Developmental Psychology
Comprehensive study of human development across the lifespan, from conception to death, including cognitive, social, emotional, and moral development theories.
Table of Contents
1. Introduction to Developmental Psychology
Definition and Scope
Developmental psychology is the scientific study of how and why human beings change over the course of their life. Originally concerned with infants and children, it has expanded to include adolescence, adult development, aging, and the entire lifespan.
Key Issues in Development
- Nature vs. Nurture: Heredity (genes) vs. environment (experience)
- Continuity vs. Discontinuity: Gradual change vs. distinct stages
- Stability vs. Change: Whether traits persist or can be modified
- Critical vs. Sensitive Periods: Timing of environmental influences
Research Methods in Development
Cross-Sectional Design
Studies different age groups at same time. Quick but cannot track individual change.
Limitation: Cohort effects
Longitudinal Design
Follows same individuals over time. Shows individual patterns but time-consuming.
Limitation: Attrition, practice effects
Sequential Design
Combines cross-sectional and longitudinal. Studies multiple cohorts over time.
Best of both approaches
Microgenetic Design
Intensive observation during brief period of rapid change. Captures transition mechanisms.
Used for learning studies
Domains of Development
| Domain | Description | Examples |
|---|---|---|
| Physical | Body growth, motor skills, health | Walking, puberty, aging |
| Cognitive | Thinking, learning, memory, language | Problem-solving, reasoning |
| Socioemotional | Relationships, emotions, personality | Attachment, identity, empathy |
| Moral | Ethics, values, right vs. wrong | Justice, fairness concepts |
2. Prenatal Development
Stages of Prenatal Development
Germinal Period (Weeks 1-2)
- • Conception: Sperm fertilizes ovum → Zygote
- • Cell division begins (mitosis)
- • Zygote travels to uterus, implants in uterine wall
- • Blastocyst forms (inner cell mass becomes embryo)
Embryonic Period (Weeks 3-8)
- • Most critical period - major organs form
- • Three layers develop: Ectoderm (skin, nervous system), Mesoderm (muscles, bones), Endoderm (digestive, respiratory)
- • Heart begins beating (week 4)
- • Highly vulnerable to teratogens
Fetal Period (Weeks 9-40)
- • Rapid growth and organ maturation
- • Week 12: Sex distinguishable
- • Week 20: "Quickening" - mother feels movement
- • Week 24-28: Age of viability (can survive outside womb)
- • Week 28+: Rapid brain development, fat accumulation
Teratogens
Teratogens are environmental agents that can cause birth defects. Effects depend on timing, dosage, and genetic susceptibility.
Major Teratogens
- • Alcohol: FAS (Fetal Alcohol Syndrome)
- • Tobacco: Low birth weight, SIDS risk
- • Drugs: Cocaine, heroin, certain medications
- • Diseases: Rubella, HIV, Zika virus
- • Radiation: X-rays, nuclear exposure
Fetal Alcohol Syndrome (FAS)
- • Facial abnormalities (thin upper lip, smooth philtrum)
- • Growth deficiencies
- • CNS dysfunction
- • Intellectual disability
- • Leading preventable cause of mental retardation
Newborn Assessment: APGAR Score
Taken at 1 and 5 minutes after birth (scored 0-2 each):
- Appearance (skin color)
- Pulse (heart rate)
- Grimace (reflex irritability)
- Activity (muscle tone)
- Respiration (breathing)
Score 7-10 = Normal; 4-6 = Moderately depressed; 0-3 = Severely depressed
3. Piaget's Cognitive Development Theory
Jean Piaget (1896-1980)
Swiss psychologist who proposed that children actively construct their understanding through interaction with the environment. Children are "little scientists" who build mental structures called schemas.
Key Concepts
Schema
Mental framework for organizing information
Assimilation
Fitting new information into existing schemas
Accommodation
Modifying schemas to fit new information
Equilibration
Balance between assimilation and accommodation
Four Stages of Cognitive Development
1. Sensorimotor Stage (Birth - 2 years)
Key Development: Object Permanence
- • Learns through senses and motor actions
- • Object permanence develops (~8 months) - understanding objects exist even when not seen
- • Begins symbolic thought at end of stage
- • Substages: Reflexes → Primary circular reactions → Secondary circular reactions → Coordination → Tertiary circular reactions → Mental representation
A-not-B error: Infant searches for object where it was previously hidden, not where they saw it moved
2. Preoperational Stage (2 - 7 years)
Key Development: Symbolic Function
- • Language development, pretend play, drawing
- • Egocentrism: Cannot take others' perspective (Three Mountains Task)
- • Centration: Focus on one aspect, ignore others
- • Animism: Believes inanimate objects are alive
- • Lack of conservation: Cannot understand quantity remains same despite appearance change
Cannot mentally reverse operations (irreversibility)
3. Concrete Operational Stage (7 - 11 years)
Key Development: Logical Operations
- • Conservation: Understands quantity unchanged despite appearance
- • Reversibility: Can mentally reverse actions
- • Decentration: Can consider multiple aspects
- • Classification: Groups objects by multiple criteria
- • Seriation: Arranges objects in order (size, number)
Logic limited to concrete, tangible objects; cannot think abstractly yet
4. Formal Operational Stage (11+ years)
Key Development: Abstract Thinking
- • Hypothetical-deductive reasoning: Can form and test hypotheses
- • Abstract thought: Can think about ideas, possibilities
- • Propositional thought: Evaluate logic of verbal statements
- • Metacognition: Thinking about thinking
- • Adolescent egocentrism: Imaginary audience, personal fable
Not all adults reach formal operations; depends on education and culture
Criticisms of Piaget
- • Underestimated children's abilities (infants show earlier competence)
- • Overemphasized stages; development more continuous
- • Neglected social and cultural influences
- • Formal operations not universal
- • Neo-Piagetian theories propose domain-specific development
4. Vygotsky's Sociocultural Theory
Lev Vygotsky (1896-1934)
Russian psychologist who emphasized the role of social interaction andculture in cognitive development. Learning occurs through interaction with more knowledgeable others (MKO).
Key Concepts
Zone of Proximal Development (ZPD)
The gap between what a learner can do independently and what they can achieve with guidance from a more skilled person.
Scaffolding
Temporary support provided by a more knowledgeable person that is gradually removed as the learner becomes more competent. Like training wheels on a bicycle.
- • Hints, prompts, modeling, feedback
- • Adjusts to learner's current level
- • Fades as competence increases
Private Speech
Children talk to themselves to guide their behavior and thinking. Becomes internalized as inner speech (thought) in adulthood.
- • Social speech → Private speech → Inner speech
- • Increases during challenging tasks
- • Piaget called it "egocentric speech" and saw it as immature
Cultural Tools
Psychological and technical tools passed down through culture that shape thinking.
- • Language: Most important psychological tool
- • Writing systems: Extend memory and communication
- • Number systems: Enable mathematical thinking
- • Technology: Computers, calculators
Piaget vs. Vygotsky Comparison
| Aspect | Piaget | Vygotsky |
|---|---|---|
| View of Child | Independent scientist | Social apprentice |
| Role of Language | Result of cognitive development | Driver of cognitive development |
| Social Interaction | Secondary role | Primary role |
| Development | Universal stages | Culture-specific |
| Teaching | Discovery learning | Guided participation |
5. Erikson's Psychosocial Development
Erik Erikson (1902-1994)
Neo-Freudian who proposed 8 stages of psychosocial development spanning the entire lifespan. Each stage presents a crisis (turning point) that must be resolved. Positive resolution leads to virtue; negative resolution leads to maladaptation.
The Eight Stages
1. Trust vs. Mistrust
Infancy (0-1 year)
Infant develops trust when caregivers provide reliable care, affection, and warmth. Mistrust develops if needs are unmet. Foundation for all future relationships.
2. Autonomy vs. Shame & Doubt
Toddlerhood (1-3 years)
Child develops independence through walking, talking, toilet training. Over-control or criticism leads to shame and doubt about abilities.
3. Initiative vs. Guilt
Early Childhood (3-6 years)
Child initiates activities, makes up games, leads. Excessive criticism of initiative leads to guilt. Corresponds to Freud's Oedipal stage.
4. Industry vs. Inferiority
Middle Childhood (6-12 years)
Child learns skills valued by society (reading, writing). Success brings sense of competence; failure leads to feelings of inferiority. School is primary arena.
5. Identity vs. Role Confusion
Adolescence (12-18 years)
Adolescent explores identity: "Who am I?" Successful resolution leads to strong sense of self. Failure leads to identity confusion. Identity crisis is normal.
6. Intimacy vs. Isolation
Young Adulthood (18-40 years)
Young adult forms intimate relationships, deep friendships. Failure leads to loneliness and isolation. Requires secure identity first.
7. Generativity vs. Stagnation
Middle Adulthood (40-65 years)
Adult contributes to society through work, raising children, community involvement. Failure leads to self-absorption and stagnation. "Midlife crisis" may occur.
8. Ego Integrity vs. Despair
Late Adulthood (65+ years)
Older adult reflects on life. Acceptance brings integrity and wisdom; regret brings despair and fear of death. Life review is important process.
6. Kohlberg's Moral Development
Lawrence Kohlberg (1927-1987)
Extended Piaget's work on moral development. Used moral dilemmas (especially the Heinz Dilemma) to study moral reasoning. Focused on how people reason, notwhat decisions they make.
The Heinz Dilemma
Heinz's wife is dying of cancer. A druggist has a cure but charges $2,000 (10x what it costs to make). Heinz can only raise $1,000. The druggist refuses to sell cheaper or let him pay later. Should Heinz steal the drug?
Three Levels of Moral Reasoning
Level 1: Preconventional Morality
Self-focused; morality based on consequences to self
Stage 1: Punishment-Obedience Orientation
Avoid punishment. "Will I get in trouble?"
Heinz: "He shouldn't steal because he'll go to jail."
Stage 2: Instrumental Relativist Orientation
Self-interest, exchange. "What's in it for me?"
Heinz: "He should steal it because he needs his wife."
Level 2: Conventional Morality
Society-focused; conformity to social norms and laws
Stage 3: "Good Boy-Good Girl" Orientation
Approval of others. "Will people like me?"
Heinz: "He should steal it because a good husband takes care of his wife."
Stage 4: Law and Order Orientation
Maintain social order. "What do the rules say?"
Heinz: "He shouldn't steal because laws must be followed to maintain order."
Level 3: Postconventional Morality
Principled; universal ethical principles above laws
Stage 5: Social Contract Orientation
Laws are social contracts; can be changed democratically
Heinz: "The right to life is more important than property rights."
Stage 6: Universal Ethical Principles
Abstract principles of justice, equality, human dignity
Heinz: "Human life has unconditional value that transcends any law."
Criticisms of Kohlberg
- • Carol Gilligan: Male-biased; women emphasize care, relationships, not abstract justice
- • Cultural bias: Individualistic Western values; collectivist cultures may differ
- • Moral reasoning vs. behavior: Knowing right doesn't ensure doing right
- • Stage 6 rare: Few people consistently reach post-conventional
Gilligan's Ethics of Care
Carol Gilligan proposed that women develop moral reasoning differently, emphasizingrelationships, responsibility, and care rather than abstract justice.
- • Level 1: Self-survival
- • Level 2: Self-sacrifice (caring for others)
- • Level 3: Care for self AND others (nonviolence)
7. Attachment Theory
John Bowlby (1907-1990)
British psychiatrist who proposed that early attachment to caregivers is essential for healthy development. Attachment is an evolutionary adaptation - infants are biologically predisposed to form attachments for survival.
Bowlby's Key Concepts
Internal Working Model
Mental representation of self, others, and relationships based on early experiences
Monotropy
Primary attachment to one figure (usually mother); hierarchy of attachments
Critical Period
First 2-3 years crucial for attachment; sensitive period up to age 5
Maternal Deprivation Hypothesis
Separation from mother leads to cognitive, social, emotional problems
Mary Ainsworth's Strange Situation
Laboratory procedure (1970s) to assess infant attachment quality. Observes infant's behavior during separation and reunion with caregiver.
Secure Attachment (Type B)
(60-65% of infants)
- • Uses caregiver as secure base for exploration
- • Distressed when caregiver leaves
- • Easily comforted upon reunion
- • Caregiver: Responsive, sensitive, consistent
Insecure-Avoidant (Type A)
(20-25% of infants)
- • Little distress when caregiver leaves
- • Ignores or avoids caregiver upon reunion
- • Does not prefer caregiver over stranger
- • Caregiver: Rejecting, unresponsive to needs
Insecure-Ambivalent/Resistant (Type C)
(10-15% of infants)
- • Very distressed when caregiver leaves
- • Ambivalent at reunion (seeks contact but resists)
- • Difficult to comfort
- • Caregiver: Inconsistent, sometimes responsive
Disorganized-Disoriented (Type D)
(Added by Main & Solomon, 1986)
- • Confused, contradictory behaviors
- • May freeze, show fear of caregiver
- • Most concerning pattern
- • Associated with abuse, trauma, parental mental illness
Adult Attachment Styles (Hazan & Shaver)
Early attachment patterns continue into adult romantic relationships:
- • Secure: Comfortable with intimacy, trusting
- • Avoidant (Dismissive): Uncomfortable with closeness, values independence
- • Anxious (Preoccupied): Fears abandonment, clingy, jealous
- • Fearful-Avoidant: Desires closeness but fears rejection
8. Adult Development & Aging
Young Adulthood (18-40)
- • Physical peak: Mid-20s; gradual decline begins 30s
- • Cognitive: Postformal thought (pragmatic, relativistic thinking)
- • Levinson's Seasons: Early adult transition (17-22), entering adult world (22-28), age 30 transition, settling down (33-40)
- • Tasks: Career establishment, intimate relationships, starting family
Middle Adulthood (40-65)
- • Physical changes: Menopause (women), vision/hearing decline, slower metabolism
- • Cognitive: Crystallized intelligence stable; fluid intelligence may decline
- • Midlife crisis: Not universal; more often a "midlife transition"
- • Empty nest: Children leave home (often positive)
- • Sandwich generation: Caring for children and aging parents
- • Generativity: Concern for guiding next generation
Late Adulthood (65+)
- • Physical: Sensory decline, slower reaction time, chronic conditions
- • Cognitive: Processing speed declines; wisdom may increase
- • Dementia: Not normal aging; Alzheimer's most common cause
- • Retirement: Major life transition; adjustment varies
- • Widowhood: Common; women more often than men
Theories of Successful Aging
Disengagement Theory
(Cumming & Henry) Gradual withdrawal from society is natural and beneficial. Criticized as too passive.
Activity Theory
(Havighurst) Staying active and engaged leads to life satisfaction. Replace lost roles with new activities.
Socioemotional Selectivity
(Carstensen) Older adults prioritize emotionally meaningful goals and relationships. Positivity effect.
Death and Dying
Kübler-Ross Stages of Grief (DABDA)
Not linear; people may skip stages or move back and forth:
- 1. Denial: "This can't be happening"
- 2. Anger: "Why me? It's not fair"
- 3. Bargaining: "If only I had..."
- 4. Depression: Sadness, regret
- 5. Acceptance: Coming to terms
Note: Modern research suggests grief is more individual and does not follow set stages.
Key Takeaways for the Board Exam
Piaget's Stages (Memorize!)
- • Sensorimotor: Object permanence
- • Preoperational: Egocentrism, no conservation
- • Concrete: Conservation, reversibility
- • Formal: Abstract, hypothetical thinking
Erikson's 8 Stages (Memorize!)
- • Trust, Autonomy, Initiative, Industry
- • Identity, Intimacy, Generativity, Integrity
- • Know ages and virtues for each
Kohlberg's Levels
- • Preconventional: Self-interest
- • Conventional: Social norms, law
- • Postconventional: Universal principles
Attachment Types
- • Secure (B): Best outcomes
- • Avoidant (A): Ignores caregiver
- • Ambivalent (C): Clingy, distressed
- • Disorganized (D): Confused, fearful
Psychology Notes
- Major Psychological Theories
- Psychological Assessment
- Abnormal Psychology
- → Developmental Psychology
- Research Methods & Statistics
Exam Tips
- • Piaget and Erikson stages are heavily tested
- • Know the age ranges for each stage
- • Understand key concepts like ZPD, scaffolding
- • Distinguish between theorists' approaches