Who did the original study?
Split brain research has been worked on since the late 50s
being pioneered by Roger Sperry where he tested and observed
animals with split brains. This section of the book is about
the combined efforts of Michael Gazzaniga and Roger Sperry
at the California Institute of Technology (Caltec) in the
early 60s.
What are the reasons the researcher(s) carried out the study?
Like most advancements made by humans, curiosity played a huge
part. For a long time all split brain research was done on
animals. But a new treatment for people with life altering
epilepsy and seizures would bring much needed life to this
research. It was found that the splitting of the two hemispheres
of the brain down the corpus callosum could cure or hinder
episodes of seizures. These findings gave these researchers
the perfect opportunity to test and observe the effects of
this procedure on humans.
Identify the theoretical propositions or hypotheses on which the research is based
The majority of their propositions consist of queries
about how both sides of the brain communicate and whether
or not both hemispheres are capable of performing the same
tasks with the same efficiency.
Methods
Many creative and intuitive tests were conducted,
The main 3 tests targeted all different forms of perception.
One for visual abilities, where they devised a
technique that would make it so only one hemisphere
of the brain could see a projected picture. A second
for tactile stimulation, they would project an
image to one hemisphere and with their hands, they
would have to locate that object through a slot in
a desk out of the visual sight of the participant.
But the third and final form of perception was much
harder, as sound sensations are sent to both
hemispheres of the brain. They found through
their study that the left hemisphere of the brain
controls language, the right arm and hand. So when the
participants were told to reach into a bag of familiar
objects and identify them with their left hand,
things became much harder.
Give a brief summary of results.
Much was learned from this study, the main and most
impactful details were the new found knowledge of
the different brain hemispheres roles. The right
hemisphere was found to be in control of the left
arm and saw through the left visual field as well
as being able to identify objects, but without
the ability to turn that information into words,
the participants could not say or convey they
recognized the object. So while both sides could
see, only the left hemisphere is able to see and
say that it saw.
Why is this study significant to the field of psychology
This research has had very significant effects in the
field of psychobiology. The research had shown that the
brain is much more specialized than when had once
thought. Now that we are aware of the parts of our
brain that are responsible for different things, in
cases of stroke or head injury we are able to identify
the area of damage and be able to presume what loss
of function the person may experience. This has also
allowed physical therapists to target the specific
areas needed for a much faster and full recovery.
While there has yet to be any evidence, it has been
theorized that some emotions could be linked to
a misconnection in the brain. This could explain
why some people feel a certain emotion, but with
no true known reason.
How has this study been questioned or criticized by others in the field?
The claims made in this research have been very rarely
disputed. The only criticisms in this field have been about
the popular culture depiction of split brain research. Many
people think that it is possible for one of their hemispheres
to be more dominant than the other. They also believe that
this affects your personality; but according to a 2013 stud
y from the University Of Utah, brain scans showed similar
activity in both hemispheres regardless of a person's
personality or character traits.