Split Brain Research & Hemispheric Lateralisation

• Which hemisphere produces & understands language


  left
• What connects the two hemispheres?

  corpus callosum
• What is the corpus callosum?

  bundle of nerve fibres which allows the two hemispheres to communicate
• What was the aim of Sperry & Gazzaniga's Research (1967)?

  investigate the extent to which hemispheres were specialised for certain functions & whether the two hemispheres performed tasks independently of one another
• Sperry and Gazzaniga's study included the participant

  1. Describing what they could see
  2. Recognition by touch
  3. Drawing tasks
  4. Composite words
• What was the process of the describe what you see study?

  picture presented in right visual field/ left visual field
• What was the result of presenting a picture in the right visual field?

  Patient was able to describe what they saw (shows superiority of left hemisphere when it comes to language production)
• What was the result of presenting a picture in the left visual field?

  The patient could not describe what was there & often reported that there was nothing there
• What was the process of the recognition by touch study?

  Object placed in left then right hand
• What happened when an object was placed in the right hand?


  1. Patient could describe what they felt

  2. Couldn't identify a similar appropriate object from a series of other objects
• What happened when the object was in the left hand?


  1. Patient couldn't describe what they felt

  2. Left hand could identify & select a similar object
• What was the process of the drawing task?

  word presented in a visual field, participant asked to draw it & say the word
• What happened when the word was presented to the right visual field?


  1. Couldn't draw a clear picture
  2. Could say the word -shows left hemisphere is superior in regards to language production
• What happened when a word was presented to the left visual field?


  1. Could draw & produce better pictures

  2. Couldn't say the word - shows right hemisphere is superior when it comes to visual & motor tasks
• What was the process of the composite words task?

  two words were presented simultaneously, either side of the visual field: key on the left visual field, ring on the right
• Process of face recognition task

  composite picture made up of two halves of a face
• what were the findings of the face recognition task?

  1. participant could describe the picture on the right

  2. participant could match the picture on the left
• Sperry & Gazzaniga's conclusion

  • left hemisphere is responsible for speech & language
  • right specialises in visual processing & motor tasks
• limitations of hemispheric lateralisation

  • population validity
  • differences may be overstated
• Strengths of hemispheric lateralisation

  • standardised procedures
  • evidence for lateralisation
• What were the findings of the composite words task?

  participants would say 'ring' as that is processed by the left hemisphere & would pick up a key as that's processed by the right hemisphere