Everybody has two cerebral hemispheres that make up one brain. The left part is where speech comes from. It also controls the right side of your body. Our logic and reasoning skills come from this half as do number skills. The right side of your brain is your creative and athletic part. Art appreciation comes from this half. The right is known as the visual side. The right side is where spatial imagery comes from. People with damage here have a hard time picturing things. As people get older, they use one side more. Other parts of my page will go in depth with this.
The two halves are connected by a bundle of nerves called the corpus callosum.
This is how the two halves communicate. Doctors used to think it served no purpose
and it is still a common procedure to have it severed to protect you from seizures.
Patients who have under gone this have little difference in the life. Doctors
were sure that the bundle of millions of nerves must have some use. They started to do a lot
of test. Most experiments used a split screen which would present a question
or image to only one side of the brain. One test I read about and thought was neat
involved a person named P.S. To the left side, the logical side, a picture of
a chicken was presented. To the right side, a picture of a snow scene was shown.
He was asked to select two cards from a series of cards. He picked one of a chicken,
with his right hand, and one of a shovel with his left hand. (The right side
of the brain controls the left hand and the left side controls the right hand.)
The selections he made went together. He was then asked why. His left brain took over
and used its language superiority to answer this. His right side couldn't contact
his left side so he did not know why he selected the shovel. His left brain
automatically employed its logic and gave the answer, "The chicken goes with the
chicken and the shovel is used to clean his pen." He thought the answer was right
but it wasn't. Pretty Neat.
For more information about this experiment and the doctor who was involved, please see Carl Zimmer's article from May 10, 2005: A Career Spent Learning How the Mind Emerges From the Brain