Thread: Split Brain and Consciousness

Sometimes for medical reasons the brain is essentially split in two. The brain has 2 hemispheres which are near duplicates, with nerves carrying information between. When the brain is split in two, the individual acts almost like 2 people.
Each hemisphere controls one side of the body. If one half's eye is covered, and it is trying to pick up an object, it will fail. If the other half of the brain can see the object, then it pushes the oher half's hand aside and picks up the object. This doesn't disturb split brained people at all.
Does this mean we are two seperate people working together?

No it doesn't. You just need to read some good, not terribly technical, stuff from people like Norman Doidge (plasticity) or Oliver Sacks (neurologist) about how the brain both works and malfunctions to realise that the 'split' brain issue is more complicated, but very similar, to partially losing other faculties.

All that happens when we have severe brain trauma or disease is that it drives home to us just how central the brain is to our self image and to our capacity to act. There is not another person lurking in the background waiting its chance to come to the fore when a motorcycle accident or Alzheimer's affects our brain function. Those events change us. Our idea of who we are, and others' perceptions of how we are, are strongly dependent on our brain function.

Originally Posted by adelady

No it doesn't. You just need to read some good, not terribly technical, stuff from people like Norman Doidge (plasticity) or Oliver Sacks (neurologist) about how the brain both works and malfunctions to realise that the 'split' brain issue is more complicated, but very similar, to partially losing other faculties.

All that happens when we have severe brain trauma or disease is that it drives home to us just how central the brain is to our self image and to our capacity to act. There is not another person lurking in the background waiting its chance to come to the fore when a motorcycle accident or Alzheimer's affects our brain function. Those events change us. Our idea of who we are, and others' perceptions of how we are, are strongly dependent on our brain function.

Do you mean both those people are us? I know that the issue is more complicated, because both halfs have the same experiences, and they share "ideas" (signals really) which causes them to become very similar.
I guess this issue could be rephrased. If we're composed of seperate neurons, are those neurons seperate intelligences? Are seperate groups of neurons seperate intelligences, which are pieces of our intelligence? Can we define anything but the whole as intelligent, and conscious, just less intelligent than the whole?
About the issue of a different person waiting to give us advice. We have many layers of intelligence. At the lowest layer, neurons represent things like corners and edges. At the highest layer, neurons represent our mental state. In between are many different levels of abstraction, which we don't consciously experience. Those layers could be working on a problem subconsciously, and then tell the highest layer about the problem.
The brain is not a single intelligence, but rather a huge number of small intelligences.

I think I understand what you're saying, and I tend to agree. What I consider consciousness, is that small fraction of the brain that is growing/changing at the moment. In a healthy individual, consciousness is continually on the move, leaving behind a useful skeleton or snapshot of its former self, that is liable to repeat the established pattern and may not change for years especially if that pattern gets refreshed often. For examples the parts of you that tie shoelaces or read the letter "K" were once at the forefront of your consciousness - now they're probably inaccessible to your present consciousness (especially the "K" reader - can you make it stop?).

Which parts are really you? One may single out or include members of a group. I could say "you" meaning all the various minds and routines and even body parts and webpages associated with you. Or I could say "you" meaning just the part that can pass me a crescent wrench out of the toolbox.

What he is saying is essentially, there is no "you". Any change in the brain changes the form of your conscious self- your identity narrative. Big changes (damage, enhancements, etc) make big changes to that narrative.

Yeah. You can't step in the same river twice.