Key Takeaways — Chapter 14: Psychological Development Across the Lifespan
The Essential Insights
1. Development is lifelong — not a process that ends in childhood. Psychological development — the ongoing reorganization of how the person perceives, relates, regulates, and constructs meaning — continues through adulthood and into old age. The tasks of each stage are genuine, requiring genuine work. The brain retains plasticity throughout life.
2. Early experience matters significantly without determining outcomes. Attachment security, adverse childhood experiences, and early cognitive and social environment all create risk and protective factors that shape developmental trajectories. But resilience is common, protective factors moderate outcomes substantially, and later experience — therapy, relationships, sustained environmental change — can modify patterns established in childhood.
3. Development has tasks — knowing yours provides orientation. Erikson's eight psychosocial stages provide a map of the developmental challenges that recur across the lifespan. Industry vs. Inferiority in middle childhood, Identity vs. Role Confusion in adolescence, Intimacy vs. Isolation in young adulthood, Generativity vs. Stagnation in midlife, and Ego Integrity vs. Despair in late life — each stage has a core conflict that is not resolved once and left behind, but worked on in ways that shape the developmental resources available at subsequent stages.
4. Identity formation is not a once-and-done process completed in adolescence. Marcia's identity statuses (diffusion, foreclosure, moratorium, achievement) apply across the lifespan. Adults revisit identity questions when life circumstances change significantly. A midcareer moratorium at 34, or a relational re-examination at 50, is developmentally appropriate — not pathological instability.
5. The developing brain produces an adolescent vulnerability to social evaluation. The developmental mismatch between limbic maturation and prefrontal development explains many of adolescence's characteristic features: risk-taking, emotional intensity, peer sensitivity. This is adaptive (the organism is preparing to leave the family) but collides with social environments that penalize its consequences.
6. Emerging adulthood is a distinct developmental period for many young people. Arnett's description — identity exploration, instability, self-focus, feeling in-between, sense of possibilities — names a developmental reality for many people in their late teens and twenties. It is more available in contexts that provide extended education and economic buffering, but the developmental tasks are real regardless of the timeline.
7. Subjective wellbeing tends to rise in later life. The U-shaped curve of life satisfaction — declining through the thirties and forties, rising in later life — and the positivity effect in emotional experience both indicate that later life is not a period of inevitable psychological decline. SST (Socioemotional Selectivity Theory) explains this through the motivational shift that accompanies a limited time horizon: depth over breadth, meaning over novelty.
8. Quality of relationships is the most powerful predictor of wellbeing across the lifespan. The Grant Study's central finding — that the quality of relationships in midlife predicts late-life wellbeing more reliably than financial success, childhood experience, or physical health — holds across the breadth of longitudinal research. Development happens in relational context; relationships are both its medium and its product.
Key Terms
| Term | Definition |
|---|---|
| Developmental plasticity | The capacity of the organism to change in response to experience — present throughout the lifespan, though variable in degree |
| Normative development | Developmental changes shared by virtually everyone in a culture or historical period |
| Non-normative development | Developmental changes driven by individual circumstances not shared by most people |
| History-graded development | Developmental changes shaped by the historical period and cohort |
| Internal working models | Bowlby's unconscious representations of relational reliability and self-worth, established in early attachment |
| Attachment patterns | Ainsworth: secure, anxious-preoccupied, avoidant, disorganized — organized responses to caregiver availability |
| Piaget's stages | Sensorimotor, Preoperational, Concrete Operational, Formal Operational — qualitative stages of cognitive development |
| Accommodation vs. assimilation | Piaget: accommodation = changing schemas; assimilation = applying existing schemas |
| Erikson's psychosocial stages | Eight stage-conflicts from Trust vs. Mistrust through Ego Integrity vs. Despair |
| Generativity | Erikson Stage 7: concern for establishing and guiding the next generation; investment in what will outlast oneself |
| Ego integrity | Erikson Stage 8: capacity to accept one's life as it actually was — without demanding it had been different |
| Identity moratorium | Marcia: active exploration without commitment; the most productive identity status when not indefinitely extended |
| Emerging adulthood | Arnett: the distinct developmental period (roughly 18–25) characterized by exploration, instability, self-focus, and possibility |
| Socioemotional Selectivity Theory (SST) | Carstensen: perceived time horizon organizes motivation; limited time → shift toward emotional meaning and relationship depth |
| Positivity effect | Older adults' tendency to attend more to positive stimuli and experience more positive emotions than younger adults |
| U-shaped curve of life satisfaction | The finding that life satisfaction declines through middle adulthood, reaches a nadir, and rises in later life |
| ACEs (Adverse Childhood Experiences) | Felitti et al.: early adversity in dose-response relationship with adult health outcomes |
| Maturity principle | Roberts et al.: normative ↑C, ↑A, ↓N across adulthood |
| Socialized mind | Kegan: self constituted primarily by external expectations and relational definitions |
| Self-authoring mind | Kegan: self uses internalized value system to evaluate and organize experience, including external expectations |
| Grant Study | Harvard Study of Adult Development; found quality of relationships in midlife is strongest predictor of late-life wellbeing |
Three Things to Do This Week
-
Identify your developmental task: Based on your current stage and Erikson's framework, write one sentence about the central developmental task you are working on. Is the work active or avoided? What would active engagement look like?
-
One early experience, traced forward: Choose one pattern in your current adult life — relational, professional, emotional — that you can trace back to an early developmental experience. Write one paragraph tracing the thread from its origin to its current expression. Note that tracing is not excusing — it is understanding.
-
The relationship inventory: Identify the three relationships in your current life that you most want to deepen or sustain over the next decade. For each, name one specific thing you would do to invest in that relationship this week — not a grand gesture, but something real.
Questions to Carry Forward
- Am I engaging with the developmental task of my current stage, or avoiding it? What would engagement actually look like?
- What early experiences shaped my default relational patterns — and where in my current life do those patterns still operate, serving me or costing me?
- What is the quality of the most important relationships in my current life? Am I the kind of person who is genuinely available to others — and genuinely available to being known by them?
- What am I becoming? Not what I intend — what does the evidence of my actual behavior and choices show?