biological approach

• • everything psychological is at first biological
  • the mind is the brain
  • all thoughts, feelings have a physical basis and rely on the chemical transmission of neurotransmitters
  • we must look to biological structures for explanations
  • neurochemistry is the action of chemicals and neurotransmitters in the brain
  • an imbalance of neurochemicals in the brain has been linked with mental disorders
  • all psychological characteristics have a genetic basis, they are inherited
  • this is tested using twin studies which analyse concordance rates
  • CR: the extent to which twins share the same characteristics
• • genotype: genetic makeup
  • phenotype: way genes are expressed through physical characteristics
  • if a characteristic is genetic we would expect all monozygotic twins to share the same characteristic
  • monozygotic twins share 100% of DNA
  • dizygotic twins share 50% of DNA
  • Charles Darwin proposed theory of evolution and natural selection which says that any genetically determined behaviour that enhances ability to reproduce and survive will continue in successive generations
  • possesser contains traits which are advantageous so they remain the gene pool for successive generations
• • increased understanding of neurochemical processes in the brain is associated with use of psychoactive drugs to treat mental disorders
  • bio approach has promoted treatment of clinical depression using antidepressant drugs that increase level of serotonin at synapses in the brain
  • these are called selective serotonin re-uptake inhibitors
  • people with depression may be able to better manage their condition and live a normal life
  • suggests biological cause is pistol cause
  • increases validity
• • suggests that there is a biological cause that we cannot control
  • if you have abnormalities with serotonin or DA you will develop OCD
  • there is evidence that the way an individual's phenotype is expressed is heavily influenced by environment due to MZ twins
  • suggests criminals have no control over their actions and is the result of a 'crime gene'
  • this undermines our legal system which is centred around criminals being held responsible because they exercised their free will in a harmful way
  • legal justice system is incorrect and we need to change the way we punish criminals
• • uses scientific methods of investigation
  • uses precise, highly objective methods
  • e.g. scanning techniques such as fMRIs and EEGs
  • advances in technology mean we can accurately measure psychological and neural processes
  • objectivity is a feature of science, so adds to psychology being a science
  • increases reliability and validity
• • concordance rates of 68% found between MZ twins and 31% for DZ twins
  • suggests there is a genetic biological predisposition
  • OCD is passed on in human genome and higher % of genes someone shares more likely to get OCD
  • shows there must be a biological basis as MZ twins share 50% more of their genes than DZ twins, so genes must be at least partly responsible
• • however, concordance rates not 100% which we would expect if it was entirely due to genes
  • suggests there must be other explanation
  • perhaps explained by the diathesis-stress model - trigger needed
  • however, MZ twins share the same environment pre and post natal and are treated similarly
  • so maybe shared environment contributes to increased concordance rates
  • almost impossible to separate role of nature and nurture