Issues And Debates

Discuss the nature-nurture debate in Psychology. Refer to at least two topics you have studied in your answer (16)

The nature-nurture debate refers to the extent to which aspects of behaviour are caused by innate and heredity influences (nature) or are the result of learning/environmental influences (nurture). Heredity refers to the genetic transmission of mental and physical characteristics from one generation to another, for example intelligence.

The nature argument suggests that individuals are born with set abilities and characteristics, which can be influenced by brain chemicals and genetics on behaviour either at birth or as an individual matures. Aspects of behaviour, such as personality, intelligence, abnormality are caused by innate and heredity factors.

The nurture argument suggests that individuals are a product of environmental factors and their interaction with the environment. Therefore, individuals abilities and characteristics, e.g. personality, intelligence, abnormality, are determined by their experiences.

Evidence to support the influence of nature includes the neural explanation of aggression. This proposes that normal levels of serotonin in the orbitofrontal cortex (OFC) are linked with reduced firing of neurons and this is associated with a greater degree of behavioural self-control. Decreased serotonin may well disturb this mechanism, reducing self-control and leading to an increase in impulsive behaviour including aggression. Furthermore, research has found that levels of serotonin are significantly lower in violent impulsive offenders compared to violent non-impulsive offenders, suggesting that serotonin plays a role in impulse control, offering a biological, nature explanation of aggression.

Further evidence to support the influence of nature includes the genetic explanation of schizophrenia, which sees schizophrenia as transmitted through hereditary means, i.e. through the genes passed on to individuals from their families. It is not believed that there is a single schizophrenic gene , but that several genes are involved (it is therefore polygenic), which increase an individual s overall vulnerability to developing the disorder. Research has indicated as many as 108 separate genetic variations to be associated with increased risk/vulnerability of schizophrenia. Genes associated with increased risk include those genes linked with the functioning of a number of neurotransmitters including dopamine.

Evidence to support the influence of nurture comes from research into schizophrenia and the schizophrenogenic mother. Fromm-Reichmann (1948) noted that many of her patients spoke of a particular type of parent, which she called the schizophrenogenic mother. The schizophrenogenic mother is cold, rejecting and controlling, and tends to create a family climate characterised by tension and secrecy. This leads to distrust that later develops into paranoid delusions, and ultimately schizophrenia. Furthermore, research has shown that schizophrenia is linked to expressed emotion in the environment, in particular negative emotion, expressed towards a patient by their carers. This includes verbal criticism of the patient, hostility towards the patient and emotional over-involvement in the life of the patient. These high levels of expressed emotion in carers directed towards the patient are a serious source of stress and this is an explanation for the relapse in patients with schizophrenia.

However, it can be argued that an interactionist approach to explaining behaviour is a better explanation as this accounts for both nature and nurture influences. For example, the diathesis-stress model has been put forward as an interactionist approach to explaining schizophrenia. The model would explain schizophrenia as the result of both an underlying genetic vulnerability (diathesis) and a psychological trigger (stress). This underlying vulnerability could be genetics and the psychological trigger could be the presence of a schizophrenogenic mother, thus combining a biological and a psychological explanation of schizophrenia. It can be argued that this is a more convincing explanation of the disorder.

In conclusion, it can be argued that the extent to which behaviour is affected by nature and nurture influences depends entirely on the behaviour in question. For instance, it could be said that schizophrenia is more affected by genetics than environmental factors, whereas aggression is more affected by environmental factors, e.g. social learning, than biological influences.