Describe & Evaluate the Nature-nurture Debate in Psychology (16 Marks)


The nature vs. nurture debate within psychology is the extent to which we are a product of biological or genetic innate factors, nature, or if our behaviour is a product of environmental influences. An example of the influence of nature is genetic explanations such as family, twin and adoption studies. These studies show that the closer two individuals are genetically the more likely that both of them will develop the same behaviours, meaning they have higher concordance rates. Research from Nestadt et al suggested that people with a first degree relative with OCD are five-times greater risk of having the illness themselves at some time in their lives, compared to the general population. This greater risk for those with similar genes shows that nature has a major contribution to the disorder. The nurture argument however also has evidence from behaviourism as behaviourists assume that all behaviour can be explained in terms of experience. Skinner used the concepts of classical and operant conditioning to explain learning. 

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Some may argue that nature and nurture cannot be separated as they work together rather than in opposition. This is called an interactionist approach. When asked whether nature or nurture was more important, the psychologist Donald Hebb said that was the same as asking whether the length or width of a rectangle was more important when working out the area of a rectangle. An example of this disorder is the disorder PKU which is an inherited disorder that prevents a certain type of amino acid being metabolised, resulting in brain damage. However, if the condition is detected at birth the infant can be given a diet devoid of the amino acid and brain damage is thus averted. This means that a supposed genetic condition can be prevented due to environmental manipulation and nature and nurture work together and can’t be seperated.

One conceptualisation of the interaction between nature and nurture is  the diathesis-stress model, commonly used to explain mental disorders such as phobias or schizophrenia. A diathesis is a biological predisposition that can be triggered by an environmental stressor to trigger the condition. However, not everyone who is predisposed to developing a disorder, such as being born with certain genes, actually develops the disorder due to the absence of environmental stressors. This means that express of the gene depends on experience thus a person’s nature is only expressed under certain conditions of nurture. 

Furthermore, it is argued that not only nature affects nurture, diathesis stress, but nurture can affect nature in the same way. For example, Macguire et al’s study of London taxi drivers showed that the region of their brains associated with spatial memory was bigger than in controls. This is not because they were born with a larger hippocampus than the controls this is infact due to neural plasticity. Neural plasticity is the brain’s ability to reorganize itself by forming new neural connections throughout life. This shows that their innate brain structure is altered through experience and that nurture affects nature.

Epigenetics refers to the material in each cell of your body that acts like a set of ‘switches’ to turn genes on or off. Life experiences such as stress and nutrition control these switches that are subsequently passed through generations. This can explain why cloning, such as the cloning of CC the kitten, doesn’t produce identical copies. This means that genetics and environment are much less separate than was previously thought.