Core Studies: Sperry

• What did he study?

  Classic study of hemispheric disconnection and unity in conscious awareness.
• What is Sperry's background part 1?


  1. It assessed lateralisation of function, where each hemisphere of the brain is responsible for different functions e.g. left controls language and the right controls creativity.
  2. It also assessed contralateral control whereby the brain is cross-wired; the left side of the brain controls the right side of body and vice versa. This shows the two hemispheres are constantly communicating through the corpus callosum.
• What is Sperry's background part 2?


  3. Sperry wanted to understand what each hemisphere was responsible for (when functioning in isolation).

  4. So Sperry used split-brain patients who'd had their corpus callosum severed to treat severe epilepsy (so hemispheres can't communicate), to assess how hemispheric disconnection impacts behaviour.
• What was Sperry's aim?


  To record the psychological effects of hemispheric disconnection and to find evidence for lateralisation of function in 'normal brains'.
• What was Sperry's sample?


  11 split brain people who'd had a split brain operation at various times before the study, to treat severe epilepsy. So opportunity sample.
• What scientific equipment did Sperry use?


  Tachistoscope which projects visual stimuli onto screen for a specified amount of time- put onto either side of the screen; right visual field processed by left hemisphere and vice versa.
• What research method did Sperry use?

  Quasi exp as naturally occurring IV split brain, DV performance on visual and tactile tasks
• What were Sperry's conclusions.


  1. split brain ps have two independent streams of consciousness- different hemispheres specialise in different tasks which evidences for lateralisation of function.
  2. people with split brains have two separate visual inner worlds, each with own train of visual images.
  3. split-brain patients have a lack of cross-integration; the 2nd hemisphere doesn't know what the 1st hemisphere has been doing
• Describe the one visual field task.

  Each p studied alone and had one eye covered. They were asked to look at a fixed point in the centre of the screen on the Tachistoscope. Visual stimuli e.g. a heart, projected onto screen, either to RVF or left visual field, shown for 0.1 seconds so they couldn't move their eyes and change their visual field. They were then asked to name what they'd seen.
• Describe the two visual fields task?


  P shown two different images, one in each visual field at the same time on the Tachistoscope, which are projected for 0.1 seconds. They still focused on fixed point in centre of screen but saw two images.
• Describe the tactile one hand task.


  Each p was given an object in one hand (hands hidden from view), asked to say or write what was in their hand.
• Describe the dual processing task.

  Ps were hands out of sight, given two different objects one in each hand, then objects taken away and p asked to find those objects by touch from a pile of items, or say what found.
• What were the results of task 1?

  When image processed in RVF, processed in left hemisphere (bcs of lack of contralateral control), which controls language, so could write and say what saw but not draw, and vice versa.
• What were the results of task 2?

  When asked to draw what they'd seen, would draw LVF image because this is processed in right hemisphere (cross-wired) which controls creativity, and vice versa for when asked to say/write what seen.
• What were the results of task 3?


  If item in ps right hand, processed by left hemisphere, and could speak/write with right hand, if in left hand can draw it with left hand but not say it.
• What were the results of task 4?


  Ps able to find objects by touch but only in hand where objects were placed Ps able to find objects by touch but only in hand where objects were placed, if other hand touched object it wouldn't recognise it- suggests two hemispheres working independently- only find object that has been held in same hand.