Thursday, January 5, 2017

The case of the split brain.

We all have two brains.

The right brain and the left brain are each completely separate operating systems, linked together by a band of nerves called the Corpus Callosum.

In some rare cases of severe epilepsy, patients have had their Corpus Callosum severed so that the electrical impulses of their seizures cannot spread from one side of the brain to the other, thereby mitigating some of the damage. For the most part, these people are not impaired by the procedure; they think and function quite normally.

A spoon is held up in the subject's right visual field, and the researcher asks "What is this?" 

The subject responds, "What is what?" They don't see the spoon.

The researcher then says, "Here, take this spoon," and the subject reaches out and takes it.

Here's what is happening:

The part of the brain that names things is in the left hemisphere, so when asked to name an object that is only visible in the right visual field, the person does not perceive an object at all (because the part of the brain that names things can't see the object and the two sides of the brain can no longer communicate).

But the person does see the object when they are told to take it. 

There are many other examples of this neurological phenomenon; the brain fails to perceive stimuli when it cannot process and categorize it.

So, on top of the whole spectrum of light that our eyes cannot even perceive, how much of the information our eyes do take in never registers in our consciousness because our brain can't categorize it. It's like that information doesn't exist at all.

The reality that we are able to perceive is very likely a tiny sliver of the reality that actually exists.