The Game of Intelligent Design

Some recent research suggests that the process of forgetting may not just be a matter of data fading away. Pretty much all of my experiments assumed that information that was not useful would simply not be reinforced, and thus – with appropriate decay mechanisms in place – would eventually disappear on its own. This kind of approach could still work well enough for a motion control system, but it’s clear that declarative memories work very differently.

When you listen to a conversation, it is sometimes possible to remember long periods of it verbatim. (Not for me so much, but there are people who are very good at it.) This ability can be useful in some situations and to some professions, but for most of us most of the time it is sufficient to merely get the gist and discard the words. Moreover, i’d suggest that the cases where it is useful to remember exact words are contemporary, like being a lawyer or journalist; there’s no reason why our ancestors of 10,000 year ago needed such skills. This means that either there’s something i’m missing, or that the ability is a happy accident of how brains work. I’ll assume the latter is the case, since it’s the domain of others to deal with the former.

Turns out, (see http://www.physorg.com/news185720165.html) that forgetting is actually a very deliberate neurological process. The RAC pathway (a process by which memories are reaped) is activated when memories are in conflict, or when important (deemed so somehow) new information is in need of space. The implication is that after having some experience (say, some particularly interesting conversation), if nothing else very interesting happens for some time after that, your memory of it will be as fresh as it originally was. (But of course there is always something that happens subsequently, so it will always have faded at least a little.) Furthermore, no matter how important a particular experience was, if you have an even more important experience shortly after, the first is likely to be forgotten. (My terminology here is absolute, but only for convenience. Obviously, if reminded you would probably be able to recall some details of the first event, and there are intermediate and long term memory processes at play that will complicate the whole matter.)

The confusion aspect of this is also interesting. If memories, or more precisely the implications of memories, are in conflict, the RAC pathway is activated to remove them, or so the research suggests. This would allow for new – hopefully cogent – information to be absorbed unhindered by past misunderstanding. But to me it sounds draconian. I won’t deny that draconian processes are fine as long as they produce a desired result, but it seems like the brain would be throwing away a lot of information that could potentially be useful. I mean, the experiences happened, didn’t they? They represent truth, at least in a context.

So, when data is in conflict, perhaps what is being mopped up are associations between them, not the memories themselves. Perhaps this mechanism is how brains gradually develop distinctions, such as “A results in B in context C, but A results in B’ in context C’”. So, the action A is initially associated with desired result B globally. But “something bad” happened when A was done in C’, so the association between A and B was dropped in this context.