BIOLOGICAL

• biological approach says our behaviour is determined by genetics, neurochemistry and evolution
• the biological approach is the most scientific
• three basic assumptions of the biological approach

  • all behaviour has biological origins
  • genes hormones the NS and evolution explain all behaviour
  • experimental research done on animals can inform us about human behaviour because of biological similarities
• genotype= all the different alleles of genes a person has
• phenotype= how these genes/alleles are expressed
• humans have 46 chromosomes
• Darwins theory of evolution= the theory that all living things are related and have evolved from common ancestors, and that natural selection led to desirable traits being passed on
• Twin studies and adoption studies are useful for research into genetic causes
• twin studies- comparing identical twins (monozygotic) with fraternal twins (dizygotic)
• adoption studies- children who were adopted at birth by parents who had no family history of mental illness compared to those whose adoptive parents did have a family history of mental illness
• adoption studies- looking at adopted children's characteristics compared to their biological parents and adoptive parents
• faulty genes are known to cause diseases with psychological effects such as Huntingtons
• biological psychologists think genetics can explain psychological traits like personality and sexual orientation
• genes are also believed to make us more susceptible to mental illness and addiction
• SZ is studied a lot by biological psychologists
• Gottesman- meta analysis of twin studies

  • meta-analysis of 40 twin studies
  • having an identical twin with SZ gave you a 48% chance of also having SZ- this is 18% with non identical twins
  • shows SZ has a strong genetic basis
• Heston- adoption study on SZ

  • 47 adopted kids whos mothers have SZ
  • Control group of 50 adoptees whos mothers dont have SZ
  • 5/47 became SZ, O/50
  • shows genetic basis for SZ
• before brain scanning tech was developed biological psychologists used case studies
• Phineas gage

  • had a metal pole go through his head
  • lived but his personality change
  • had extensive damage to his frontal lobe- suggesting it is responsible for personality and emotional regulation
• Ways of studying the brain

  • PET scans- shows brain activity
  • CAT scans- shows damaged parts of brain and blood clots/tumours
  • MRI scans- detect small tumours and show structure
  • fMRI scans- show structural and functional info
  • SQUID magnetometry- shows brain activity using magnetic fields
• Maguire- taxi drivers

  • natural experiment
  • compared brains of london taxi drivers to normal drivers
  • london taxi drivers had more grey matter and larger right posterior hippocampus'
  • shows that brain structure is adaptive
• brain structure has been used to investigate lots of behaviours

  • aggression- Bard and Mountcastle found lesions made cats more aggressive
  • memory- Milner did a case study on patient HM had a damaged hippocampus and so had impaired LTM
  • psychopathology- Szeszko found people with SZ had differences in the prefontal cortex
• neurochemistry can also affect behaviour

  • too much or too little of a neurotransmitter can lead to mental illness ie too much dopamine and too little serotonin= OCD