Human Growth and Development Lecture Notes PDF

**LECTURE THREE** **Postnatal ( Postpartum) development** **Factors affecting human growth and development at the postnatal stage** - Broadly these factors are categorized into nature and nurture (environmental) factors **Nature factors** - These are hereditary factors such as genetic c...

**LECTURE THREE** **Postnatal ( Postpartum) development** **Factors affecting human growth and development at the postnatal stage** - Broadly these factors are categorized into nature and nurture (environmental) factors **Nature factors** - These are hereditary factors such as genetic composition which determine the sex of an individual and hormones. These influence human growth and development in profound ways **Environmental or nurture factors** Postnatal environmental factors affecting growth include **nutrition, disease, socioeconomic status, geographical factors (where one lives), physical activity or exercise, climate, family characteristics and early experience during early childhood.** **Socioeconomic factors:** Children of higher socio-economical classes are taller than the children of the same age and sex in the lower socioeconomic groups. Urbanization has positively influenced growth. The secular trend is observed in growth where the kids grow taller and mature more rapidly than the previous generation. This secular trend is observed significantly in developed countries like North America. **The family characteristics: **Higher family education levels have a positive impact on growth. The inadequate emotional support and inadequate developmental stimulus, including language training, might cause growth and development deterioration.  **Nutrition**  - Malnutrition plays a detrimental role in the process of growth and development.  - Deficiencies of trace minerals can affect growth and development. Iron deficiency usually affects psychomotor development and does not affect growth. Zinc deficiency might cause growth retardation and developmental delay. Selenium, iodine, manganese, and copper also play a significant role.  - Growth faltering or rapid weight gain in early childhood influences health in the later part of life. The diet in early childhood has a strong association with the likelihood of obesity later in life. \'Early Protein Hypothesis\' shows that lowering the protein supply during infancy helps achieve normal growth and reduce obesity in early childhood. This concept of the early protein hypothesis helps in improving the food products for children.  **Role of experience during early childhood** -  Exposure to adverse experiences in early childhood might hinder development. Profound neglect during early childhood can impair development. - Children adopted before six months of age have similar development when compared to their non-adoptive siblings. - If children adopted after six months have a high risk of cognition deficits, behavioral issues, autism, and hyperactivity. -  Early intervention for children with adverse experiences is the pillar in healthy development. Genetic and environmental factors influence the growth and development in profound but interrelated ways. Genetic and environmental factors are not mutually exclusive. Both genetic (nature) and environmental (nurture) factors have an influence on the physical, intellectual, emotional and social development, as well as an individual's self-concept. **Postnatal stages of human growth and development** The process of postnatal growth and development happens together but at different rates. The stages in postnatal growth and development are; - Neonatal - Infancy - Childhood - Adolescence and - Adulthood **Neonatal period** - Refers to the first two weeks of life and marks a transition from the womb to an independent life - Physically the neonate is weak and dependent on adults. - It cannot raise its head or roll it over by itself - The neonate does have several useful reflexive behaviors e.g. when stimulated on side side of the mouth, the neonate turns its head toward the stimulation and begins searching and sucking until something is in its mouth. This is referred to as the rooting reflex. - The neonate has exceptionally good sensory abilities. Their hearing is fairly good and they react differently to different odours and tastes. - They are poor sighted and can only see up to about 12 inches from their eyes. - They have a distinct preference for staring at complex objects that have a lot of details - Their skin is quite sensitive to touch. - Few cognitive abilities are developed during the neonatal period - Emotions of the neonate are quite diffuse. - Sleep is very common at this stage and occupies about 16 hours a day. - The neonate engages in little of what could go for social behavior except the intimate contact between neonate and parent in cuddling and nursing ***Infancy: 2 weeks to 2 years*** - At two weeks the baby is known as an infant - Physical growth and development is very rapid in the first year of life than at any other period in life (growth spurt). - At two months, many infants can raise their head and chest on their arms and can grasp an object that is held directly in front of their head and shoulders. Infants reflexively move their heads to free their mouth and nose when something blocks their breathing. - As infants mature, this reflex begins to cease to occur around the age of 2 months and the infant increasingly relies on voluntary movements to keep its nose and mouth clear. - During the transition period from reflexive to voluntary movements during 2 to 5 months, however, infants are sometimes unable to free their airways. This is why infants require support to keep sleeping on their backs. - By 6 months, many can roll over from back to front, sit, and begin to crawl. - By one year, many can walk alone and grasp small objects with their fingers and thumbs. - By two years, they are getting into everything and walking well, but with peculiar gait thus the nickname toddler. - By 2 weeks to 2 months, rapid changes take place in all the senses. - Clear vision increases to 12 feet. - By six months, their vision is 20/20 (normal). - During the early part of this stage, the infant moves from pure reflexive actions to the ability to coordinate sensations and motor movements, such as voluntarily taking a nipple into the mouth and sucking. - From about two months, the infant begins to interact actively with its environment. - By 4^1^/~2~ months, most infants respond positively to the sound of their names. - From about 2 months, infants remember some of what they had experienced for a time - Infants of 6 months show memory for a task for two weeks, one year olds for 8 weeks and 18 month old for 12 weeks. - Cognitive representation of the world is developed e.g. at 6 to 9 months of age, an infant begins to understand that objects continue to exist even when they are out of their sight (object permanence). - By about 9 months, too, infants begin to understand some nouns, such as ball and cookie and can respond to bye-bye gestures. - By 12 months, some infants can say some words and by 18 months the infant has a speaking vocabulary of 20 words. - By 18 months, an infant can respond to prohibitions such as No, no... do not touch. - By age two, the infant has a speaking vocabulary of 300 words and uses telegraphic speech. - Pleasure emotion by the child is expressed through general relaxation of the total body. It is followed by smiling, cooing and laughing response. Learning to walk is a pleasant emotion to the child - Crying is a common way of infant\'s expression of displeasure. They cry in distress because of physical discomfort and pain. Displeasure is shown not I by crying, but also by sulking, running away, verbalizing his/her displeasure and hiding. Grownup children express their displeasure through language, sometimes using slang. **Early Childhood (2-7 years)** - Is still a period of rapid physical growth, but the growth is far less explosive than in infancy and declines in rate annually. - Quite a considerable development occur in the coordination of small and large muscle groups which is seen in the emergence of hopping, skipping, throwing, and other motor behaviours that are much a part of early childhood - By 2 years, most children are able to think in mental images. - The child's thinking is egocentric or self-centred i.e. the child can only see things from his/her perspective. - This leads the young child to believe that inanimate things are a life, just as they are. The child has difficulty distinguishing real from imagery. - Transductive reasoning -- errors in inferring cause-and-effect relationships- is also common in the preoperational child. - By the end of this period, the preoperational child begins to grasp logical operations and make fewer cause-and-effect errors - Children at this stage are able to sense themselves as being distinct from other persons and develop an autobiographical memory for events that define their lives. - There is also quite a phenomenal growth in memory. - From a speaking vocabulary of 300 words at 2 years, children in all cultures reach a vocabulary of more than 14,000 words by age six and 60,000 words by 18 years. **Emotional and social development** - Both positive and negative emotions are fairly developed by age 2 - Emotional development seems to be linked to cognitive development. - Considerable change also occurs in how they relate with their peers. - At age two most children engage in solitary play which eventually gives way to parallel play - Similar shifts occur in emotional development. - 2 to 3 year olds normally engage in temper tantrums that are directed at no one whereas 4 to 7 year olds direct their aggression at others - By age 2, most boys and girls have started acting in sex typed ways. Males tend to play with trucks, blocks etc while girls play with dolls, stuffed animals etc **Middle childhood: 7 to 11 years** - Are elementary school years and children are socially and physically ready for the demands of the school. - Physical growth proceeds at a fairly slow pace in middle childhood, but it's a healthy period in which most of the children experience little illness. - Continued improvements in strength and coordination are the only notable advances - Children emerge as capable thinkers who use most of the adult concepts except the abstract. - They can order objects according to size, weight and other dimensions. - They understand reversibility of logical operations - They acquire the concept of conservation as their thoughts are decentered i.e. they can think of more than one thing at a time. - The rapid growth in cognitive abilities during this stage is based on rapid increases in children's speed of processing information and expansions in the capacity of short-term memory. **Emotional and social development** - Fewer changes occur in the expressions of emotions but social relationships are markedly different than before. - Children enter this stage with very close ties with the parents. - However, at this stage, relationships with the peers become increasingly important - Before age 7, children have friendships, but they are generally not enduring and typically are not close - Friendship groups or cliques emerge during this period. - Most friendships are with members of the same sex and those cross-sex friends are generally "just friends." **Adolescent development** - Adolescence is ushered in by a series of physiological changes - This is a period of rapid physical growth and change and by a heightening of sexual and romantic interest in others - Peers become more important than parents in terms of attachment and influence - Is capable of reasoning in abstractions for the first time **Physical development** - This is the onset of puberty - There is production of sex hormones by the ovaries and testes - These hormones trigger a series of physiological changes that lead to ovulation and menstruation in females and the production of sperms in the males - These are the primary sex changes that indicate that the adolescent has the ability to reproduce - These physical changes are accompanied by corresponding increases in dating, kissing, petting, masturbation, and other sexual activities - Menarche, or the first menstrual period occurs on the average at about 12 years and the production of sperms begin at about 14 years in males. - The age of the menarche is younger than before due to improved nutrition and health and could also be due to the hormones in the milk. - Secondary sex characteristics also develop. In the females, there is an accumulation of fat in the breasts which makes them to enlarge, there is also an accumulation of fat around the hip area giving the shape of an adult female. Finally, about the time of the menarche, pubic hair begins to grow. - In males the secondary sex characteristics include enlargement and growth of tests, followed by a broadening of the shoulders, lowering of the voice, and the growth of the penis. Soon, pubic and facial hair begins to grow, thus creating the physical image of an adult male. - Adolescence is also a growth spurt resulting in a tremendous increase in weight and height. - The most significant changes also take place in the brain. The structure and organization of the limbic system and the frontal lobes change rapidly from adolescence in ways that promote risk taking, novelty seeking, and emotional response to stress. - These changes are reversed in late adolescence as the brain takes its full adult organization **Cognitive development** - David Elkind (1967, 1981) has pointed out that adolescents often possess a form of egocentrism that, although different from the egocentrism of young children, similarly distorts their perception of reality. - According to Elkind, there are four primary features of adolescent egocentrism 1. ***Imaginary audience.*** Many adolescents act as though there is an imaginary audience that is watching everything they do. 2. ***Personal fable***. They believe that nobody has their kind of experience and can possibly know what they are going through. 3. ***Hypocrisy***. 4. ***Pseudostupidity***. Adolescents often use oversimplified logic e.g. if alcohol kills, why can't one stop drinking without actually considering the underlying causal factors. **Emotional and social development** - There is marked changes in the emotional and social spheres in the adolescent - Socially the adolescent show marked changes in their social relationships. - Adolescence is time of drifting away, from the family. - The peers become the most important than the parents - Much time is spent with peers rather than parents. - In terms of emotions, the adolescent has greater problems than adults in the following areas; 1. ***Parent-child conflicts***. Conflicts with parents increase in early adolescence and start declining in late adolescence. Conflicts are on dating, spending time away from home etc 2. ***Mood changes***. Adolescents have more mood shifts. They feel much more self-conscious, embarrassed, awkward, lonely, nervous and ignored. 3. ***Risky behavior***. In adolescence, there is sharp increase in the amount of risky behavior that exposes the child to danger e.g. drinking, unprotected sex, reckless driving, aggression, delinquent behavior etc **Adulthood: Young adulthood through older adulthood** - Adulthood is a time of taking on responsibilities in work and social relationships - Adulthood is not a single phase of life - The challenges of work, adult love and play change considerably during adulthood. - Adulthood is therefore not the end of the process of development. - Developmental changes continue throughout adulthood. **Physical development** - The body begins a slow process of physical decline after early adulthood. - Physical speed and endurance decline gradually from early childhood on. - Visual acuity declines - Ability to hear high-pitched sounds start declining after the age of twenty - Our sense of taste remain largely intact, though some adults report food becomes a little bland. This is due to the decline in taste buds and the reduction in the sense of smell with age. - These declines are ealier in men than women. - There is also a substantial decline in intellectual ability due to cerebral arteriosclerosis (hardening of the arteries). - This, however, depends on a healthy exercise and activity that the individual maintains during adulthood. **Cognitive Development** - Continues throughout life as some cognitive abilities decline while others improve - In general fluid intelligence declines by a third by the late 80s, but different people decline at different rates as they grow older. - Crystallized intelligence (Knowledge and skills) improves until the late 30s and then declines very slowly afterward. **Emotional and social development** - Developments in these areas realize both improvements and decline - On average, adults become less anxious and emotional, less socially outgoing and less creative as they grow older. - But they become more dependable, agreeable, and accepting of life's hardships. - Women tend to become more assertive, confident, and independent, and men become more aware of their aesthetic needs and their need for affection. **Death and dying: The Final stage** - Older adults seem to spend more time thinking about death than younger adults and tend to be frightened by it - Religious belief is very critical at this stage - People who learn about their impending death according to Elisabeth Kubler-Ross (1969,74) pass through the following stages 1. Denial -- No it is not true 2. Anger -- why me experience 3. Bargaining -- the person tries to strike a bargain to prolong life e.g. willingness to undergo painful medical procedures 4. Depression -- the inevitability of death brings loss of hope 5. Acceptance -- depression lifts and the person finally achieves an acceptance of death. **Growth and development abnormalities** Growth disorders are problems that **prevent children from developing normal height, weight, sexual maturity or other features**. Very slow or very fast growth can sometimes signal a gland problem or disease. What causes growth problems? ---------------------------- Growth problems can be caused by a number of factors, including genetics, hormonal disorders, systemic illnesses, and poor absorption of food. Causes of growth problems usually fall into the following categories: - familial short stature, a tendency to follow the family\'s inherited short stature (shortness) - Constitutional growth delay, also known as delayed puberty. A child with this condition enters puberty later than average, but is growing at a normal rate. Most of these children tend to eventually grow to about the same height as their parents. - illnesses that affect the whole body, also called systemic or chronic illnesses, or illnesses that affect the digestive tract, kidneys, heart, or lungs - Malnutrition. Constant malnutrition prevents a child from growing as tall as she could; a well-balanced diet generally prevents or corrects this. Malnutrition is the most common cause of growth failure around the world. - severe stress - endocrine (hormone) diseases, such as diabetes  or a lack of thyroid hormones, which are necessary for normal bone growth - Syndromes (genetic disorders). Growth problems may be a feature of syndromes such as Cushing's syndrome, Turner syndrome, Down syndrome, Noonan syndrome, Russell-Silver syndrome, and Prader-Willi syndrome. - Growth hormone deficiency. A child with this growth disorder has a problem with the pituitary gland (small gland at the base of the brain) that secretes several hormones, including growth hormone. - congenital (present at birth) problems in the tissues where growth occurs - Intrauterine growth restriction (IUGR). This condition results from a fetus's slow growth within the uterus. The baby is born smaller in weight and length than normal, in proportion to his short stature. - Chromosome abnormalities. Having too many or too few chromosomes can result in health problems, including problems with growth. - Skeletal abnormalities. There are more than 50 bone diseases that affect height and growth, many of which are genetic. The most common is achondroplasia, a type of dwarfism in which the child\'s arms and legs are short in proportion to his/her body length. The head is often large and the trunk is normal-sized. - Precocious puberty This growth disorder is characterized by an early onset of adolescence in which a child is tall for his age initially, but due to rapid bone maturity, growth stops at an early age and the child may be short as an adult. - genetic conditions. There are a few genetic conditions that result in tall stature, where other health problems are also present. - Idiopathic. There are several growth disorders that are idiopathic, meaning that there is no known cause for the growth problem. What are the symptoms of a growth problem? ------------------------------------------ The primary symptom that may indicate a growth problem is when a child grows less than 2 inches a year after his second birthday. Other symptoms may include: - slow development of physical skills, such as rolling over, sitting up, standing, and walking - delayed social and mental skills - delayed development of secondary sexual characteristics in adolescence How are growth problems treated in a child? ------------------------------------------- Many conditions that cause growth problems can be managed or corrected with medical treatment. Treatment for growth problems will be based on: - What may be causing the growth problem - How severe the problem is - The child\'s current health and health history - The child\'s ability to deal with medical procedures and take medicines - The parents' wishes about treatment Key points about growth problems in children -------------------------------------------- - A growth problem means that a child falls either below or above the average range of growth for a child\'s age, sex, family history, or racial background. - Growth disorders have many causes. They can include genes, illness, or problems with hormones. - Most growth problems are noticed when the child appears smaller than their classmates, or when growth slows over several months. - One main sign of a growth problem is when a child grows less than 3.5 cm (about 1.4 inches) a year after their 3rd birthday. In other cases, a baby may be abnormally small for their gestational age at birth. - Many conditions that cause growth problems can be managed or corrected with medical treatment. - Children who are shorter or taller than their peers may have poor self-esteem or depression. It's important to talk about these problems with your child\'s healthcare provider. They can recommend support groups for you and your child. **Educational implications of growth and development** 1. Education is not only a process and a product of growing, it means growing. It aims at the fullest possible realization of all the potentialities of children. This implies that teachers and parents must know what children are capable of and what potentialities they possess. Equipped with this knowledge they should provide suitable opportunities and favourable environmental facilities which are conducive to the maximum growth of children. Apart from these opportunities, it is necessary that their attitudes are helpful, encouraging and sympathetic. 2. School programs, procedures and practices should be adjusted to the growth and maturational levels of children, bearing in mind the individual variations in rates of growth. Since various aspects of growth are interrelated, parents and teachers should pay attention to all aspects. Good physical growth, for example, through the provision of play, games and sports, is conducive to effective intellectual development; malnutrition has been found to be an important factor that retards development: hence, teachers and parents should cooperate in cultivating among pupils habits of balanced eating. 3. The principles of development have highlighted the importance of "individual differences" from one child to the other and from one stage to another. This fact justifies the provision of diversified courses for the development of specific talents, abilities and interests and a rich and varied programme of co-curricular activities. Similarly, the curricular activities should be based on the needs and interests of various stages of growth i.e., childhood, boyhood or later childhood, pre- adolescence and adolescence. 4. Each stage of growth has its possibilities and limitations. This implies that teachers and parents should not demand of pupils or children what is beyond their stage of growth. If they do so, they will only cause frustrations, heighten tension and nervousness in children. For example, it is wrong to expect a primary school child to appreciate abstract concepts and theories. Teachers should therefore employ developmentally appropriate activities. 5. The 'inter-relatedness of growth' demands presentation of knowledge in an interrelated manner and its integration with action. Since each child grows in his own unique way, parents and teachers should treat each child as a unique individual and provide for this special needs and interests. Thus we need to adapt teaching methods and materials to suit diverse learning styles and varying rates of development. 6. Early intervention. Identifying developmental delays or learning disabilities early enables timely intervention which can significantly improve educational outcomes. 7. Holistic education. Knowledge of human growth and development makes educators to emphasize all aspects of growth and development thus encouraging holistic education 8. Parental involvement. Educators can engage parents in the learning process by sharing insights about the child's development and suggesting ways to support their learning. Such partnership can enhance their educational experience and reinforce developmental milestones.