The nature-nurture debate

• The nature-nurture debate centres on whether behavioural characteristics are inherited or learned. The nature view is that all behaviour is innate (we are born with it). They believe that behavioural characteristics are just like physical characteristics; they are genetically inherited from parents (biological approach).
•  The nurture view is that we are born as a blank slate and learn all of our behaviour from the environment (learning approach). This begins from the moment of conception and includes the environment of the mother's womb. Most psychologists do not take an extreme position on this debate.
•  The interactionist approach believes that behaviour is best explained by a combination of genes and the environment and exploring how they interact with each other to determine behaviour (this should remind you of phenotype).
• One example of the nature and nurture debate is in the topic of schizophrenia. Twin studies support the nature side of the argument. MZ twins share 100% of their genes, whereas DZ twins share 50%. If concordance rates for schizophrenia (likelihood of sharing characteristics) are higher in MZ twins than DZ twins this suggests a genetic component for schizophrenia. Gottesman found the concordance rates to be 48% for MZ twins in comparison to 17% for DZ twins.
•  This suggests that there is a contribution of genes to schizophrenia. However, the concordance rates are not 100% so schizophrenia cannot purely be genetic and environmental factors must contribute. One alternative explanation is family dysfunction when schizophrenia may be caused by high levels of expressed emotion in the home or contradictory messages are received from parents when the schizophrenic child is growing up. This therefore suggests that nurture is also involved in the development of schizophrenia and best explained from an interactionist viewpoint.
• Another example of the nature and nurture debate is in the topic of OCD. Researchers have linked specific genes, such as the 5HT1-D-beta gene (which lowers serotonin ) to OCD. This suggests the development of OCD may be innate. However, not all individuals with the 5H1-D-beta gene develop OCD suggesting the environment, and therefore nurture, play a part.
•  The interactionist model may best explain behaviour here as it takes into account both nature and nurture. Someone may have a genetic vulnerability to developing OCD (nature) but the disorder only manifests in certain environmental conditions (nurture). For example, a person may have the gene and be burgled after leaving a door unlocked and this leads to worries and compulsions about checking locks.
• This means the experiences in the environment ultimately act as a 'stressor' which triggers the development of the disorder.

  Without this negative experience the individual would not develop OCD. This highlights the importance of an interactionist approach using both nature and nurture to explain human behaviour.
• The nature-nurture debate has real world implications. Extreme beliefs in the influence of nature can have negative implications for how we view behaviour; If we believe that genes determine behaviour then in order to manage undesired behaviour it may be suggested that we look at sterilisation and other controversial methods to eliminate these genes out of the gene pool.
• On the other hand, a nurture perspective is more positive as it suggests if a behaviour is learned from the environment it can be unlearned. This notion lends itself to therapies based on operant conditioning, where desirable behaviour can be encouraged with rewards and undesirable behaviour can be discouraged with punishment.
• A limitation of the nature-nurture debate is that it is impossible to separate the two factors.

  Plomin's theory about niche-picking suggests that people create their own 'nurture' by actively selecting environments that are appropriate for their 'nurture'. Thus, a naturally aggressive child is likely to feel more comfortable around children who show similar behaviours and will 'choose' their environment accordingly. This environment then effects their development.