Developmental Psychology

Human development across the lifespan: how we change from birth to death.

Core Questions

• How do nature and nurture interact?
• Is development continuous or stage-based?
• What's consistent across the lifespan?
• What can change and when?

Prenatal Development

Stages

Teratogens

Harmful influences on prenatal development:

• Alcohol (fetal alcohol syndrome)
• Drugs (prescription and recreational)
• Infections (rubella, HIV)
• Environmental toxins
• Maternal stress

Infancy (0-2 years)

Physical Development

• Brain triples in size
• Motor development (rolling → sitting → crawling → walking)
• Sensory systems mature

Cognitive Development

Piaget's Sensorimotor Stage:

• Learning through senses and action
• Object permanence develops (~8 months)
• Beginning of symbolic thought

Social-Emotional Development

Attachment (Bowlby/Ainsworth):

What creates secure attachment:

• Responsive caregiving
• Consistent availability
• Sensitivity to needs
• Warmth and affection

Long-term effects: Childhood attachment patterns are associated with later relationship styles, but the link is modest and not deterministic. Attachment styles can and do change with new experiences, therapy, and corrective relationships.

Early Childhood (2-6 years)

Cognitive Development

Piaget's Preoperational Stage:

• Symbolic thinking (language, pretend play)
• Egocentrism (difficulty taking others' perspective)
• Animism (attributing life to objects)
• Centration (focusing on one aspect)

Theory of Mind: Understanding that others have different thoughts, beliefs, knowledge (~4 years)

Language Explosion

Social-Emotional Development

• Self-concept emerges
• Gender identity develops
• Play becomes social
• Emotional regulation improves
• Conscience begins forming

Middle Childhood (6-12 years)

Cognitive Development

Piaget's Concrete Operational Stage:

• Logical thinking about concrete objects
• Conservation (quantity remains despite appearance change)
• Classification and seriation
• Decreased egocentrism

Social Development

• Peer relationships become central
• Social comparison increases
• Industry vs. inferiority (Erikson)
• Moral reasoning develops
• Self-esteem more realistic

School and Learning

• Formal education shapes development
• Learning disabilities may become apparent
• Work habits form
• Academic self-concept develops

Adolescence (12-18 years)

Physical Development

Puberty:

• Hormonal changes
• Growth spurt
• Sexual maturation
• Brain development (prefrontal cortex not complete until ~25)

Cognitive Development

Piaget's Formal Operational Stage:

• Abstract thinking
• Hypothetical reasoning
• Systematic problem-solving

Adolescent egocentrism:

• Imaginary audience (everyone's watching)
• Personal fable (I'm special/invulnerable)

Identity Development

Erikson's Identity vs. Role Confusion:

Identity exploration in:

• Occupation
• Values and beliefs
• Relationships
• Sexuality
• Politics

Social Changes

• Peer influence peaks
• Parent-child conflict increases
• Risk-taking increases
• Emotional intensity
• Need for autonomy

Early Adulthood (18-40 years)

Physical Peak and Decline

• Peak physical abilities (mid-20s)
• Slow decline begins (30s)
• Health habits matter more

Cognitive Development

• Expertise develops in chosen domains
• Practical intelligence grows
• May develop more relativistic thinking

Social-Emotional Development

Erikson's Intimacy vs. Isolation:

• Forming close relationships
• Career establishment
• Identity refinement

Major tasks:

• Choosing career
• Forming partnerships
• Starting family (often)
• Establishing independence

Middle Adulthood (40-65 years)

Physical Changes

• Visible aging begins
• Menopause (women)
• Decreased strength, sensory acuity
• Chronic disease risk increases

Cognitive Changes

• Fluid intelligence declines
• Crystallized intelligence stable/growing
• Expertise compensates for decline
• Wisdom may develop

Psychosocial Development

Erikson's Generativity vs. Stagnation:

• Contributing to next generation
• Career mastery or reinvention
• Caring for aging parents
• Empty nest transition

Midlife transition (not necessarily crisis):

• Time perspective shifts
• Priority reassessment
• Mortality awareness
• Search for meaning

Late Adulthood (65+ years)

Physical Changes

• Continued decline (variable rate)
• Increased disease risk
• Sensory loss
• Changes in sleep

Cognitive Changes

Normal aging:

• Slower processing
• Working memory decline
• Some memory difficulties
• Wisdom and knowledge preserved

Pathological aging:

• Dementia (not normal aging)
• Alzheimer's disease
• Significant functional impairment

Psychosocial Development

Erikson's Integrity vs. Despair:

• Life review
• Accepting one's life
• Coming to terms with mortality
• Wisdom

Successful aging:

• Maintaining engagement
• Adapting to limitations
• Sustaining relationships
• Finding meaning

Death and Dying

Kübler-Ross stages (not linear, not universal):

1. Denial
2. Anger
3. Bargaining
4. Depression
5. Acceptance

Development Across the Lifespan

What Stays Stable

• Temperament/personality traits
• Intelligence (relative to peers)
• Attachment style (unless addressed)
• Some values and interests

What Changes

• Knowledge and skills
• Perspective and wisdom
• Priorities and goals
• Specific behaviors
• Coping strategies

Key Influences on Development

Practical Applications

Parenting Implications

• Secure attachment is foundational
• Responsive caregiving matters most
• Age-appropriate expectations
• Consistency and warmth
• Support autonomy with boundaries

Understanding Yourself

• Your attachment history affects relationships
• Earlier challenges may explain current patterns
• Development continues, change is possible
• Middle adulthood is for generativity
• Late life is for integration and wisdom

Working with Different Ages