This will only be a brief entry, but it's a subject which I'm truly fascinated about so at some point in the future I may delve further (for this week I've only done the bare minimum of research).
The origin of this idea came when I had a brief course in psychology back at university. Some of the work I did was an essay about experiments done on split brain patients*. That is people who, due to epilepsy, had the connection between the two halves of their brain severed.
In the experiments a different image is presented to each eye of the patient, they are then asked to point to one of a set of images in front of them which they associate with what they're seeing. What happens is that the left hand points to an image connected to what the left eye is seeing and the same for the right hand **. That is, if the left eye sees a car, the left hand will point to a wheel, and if they right eye sees a desk the right hand will point to a computer. This is because each half of the brain is only connected to one eye. The point is that these two halves of the brain, although they can no long communicate with one another, are still both operating as separate entities. It's as though they are two full people in this one body.
That's fascinating enough, but the experiment which really got me was when the left brain (which deals with all of our language) was asked to explain why the right brain had pointed at something. The example given below (* under the section 'false memories') is that the left brain saw a chicken's foot, so pointed to a chicken, and the right brain saw a snowstorm, so pointed to a shovel. Obviously, with no communication, the left brain has no idea what caused the other hand to point at a shovel, but when questioned the subjects would confidently explain that it was to clear out the chicken coop. They would completely believe this reasoning, providing similar examples in other tests. Whenever I read about it in the literature this seems to be treated like an afterthought, a fun little trick which they caught the brain playing on itself, but to me it seems huge.
I've always been a little suspicious of my brain and of the reasons I give for doing things. Here is evidence that, even if we have a decent sounding reason for an action, we may actually not know the real explanation behind it at all.
I realise that most people are pretty confident that, when they take some action, they know why they took it. This may all sound like hand waving rubbish to you, but just for a moment entertain the possibility that it isn't so certain.
There are often times when I will look around as I walk along the street and, finding I have looked around, I will think to myself that the reason I did so was to look at that pretty lady who just walked past. Upon careful examination, if I'm particularly awake, sometimes I catch the fact that I didn't even notice the lady until after I'd turned around. I really looked around because I saw a flash of colour, or because I thought I saw an old friend, or some other reason which is no longer retrievable from the ether. However, in my internal narrative I came up with an explanation for the action after it happened, using the information available to me at the time (just as the split brain patients do).
I used to ponder this idea a lot, thinking about the possibility that perhaps we all live just a split second after the moment. That we are simply observers of our actions who come up with explanations for our actions after the fact.
Clearly this isn't always the case. After all there are certainly times in conversation where I consciously stop myself from saying something, realising that it would offend or upset the person I'm talking to. However it is noticeable, to me at least, that when I'm policing my thoughts like this my repartee is noticeably more stilted and awkward. The times when I'm really enjoying myself and connecting with someone else are precisely the times when I'm not thinking about what I'm saying, when the words come out long before the thoughts which follow.
That is why, nowadays, I tend to think in terms of a thinking brain and a flowing one. The flowing one, like a carefree person, can enter any situation and speak or act easily without worrying, until something knocks the thinking brain into action. However, all my greatest thoughts and achievements came about as a collaboration. Without the thinking brain the flowing one wouldn't ever get anything done.
I suppose nowadays I wonder more about what the right balance is between the two and how to more accurately call upon each brain as and when I have need of it.
* [http://www.utdallas.edu/~otoole/CGS2301_S09/7_split_brain.pdf is a pretty decent round up of a lot of this research. There is much much more, but that will have to wait for a later entry]
**[confusingly, the left brain is actually in control of the right eye/hand and vice versa because of the way the brain is wired. I'm going to mostly gloss over this here, because although interesting it's not really relevant.]