Nature-Nurture

• Nature

  • behaviour coming from 'within' - internal biological processes
  • often referred to as innate characteristics that are unchangeable
  • heredity - the genetic transmission of mental and physical characteristics
  • acknowledge that maturation plays a role - some characteristics may only appear after a person has matured
  • sexual behaviour - after pubity
  • genes provide the blueprint for all behaviours
  • some of these behaviours are present at birth
  • some are 'pre-programmed' to emerge with age
• Nuture

  • causes of behaviour come from the environment
  • include: education, upbringing, social pressure, culture and conditioning
  • must be some sort of external stimulation to create behaviour
• Importance of heredity and environment

  • general figure for heritability is a correlation coefficient of 0.5 NOT 100% (suggest the environment is also important)
  • nature and nurture are so closely intertwined, it's difficult to separate the two factors e.g. in twin studies it is difficult to tell whether concordance rates are more a result of shared genetics or shared (very similar) upbringing
• The interactionist approach

  • suggest nature and nurture work together to shape human behaviour
  • e.g. the diathesis-stress model
  • suggest mental disorders are caused by a genetic vulnerability like a genetic variation which is triggered by a stressor in the environment such divorce
• The extremes can be dangerous

  • practical applications = extreme views on either side of the debate that can be dangerous
  • position of the legal system on responsibility
  • a purely nativist view that the all behaviour and actions are innate does not align with the legal system
  • suggests that people cannot control their behaviour, that their genes make them more likely to act a certain way
  • this would make individuals very difficult to prosecute
  • may also have implications for 'validating' historical eugenics - breeding out undesirable behaviours
• Difficult to separate the contribution of nature and nurture from each other

  • in twins that share 100% DNA, they are very likely to have had very similar upbringing, so it is hard to separate the influences of nature vs nurture
  • individual differences will mean that twins will still experience life events differently for example who they are friends with
  • epigenetics has shown that nurture can influence nature by altering gene expression through environmental factors
  • can explain why MZ twins do not always look exactly the same and why they do not have 100% concordance rates
  • reinforcing the idea that nature and nurture are not separate, validating the interactionist approach in psychology
• Evidence for genotype x environment interacting

  • Tienari - child-rearing style characterised by high levels of criticism and conflict and low levels of empathy was implicated in the development of schizophrenia, but mostly for children with a high genetic risk
  • Caspi - children with low MAOA were more likely to grow up to exhibit antisocial behaviour, only if they had been maltreated, suggesting an interaction between genes and the environment
  • suggests a more complex relationship between nature and nurture, perhaps an interactionist explanation is more able to explain these processes