split-brain research

• split-brain research was conducted buy Roger Sperry
• split-brain studies involved those who have undergone commissurotomy allowing Sperry to see the extent to which the hemispheres were specialised to certain functions
• what is commissurotomy?

  the corpus callosum which connects the 2 hemispheres were cut down the middle to separate the 2 hemispheres to control frequent and server epileptic seizers
• Sperry devised a general procedure in which an image/word be projected in an individuals right visual field (left hemisphere) and the same image/word be projected in the left visual field (right hemisphere).
• how would a 'normal brain' react to Sperrys research ?

  the corpus collosum would immediately share the information giving a complex picture of the visual world
• the key findings from Sperry's split brain research

  1. describing what you see
  2. recognition from touch
  3. composite words
  4. Matching faces
• when describing what they saw, the Split-brain patients could describe what they saw when a image was shown to the right visual field. When shown to the left visual field they reported nothing there.
• why could the participants not describe the image when shown to the left visual feild?


  language is processed in the left hemisphere
• when recognising buy touch, the split-brain participants were able to select a matching object that was associated with an object presented to the left visual field even though they couldn't describe it
• why could SB participants match associated objects to the image but not describe it?

  they could understand what the object is using the right hemisphere
• if 2 composite words were presented simultaneously, one either visual field, the one shown to the LVF could be pointed out with the left hand and the RVF would be said
• when matching faces, the right hemisphere appeared dominant. the picture present to the RH was consistently selected
• Sperry's work into split brain phenomenon has produced an impressive body of research.

  • showed that the LH is geared towards analytic and verbal tasks
  • the RH is more adept at performing spatial tasks and music
• how does Sperry's research have strengths in it methodology?

  • specialised and standardised procedure
  • method was ingenious
  • the image would be flashed - meaning that individuals would have enough time to spread info across the brain
  • ensured that one hemisphere was receiving information at a time
• what limits Sperry's research is that it could only be applied for specific people since all of his participants had previously had server epilepsy