AO3 - Hemispheric Lateralisation

• • Split-brain research used to support the idea of lateralisation was well controlled.
  • This means the methodology can be praised for using highly standardised procedures conducted in a controlled environment to control possible confounding variables.
  • This is positive as it ensured the research measured what it intended to - giving the evidence high internal validity.


  AO3 - Split brain research
• • Flawed.
  • Findings came from a very unusual and limited sample of people who were not well matched to a control group.


  AO3 - Split brain research
• • Some participants may have felt more disconnection of the two hemispheres than others as part of their surgery.


  AO3 - Split brain research
• • The control group consisted of participants with no history of epilepsy, making them poorly matched.
  • Problematic as it brings the conclusions of the research and support for lateralisation into doubt.


  AO3 - Split brain research
• Gazzaniga (1998)

  • Reported on the case of JW who developed the ability to speak out of the right hemisphere. He can now speak about information presented to either side of the brain.
  • Problem as it disconfirms the conclusion that the right hemisphere cannot handle language.


  AO3 - Split brain research
• Szflarski (2006)

  • Language became more lateralised as children developed into adolescents.
  • After the age of 25, lateralisation decreased with each decade of life.
  • Problem because it suggests it is a much more complex process than many realise - with many questions remaining as to why this happens.


  AO3 - Lateralisation
• • Differences in functions may be overstated.
  • split-brain research has given rise to the belief that functions are distinct between left and right hemispheres of the brain.
  • Modern neuroscientists would argue that it is much messier due to the constant communication between both hemispheres when performing everyday tasks.
  • Suggests lateralisation is much more complex and more research is needed to fully understand it.


  AO3 - Lateralisation