Split Brain Research

• What part of the brain must be severed to research split brains?


  corpus callosum
• Why was the corpus callosum split (not research)


  Epileptic seizures involve excess firing between hemispheres
• Who (that I need to know) investigated split-brains?


  Roger Sperry (1968)
• Sperry's Findings:


  when picture of an object shown to ppt’s RVF, they could describe what was seen. 

  When image shown to LVF, they said there was nothing there. 

  = in the connected brain, messages form RH are relayed to language centres in LH but cannot happen because of the split.

  If seen by LVF = could select the matching (or associated) objects by touch (no sight) by left hand. If LVF shown a pinup = emotional reaction (e.g. giggle) but said they saw nothing or a flash of light.  
• Sperry's procedure:


  11 people with split brains operation studies using set up in which ppts oculd see an image in RVF and then in LVF.

  Selected objects shown to LVF and told to select the same, or associated object e.g. if seen a cigarette select an ashtray
• Conclusions from Sperry's research:


  LH is verbal and RH ‘silent’ but emotional. 
• Strength (of split brain research) = Research Support


  Gazzangia (1989)

  split brain participants perform better than connected brains on certain tasks = faster at identifying the odd one out in an array of similar objects
• Limitation = confounding variables

  Participants has severed corpus callosum due to epilepsy.

  Therefore, generalisation issues