BIOLOGICAL APPROACH

• Biological approach


  Emphasises the importance of physical processes in the body such as genetic inheritance and neural (brain) function
• All our thoughts, feelings and behaviours have a physical basis
• Key assumptions of biological approach


  • Neurochemistry
  • Genetic basis of behaviour
  • Evolution and behaviour
• Neurochemistry


  The action of the chemicals in the brain. Much of our thought and behaviour relies on chemical transmission in the brain via chemicals called neurotransmitters. An imbalance in the brain has been implicated as a possible cause of mental illness
• Neurochemical basis of depression


  • Low levels of serotonin and/or dopamine
• Genes


  Make up chromosomes and consist of DNA - inherited from parents
• Monozygotic twins

  Identical twins
• Dizygotic twins

  Non-identical twins
• Concordance rates


  The extent to which both twins share the same characteristics
• Genotype


  A person's genetic make-up
• Phenotype


  The expression of the genes through physical, behavioural, and psychological characteristics - influenced by environmental factors
• Behavioural geneticists study whether behavioural characteristics such as intelligence, personality and mental disorders are inherited in the same way as eye colour, hair colour etc.
• Twin studies

  Compare concordance rates between pairs of twins to see if certain traits have a genetic basis
• If monozygotic (MZ) twins share more of the same traits e.g. for OCD than dizygotic (DZ) twins, this would suggest a genetic basis
• Phenylketonuria (PKU)

  • A genetic disorder that causes severe learning difficulties in those carrying the genotype. If detected early a person can have a restricted diet (phenotype) and will develop normally
• Evolution


  The changes in inherited characteristics in a biological population over successive generations
• Natural selection

  Any genetically determined behaviour that enhances survival and reproduction will be passed down to future generations
• Evolution


  • Ape to human
  • Short necked giraffes to long necked giraffes to reach the tallest trees
• Strengths of biological approach


  • Uses scientific, precise, and highly objective methods of investigation
  • Real world application - use of psychoactive drugs to treat mental disorders
• Weaknesses of biological approach


  • Biological determinism - sees human behaviour as determined by internal and genetic causes over which we have no control
  • Family members have similar genes, but this could be due to similar environmental conditions not just genetics
• Evolution cannot be proved or falsified as it is not observable but only inferred
• The basic principles of evolution can be supported by the evidence of fossil records