Is behaviour the product of nature or nurture?
The nature-nurture debate: the relative importance of heredity and environment in determining behaviour; the interactionist approach.
Covers AQA 4.8 the nature-nurture debate: heredity versus environment, the concept of heritability, the interactionist approach and concepts like diathesis-stress and epigenetics.
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What this dot point is asking
AQA wants you to explain the nature-nurture debate, the interactionist approach and related concepts such as diathesis-stress and epigenetics. The exam skill is to present evidence for both sides, to interpret heritability correctly, and to argue that the modern resolution is interactionist.
Nature, nurture and heritability
The nature side, traditionally associated with nativists, holds that behaviour is the product of innate biological factors: genes, hormones and brain structures. Evidence comes largely from twin and family studies, where a higher concordance rate for a trait in identical (MZ) twins than in non-identical (DZ) twins points to a genetic contribution. The nurture side, associated with empiricists and the behaviourist approach, holds that the mind is a blank slate at birth and that all behaviour is learned from the environment through conditioning and experience. Psychologists try to quantify the relative contribution using heritability, a statistic expressing the proportion of the variation in a characteristic across a population that can be attributed to genetic factors (for example, IQ heritability is often estimated at around 0.76). The crucial point about heritability, and a common exam trap, is that it refers to variation within a population, not to an individual: a heritability of 0.76 does not mean 76% of one person's intelligence is genetic.
The interactionist approach
The modern consensus is that the question "nature or nurture?" is badly posed, because the two are so tightly intertwined that they cannot be cleanly separated. Even twin studies cannot fully isolate genes, since identical twins also tend to share very similar environments, and the fact that MZ concordance is rarely 100% shows the environment must contribute. The interactionist approach therefore reframes the debate as a question of how nature and nurture interact. Two concepts make this concrete. The diathesis-stress model proposes that a person inherits a genetic vulnerability (the diathesis) but only develops a disorder such as schizophrenia if exposed to an environmental trigger (the stress), so neither factor alone is sufficient. Epigenetics goes further, showing that life experiences (such as diet, trauma or pollution) can switch genes on or off without altering the underlying DNA sequence, and that these epigenetic changes can even be passed to later generations, so the environment can shape how genes are expressed. The conclusion examiners reward is that behaviour is the product of an inseparable interaction of nature and nurture.
Exam-style practice questions
Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AQA 20194 marksExplain what is meant by the interactionist approach to the nature-nurture debate. Use an example.Show worked answer →
A 4-mark item (about 2 AO1, 2 AO2). Markers want the idea that nature and nurture combine, plus an example.
The interactionist approach argues that nature and nurture are so closely intertwined that it makes little sense to try to separate them; behaviour is the product of both working together. Rather than asking how much of a behaviour is genetic and how much environmental, it asks how the two interact.
Example: the diathesis-stress model of schizophrenia proposes that a person inherits a genetic vulnerability (the diathesis, nature) but only develops the disorder if exposed to an environmental trigger such as stress or cannabis use (nurture). A full-mark answer states that nature and nurture interact and cannot be meaningfully separated, and applies this to a concrete example such as diathesis-stress.
AQA 20216 marksDiscuss the nature-nurture debate in psychology.Show worked answer →
A 6-mark item, roughly 3 AO1 and 3 AO3.
Outline: the nature view holds that behaviour is inherited (genes, biology), evidenced by twin studies showing higher concordance for identical twins. The nurture view holds that behaviour is learned from the environment, as in the behaviourist account. Heritability estimates (such as around 0.76 for IQ) try to quantify the genetic contribution to variation in a population.
Discussion: a key point is that nature and nurture are difficult to separate, since twins also share environments, so concordance below 100% shows the environment matters. The modern resolution is interactionism, including the diathesis-stress model (genetic vulnerability triggered by environmental stress) and epigenetics (experiences switching genes on or off, even across generations). A balanced answer concludes the debate is best framed as how nature and nurture interact, not which one dominates. Markers reward evidence for both sides plus an interactionist conclusion.
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Sources & how we know this
- AQA A-level Psychology (7182) specification — AQA (2015)