How does personality develop across the lifespan, and how do nature and nurture interact in development?
Describe Erikson's psychosocial stages of development and explain the nature-nurture interaction, including evidence from twin studies
WACE Year 12 Psychology Unit 4: Erikson's eight psychosocial stages and their crises, the nature-nurture debate, gene-environment interaction, and evidence from twin and adoption studies.
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What this dot point is asking
SCSA asks you to outline Erikson's lifespan stages and their crises, define the nature-nurture debate, and explain how twin and adoption studies reveal the interaction of heredity and environment. The marked skill is recognising the relevant stage and arguing for interaction rather than one side.
Erikson's psychosocial stages
Erik Erikson proposed that development continues across the whole lifespan, not just childhood, and that at each stage the person faces a psychosocial crisis between two outcomes. Resolving each crisis well builds a healthy personality; failing to resolve it causes lasting difficulty.
The eight stages and their central crises are:
- Trust versus mistrust (infancy): learning that the world is dependable.
- Autonomy versus shame and doubt (toddlerhood): developing independence.
- Initiative versus guilt (early childhood): asserting control and purpose.
- Industry versus inferiority (school age): developing competence.
- Identity versus role confusion (adolescence): forming a sense of self.
- Intimacy versus isolation (young adulthood): forming close relationships.
- Generativity versus stagnation (middle adulthood): contributing to the next generation.
- Integrity versus despair (late adulthood): reflecting on a life well lived.
The adolescent stage, identity versus role confusion, is especially examinable: teenagers experiment with roles and values to form a stable identity, and failure leads to confusion about who they are.
The nature-nurture debate
The nature-nurture debate concerns the relative contributions of heredity and environment to behaviour and development.
- Nature refers to genetic and biological influences inherited from our parents.
- Nurture refers to environmental influences such as upbringing, culture, learning and experience.
The modern view is interactionist: nature and nurture continually interact. Genes set a range of possibilities, while the environment determines where within that range a person develops. Gene-environment interaction means that the effect of a gene can depend on the environment, and that people partly shape their own environments.
Evidence from twin and adoption studies
Twin and adoption studies are the main tools for separating genetic from environmental influences.
- Identical (monozygotic) twins share all their genes; fraternal (dizygotic) twins share about half. If identical twins are more alike on a trait than fraternal twins, that points to a genetic contribution.
- Twins reared apart who still resemble each other strongly suggest a genetic influence, while differences between them highlight the environment.
- Adoption studies compare adopted children with both their biological and adoptive parents, separating shared genes from shared environment.
These studies consistently show that most psychological traits, such as intelligence and personality, are influenced by both genes and environment, with neither fully determining the outcome.
Why this matters
Erikson extends development across the whole lifespan and frames identity formation in adolescence, a key concern for Year 12 students. The nature-nurture interaction underlies all developmental and individual-difference psychology and cautions against simplistic claims that a behaviour is purely genetic or purely learned.