Describe and evaluate the nature-nurture debate in psychology. (16 marks)
Nature refers to behaviour being seen as a product of innate (biological or genetic) factors and nurture suggests that behaviour is a product if environmental influences. The nature-nurture debate is the argument as to whether a person’s development is mainly due to their genes or to environmental influences. It is an accepted view that the two processes are inextricably entwined, the idea that the processes work together rather than in opposition is known as the interactionist approach. The interdependence of nature and nurture makes adaptive sense because it ensures that by responding to the environment an individual makes the best use of their innate qualities. The influence of nature can be seen in genetic explanations such as twin studies which show that the closer two people are genetically the more likely it is they will develop the same behaviours. For example, Raine (1993) reviewed research on delinquent behaviour in twins and found a 52% concordance rate for MZ twins (identical genes) compared to 21% for DZ twins (on average share 50% of genes).
The higher concordance for those with the same genes suggests nature is a significant contributor to delinquent behaviour. The influence of nature can also be seen in evolutionary explanations, if behaviour is adaptive genes for this behaviour will be passed on to subsequent generations. For example, Bowlby proposed attachment is adaptive because it means infants are more likely to be protected and therefore survive. This means attachment behaviours are naturally selected, which can only be done through genetic mechanisms. The influence of nurture can be seen in behaviourism. For instance, behaviourists suggested attachment could be explained in terms of classical conditioning, food is the mother who feeds the baby, and operant conditioning, food is rewarding because it reduces discomfort. Nurture is also prominent in social learning theory, Bandura suggested behaviour is acquired through learning, he acknowledged the urge for aggression can be biological but said the way a person learns to express anger is acquired through environmental influences.
When evaluating the nature-nurture debate it is important to consider how the principles of nature and nurture can be applied in psychology and the importance of an interactionist approach. When judging the nature-nurture debate it is important to consider that nurture affects nature. Your life experiences can shape your biology as seen with neural plasticity, Maguire et al.’s (2000) study of London taxi drivers showed how your environment can affect your biology. They found that the region of their brains associated with spatial memory was bigger than in controls, the taxi drivers were not born with larger hippocampi, but their hippocampi had responded to increased use. Another example of how nurture can affect nature is Blakemore and Cooper’s (1970) study. New-born kittens were given large collars restricting what they could see and raised in a circular drum where they could only see either vertical or horizontal lines. When introduced to the real world they could no longer see lines of the opposite orientation, their innate visual system had been altered through experience. These examples clearly demonstrate how nurture can affect nature and highlights the importance of an interactionist approach.
One way to understand the relationship between nature and nurture is the diathesis-stress model. The model proposes that behaviour is a result of interaction between genetic vulnerability and environmental stressors. A diathesis is a biological vulnerability, such as being born with certain genes that predispose a person to developing a disorder. However, research has shown not everyone with those genes does develop the disorder. The expression of genes depends on experience in the form of a stressor which triggers the condition. It is often used to explain mental disorders such as OCD, for example the COMT and SERT gene has been implicated in OCD, but some people may possess these genes but not develop OCD due to a lack of a stressor. This illustrates how in certain cases a person’s nature is only expressed under certain conditions of nurture. This emphasises the importance of taking an interactionist approach. This is key because the interactionist approach has led to the development of theories which have helped to improve our understanding and treatment of many physical and psychological illnesses.