Developmental Themes and Methods — AP Psychology Notes

Aspects That Tend to Show STABILITY:

• Temperament: Basic emotional reactivity patterns established early in life
• Core personality traits: Five-factor model traits (openness, conscientiousness, extraversion, agreeableness, neuroticism)
• Intelligence: Relative ranking on cognitive abilities tends to remain stable
• Attachment patterns: Early relationship styles often persist

Areas That Typically Show CHANGE:

• Physical abilities: Strength, speed, sensory acuity change with age
• Cognitive skills: Knowledge, expertise, wisdom accumulate over time
• Social roles: Student → employee → parent → retiree
• Emotional regulation: Ability to manage emotions typically improves
• Attitudes and beliefs: Often shift with experiences and maturity

NATURE (Biological/Genetic Influences):

• Heredity: Traits passed from parents through genes
• Maturation: Biologically programmed sequences of growth (walking, puberty)
• Temperament: Innate personality tendencies
• Physical characteristics: Height potential, eye color, predispositions
• Brain structure: Neural organization and development patterns

NURTURE (Environmental/Experiential Influences):

• Parenting and family dynamics: Caregiving styles and relationships
• Culture and society: Values, norms, expectations
• Education and learning: Formal and informal instruction
• Nutrition and healthcare: Physical environment quality
• Life experiences: Trauma, enrichment, opportunities

Modern Understanding: Interaction Model

Contemporary accounts treat genes, environments and the developing person as interacting over time. Nutrition can influence growth, while education and experience affect cognitive performance. An individual’s exact genetic “potential range” is not directly known, and development is not a fixed genetic blueprint with environment merely choosing one point on it.

CONTINUOUS Development (Gradual Change)

Development is a smooth, ongoing process like climbing a ramp — changes are quantitative (more of the same).

Characteristics:

• Gradual, incremental changes over time
• No clear boundaries between developmental phases
• Skills build upon each other steadily
• Differences are matters of degree, not kind

Examples: Height/weight growth, vocabulary expansion, gradual improvement in motor skills

DISCONTINUOUS Development (Stage-Like Change)

Development occurs in distinct stages like climbing stairs — changes are qualitative (different kinds of thinking/behavior).

Characteristics:

• Development occurs in distinct, identifiable stages
• Each stage has unique characteristics and capabilities
• Transitions between stages are relatively abrupt
• Earlier stages provide foundation for later ones
• In a strict stage theory, stages are proposed to follow an ordered sequence; real performance can be uneven and task-dependent

Examples: Piaget's cognitive stages (sensorimotor → preoperational → concrete operational → formal operational), Erikson's psychosocial stages, Kohlberg's moral development stages

How It Works:

Researchers study multiple age groups (e.g., 20-year-olds, 40-year-olds, and 60-year-olds) all at the same time and compare their performance on various measures.

Example: Testing memory in groups of participants aged 20, 40, 60, and 80 years old — all tested in 2025.

ADVANTAGES:

• Quick results: Data collected at one time point
• Cost-effective: Less expensive than longitudinal studies
• Large sample sizes: Easier to recruit many participants
• No attrition: Participants don't drop out over time
• No practice effects: Participants only tested once
• Useful for: Identifying age differences and patterns

DISADVANTAGES:

• Cohort effects (MAJOR LIMITATION): Differences between age groups may reflect generational experiences rather than true developmental changes
• Cannot track individual change: Only shows group differences, not how individuals develop
• No causal inferences about development: Can't determine if aging causes differences
• Doesn't show stability vs. change over time

How It Works:

Researchers recruit a group of participants and test them multiple times over months, years, or even decades as they age.

Example: Testing the same group of people at ages 20, 30, 40, 50, and 60 to track how their memory changes over 40 years.

ADVANTAGES:

• Tracks true individual change: Shows how the same people develop over time
• Follows change within one cohort, but age and historical period can remain confounded; generalization to other cohorts requires evidence.
• Reveals patterns of stability vs. change: Best for determining which traits persist vs. shift
• Establishes temporal ordering of measured events, but an observational longitudinal design does not by itself prove that an earlier experience caused a later outcome.
• Rich, detailed data: Deep understanding of developmental trajectories
• Tests continuous vs. discontinuous development: Can identify gradual changes or stage-like shifts

DISADVANTAGES:

• Time-consuming: Takes years or decades to complete
• Very expensive: Requires long-term funding and resources
• Attrition (dropout): Participants move away, lose interest, or die before study completion
• Practice effects: Repeated testing may improve performance artificially
• Outdated measures: Tests designed at study start may become obsolete
• Limited to one cohort: Results may not generalize to other generations

How It Works:

Researchers recruit several age cohorts and follow each group over time, then compare both within-group changes and between-group differences.

Example: Recruit 20-, 30-, and 40-year-olds in 2025, then test all three groups again in 2030 (when they're 25, 35, and 45) and in 2035 (when they're 30, 40, and 50).

ADVANTAGES:

• Reduces cohort effects: Multiple cohorts allow comparison across generations
• Faster than pure longitudinal: Don't have to wait entire lifespan
• Tracks individual change: Still follows people over time
• More comprehensive: Combines strengths of both methods