Biological approach

• 3 assumptions of biological approach

  1. Can only fully understand behaviour if we look to biological structures and processes within the body
  2. our genes , neurochemistry and nervous system are the basis of any psychological process/ behaviour
  3. human behaviour is genetically determined through process of evolution And natural selection
• Difference between genotype and phenotype

  Genotype - individuals genetic make up

  phenotype - the product of what happens once the genotype has interacted with the environment ( Hair colour , height , blood type , eye colour )

  phenotype is the physical manifeststion of an organisms allelic combination (genotype )
• 2 example Of how the genotype has interacted with the environment

  PKU - rare genetic disorder if left unchecked can cause learning difficulties, if detected early enough it can be controlled through diet

  how active you are on weight
• Difference between MZ twins and DZ twins

  MZ - share 100% of their genes

  DZ-share 50% of their genes
• Concordance 


  The presence of the same trait in Both members of a pair of twin
• How do twin studies allow us to see the genetic influence on behaviour

  • if MZ TWINS show a higher likelihood of sharing behaviours /disorders than DZ twins —-> suggests a genetic component
  • this is thought to be because the only difference between the pairs of twins is how genetically similar they are
• 4 biological factors which influence behaviours

  genes , neurochemistry , nervous system and evolution
• Example showing the behaviour of neurotransmitters on our behaviour

  Increased levels of dopamine leading to schizophrenia
• 2 examples of the influence of the nervous system on our behaviours

  • Damage to the limbic system ( emotional centre in brain ) = increased aggression
  • damage to Broca’s area = inability to produce speech
• Example of a behaviour that could become widespread due to evolution

  AGRESSION :

  • agression in our ancestry = more able To gather resources and protect family

  • more likely to survive

  • increased chances of reproduction

  • genetics for aggression passed onto generations

  • aggression becoming more widespread
• What is biological approach

  Personality Is influenced by biological factors e.g genetics and biochemistry