Human Development

Activity . O VERVIEW OF D EVELOPMENTAL S TAGES Development is commonly described in terms of periods or stages. You must have observed that your younger brother or sister, or parents, and even yourself, all behave in different ways. If you observe people living in your neighbourhood, you would find that they too do not behave in a similar manner.

This variation is partly because everyone is in a different stage of life. Human life proceeds through different stages . For example, you are at present in the stage of adolescence and after a few years you will enter the stage of adulthood. Developmental stages are assumed to be temporary and are often characterised by a dominant feature or a leading characteristic, which gives each period its uniqueness.

During a particular stage, individual progresses towards an assumed goal - a state or ability that s/he must achieve in the same order as other persons before progressing to the next stage in the sequence. Of course, individuals do vary with respect to the time or rate of development from one stage to another. It may be noted that certain patterns of behaviour and certain skills are learned more easily and successfully during certain stages. These accomplishments of a person become the social expectations of that stage of development.

They are known as developmental tasks . You will now read about the different stages of development and their main features. Prenatal Stage The period from conception to birth is known as the prenatal period. Typically, it lasts for about weeks.

You know by now that the genetic blueprint guides our development during the prenatal period and after birth. Both genetic and environmental factors affect our development during different periods of prenatal stage. Prenatal development is also affected by maternal characteristics, which include mother’s age, nutrition, and emotional state. Disease or infection carried by the mother can adversely affect prenatal development.

For example, rubella (German measles), genital herpes, and Human Immunodeficiency Virus (HIV) are believed to cause genetic problems in the newborn. Another source of threat to prenatal development is teratogens - environmental agents that cause deviations in normal development that can lead to serious abnormalities or death. Common teratogens include drugs, infections, radiations, and pollution. Intake of drugs (marijuana, heroin, cocaine, etc.), alcohol, tobacco, etc.

by women during pregnancy may have harmful effects on the foetus and increase the frequency of congenital abnormalities. Radiations (such as X-rays), and certain chemicals near industrial areas can cause permanent change in the genes. Environmental pollutants and toxic wastes like carbon monoxide, mercury and lead are also sources of danger to the unborn child. I NFANCY The brain develops at an amazing rate before and after birth.

You have already read in Chapter about the parts of the brain and the important role played by cerebrum in human functions, such as language, perception, and intelligence. Just before birth the newborns have most but not all brain cells. The neural connections among these cells develop at a rapid rate. The newborn is not as helpless as you might think.

The activities needed to sustain life functions are present in the newborn — it breathes, sucks, swallows, and discharges the bodily wastes. The newborns in their first week of life are able to indicate what direction a sound is coming from, can distinguish their mother’s voice from the voices of other women, and can imitate simple gestures like tongue protrusion and mouth opening. Motor Development : The newborn’s movements are governed by reflexes — which are automatic, built-in responses to stimuli. They are genetically-carried survival mechanisms, and are the building blocks for subsequent motor development.

Before the newborns have had the opportunity to learn, reflexes act as adaptive mechanisms. Some reflexes present in the newborn — coughing, blinking, and yawning persist throughout their lives. Others disappear as the brain functions mature and voluntary control over behaviour starts developing (see Table . ).

As the brain is developing, physical development also progresses. As the infant grows, the muscles and nervous system mature which lead to the development of finer skills. Basic physical (motor) skills include grasping and reaching for objects, sitting, crawling, walking and running. The sequence of physical (motor) development is universal, with minor exceptions.

Sensory Abilities : You know by now that newborns are not as incompetent as they look. They can recognise their mother’s voice just a few hours after birth and have other sensory capabilities. How well can infants see? Newborns prefer to look at some stimuli rather than others such as faces, although these preferences change over the first few months of life.

The newborn’s vision is estimated to be lower than the adult vision. By months it improves and by about the first year, vision is almost the same as that of an adult ( / ). Can a newborn see colour? The current consensus is that they might be able to distinguish between red and white colours but in general they are colour deficient and full colour vision develops by months of age.

What is the nature of hearing in newborns? Infants can hear immediately after birth. As the infant develops, proficiency at localising sound improves. Newborns respond to touch and they can even feel pain.

Both smell and taste capacities are also present in the newborn. Cognitive Development : Does a year old child understand things the same way as would an year old? Jean Piaget stressed that children actively construct their understanding of the world. Information does not simply enter their minds from the environment.

As children grow, additional information is acquired and they adapt their thinking to include new ideas, as this improves their understanding of the world. Piaget believed that a child’s mind passes through a series of stages of thought from infancy to adolescence (see Table . ). Each stage is characterised by a distinct way of thinking and is age related.

It is important to remember that it is the different way of thinking which makes one stage more advanced than the other and not the amount of information. This also shows why you at your age think differently from an year old. The child during infancy, i.e. the first two years of life, experiences the world through senses and interactions with objects — through looking, hearing, touching, mouthing, and grasping.

The newborn lives in the present. What is out of sight is out of mind. For example, if you hide the toy in front of the child with which the child has been playing, the young infant would react as if nothing has happened, i.e. s/he will not search for the toy.

The child assumes the toy does not exist. According to Piaget, children at this stage do not go beyond their immediate sensory experience, i.e. lack object permanence — the awareness that the objects continue to exist when not perceived. Gradually by months of age the child starts pursuing the object partially covered in her/his presence.

The basis of verbal communication seems to be present in infants. Vocalisation begins with the infant’s babbling, sometime between to months of age. You will read about early language development in Chapter . Socio-emotional Development : Babies from birth are social creatures.

An infant starts preferring familiar faces and responds to parent’s presence by cooing and gurgling. They become more mobile by to months of age and start showing a preference for their mother’s company. When frightened by a new face or when separated from their mother, they Reflex Description Developmental Course Rooting Turning the head and opening the Disappears between and months mouth when touched on the cheek Moro If there is a loud noise, the baby Disappears in to months will throw her/his arms outward (although reaction to loud noises is while arching her/his back, and permanent) then bring the arms together as if grasping something Grasp When a finger or some other object is Disappears in to months; pressed against the baby’s palm, the replaced by voluntary grasping baby’s fingers close around it Babinski When the bottom of the baby’s foot Disappears in to months is stroked, the toes fan out and then curl TTTTTable able . Some Major Reflexes in the Newb Some Major Reflexes in the Newb Some Major Reflexes in the Newb Some Major Reflexes in the Newb Some Major Reflexes in the Newbooooornrnrnrnrn cry or show distress.

On being reunited with the parent or caregiver they reciprocate with smiles or hugs. The close emotional bond of affection that develop between infants and their parents (caregivers) is called attachment . In a classic study by Harlow and Harlow ( ), baby monkeys were separated from their mothers approximately hours after birth. The baby monkeys were placed in experimental chambers and reared for months by surrogate (substitute) “mothers”, one made of wire and the other of cloth.

Half the baby monkeys were fed by the wire mother, half by the cloth mother. Regardless of whether they were fed by the wire or the cloth mother the baby monkeys showed a preference for the cloth mother and spent a lot more time with her. This study clearly demonstrates that providing nourishment or feeding was not crucial for attachment and contact-comfort is important. You too may have seen young children having a strong attachment to a favourite toy or blanket.

There is nothing unusual in this, as the children know that the blanket or toy is not their mother. Yet it provides them comfort. As children grow and become more sure of themselves, they abandon these objects. Human babies also form an attachment with their parents or car egivers who consistently and appropriately reciprocate to their signals of love and affection.

According to Erik Erikson ( ), the first year of life is the key time for the development of attachment. It represents the stage of developing trust or mistrust . A sense of trust is built on a feeling of physical comfort which builds an expectation of the world as a secure and good place. An infant’s sense of trust is developed by responsive and sensitive parenting.

If the parents are sensitive, affectionate, and accepting, it provides the infant a strong base to explore the environment. Such infants are likely to develop a secure attachment. On the other hand, if parents are insensitive and show dissatisfaction and find fault with the child, it can lead to creating feelings of self-doubt in the child. Securely attached infants respond positively when picked up, move freely, and play whereas insecurely attached infants feel anxious when separated and cry due to fear and get upset.

A close interactive relationship with warm and affectionate adults is a child’s first step towards healthy development. C HILDHOOD The child’s growth slows down during early childhood as compared to infancy. The child develops physically, gains height and weight, Stage Approximate Age Characteristics Sensorimotor - years Infant explores the world by coordinating sensory experiences with physical actions. Preoperational - years Symbolic thought develops; object permanence is established; the child cannot coordinate different physical attributes of an object.

Concrete operational - years The child can reason logically about concrete events and classify objects into different sets. Is able to perform reversible mental operations on representations of objects. Formal operational - years The adolescent can apply logic more abstractly; hypothetical thinking develops. TTTTTable able .

Piaget’s Stages of Cognitive Development Piaget’s Stages of Cognitive Development Piaget’s Stages of Cognitive Development Piaget’s Stages of Cognitive Development Piaget’s Stages of Cognitive Development learns to walk, runs, jumps, and plays with a ball. Socially, the child’s world expands from the parents to the family and adults near home and at school. The child also begins to acquire the concepts of good and bad, i.e. develops a sense of morality.

During childhood, children have increased physical capacities, can perform tasks independently, can set goals, and meet adult expectations. The increasing maturation of the brain along with opportunities to experience the world, contribute to development of children’s cognitive abilities. Physical Development : Early develop- ment follows two principles : (i) development proceeds cephalocaudally , i.e. from the cephalic or head region to the caudal or tail region.

Children gain control over the upper part of the body before the lower part. This is why you would notice that the infant’s head is proportionately larger than her/his body during early infancy or if you see an infant crawling, s/he will use the arms first and then shift to using the legs, (ii) growth proceeds from the centre of body and moves towards the extremities or more distal regions — the proximodistal trend, i.e. children gain control over their torso before their extremities. Initially infants reach for objects by turning their entire body, gradually they extend their arms to reach for things.

These changes are the result of a maturing nervous system and not because of any limitation since even visually impaired children show the same sequence. As children grow older, they look slimmer as the trunk part of their bodies lengthens and body fat decreases. The brain and the head grow more rapidly than any other part of the body. The growth and development of the brain are important as they help in the maturation of children’s abilities, such as eye- hand coordination, holding a pencil, and attempts made at writing.

During middle and late childhood years, children increase significantly in size and strength; increase in weight is mainly due to increase in the size of the skeletal and muscular systems, as well as size of some body organs. Motor Development : Gross motor skills during the early childhood years involve the use of arms and legs, and moving around with confidence and more purposefully in the environment. Fine motor skills — finger dexterity and eye-hand coordination — improve substantially during early childhood. During these years the child’s preference for left or right hand also develops.

The major accomplishments in gross and fine motor skills during early childhood years are given in Table . . Cognitive Development : The child’s ability to acquire the concept of object permanence enables her/him to use mental symbols to represent objects. However, the child at this stage lacks the ability that allows her/him to do mentally what was done physically before.

Cognitive development in early childhood focuses on Piaget’s stage of preoperational thought (see Table . ). The child gains the ability to mentally represent an object that is not physically present. You may have observed children draw designs/ figures to represent people, trees, dog, house, Age in Years Gross Motor Skills Fine Motor Skills years Hopping, jumping, running Build blocks, pick objects with forefinger and thumb years Climb up and downstairs with Fit jigsaw puzzle precisely one foot on each step years Run hard, enjoy races Hand, arm, and body all coordinate with eye movement TTTTTable able .

Major Accomplishments in Gross and F Major Accomplishments in Gross and F Major Accomplishments in Gross and F Major Accomplishments in Gross and F Major Accomplishments in Gross and Fine Motor Skills ine Motor Skills ine Motor Skills ine Motor Skills ine Motor Skills etc. This ability of the child to engage in symbolic thought helps to expand her/his mental world. The progress in symbolic thought continues. A salient feature of preoperational thought is egocentrism (self- focus), i.e.

children see the world only in terms of their own selves and are not able to appreciate others’ point of view. Children because of egocentrism, engage in animism - thinking that all things are living, like oneself. They attribute life-like qualities to inanimate objects. For example, if a child while running slips on the road, s/he might show animism by saying “road hurt me”.

As children grow and are approximately between and years of age they want answers to all their questions like: Why is the sky blue? How do trees grow? and so on. Such questions help the child to know why things are as they are.

Piaget called this the stage of intuitive thought . Another feature of thought during preoperational stage is characterised by children having a tendency for centration , i.e. focusing on a single characteristic or feature for understanding an event. For example, a child may insist on drinking a “big glass” of juice, preferring a tall narrow glass to a short broad one, even though both might be holding the same amount of juice.

As the child grows and is approximately between and years of age (the period of middle and late childhood) intuitive thought is replaced by logical thought . This is the stage of concrete operational thought , which is made up of operations — mental actions that allow the child to do mentally what was done physically before. Concrete operations are also mental actions that are reversible. In a well- known test, the child is presented with two identical balls of clay.

One ball is rolled by the experimenter into a long thin strip and the other ball remains in its original shape. On being asked which has more clay, the child of or years, would answer that, both have the same amount of clay. This is because the child imagines the ball rolled into thin strip and then into a ball, that means s/he is able to imagine reversible mental action on concrete/real objects. What do you think a preoperational child would have done?

S/he is likely to focus on only one aspect-length or height. Concrete operations allow the child to focus on different characteristics and not focus on one aspect of the object. This helps the child to appreciate that there are different ways of looking at things, which also results in the decline of her/his egocentrism. Thinking becomes more flexible, and children can think about alternatives when solving problems, or mentally retrace their steps if required.

Even though the preoperational child develops the ability to see relationships between different properties of an object, s/he cannot do abstract thinking, i.e. s/he still cannot manipulate ideas in the absence of objects. For example, steps required to complete algebraic equations, or imagining line of longitude or latitude of the earth. The growing cognitive abilities of children facilitate the acquisition of language.

You will read in Chapter , how children develop vocabulary and grammar. Take two transparent glasses of the same size and pour same amount of water in both. Ask a child of Class II and Class V of your school: whether the glasses contain the same amount of water? Take another tall thin glass and in front of the child empty water from one of the earlier glasses to the third glass.

Now ask her/him which glass has more water? Did you find any difference in their responses?