Saturday 13 January 2007

Pic of the day: OK, so it is not JUST American teens... (Screenshot from the anime Suzuka.)

Brains! And teens.

I recently read an article in the Norwegian popular science magazine Illustrert Vitenskap. They had a theme issue about humans, and there was one article about how our brain grows. As they showed, it grows like crazy at first but then slows down. At 11 it has reached its full adult weight. What? I don't really disbelieve this, because when you think about it, teens don't have small heads. (It may look that way because of all the hair, perhaps.) But I remember reading when I was young that the bones in the cranium don't "close" or ossify until age 18 for women, 21 for men. The book may never have said right out that the brain continued to grow until then, but it was clearly implied. And like the gullible person I evidently am, I accepted this without measuring my own head or others'.

What does happen instead is that the brain reorganizes. The article mindlessly repeated the American science of the teen brain being out of control and unable to act rationally, because the connections between the rational part and the emotional part is still not grown into place. I find it highly unlikely that American brains grow at a different pace than Asian brains, with European brains somewhere in between. The reason why American teens are acting crazy is almost certainly American culture, not the brain as such. There is no doubt that the teen brain is less efficient than the adult in various ways, including managing emotions. But the difference is rather more subtle. Another scientific article that I read, but forgot to write down, concluded that the weakness of the teen brain is in handling multiple tasks under stress. If you don't overstress it, it works quite fine. This was given as the reason why teens in other cultures did not succumb to major angst and rebellion: They had a predictable framework for their lives and were not challenged to make decisions constantly while going about their life.

I'll add that I suspect people in most of the world live more slowly than in the USA. Certainly people in rural areas live more slowly than in the cities. You can see this when they walk. Speaking of which, even in Japan it is perfectly normal to actually walk in towns, rather than driving a car. The Japanese can afford cars (and frequently have one) but there simply isn't room for everyone driving whenever they need to move their body 500 yards, so they don't. Americans do. This probably stresses them too, because walking and stress are clearly opposites. I know this from practical experience, and so do many others.

Back to brains. Another fascinating tidbit was that the brain burns the most sugar when it is 6 years old! This is also when it has the most connections between cells; pruning stars soon after. Once again I have been misled to think that the first mass extinction of brain cells happens during puberty (except in males, where it starts already in the fetus, caused by the brief initial flush of testosterone that makes men different from women). In all fairness, it wasn't easy to know these things in the past, because you could not study the living brain at work, the way you can now with various brain scanning technologies. Anyway, make sure to feed your first-graders plenty of carbs, eh? And small children need fat, because fat is the substance that makes up most of the brain's volume, and the wee ones grow brains like crazy. You will probably be able to see when they have more fat than they need for their brains, because it will settle elsewhere on their bodies.

One fact that I think I have seen before was that the older brains worked differently from the young. They were about as good at solving problems, but they did so by involving much of the brain at the same time, whereas the young brains had parts working furiously and other parts inactive. I am not sure whether this is a software solution, that the brain has found a more efficient way to distribute the tasks through experience, or whether the different parts of the brain gradually learn to differentiate over time. This is possible, you know. It could be that they are only slightly involved at first, but gradually build their skills. I am sure there will be more research into this in the future, if any.

One thing we did not know when I was young was that old brains still have stem cells, most notably in the hippocampus, where the brain seems to keep an index of all new things we learn. Using the brain is the best way to keep it from deteriorating too early, but using the body does seem to help too. I guess that makes sense. I am not sure if playing Sims2 counts as "using the brain" though, or if you have to do unpleasant maths for that. Of course, it may not be a big deal for me anyway: If I cling to life for another 20-30 years, computer-enhanced brains should be standard anyway. These things are always 20 years into the future, like the flying car and travel to Mars. Then again I used to have the flat-screen TV on that list too, and look what happened...