his brain learns to plan and carry out a sequence of movements in proper order. Every time he makes a mess of his food with a spoon or scribbles with a crayon, he learns something about tools and how to use them.
Standing up. One of the biggest events in early childhood is standing up alone. Few adults can ever realize the significance of this magnificent achievement and what it means to the child’s self-concept. It is the end product of all the integration of gravity, movement, and muscle and joint sensations of the months before. Standing up requires the integration of sensations from every part of the body, including the eye and neck muscles, which continue to be essential. Standing up is quite a challenge since a relatively tall body must balance itself on two small feet. It is best to allow the child to practice standing up on his own, so that he masters that challenge by himself.
Words. The child can now understand a fair amount of what his parents say, but he can speak only a few simple words like “mama” and “dada.” It appears that the sensations arising from body movement help to stimulate the part of the brain that is involved in making these sounds.