Nature nurture debate

• Interactionist approach

  It is not really a debate about one or the other because any behaviour/characteristic arises from a combination of both - even something as simple as eye colour is not completely determined by your genes colour is about .80 heritable .

  Bowlby - attachment type comes from parental love, kagan - baby innate personality affects attachment type so nature and nurture interact

  this approach discusses how nature and nurture interact
• Diathesis stress model 


  Suggests behaviour caused by biological or environmental vulnerability which is only expressed when coupled with a biological or environmental trigger (stressor)

  For example - person who inherits a genetic vulnerability for OCD may not develop the disorder but combined with a psycholigcal trigger it may result in the disorder appearing
• Epigenetics 


  Refers to change in genetic activity without changing the genes themselves - process that happens throughout life and is caused by interaction with the environment. Aspects of our lifestyle or events we encounter (eg smoking) leave marks on our DNA which switch genes on or off - explains why factors such as smoking have a lifelong influence even after you actually stop - changed way your genes will be expressed -

  These may influence the genetic codes of our children as well

  introduces a third element into nature nurture debate - the life experience of previous generations.
• Measuring nature and nurture

  Degree in which two people are similar on particular trait can be represented by correlation coefficient and called concordance- provides estimate about extent to which trait is inherited - called heritability

  heritability - proportion of differences between individuals in a population with regards to particular trait - due to genetic variation

  .01 - genes contribute almost nothing to individual differences

  1.0 -means genes are only reason for individual differences.

  General figure for heritability in IQ is .5
• Adoption studies 


  Useful bc seperate competing influences of nature and nurture

  Meta analysis on adoption studies found genetic influences accounted for 41% of variance in agression

  --> research can seperate the influences of nature and nurture
• s: support for epigenetics 


  1944 nazis blocked the distribution of food to the Dutch people and 22,000 died of starvation, reported that women who became pregnant during the famine went on to have low birth weight babies - these babies twice as likley to develop schizophrenia

  --> supports that life experience of previous generations can leave epigenetic markers that influence the health of their offspring.
• S: Real world application

  Research suggests OCD is a highly heritable mental disorder, .76, such understanding can inform genetic counselling bc important to understand high heritability does not mean it is inevitable that indivudal will develop disorder - so ppl w high genetic vulnerablity can get advice on how to prevent disorder developing.

  --> not just aa theoretic debate, it's important at a practical level