Discuss the nature-nurture debate in psychology (16 marks)

The nature-nurture debate in psychology concerns the extent to which behaviour is influenced by genetics (nature) or environment and experience (nurture). The nature side supports a nativist view, arguing that abilities and traits are innate, inherited from our biological parents. In contrast, the nurture side is based on empiricist theory, proposing that we are born as a ‘tabula rasa’ (blank slate), and behaviour is shaped by learning and experience. The debate spans many areas of psychology, from intelligence and aggression to mental illness. Increasingly, psychologists adopt an interactionist approach, suggesting that both genes and environment interact to influence behaviour. For example, the diathesis-stress model suggests a genetic predisposition (diathesis) may be triggered by environmental stressors.

A strength of the nature side is that it is supported by evidence from twin and adoption studies. Research has found higher concordance rates for traits like schizophrenia in monozygotic twins than dizygotic twins, even when raised apart. This supports the idea that genetics play a significant role in determining behaviour. However, even in identical twins, concordance rates are not 100%, suggesting that environmental factors also influence the development of psychological disorders.

The nurture side is supported by evidence from learning theories and behaviourist experiments. For example, Bandura’s Bobo Doll study shows that children learn aggression by observing and imitating role models. This demonstrates how behaviour can be acquired through the environment, reinforcing the importance of nurture in shaping individuals. Still, not all children exposed to aggressive role models become aggressive, suggesting that innate temperament or genetic predisposition may mediate the learning process.

A more balanced view comes from the interactionist approach, which recognises the dynamic interplay between genes and environment. The diathesis-stress model explains how a person might inherit a genetic vulnerability for a disorder, but only develop it when exposed to stressors.
This model provides a more comprehensive explanation for behaviour and is supported by real-world applications in mental health treatments.
However, measuring the exact contribution of nature versus nurture is still extremely difficult, making conclusions based on this model hard to test scientifically.

Recent developments in epigenetics provide further support for the interactionist view.
Epigenetics refers to how environmental factors can affect gene expression, meaning that experiences such as trauma or diet can "switch on" or "off" certain genes.
This blurs the line between nature and nurture and suggests that environmental influences can be passed down to future generations.
Although promising, epigenetics is still a developing field, and its findings are complex and not yet fully understood.