Transcript 40 Studs: One Brain or Two?

One Brain or Two?
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
Three Types of Tests
Visual abilities 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
Results
Visual test –
Right visual field, said object
Left visual, saw nothing
When asked to point to object in left
field, did so with left 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
Criticisms
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.