How do cognitive, emotional and moral capacities develop across the lifespan?
Explain theories of development including Piaget's cognitive stages, attachment, and Erikson's psychosocial stages, with reference to nature and nurture.
A focused answer to the WACE Year 12 Psychology Unit 4 dot point on developmental psychology. Covers Piaget's stages of cognitive development, attachment theory (Bowlby and Ainsworth), Erikson's psychosocial stages, and the nature versus nurture debate with named research.
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What this dot point is asking
This Unit 4 dot point asks you to describe how thinking, relationships and identity develop across the lifespan and to apply the nature-nurture framework.
Piaget's cognitive development
Jean Piaget proposed that children construct understanding through schemas (mental frameworks), modified by assimilation (fitting new information into existing schemas) and accommodation (changing schemas to fit new information). He described four stages:
- Sensorimotor (0 to 2 years): learning through senses and movement; the key achievement is object permanence (knowing objects exist when out of sight).
- Preoperational (2 to 7 years): symbolic thought and language, but egocentrism (difficulty taking another's view) and a lack of conservation (not understanding that quantity stays the same despite changes in appearance).
- Concrete operational (7 to 11 years): logical thinking about concrete objects; conservation is achieved.
- Formal operational (11+ years): abstract and hypothetical reasoning.
Attachment (Bowlby and Ainsworth)
John Bowlby proposed that infants form an attachment to a primary caregiver that is biologically adaptive and provides a secure base. He argued for a critical (sensitive) period for forming attachments and that disruption could have lasting effects (his maternal deprivation hypothesis).
Mary Ainsworth's Strange Situation procedure classified infant attachment styles:
- Secure: distressed at separation, comforted on reunion, uses the caregiver as a base.
- Insecure-avoidant: little distress at separation, avoids the caregiver on reunion.
- Insecure-resistant (ambivalent): very distressed, but hard to soothe and resists contact on reunion.
Harry Harlow's monkey studies showed infant monkeys preferred a soft cloth "mother" over a wire one that provided food, indicating attachment is driven by contact comfort, not just feeding.
Erikson's psychosocial stages
Erik Erikson described eight stages across the lifespan, each centred on a psychosocial crisis to be resolved.
Other stages include trust versus mistrust (infancy), autonomy versus shame and doubt, initiative versus guilt, industry versus inferiority, intimacy versus isolation (young adulthood), generativity versus stagnation, and integrity versus despair (late adulthood).
Nature versus nurture
The nature position emphasises heredity, genes and maturation; the nurture position emphasises environment, learning and experience. The modern consensus is interaction: development arises from genes and environment together. Twin and adoption studies, especially comparing identical (monozygotic) and fraternal (dizygotic) twins, are the main method for estimating the relative contribution of each, because identical twins share all their genes.
In the exam, name the theorist, the stage or style, and link it to observable behaviour, then close development questions with the interactionist view of nature and nurture.
Exam-style practice questions
Practice questions written in the style of SCSA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WACE 20226 marksDescribe Piaget's four stages of cognitive development, naming the age range and one defining achievement or limitation of each stage.Show worked answer →
A 6 mark response needs all four stages with an age range and a defining feature.
- Sensorimotor (0 to 2 years)
- Learning through senses and movement; the key achievement is object permanence, knowing objects exist when out of sight.
- Preoperational (2 to 7 years)
- Symbolic thought and language, but egocentrism and a lack of conservation.
- Concrete operational (7 to 11 years)
- Logical thinking about concrete objects; conservation is achieved.
- Formal operational (11+ years)
- Abstract and hypothetical reasoning.
Markers reward each stage paired with the correct age range and a defining ability or limitation, without mismatching abilities to stages.
WACE 20238 marksExplain how the nature-nurture interaction shapes development, and discuss how twin and adoption studies help estimate the contributions of heredity and environment.Show worked answer →
An 8 mark extended response needs the interactionist view plus the research method.
- Nature and nurture
- Nature refers to genetic and biological influences; nurture refers to environment, learning and experience. The modern consensus is interaction: genes set a range of possibilities and the environment determines where within that range a person develops, and people partly shape their own environments.
- Twin studies
- 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 strengthen this, while their differences highlight the environment.
- Adoption studies
- Comparing adopted children with both biological and adoptive parents separates shared genes from shared environment.
- Conclusion
- Markers reward the interactionist framing, the logic of comparing twin types, and the conclusion that most traits reflect both genes and environment rather than either alone.