biological approach

• what are the key assumptions of the biological approach (AO1)?


  • believes that all thoughts, feelings, and behaviours have a biological basis.
  • suggests that an understanding of brain structure and function can explain human thoughts and behaviour, as the mind lives within the brain.
  • believes behaviour can be inherited as it is determined by genetic information that is passed on from one generation to the next.
• the role of neurotransmitters:

  • biological psychologists also recognise the role of chemicals in determining behaviour.
  • at the synapse, signals are sent between neurons by chemicals called neurotransmitters.
  • imbalances in the number of neurotransmitters are associated with atypical behaviour, e.g. too little serotonin has been associated with depression and too much dopamine with schizophrenia.
• the role of biological structures:

  • biological psychologists believe that the structure of organs, such as the brain, CNS, PNS, and the endocrine system determine our behaviour.
  • the CNS transmits neurons (messages), e.g. feeling hungry and breathing.
  • research has shown that the different lobes of the brain are linked with general functions, e.g. occipital lobe is linked with visual perception, and the parietal lobe is linked with the processing of sensory information.
  • a case study involving the different lobes of the brain would be Phineas Gage.
• What are twin studies used for?

  To determine genetic basis of traits
• How do twin studies determine the genetic basis of traits?

  By comparing concordance rates between twins
• What does a higher concordance rate in identical twins (MZ) compared to non-identical twins (DZ) suggest?

  It suggests a genetic basis for traits
• What percentage of genes do identical twins (MZ) share?

  100%
• What did McGuffin (1996) find regarding identical twins and depression?

  If one twin has depression, the other may too
• What does McGuffin's finding suggest about illnesses like schizophrenia and depression?

  There is a genetic component to these illnesses
• what are the strengths of the biological approach (AO3)?


  • scientific credibility - the approach is grounded in vigourous scientific methods, such as brain imaging, genetic analysis, and neurochemical studies.
  • real-world applications - led to important medical advancements, e.g. antidepressants.
  • nature focus - importance of genetics and evolution theory (Darwin)
• what are the limitations of the biological approach (AO3)?


  • reductionist - approach often reduces behaviours that are complex to simple biological mechanisms, ignoring social, environmental, and psychological influences.
  • deterministic - it implies that behaviour is pre-determined by biological factors, minimising the role of free will.
  • over-simplification of mental disorders.