Perceptual and Physical Development during Infancy
6.1 Describe the physical appearance of a newborn
A few weeks ago I was talking to my friend, Esther and her husband. They were both very excited as they narrated their experience with their then, 7 months old first-born child. Their story was fascinating and they said something like this “We did not know how much fun it was going to be to watch our son Dan grow. He is changing every hour. At birth he was a little helpless creature. He could hardly turn on his own. In fact he couldn’t even move. Surprisingly he is crawling all over. He throws his legs and arms with excitement when he sees us after work. He can hold his small ball and reach out for things by crawling round the tables. You can hardly believe it. It’s fun to watch him change from moment to moment”.
Their story is similar to many others that parents tell. Many changes take place in a child after infancy causing amazement to those that watch as they grow. In this unit I want us to have a look at the physical and perceptual changes that take place in the child from birth to about 2 years of age.
Why are Changes in Physical Characteristics Important?
Physical development follows a predictable and orderly sequence. This is governed by the interaction between genetic and environmental factors. Most infants follow a normal course of physical growth and development. Some are born with physical disability or are identified as disabled shortly after birth. Information on what normal physical growth constitutes helps us to identify children with disabilities and to develop programs to help them.
Characteristics of the Newborn
The newborn has perfect physical features e.g. hands, toes, fingernails etc. He or she is relatively tiny. However there is a perfectly formed human being capable of responding to the environment. The following characteristics are evident.
1. Appearance of the Newborn:
Many adults are naturally attracted to a new born. A newborn’s appearance surprises many people. Some aspects of physical appearance are odd for instance the newborn appears fragile and has a short neck. Sometimes this makes other people hesitant and insecure in caring for them. An oily substance called vernix caseosa covers the body. This dries a few days after birth. Some have a growth of fine textured hair called lanugo all over the body. The abdomen appears to be bulging. They have dissapropriately small arms and legs and a large head that may be misshapen. The bones are flexible. Both boys and girls may have swollen breasts and genitals. This is due to maternal hormones that crossed over to their bodies from the mother before birth. The newborn has large eyes, bulging forehead and a small nose.
Babies vary greatly in size, shape, degree of physical maturity and personality traits. They differ in the way they cope with stress, hunger, thirst etcetera. It is not unusual to hear adults saying a baby is cool, irritable, quiet, calm, tense etc. Babies have different patterns of responding to the environment (temperament). Children range from easy to difficult. Some of these temperament traits persist to adulthood.
3. Dependence and Competence:
For several months the infant is totally dependent on adult care for instance she must be fed, cleaned, protected and cared for in every way. The infant on the other hand, is born with remarkable capacities for survival such as he or she is able to eat, eliminate body waste and regulate body temperature etc
Newborns actually cry less of the time than you might think. Crying seems to increase over the first 6 weeks of life and then decreases. Initially, infants cry most in the evening and then shift their crying more toward times just before feedings. The basic function of the child’s cry, obviously, is to signal a need. Because babies can’t move to someone to get care. They have to bring someone to them, and crying is the main way they have to attract attention. Infants have a whole repertoire of cry sounds, with different cries for pain, anger, or hunger. Infants cry in different ways depending on their needs. So each parent must learn the specific sounds of his or her own baby.
Fifteen to twenty percent of infants develop a pattern called colic, which involves daily, intense bouts of crying, totaling 3 or more hours a day. The crying is generally worst in late afternoon or early evening. Colic typically appears at about 2 weeks of age and then disappears spontaneously at 3 or 4 months of age. It is not known why some babies experience colic.
5. States of Consciousness:
Researchers have found that there are five states of sleep and wakefulness in the baby. These states and their characteristics are as follows:
- Deep Sleep: Eyes closed; there is regular breathing and no movement except occasional startles.
- Active Sleep: Eyes are closed, breathing is irregular and there is no gross body movement
- Quiet Awake: Eyes open, no major body movement and there is regular breathing.
- Active Awake: Eyes are open, with movements of the head, limbs and trunk and irregular breathing.
- Crying and Fussing: Eyes may be partly or entirely closed. There is vigorous diffuse movement with crying or fussing sounds. These five states tend to occur in cycles.
6. Sleeping behaviour
Newborns sleep about 15 to 16 hours each day, with little day- night rhythm. They sleep equal lengths of time at any time of day or night. By 6 or 8 weeks of age, the total amount of sleep per day drops and the first signs of circadian rhythm (day-night rhythm) merge. Babies vary a lot in their sleep patterns with the average hours of sleep ranging from 88 to 22 hours. Marked irregularity of sleep patterns may be a sign of disorder or problem.
Another interesting thing about sleep in newborns is that they show the external signs that signify dreaming in adults and older children. This is seen in the fluttering of eyeballs under closed lids, a characteristic referred to as Rapid Eye Movement or REM Sleep.It is a recurring sleep stage dring which the baby and adults seemingly dream. About one half of the infant’s sleep is REM sleep.
7. Infants Reflexes:
Nature equips the newborn with reflexes to ensure survival. A reflex is a specific involuntary response to stimuli. A baby is born with a host of reflexes. Many of them disappear after the first 2 or 3 months of life. These reflexes include:
- Breathing reflex: Normal newborns take their first breath soon after birth. Breathing is usually irregular for the first few days and reflexive hiccups, sneezes and spit-ups are common as the newborn tries to coordinate breathing, sucking and swallowing.
- Sucking Reflex: Newborns suck anything that touches their lips – fingers, toes, blankets and nipples
- Rooting Reflex: Babies turn their heads wherever anything touches their cheeks. This reflex helps them to find the nipple
- Swallowing Reflex: They swallow anything that gets into their mouth.
- Babinski reflex: When their toes are stroked, their toes fan upward.
- Stepping Reflex: When their feet touch a flat surface, they move as if to walk.
- Swimming Reflex: When they are held horizontally on their stomachs, their arms and legs stretch out.
- Grasping Reflex: When something touches their palms, their hands grip tightly .
- Moro Reflex: When someone bangs on the table they are lying on, they fling their arms outward and then bring them together on their chests as if to hold on to something and they may cry and open their eyes wide.
Most of these reflexes disappear in the first months of life. Preterm babies usually develop and lose these reflexes later than full term babies. These reflexes are useful as signs of normal brain and baby function. Tests of reflexes are used to assess the newborns physical condition.
8. Size and Shape
The average newborn measures about 50 centimetres in length and about 3 kg in weight, (this varies from infant to infant). In the first days of life, most newborn lose a little of their weight as they bodies adjust to sucking, swallowing, digesting their own food etc.
Once they have made these adjustments, they grow rapidly, doubling their weight by the 4th month and tripling it by the end of their first year. They increase by about 2.5 centimetres in height every year for the first 12 months. Growth in the second year proceeds at a slower rate. Boys by the end of the end year are slightly heavier and taller than girls. By the end of the second year the child is about one fifth of the adult weight and half their adult height. Much of the weight again in the first months of life is fat providing both insulation and energy that can be drawn on in case of teething or other problems.
6.2 Describe the physical development of a child in the first two years of life
Brain Growth and Maturation:
The newborn’s skull is relatively large. This is because it must accommodate the brain. The brain is about 25% it’s adult weight at birth. By the age of 2 years, the infants brain is about 75% of its adult weight.
The Building Blocks: Neurons and Their Function
There are significant changes in the maturing nervous system (which consists of the brain, spinal cord and the nerves). The nervous system is made up of long thin, nerve cells called neurons. At birth it contains most of or perhaps all the neurons it will ever have.
Further development consists of the growth and branching of these cells into increasingly dense networks that transmit messages in form of electrical impulses between the brain and the rest of the body. As the nervous system matures the neurons become coated with a fatty insulating substance called myelin. This helps to transmit messages faster and more efficiently. This process is called myelination. The process continues until adolescence. The development of the nervous system allows children to gain increasing control over their motor functions and to experience refined perceptual abilities.
Axons are covered with a fatty coating of cells. This coating, called myelin. It insulates the axon and helps it transmit electrical impulses faster and more efficiently. When myelination occurs in certain regions of the brain, the child gains specific forms of motor skill and muscle control that are associated with those regions. Consequently the timing of an infant’s milestones – the visually directed grasp, rolling over, sitting up, standing, and walking etcetera are directly related to developments in that child’s nervous system. Anything that interferes with myelination affects motor development.
Structure of the Brain
Different regions of the brain develop at different rates before and after birth. The motor regions, which control gross body movements, develop first. The sensory regions, which receive information from the sense organs (nose, eyes, ears, mouth, and skin) develop next. These are the only areas of the brain that function at birth. The sensory and motor regions continue to mature up until the eighth month of life. The association regions, which mediate thought, are the last to develop and their growth continues well into adulthood (Suomi, 1982).
6.3 Describe the perceptual development of a child in the first two years of life.
Sensation and Perception
What are sensation and perception?
How does a newborn know that her mother’s skin is soft rather than rough? How does she know the smell of her mother’s milk? Infants know these things because of their senses. All information comes to the infant through senses. These senses include: sight (vision), hearing, touch, taste and smell. Sensation ocurrs when information contacts the sensory receprors-the eyes, ears, skin, tongue and nostrils.
Perception is the interpretation of what is sensed. For example sounds that are received by the ears may be interpreted as musical sounds or the sound of a human being.
At birth sensation and perception are apparently present. Neonates (infants) see, hear, smell and taste. Newborn perception is very selective. They pay attention to certain things and not others. For example they pay attention to bright lights, loud noises and objects within a foot of their eyes and they almost screen out everything else.
At birth, vision is the least developed of the senses. Newborns focus both eyes on the same spot focusing well on objects that are about 8 inches away (Bee, 1995). It is not easy to tell whether they perceive these objects or whether they just stare at whatever they see. Within a few weeks the baby can at least roughly follow a moving object with his eyes.
By age of 3 months , babies recognize the mother’s facial expressions. They can recognize their mother’s photograph. Newborns do not use their eyes together but by age 4 months they are able to use both eyes together. This makes them better observers. They can differentiate the photos of men from those of women. They show preference for happy faces over sad or angry ones.
Unborn babies can respond to loud noises even 4 months before birth. At birth the newborn’s auditory canals are filled with amniotic fluid. Thus for the first day or two after birth, they have difficulty hearing. As soon as the fluid left in the ears is discharged or absorbed, their hearing improves and they can hear relatively well. Newborns can localize sounds that is detect the direction of a sound. They are especially sensitive to high pitched sounds. Sudden noises startle babies and make them cry. While awake they turn their heads to the direction of a noise and pay attention to the sound of a conversation. By the end of first month, the baby prefers the mother’s voice to other voices. By 4 months, the baby can identify the voices of most familiar people in their lives. Infants are born with the ability to respond to all speech sounds. However, they eventually tailor their speech perception (attention) to the speech sounds they hear.
C. Touch and Pain
Newborns are sensitive to touch (this is evident in their reflexive response. We can soothe a baby by holding or picking them up. Research shows that the experience of being touched has a direct effect on the infant’s growth and development. Premature infants who are massaged gain more weight than those who are not massaged given the same calorie intake.
Infants respond to pressure on the skin by certain reflexive behaviours: If you press their palm with your finger, they will respond by grasping it, and if you stroke the sole of their foot, they curl their toes outward. The mouth shows considerable touch sensitivity in early infancy (Kislevsky & Muir, 1984), followed later in the first year by increasing sensitivity in the extremities (arms, hands, and legs).
We also know that infants feel pain. During the neonatal period babies respond to injections by fussing and crying.
D. Taste and Smell
There is considerable evidence that sensitivity to taste is present soon after birth (Haith, 1986). Newborns have been found to suck harder and longer to obtain sweetened liquids than clear water (Crook, 1978 ). This innate preference for the sweet taste attracts the infant to breast milk, thereby promoting the bond between mother and child.
The sense of taste develops quite rapidly during the first month. It’s easy to tell which tastes infants prefer by observing their facial expressions. Neonates display a slight smile and sucking movements to sweet substances. They purse the lips, wrinkle the nose, and blink to sour substances and they spit up and choke on bitter substances (Steiner, 1977,1979).
Infants continue to enjoy sweet substances and, after four months, show interest in salty liquids (Beauchamp & Cowart, 1985). Infants’ preferences and parents’ approaches to food selection may have long-term effects on food preferences later in childhood. For example, infants who had been regularly fed with sugar water in the first year showed stronger preference for sweet liquids at age two than infants who had not had sugar water (Beauchamp & Moran, 1985). Moreover, infants who experienced a greater variety of foods developed more diverse food preferences than infants who experienced less variety (Frietas, 1984).
Do Infants perceive faces?
The human face is perhaps the most important visual pattern for infants to perceive. At about 4 weeks the infant is fascinated with the eyes. At 2 months and older, the infant begins to differentiate facial features; the mouth is noticed and movements of the mouth draw attention to it. By 6 months of age the infant distinguishes familiar faces. For example he or she can distinguish mother from stranger, masks from real faces and so on.
Do infants have depth perception?
Another question about what babies see and know is whether they have depth perception, that is, the ability to tell how far away something is in terms of depth. In one study (Gibson & Walk, 1960) placed 6 to 14 months old infants on a special surface that appeared “shallow” on one side and “deep” on the other side. The deep side was covered with glass so babies could crawl across it just as they had crawled the shallow side. Their mothers stood on the far side and encouraged them to crawl across to them. The babies in this study could not crawl across the deep side even after they felt the glass. This study shows that these infants were somehow aware of depth. However it is known exactly when depth perception is acquired.