Human Growth and Development

Human Growth and Development

• Explores how humans change and grow from conception to death

Developmental Psychology Domains

• Physical: growth and changes in the body, brain, senses, motor skills, health, and wellness
• Cognitive: learning, attention, memory, language, thinking, reasoning, and creativity
• Psychosocial: emotions, personality, and social relationships

Nature vs Nurture

• Nature: biological endowment and genes inherited from parents
• Nurture: environmental influences (social and physical)
• Free development happens neither free of environmental influences nor without the effect of hereditary makeup.
• Development is considered an interaction between heredity and environmental factors.
• Environmental experiences influence particular traits, and genes influence interactions with the environment.

Basics of Genetics

• Conception results in a one-cell entity with 23 pairs of chromosomes which contain hereditary information.
• One member of the chromosome pair comes from the mother, and the other is from the father.
• Chromosomes contain thousands of genes.
• Genes: smaller units that transmit genetic information to produce particular characteristics
• Genes are composed of sequences or coils of DNA (deoxyribonucleic acid).
• Some genes direct development common to humans.
• Others shape unique human characteristics like facial features, height, and eye color
• Sex is determined by the combination of genes; XX combination becomes a female, and XY combination becomes a male.
• Children inherit an X chromosome from their mother and either an X or Y chromosome from their father

Earliest Development - Prenatal Stages

• Zygote: the one-cell entity immediately starts to develop following the egg being fertilized by the sperm.
• The zygote starts off tiny and only visible with a microscope.
• The zygote increases to around 32 cells three days after fertilization
• The zygote grows to 100-150 cells within a week.
• Germinal Period: the first two weeks.
• Embryonic Period: from week 2 through week 8
• The developing individual is now called an embryo.
• A rudimentary beating heart, brain, intestinal tract, and other organs develop.
• Organs are recognizable, but still at an early stage of development
• By week 8, the embryo is about an inch long, with discernible arms, legs, and a face.
• Fetal Period: from week 8 until birth, the developing individual is called a fetus.
• The fetus begins to respond to touch and bends its fingers when touched on the hand.
• At week 16-18, the fetus' movements become strong enough to be sensed by the mother.
• At about 22 weeks, the fetus reaches the age of viability, when it can survive prematurely if born
• By week 24, the fetus has developed many newborn characteristics.
• In the final weeks of pregnancy, the fetus continues to grow and gain weight.
• At the end of the normal 38 weeks of pregnancy, the fetus weighs about 7 pounds and is about 20 inches in length.

Prenatal Environmental Influences

• Mother’s nutrition and emotional state.
• Mother's illness, such as rubella (German measles), syphilis, high blood pressure, or diabetes
• Mother's use of drugs and nicotine.
• Fetal alcohol syndrome disorder (FASD) can result from alcohol use
• Rubella's effect on prenatal development entails heart abnormalities, deafness, blindness and stillbirth.
• Syphilis' effect on prenatal development entails intellectual disability, maternal miscarriage, and physical deformities.
• Addictive drugs', and alcohol's effect on prenatal development entails low birth weight, addiction and possible death
• Nicotine's effect on prenatal includes premature birth, low birth weight and length.
• Radiation from X-rays contributes to physical deformities and intellectual disability
• Inadequate diet contributes to the reduction in brain growth, smaller weight and length at birth.
• Younger-than-18 mothers' effect on prenatal development entails premature birth and an increased risk for Down Syndrome diagnosis.
• Older-than-35 mothers' effect on prenatal development entails increased risk for Down Syndrome diagnosis.
• DES (diethylstilbestrol) contributes to reproductive complications and increased cancer rates in children.
• Aids causes facial deformities, growth failure and the spread of the virus to the infant.
• Accutane contributes to intellectual disability and physical deformities.

Post-natal Development: Infancy and Childhood

• Neonates: newborns.
• Reflexes: unlearned, involuntary responses occurring automatically in the presence of certain stimuli.
• Reflexes are critical for survival and unfold as part of on-going maturation
• Rooting reflex: causes neonates to turn their heads towards things touching their cheeks such as a nipple or bottle
• Sucking reflex: prompts infants to suck at things that touch their lips.
• Grasping reflex: automatic grasp of anything touching their palms.
• Babies roll over by 3 months, sit without support around 6 months, stand alone at 11 months, and walk at just over 1 year.
• Fine-muscle movements improve as large-scale movement improves, becoming more sophisticated.

Developmental Milestones (Ages 2-5 Years)

• Age 2:
• Physical: kicks a ball, walks up and down the stairs.
• Social: plays alongside other children and copies adults.
• Language: points to objects when named, puts 2-4 words together in sentences.
• Cognitive: sorts colors and shapes, follows instructions in two steps.
• Age 3:
• Physical: climbs and runs, pedals tricycle.
• Social: takes turns, expresses many emotions, dresses self.
• Language: names familiar things, uses pronouns
• Cognitive: works toys with levers and handles, plays make believe.
• Age 4:
• Physical: catches balls, uses scissors.
• Social: has an idea of likes and interests, prefers solo play to social play.
• Language: knows songs and rhymes by memory
• Cognitive: writing letters, names colors and numbers.
• Age 5:
• Physical: hops and swings, uses forks and spoons
• Social: likes to please friends, distinguishes real from pretend.
• Language: speaks clearly; uses full sentences.
• Cognitive: counts to 10 or higher; copies basic shapes and letters.

Piaget’s Theory of Cognitive Development

• Cognitive development: changes in a child's understanding of the environment based on age and experience.
• Children proceed through four stages in a fixed order.
• Movement to the next stage occurs when a child reaches an appropriate level of maturation and is exposed to relevant experiences.
• The four stages are sensorimotor, preoperational, concrete operational, and formal operational.

Piaget's Stages of Cognitive Development

• Sensorimotor Stage (Birth to 2 years)
• Children understand the world by touching, sucking, chewing, shaking, and manipulating objects.
• Children have little competence in representing the environment with images, language, or symbols early in the stage.
• Infants lack object permanence, the awareness that objects continue to exist even when out of sight.
• Preoperational Stage (2 to 7 years)
• Children develop the use of language, and representational systems allow use to describe events, people and feelings.
• Children pretend with symbols
• Children demonstrate egocentric thought; thinking the world from your perspective.
• Preoperational children believe everyone shares their knowledge and perspective.
• They cannot understand the principle of conservation of mass.
• Children do not understand that the amount and volume doesn't change based on appearance.
• Concrete Operational Stage (7 to 12 years)
• Mastery of the principle of conservation marks the start of this stage.
• Children do not fully understand weight and volume conservation for a number of years
• Children become more logical and begin to overcome egocentrism.
• Children show reversibility: the idea that actions can be undone by reversing an earlier action.
• Children are bound to the concrete, physical reality of the world.
• Formal Operational Stage (12 Years to Adulthood)
• Individuals display abstract, formal, and logical thinking.
• Thinking is no longer tied to observations.
• Individuals are able to use logical techniques to resolve problems.

Development of Social Behavior

• Attachment: the emotional link that forms between a child and a particular person, and an important form of social development in infancy.
• Harry Harlow’s study showed that monkeys cuddled the warm, soft monkey instead of the wire one, regardless of which provided milk.
• Human attachment grows through the responsiveness of caregivers to signals such as crying, reaching, clinging, and smiling.
• Ainsworth did research on various degrees of attachment that children hold for their caregivers.
• Securely attached children.
• Avoidant children.
• Ambivalent children.
• Disorganized-disoriented children.

Degrees of Attachment

• Securely attached children
• Use the mother as a home base
• Explore independently but return to her occasionally
• Avoidant children
• Do not cry when the mother leaves
• Seem to avoid her when she returns
• Ambivalent children
• Display anxiety before separation
• Are upset when the mother leaves
• Show ambivalent reactions upon return
• Disorganized-disoriented children
• Show inconsistent and contradictory behavior
• Display avoidance of eye contact
• The nature of attachment between children/mothers entails consequences for later development.
• Those securely attached tend to be more emotionally and socially competent.
• They also find others more cooperative capable.
• At age 1, a securely attached children show few psychological difficulties when they are older.
• As adults, securely attached children tend to have more successful romantic relationships.

Parenting Styles

• There is importance to note that no authoritative parents produce perfectly well-adjusted children.
• Children are born with particular temperament, a basic inborn characteristic.
• Some children are easy-going and cheerful while some are irritable or pensive.
• Erik Erikson created comprehensive theories of social development

Erikson's Stages of Psychosocial Development

• Erikson viewed developmental changes throughout life as a series of eight stages of psychosocial development
• Four of these stages occur during childhood
• Passage through each of these stages necessitates resolving a crisis or conflict.
• Trust-versus-mistrust stage (birth to 1 1/2 years)
• If the caregiver meets physical and psychological needs, then the child will develop trust.
• Inconsistent care will lead to mistrust and a view that the world is harsh and unfriendly.
• Autonomy-versus-shame-and-doubt stage (1 1/2 to 3 years)
• Children develop autonomy and independence if exploration is encourages
• They experience shame, self-doubt and unhappiness if restricted and protected
• Key to independence involves providing a reasonable amount of control.
• Overly controlled children cannot assert themselves. If parents provide too little control, children can become demanding and dictatorial.
• Initiative-versus-guilt stage (3 to 6 years)
• Desire to act independently conflicts with guilt through unintended consequences.
• Children begin to understand independence and make decisions about their behavior.
• Positive parental reaction allows children to develop skills in accomplishing tasks
• Industry-versus-inferiority stage (6 to 12 years)
• Successful psychosocial development includes increasing competency in all areas.
• Difficulty leads to feelings of failure and inadequacy.
• The theory suggests that psychosocial development continues throughout life and presents four more crises

Adolescence

• Adolescence is a crucial developmental stage between adulthood and childhood.
• It is a time of profound change
• Identity-versus-role confusion stage:
• Encompasses adolescence
• Individuals try to determine uniqueness.
• People discover their strengths and find roles suited for the rest of their life
• Confusion about their role may manifest through lack of a stable identity, the adoption of a social deviant, and an inability to maintain relationships later in life

Adulthood

• Intimacy-versus-isolation stage (early adulthood to the early 30s):
• Focuses on developing close relationships
• Difficulties in this stage can result in loneliness
• Resolution creates intimate relationships physically, intellectually, and emotionally.
• Generativity-versus-stagnation stage:
• Generativity is the ability to contribute to family, community, work, and society and to assist the development of the younger generation.
• People feel positive and optimistic about humanity.
• Lack of contribution can lead to trivial thoughts and life stagnancy, and the feeling of poor career choices.
• The ego-integrity-versus-despair stage:
• Spans later adulthood until death
• People ask if they have lived a meaningful life
• If they see their lives positively, they feel accomplished; if not, regret will set in
• Erikson's theory suggests that development does not stop at adolescence but continues throughout adulthood.