Human Development Chapter 9 (Part 1 and 2)

Prenatal period

conception to birth

Infancy

birth to 18-24 months

Childhood

end of infancy to 11-14 years

Adolescence

end of childhood to 18-21 years

Adulthood

last stage (can be broken down further)

Prenatal period- Conception

• sperm unites with egg to create the zygote, the first cell of a new life

What happens within 2 weeks of the zygote?

It is firmly implanted in the uterine wall, and the next stage of development begins

What happens between 2 weeks and 2 months of the zygote?

• developing human is known as embryo

• organs and internal systems begin to form

• exposure to harm- such as toxins, drugs, extreme stress, or poor nutrition-can having lasting effects on developing organ systems

What happens after 2 months during the prenatal period?

growing human is called fetus

What is the healthy full-term pregnancies?

birth of the baby between 38 and 42 weeks

Brain development during prenatal period

• brain regions mature and gain functionality

• brain regions learn to communicate = synaptic pruning

• myelination occurs

Early experiences can have lasting effects

• environmental experiences can affect brain development

• environmental experience can also foster development

Examples of environmental experiences that affect brain development

nutrition, lack of stimulation, stress, neglect, exposure to violence (poverty context)

Example of environmental experience that can foster development

Interventions

Teratogens

A substance that crosses the placenta and harms the fetus

Examples of teratogens

infectious diseases, medications, and recreational drugs

Toxoplasmosis (infectious disease)

• parasite in raw meat and cat feces

• sensory and cognitive impairments

Zika Virus (Infectious disease)

• mosquito born illness

• when contracted in 1st semester

• high risk of miscarriage and microcephaly

Thalidomide (medication)

• drug prescribed in 1950’s for nausea in 1st trimester

• prevented baby’s arms and legs from fully developing

Antibiotics (medication)

• streptomycin linked to hearing loss

• tetracycline linked to stained infant tooth enamel

Opioids (medication)

• premature birth, slow growth

• excessive crying, tremors in first month of life

Smoking and vaping (recreational drugs)

• smaller than normal, less healthy baby; inhibition of growth

• nicotine and effects on nutrients

Alcohol (recreational drug)

• fetal alcohol syndrome (FAS): a cluster of birth defects

• - smaller than normal birth weight and brain

• fetal alcohol spectrum disorders: less severe syndrome

• - deficits in learning and impaired mental health

Grasping reflex

holding things

Rooting reflex

searching for food source

Sucking reflex

sucking when food source is located

Motor development milestones

• development generally follows similar trajectory

• influenced by environment

• EX) Ugandan infants walk sooner than European infants

Infants are prepared to learn

Imitation is the baby’s first social interaction

Newborn perception

• born with some perceptual skills

• sound- prefer high pitch, exaggerated, expressive = baby talk!

• taste- prefer sweet tastes

• smell- refer smells associated with feeding or sweet sweet smells (flowers)

• poor eyesight at birth

How we study infants? Monitor infant attention

Preferential looking technique

• how long infants look at something

How do we study infants? Habituation technique

• Habituation- “getting bored” with previous stimuli

• Dishabituation- looking longer at a new stimuli

Attachment

a strong, intimate, emotional connection

• encourages proximity

• adaptive- security and investment

• infant attachment behaviors- behaviors that motivate adult attention like crying, smiling, reaching

Chemistry of Attachment

• Oxytocin plays a role in maternal tendencies, feelings of social acceptance and bonding

• Infant sucking during nursing triggers the release of oxytocin in the mother. This release stimulates biological processes in the mother that move milk into the milk ducts so the infant can nurse

Strange situation

method of studying attachment in young children, ex: Mary Ainsworth

• measure how infant/child responds to given scenarios

• basically, how does the child cope with the stress

Secure attachment style

May be distressed when caregiver leaves. Happy when caregiver returns

Insecure- avoidant

Not distressed when caregiver leaves. Do not acknowledge when caregiver returns

Insecure-anxious/ambivalent

Distressed when caregiver leaves. Not happy when caregiver returns-still distressed

Disorganized

No consistent pattern of responses

Imprinting

a sensitive period during which young animals become strongly attached to a nearby adult

Rhesus Monkey Study

Harlow (1971) showed baby rhesus monkeys bond with surrogate mothers because of bodily contact, not because of nourishment

Piaget’s developmental stages

Piaget: children are qualitatively different than adults

• different ways of thinking about the world

Schemes

ways of thinking based on personal experience

Assimilation

The process by which new information is placed into an existing scheme

Accommodation

The process by which infants revise their schemes in light of new information

What time frame is sensorimotor stage?

Birth to 2 years

What time frame is pre-operational stage?

2 to 7 years

What time frame is concrete operational stage?

7 to 11 years

What time frame is formal operational stage?

12 and up years old

Sensorimotor stage

• infants acquire information about the world through senses and motor skill

• reflex responses develop into deliberate actions through scheme development

Object permanence

the idea that objects continue to exist even when they are not visible

• 9 months exhibit this skill

• still limits on search skill (A not B error)

Pre-operational Stage

• Children have preliminary understanding of the physical world and begin to develop symbolic capacity

• classify objects by single feature

• - group blocks by shape OR color, but not shape AND color

• egocentrism

Egocentrism

failure to understand that the world appears differently to different observers

Conservation

understanding appearance can change while quantity remains unchanged

Theory of Mind

ability to understand that the world appears differently observers

-testing using the false belief test

-typically achieved around age 4 or 5 years of age

Concrete Operational Stage

• children learn how various actions or operations can affect or transform concrete objects

• learn how to classify the same object in multiple ways

• conservation of number, mass, and weight

• egocentrism decreases (Piaget thought this developed much later)

Formal Operational Stage

• children can solve non-physical problems

• abstract logical thinking

• systemic thinking

• can think of hypothesis and the future

Challenges to Piaget’s Theory

• differing cognitive strategies or skills among individuals

• the role of social and cultural differences

• children move back and forth between stages

Adolescence

the period of development that begins with puberty and lasts until the beginning of adulthood (about 18-21 years of age)

What does HPG axis triggers?

Triggers puberty

What does HPG axis stand for?

Hypothalamus, pituitary gland, gonads (testes, ovaries)

First phase chain reactions within the HPG axis

9 or 10 years old, hypothalamus releases a hormone to stimulate pituitary gland to produce hormones

Second phase chain reaction within the HPG axis

the ovaries and testes grow and secrete estrogens and testosterones

Third phase chain reaction within the HPG Axis

physical changes of puberty occur

Puberty causes physical changes like what?

Adolescent growth spurt, primary sex characteristics, and secondarry sexual characteristics

Adolescent growth spurt

a rapid, hormonally driven increase in height and weight

Primary sex characteristics

maturation of the male and female sex organs

Secondary sexual characteristics

pubic hair, body hair, muscle mass increases for boys, and fat deposits on the hips and breasts for females

Biology and environment

• the frontal cortex of the brain is not fully myelinated until the mid-20s

• the limbic system tends to mature more quickly than the frontal cortex

Physical changes from early to middle adulthood

• Between the ages of 20 and 40, we experience a steady decline in muscle mass, bone density, eyesight, and hearing

• trivial physical changes include the graying and whitening of hair and wrinkling of skin

Cognitive changes

• frontal lobes shrink as people age

• mental processing speed slows

• Sensory-perceptual changes occur with age and may account for some of the observed decline.

• Sensitivity to sound also decreases with age, especially the ability to tune out background noise.

• Aging also affects memory and intelligence

Dementia

a brain condition that causes thinking, memory, and behavior to deteriorate progressively

Alzheimer’s disease

profound memory deficits and personality changes

What causes Alzheimer’s disease?

cholesterol functioning, synaptic plasticity/repair, low AcH

Socioemotional selectivity theory

As people grow older, they view time as limited and therefore shift their focus to meaningful events, experiences, and goals