Hemispheric lateralisation + split brain

• Hemispheric lateralisation

  Two halves of the brain are functionally different and certain mental processes + behaviours are mainly controlled by one hemisphere rather than the other.
• Strength - research evidence for lateralisation 


  Fink et al

  Used PET scans to identify which areas of the connected brain were active during a visual processing task.

  RH more active when asked to look at global elements

  LH more active when had to to focus on finer details.
• Split-brain research

  Studies of how the hemispheres function when they cannot communicate
• Sperry's Research - procedure

  11 people who had split-brain operation studied.

  Image projected to the LVF, processed by the RH and another image (could be the same or different) projected to the RVF, processed by LH.

  Info cannot be conveyed from one hemisphere to the other.
• Sperry's research - findings

  When picture shown to the RVF, participant could describe what was seen.

  Couldn't when it was shown to the LVF - said nothing was there.

  They could select a matching object out of sight using their left hand.
• Strength - research support Split-brain

  Gazzaniga

  Showed split brain participants perform better than connected on certain tasks.

  Faster at identifying odd one out of similar objects.

  Controls - LH is watered down by inferior RH.

  Shows distinction between LH and RH
• Limitation - causation

  None of the control participants in Sperry's research had epilepsy.

  Adds a major confounding variable.

  Could have been due to epilepsy and not the split brain.