Lateralisation & split-brain research

• Split-brain research:

  • Sperry & Gazzaniga
  • Split brain patient would fixate on a dot in the centre of the screen while stimuli was presented to the left or right visual field
  • If a picture flashed on the right visual field, they’d be able to say what it was as it would be processed in the left hemisphere
  • Stimuli presented in the right hemisphere wouldn’t produce a verbal response
  • Conclusion: left hemisphere is responsible for speech & language, the right specialises in visual-spatial processing
• Hemispheric lateralisation:

  • The specialization of mental processes to either the left or right hemisphere
  • Left hemisphere is responsible for language whereas the right specializes in visual- motor tasks
  • Corpus callosum - a bundle of nerve fibres connecting the two hemispheres
  • The corpus callosum is cut in a treatment for severe epilepsy to prevent seizures from spreading between the two hemispheres
• Split brain research AO3:

  • ✅ Scientific methodology - highly controlled lab experiments, presented stimuli to one visual field at a time - high internal validity
  • ❌ Limitations of split-brain research - studies have very few pts & many confounding variables - lacks generalisability
• Hemispheric Lateralisation AO3:

  • ✅ Research support from Split-brain research - findings show that left hemisphere is responsible for language & right is spatial & visual- motor tasks
  • ✅ Increased neural capacity - can perform two tasks simultaneously by using only one hemisphere ( e. g. chickens) ❌ Little empirical evidence
  • ❌ Too simplistic - both hemispheres are involved in most tasks - brain is highly integrated