A01

• What is hemispheric lateralisation?

  Refers to the fact that some mental processes in the brain are mainly specialised to either the left or right hemisphere
• Which sides of the body does each hemisphere control?

  - Left hemisphere = right side of the body

  - Right hemisphere = left side of the body
• Which functions is the left hemisphere responsible for?

  Language, movement of right side of body and processes information from right visual field
• Which functions is the right hemisphere responsible for?

  Visual-motor tasks, movement of left side of body and processes information from left visual field
• What is the corpus callosum?

  A bundle of nerve fibres which join the two hemispheres of the brain
• What is split-brain research?

  Research that studies individuals who have been subjected to the surgical separation of the two hemispheres of the brain as a result of severing the corpus callosum
• Name a split-brain study

  Sperry and Gazzaniga (1967)
• An object is placed in the left hand and the patient is asked to name it - predict what would happen and explain why

  The patient will not be able to name it because object will be processed by right hemisphere, but language is in left hemisphere
• An object is placed in the left hand and the patient is asked to find the object with the right hand - predict what will happen and explain why

  They will not be able to find the object because the object will be processed by the right hemisphere, which controls the left hand, not the right
• What is a strength of this research?

  High internal validity: made use of highly specialised and standardised procedures = high degree of control over variables
• Study showing evidence for brain lateralisation

  Sperry and Gazzaniga (1967)

  • Patients had a split visual field - an image or word is projected to the patient's left visual field (which is processed by the right hemisphere) or the right visual field (which is processed by the left hemisphere)
  • Image flashed for 1/10 of a second
• What were the three tasks presented?

  1. Describe what you see test - a picture was presented to either the left or right visual field and the participant had to simply describe what they saw
  2. Tactile test - an object was placed in the patient's left or right hand and they had to either describe what they felt, or select a similar object from a series of alternate objects
  3. Drawing test - participants were presented with a picture in either their right or left visual field, and they had to simply draw what they saw
• Conclusion of Sperry and Gazzaniga's research

  • Certain functions are lateralised to one hemisphere over the other
  • Left = language
  • Right = visual-motor tasks and facial recognition