interactionist approach

• Interactionist approach


  The idea that nature & nurture are linked to such extent that is doesn't make sense to separate the two, so researchers instead study how they interact & influence each other.
• How does PKU support the interactionist position?

  Nurture element -> Causes brain damage if given protein - diet. If child is diagnosed, then can be given a special diet & no brain damage occurs. The NHS tests very child at birth. Nature elements -> Inherited condition (2 recessive genes). Can't break down amino acids in food.
• How does epi-genetics support the interactionist position?

  Epi-genetics refers to changes in our genetic activity without changing our own genetic code caused by environmental factors. Aspects of our lifestyle & the events we encounter from smoking, diets or stressful life events, eg. terrorist attacks can leave epigenetic marks on our DNA. These may impact on the turning on & off of certain genes which may even go onto influence the genetic code of our offspring.
• Dias - interactionist approach

  Mice were conditioned to fear a perfume smell due to being given electric shocks, however this caused the same fear in their offspring without any conditioning at all. They were even born with more cherry-blossom- detecting neurons in their noses & more brain space devoted to cherry-blossom-smelling. This experience has altered the genetic activity
• Groothest - interactionist approach

  Meta-analysis of 28 studies. Higher concordance rates for OCD for MZ twins. Concordance rate not 100% so suggests there must be some environmental influence as well. Biological predisposition -> low serotonin levels, leaky basal ganglia Environmental factor -> stress
• Meaney - interactionist approach

  Studies licking & grooming behaviour of rats towards pups
• Meaney's study


  1. Divided pups into high or low licking group

  2. Pups in the high licking condition were less likely to be affected by stress

  3. The licking, changed the expression of genes, protecting the pups from stress when they were older
• It is difficult to directly correlate these results to human behaviour
• Looking at autopsy reports of people who have died via suicide & looking at their reported life histories


  Meaney has found a correlation between early abuse & increased methylation (a process that influences gene expression)
• This suggests that early experiences in humans does effect gene expression in adult life similar to the licking & grooming behaviour experiment
• Interactionist summary


  Mix of nature & nurture, eg. genotype & phenotype & epi-genetics. Supported by the cognitive approach, phenotypes, epi-genetics & the diathesis-stress model to help explain schizophrenia.