A01

• State the three assumptions of the 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 the process of evolution and natural selection
• Explain the difference between genotype and phenotype

  Genotype is an individual's genetic make-up whereas phenotype is the product of what happens once the genotype has interacted with the enviroment
• Give two examples of how the genotype has interacted with the environment

  1. PKU - rare genetic disorder if left unchecked can cause learning difficulties but if detected early enough can be controlled through diet

  2. How active someone is -> fluctuations in weight
• Explain the difference between MZ twins and DZ twins


  MZ twins share 100% of their genes, whereas DZ twins share 50% of their genes
• Define concordance

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

  - If MZ twins show a higher likelihood of sharing behaviour/ disorders than DZ twins -> suggests a genetic component

  - This is thought to be because the only difference between the two pairs of twins is how genetically similar they are
• State four biological factors which influence behaviour

  Genes, neurochemistry, nervous system and evolution
• What is an example showing the influence of neurotransmitters on our behaviour?

  Increased levels of dopamine leading to schizophrenia
• Give two examples of the influence of the nervous system on our behaviour

  1. Damage to the limbic system (emotional centre in brain) -> increases aggression

  2. Damage to Broca's area -> inability to produce speech
• What is an example of a behaviour that could have become widespread due to evolution?

  Agression (MAO-A gene):

  1. Aggression in our ancestry - more able to gather resources and protect family = more likely to survive

  2. Increased chances of reproduction

  3. Genetics for aggression passed on through generations

  4. Aggression becoming more widespread