1. One Brain or Two?

2. Roger Sperry & Michael Gazzaniga
Rare and extreme cases of epilepsy, radical but effective treatment – cut the corpus callosum
Of 10 operations, 4 subjects agreed to further testing

3. Three Types of Tests Visual abilities test Tactile test Auditory test
Picture shown to one visual field
Tactile test
Feel but not see object
Auditory test
Told to reach in bag and find asked for object

4. Results Visual test – Tactile test – Vicki
Right visual field, said object
Left visual, saw nothing
When asked to point to object in left field, did so with right hand
Conclusion: both “brains” see the object, only left hemisphere has language skills to say what they saw
Tactile test –
Object in right hand, could say
Object in left hand, couldn’t say what it was
They could point to the same object from group in front of them
Vicki

5. Criticisms Recent Applications Jarre Levy
Disputes pop culture ideas of being right-brained or left-brained
Two hemispheres necessary to do practically everything
Recent Applications
As above, attempts to clarify the misunderstandings and misapplications
Schiffer (1996) – hypothesized that MPD person has more-than-usual level of independence in one hemisphere, takes ‘control’ of consciousness, etc.