Prenatal stage
From conception to birth (about 38–40 weeks):
- Germinal period (first 2 weeks): the fertilised egg (zygote) divides and attaches to the uterus wall.
- Embryonic period (2–8 weeks): heart, brain, limbs and other organs begin to form. This is the most sensitive time for harm.
- Fetal period (9 weeks to birth): organs grow and start working; the fetus moves and grows fast.
Teratogens are agents that can harm the unborn baby: alcohol, tobacco, some medicines and drugs, radiation, infections like rubella. The mother's age, nutrition, emotional stress and health care also matter.
Infancy (0–2 years)
- Reflexes: automatic responses present at birth — rooting (turning to a touch on the cheek), sucking, grasping, Moro (startle) and Babinski (toes fan out when the sole is stroked).
- Senses: newborns can see faces at close range, hear and recognise the mother's voice.
- Motor milestones: holding the head, sitting, crawling, standing, walking — in a set order, at slightly different ages.
- Cognitive: Piaget's sensorimotor stage — learning through senses and actions; object permanence (knowing things exist when out of sight) develops around 8 months.
- Socio-emotional: attachment — a close emotional bond with the caregiver. Harlow's studies showed comfort and warmth matter more than food alone; sensitive care builds secure attachment and trust.
Childhood
Early childhood (2–6 years)
- Body grows steadily; running, drawing, buttoning improve.
- Piaget's pre-operational stage: children use symbols and pretend play, but show egocentrism (cannot see from another's view), animism (believing objects are alive), centration (focus on one feature) and fail conservation.
- Self-concept and gender roles begin; parents shape early moral ideas.
Middle and late childhood (6–11 years)
- Piaget's concrete operational stage: logical thinking about real, concrete objects; conservation and classification.
- Self-esteem, friendships and school achievement become important; moral reasoning grows from obeying rules to understanding fairness.
Challenges of adolescence
Adolescence (about 12–18 years) begins with puberty: a growth spurt and sexual maturity. Thinking becomes formal operational: abstract, hypothetical and idealistic. Teens may show adolescent egocentrism — feeling that everyone is watching them (imaginary audience) or that nothing bad can happen to them (personal fable).
Identity formation: Erikson called this stage "identity versus role confusion" — trying out roles to answer "Who am I?". Career choice and values are part of it.
Major challenges
- Delinquency: breaking rules or laws, often linked with poor supervision or bad company.
- Substance abuse: smoking, alcohol, drugs — sometimes to fit in or escape stress.
- Eating disorders: anorexia and bulimia, linked to body-image worries.
- Also: peer pressure, exam stress, conflicts with parents.
Supports: open family talk, good friends, clear goals, sports and hobbies, and counselling.
Adulthood and old age
- Early adulthood: career and work, choosing a partner, marriage, becoming a parent. Adjusting to these new roles is a major task.
- Middle age: physical changes (eyesight, energy; menopause in women), reviewing goals, caring for both children and ageing parents.
- Old age: retirement, "empty nest" when children leave, loss of spouse or friends, health problems. Crystallised abilities (knowledge, vocabulary, wisdom) stay strong; fluid abilities (speed, new problem solving) slow. Active, socially connected elders do well; in India, respect and joint family care can help, though changing family patterns also bring loneliness.
Try it
Interview one family member from another stage. Ask: "What was the biggest challenge at my age?" Then use the age slider in the 3D free-play step to compare stages.
Key formulas and definitions
- Prenatal: germinal (0–2 wk) → embryonic (2–8 wk) → fetal (9 wk–birth)
- Piaget: sensorimotor (0–2) → pre-operational (2–7) → concrete operational (7–11) → formal operational (11+)
- Erikson (adolescence): identity vs role confusion
- Old age: crystallised abilities hold; fluid abilities decline
Worked examples
1. Why is the embryonic period the most sensitive to teratogens?
Because the main organs (heart, brain, limbs) are forming then; harm at this time can cause lasting defects.
2. A 6-month-old stops looking for a toy when it is covered, but a 10-month-old lifts the cloth. Explain.
The older baby has object permanence (knows objects exist out of sight), which develops around 8 months in the sensorimotor stage.
3. A 4-year-old says the moon follows her and her teddy is hungry. Name the features.
Egocentrism (the world centred on her) and animism (believing objects are alive) — pre-operational thinking.
4. A 15-year-old feels everyone at the party noticed his pimple. Which idea explains this?
Imaginary audience, a part of adolescent egocentrism.
5. Suggest three ways a school can help teens avoid substance use.
Life-skills and peer-refusal training, counselling services, and sports or clubs that give healthy belonging and stress relief.
Common mistakes
- Thinking the fetal period is the most sensitive to harm. The embryonic period is.
- Believing reflexes are learned. They are present at birth.
- Treating adolescence only as a "problem age". It is also a time of growth, ideals and identity.
- Saying all abilities fall in old age. Knowledge and wisdom often stay strong or grow.