Tuesday 3 April 2001

Pic of the day: Walking in a fog, or seeing things clearly?

Whose memories anyway?

I usually don't read my "year ago" entries until after I have uploaded. So yesterday I wrote my brief history of fat with no memory that exactly one year earlier, I wrote half an entry about the various fats and their history. Really. And this is not the first time either. In January, I had 3 years in a row with Civilization II and its Mars now! scenario, complete with screenshots. I've written about my best friend 2 years in a row, but then again I guess I write about her even more than about fat. Even so, it is hard to explain away the impression that my subconscious seems to remember my previous entries while I don't. That's vaguely disturbing, don't you think?

When I was a young boy, I loved to read about the incredible capacity of our brain. There were mathematical proofs that the brain could easily store everything we ever sensed during our lifetime and much much more. "We only use [tiny fraction] of our brain", all that jazz. I suppose this gave rise to the wild speculation of levitation through linguistics, that some sci-fi authors reveled in. Or healing through shamanism, stuff like that. Well, today we actually have the placebo effect, so I guess there is something to it.

But brain improvement has turned out to be much harder than you would expect from the self-help books. From the brisk sales of "use your brain better", "speed reading", "super memory" and what not, you would expect that you could no longer walk to the grocer's and back without wading through a throng of superhumans, all of who would immediately see that you had not read the book and could still not solve differential equations in your head while biking and chewing bubble gum. But so far, the most common superhuman feat seems to be driving while screaming in the cell phone.

In fact, the gradual increase in intelligence seems to come in the form of smarter children growing up and replacing dumber pensioners. This is probably less due to self-help books and more to good nutrition and a hyper-charged childhood environment.

***

The brain is hardly the only body part with a serious overcapacity. Generally people do quite fine with only one kidney. As a matter of fact, unless you are into sports, you can get along with one lung too, though I don't volunteer. There is a similar reserve in the liver. This does not mean that we can drink poison with impunity: The liver and the kidneys may filter out moderate amount of toxins over many years, but cannot handle large amount at any one time. In the same way, there may be some bottleneck in the brain that keeps most of us from becoming superhumans.

Indeed, such a bottleneck seems to exist. Our short term and long term memory seem to work on two different principles. The short term memory is fluid and temporary: Concussion or electroshock will often erase half an hour backward from the incident. Long term memories are much more stable; they fade away gradually, but are easily refreshed through repetition or association. Our dream sleep seems to provide such an opportunity. Both during learning and during REM sleep, there is a small area that is active in placental mammals, including us. It is called hippocampus. And if it is damaged, the person can never again learn anything for more than a few minutes.

One plausible theory is that hippocampus maintains a "map" of where our memories are stored. Sort of like the file allocation table on a hard disk. If this map is destroyed, the data are still saved; but they can not be found except by accident. Probing a living brain with an electrode has been found to give sudden, vivid memories of some completely random experience. It is possible that indeed much of our lives are stored somewhere in there. But we only have access to a limited amount of it, if indeed it is there at all.

***

The human brain is not actually like a personal computer. It is more like the Internet: It consists of millions (well, actually billions) of small units rather randomly connected together. Some neurons work together because they are physically close. Some areas have thick, fast cables that connect them to other parts. All in all, every neuron in the brain is somehow connected to any other, though the connection can sometimes be so remote as to be of little use. Still, this is clearly an environment suited for massive parallel processing.

This goes well with the theory of complexes, as detailed in particular by G.G. Jung. In his view, there is mainly a difference in degree between a complex and a personality. Our ego is just a really big complex that is anchored to our body consciousness. Other, lesser complexes may be of little import overall, but they can reign supreme within their own small confines. For instance, if you have a phobia, you probably see what I mean. Whenever you meet a snake, or spider, or a dark room, or a cramped tunnel - whatever sinks your boat - you discover that you are practically powerless. The tiny part of you, which you may not even have known about, grabs the steering wheel and you have no control until you are safely out of the situation. At which point the complex retreats into the shadows again.

This multitasking environment flies in the face of much of western philosophy, which decrees that we have one and only one soul, which supposedly is made from the same soul-stuff all the way through, like a pearl. Instead, it seems that our brainware runs a truckload of applets, some small and some large, some well-behaved and some rather independent. And some of them may have their own memory access.

Then again, it might be just blind random chance. I do after all have many of the same interests and the same lifestyle from year to year, you know. (Yeah, right, tell yourself that ...)