My basic question is as follows:
Why is it that the brain can easily control actions of the body, but not its own thoughts?
For example - I tell you not to think of pink elephants. Try as you might, you will not be able to avoid thinking of them! However, I tell you not to hit somebody - no problem. Even though the impulse might occur to you, you will easily be able to control it. (usually)
Ideas?
One of the major functions of a brain is to serve as an information processing device. If you present it with a stimulus (saying “don’t think of pink elephants”), it’ll try to interpret that stimulus to determine an appropriate response consistent with the organism’s goals of survival and reproduction. Thinking of pink elephants does not get you closer to these goals, but being able to understand what people are saying to you does; associating sound waves with certain images/objects/sensations is essential for a person to function in society.
When you tell that person “don’t hit someone,” they still process that to understand what you say, but they don’t carry it through into action. Why not? Because following up that understanding with automatic action does not further your goals of survival and reproducation (usually).
I also sounds like you’re confusing the idea of a “conscious mind” with the brain. The “conscious mind” (if there really even is such a thing) does not control the brain, which carries out many of its functions without conscious thought.
It reminds me of a quote from “Dune” by Frank Herbert - something like “The mind wills the body, and the body follows; the mind wills itself and meets resistance.”
Before taking a guess at the answer to your question, I’d like to point out that there are some actions of the body that are very difficult to (consciously?) control. For example, it’s difficult (at least for me) to “will” my heart to beat that much slower or faster. I have experimented with a watch, and I can make my heart beat a little bit faster or slower, but not much. I imagine with practice I could get better, but I doubt I could get my heart rate up to 180 without running around or something.
Also, note that what control I have I accomplish through “tricks,” such as imagining myself on a roller coaster or being chased.
I think that mind has similar aspects - certain things are very easy to control. For example, if you decide you want to think about a particular issue, you can just do it. Some things are a lot harder. For example, NOT thinking about a disturbing experience is very difficult. As with the heartbeat thing, it is possible to increase the amount of your control using certain tricks. For example, a friend of mine showed me how it is possible to greatly reduce the amount of stuff you are thinking about using the following trick: Visualize a pond with little ripples on it, and imagine that the ripples are your thoughts. Now imagine the pond becoming more and more still until the ripples go away and the pond is (almost?) completely still.
Anyway, now, here’s my WAG about your question. I think that there’s just way too going on in your body and mind for it all to be under conscious control. We just don’t have the “processing power,” if you will. Evolutionarily, humans have a very limited amount of ability to be conscious, and nature has rationed that conscious reasoning ability as best she could – some to the body and some to the mind itself, but in a limited fashion.
To see the limits of your conscious mind, imagine the last time you tried to quit smoking / lose weight etc. It is REALLY hard (at times) for the conscious part of your mind to control your hands, mouth, etc. Otherwise it would be easy to stop smoking, lose weight, etc.
Interesting question, but the only answer I could give is a big WAG. It looks like we are talking about two parts of the brain here. Motor control and cognitive thinking. Moving your arms and legs doesn’t come from a single thought, the muscles must move in coordination for any effecive movement to be carried out. If our muscles moved everytime we had a thought this coordination would be thrown off and little useful movement would result.
Our brain actually takes steps to limit the activity of the brain cells which contol our muscles. In the motor cortex a large number of dopamine producing cells are present. Dopamine is a inhibitory neurotransmiter. These cells reduce the number of fires the neurons in the motor cortex accomplish. In patients with Parkinson’s disease these dopamine producing cells begin to die off. The tremors experienced by them are a result of the overactive neurons in the motor cortex.
What we think of as thoughts are brain messages in the cognitive portion of the brain. This part of the brain can be allowed more activity because it doesn’t have direc control over anything. This is a good thing because it allows humans to think abstractly. We can imagine and plan for things we have never actually seen. Some people argue that this type of thought is what separates us from other animals. This type of thought requires us to imagine many possiblities, including ones that have been suggested to us. We imagine first and sort it out later. As a result we think of many things immeadiaty when they are suggested without realizing the implicaions of it.
That’s my guess, maybe someone else can come along and give a better explanation.