One often hears that the brain is not like a computer. I suggest here that part of the brain is like a computer in a few important ways.
I propose that there is a plausibly localized mechanism in the brain that orchestrates a sequence of conscious thoughts. It is not a homunculus, any more than the program counter of a computer is a computer. It is merely the mechanism where the identity of the current ‘activation’ sits. (‘activation’ as in spreading activation) We learn processes in school, such as performing multi digit addition, which somehow guides us thru unnatural steps, scarcely aware of the unnatural rules we are following. We do have conscious access to these rules for most of us are able to explain to someone else how to perform addition. Perhaps the rules for addition are a bit like reflexes—except for the fact that we are usually unable to speak of our reflexes so as to convey the reflex to others, but dance instructors do some of this.
An activation is a bit like a reflex—learned or innate. It is evoked when some pattern is detected. One activation can evoke the next, as some early computers which included the address of the next instruction in each instruction. See Kanerva about what a “brain address” might be.
As one ‘activation’ follows another, we apply a large portion of our brain and memories as we seek connections with higher level activations. When we are trying to remember where we first met someone who we have just encountered, we activate many memories while keeping ‘in mind’ that we are trying to remember where we first met someone. Failure to do this is a frequent butt of humor. When we are interrupted by a multi tasking imperative we are able to return to our original task with varying degrees of integrity. It may be that we merely ‘remember’ what we were doing but if so, that puts memory near the seat of this mental ‘program counter’. In my mind that pushes sort term memory into confluence with awareness (or consciousness)—this is a matter of terminology.
When I feel that I have finished some task adequately I will ‘relax the brain’, close my eyes perhaps, close the lid of my computer if the task involved the computer, let in deferred tasks that had been interrupted by some more urgent task. This is somewhat like what happens as a computer finishes an interrupt routine, or when the task scheduler of an OS kernel consults the ready queue to see what to do next.
All this “spreading activation” sounds suspiciously like following a linked list à la Kanerva.
I am subjectively aware of the difference between long and short term memory. I think there are several levels based on a few underlying mechanisms. I am subjectively unaware of the division points. The imaginary landmark phenomenon fits here somehow. This brain feature is missing from computing architectures unfortunately.
An article in the 2012 Feb 25 issue of Science News reports that V1 is very active (fMRI) when the two eyes get different images. I presume that this follows the failure of the LGN to arrange image alignment. The article goes on to suggest that we must learn to distinguish between ‘consciousness’ and ‘attention’. (I wonder where ‘awareness’ fits here.) While we are presumably unable to become unconscious of a large tree directly ahead of us, it does seem possible to direct our attention elsewhere, even as we still observe the tree. (As in “Pay attention to what the guide is saying.” as we still see the tree.) I would say that ‘awareness’ of something like the tree, means that after the lights are turned out without warning, we are able to recall that there was a tree in front of us. There are dramatic tests proving that we are unaware of many large things in plain sight by this definition. You are asked to look at a clearly printed page with about 10 squares of vivid colors and then to turn the page where you find the question “Where is the red square?”. The common experience is to be sure that you know where everything is and that you will remember it; after turning the page the information is unavailable.