8.2 Typical and Atypical Development Across the Lifespan

Key Takeaways

  • Erikson's eight stages map a lifespan arc of psychosocial tasks from trust vs. mistrust (infancy) to integrity vs. despair (older adulthood); each stage produces a virtue (hope, will, purpose, competence, identity, intimacy, care, wisdom).
  • Piaget's four cognitive stages (sensorimotor, preoperational, concrete operational, formal operational) and Bowlby/Ainsworth's attachment styles (secure, anxious/ambivalent, avoidant, disorganized) define typical and atypical cognitive and relational development.
  • Attachment styles observed in childhood correspond to adult attachment styles (secure, anxious-preoccupied, dismissive-avoidant, fearful-avoidant) that shape therapeutic engagement and assessment of relationship functioning.
  • Aging assessment attends to cognitive changes, grief and loss accumulation, role transitions, and elder-specific risk; racial, ethnic, cultural, and spiritual-faith development, body image, and technology/social media exposure are assessment factors across the lifespan.
  • Atypical development is flagged by deviation from expected milestones, regressions, or task failure (e.g., failure to form intimate relationships in young adulthood, despair in late life) and requires assessment of biological, psychological, social, and cultural contributors.
Last updated: August 2026

Assessment requires a developmental baseline: you cannot judge a behavior atypical unless you know what is typical for the client's life stage. The ASWB Clinical exam expects fluency with the major developmental frameworks and the ability to apply them to vignettes across the lifespan.

Erikson's Eight Psychosocial Stages

Erik Erikson described eight stages, each defined by a crisis whose resolution yields a virtue. Failure at one stage biases later stages but does not lock development in place.

StageAgeCrisisVirtueAtypical indicator
1Infancy (0–1)Trust vs. mistrustHopeWithdrawal, feeding disruption, failure to seek comfort
2Toddler (1–3)Autonomy vs. shame/doubtWillExtreme self-doubt, compulsive compliance
3Preschool (3–6)Initiative vs. guiltPurposeInitiation avoided, excessive guilt
4School age (6–12)Industry vs. inferiorityCompetenceSchool refusal, learned helplessness
5Adolescence (12–18)Identity vs. role confusionIdentity/FidelityForeclosed or diffuse identity, extreme conformity
6Young adult (18–40)Intimacy vs. isolationLoveIsolation, chronic shallow relationships
7Middle adult (40–65)Generativity vs. stagnationCareStagnation, self-absorption
8Older adult (65+)Integrity vs. despairWisdomDespair, bitterness, death fear

Piaget's Cognitive Stages

Jean Piaget mapped four cognitive stages. Knowing them lets you assess whether a child's thinking is age-appropriate and calibrate explanations accordingly.

  • Sensorimotor (0–2): Object permanence develops; thinking is sensory and motor. Atypical: no stranger anxiety, no object permanence by ~12 months.
  • Preoperational (2–7): Symbolic thought, egocentrism, magical thinking. Atypical: no symbolic play, persistent egocentrism beyond expected.
  • Concrete operational (7–11): Conservation, classification, logical thought about concrete objects. Atypical: failure of conservation by ~8.
  • Formal operational (11+): Abstract, hypothetical reasoning. Atypical: cannot reason hypothetically by adolescence.

Attachment: Bowlby, Ainsworth, and Adult Styles

John Bowlby theorized attachment as a biologically based behavioral system; Mary Ainsworth's Strange Situation classified infant attachment into styles later extended to adulthood.

Child styleStrange Situation behaviorAdult correlate
SecureDistressed at separation, comforted by reunion, returns to playSecure — comfortable with intimacy and autonomy
Anxious/ambivalentDistressed, hard to soothe at reunion, clingyAnxious-preoccupied — preoccupied with relationships, fears abandonment
AvoidantMinimal distress, ignores caregiver at reunionDismissive-avoidant — devalues intimacy, emphasizes self-reliance
DisorganizedContradictory, freezing, apprehensionFearful-avoidant — wants but fears closeness; often trauma history

Disorganized attachment is strongly associated with maltreatment, parental fright, and unresolved trauma and is the highest-risk style for later psychopathology. Adult attachment styles shape the therapeutic alliance: an anxious-preoccupied client may idealize and cling; a dismissive client may minimize distress; a fearful client may approach and withdraw.

Mahler's Separation-Individuation

Margaret Mahler described how the infant differentates from the primary caregiver: autistic (0–2 months) → symbiotic (2–6 months) → separation-individuation (6–24+ months), subphases including differentiation, practicing, rapprochement, and object constancy. Failure here underlies later borderline and narcissistic dynamics and informs assessment of object-relations functioning.

Lifespan Milestones and Aging

  • Infancy/early childhood — Motor, language, social milestones; attachment formation. Atypical: speech delay, regression, failed attachment.
  • School age — Peer relationships, academic identity, industry. Atypical: school refusal, bullying dynamics, learning difficulties.
  • Adolescence — Identity formation, peer orientation, risk-taking, sexual development. Atypical: identity foreclosure/diffusion, self-harm, eating disorders.
  • Young adulthood — Intimacy, partnership, career launch. Atypical: isolation, role transition failure.
  • Middle adulthood — Generativity (parenting, mentoring, work), caregiving for parents. Atypical: stagnation, midlife crisis, sandwich-generation stress.
  • Older adulthood — Cognitive changes (slower processing, preserved crystallized intelligence), grief and loss accumulation, role transition (retirement, widowhood), elder risk. Integrity vs. despair is the central task; despair, bitterness, and death anxiety signal trouble.

Cultural, Spiritual, Body-Image, and Technology Factors

Assessment must include racial, ethnic, cultural, and spiritual-faith development. James Fowler described faith stages (primal, mythic-literal, synthetic-conventional, individuative-reflective, conjunctive, universalizing) paralleling cognitive development; assessing a client's faith stage clarifies how they make meaning of suffering and treatment. Racial and ethnic identity models (Cross, Helms) describe stages from pre-encounter to internalization and inform assessment of identity-related distress and strengths.

Self- and body-image develop across the lifespan — adolescent body image, postpartum body image, aging-related body image, and body image in chronic illness are all assessment targets. Technology and social media influence development beginning in childhood: adolescent identity formation, social comparison, cyberbullying, online grooming risk, and adult loneliness and information overload are all factors the contemporary assessment should ask about.

Atypical Development: When to Investigate

Atypical development is signaled by regression (loss of previously acquired skills), persistent deviation from milestones, failure of the stage's virtue to emerge, or symptoms disproportionate to context. Each warrants assessment of biological contributors (medical, genetic, substance exposure), psychological contributors (trauma, defense, cognition), and social contributors (attachment, family, school, culture). The ASWB exam favors answers that investigate all four domains before concluding a single cause.

Erikson's eight stages ordered across the lifespan (stage number)
Test Your Knowledge

A 19-year-old client reports chronic shallow relationships, a history of being bullied in adolescence, and identifying completely with a peer group whose values he cannot articulate. Using Erikson's framework, which developmental task has he most clearly failed to resolve, and what is the prior unresolved crisis?

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Test Your Knowledge

A 14-month-old, observed in Ainsworth's Strange Situation, shows contradictory behaviors — freezing, then approaching the caregiver with averted gaze, then retreating — and the caregiver has an unresolved trauma history. Which attachment classification, and what is its strongest developmental correlate?

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B
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D