I've been thinking about an article by Steven Johnson in Discover magazine.

Recent research shows that when something bad happens to you, part of your brain begins thinking independently, storing its own memories so it can save you next time. That worked fine a million years ago.

The article is about how fear effects memory and more broadly about how fear effects the brain - and more generally yet about how certain behavior patterns that were useful during most of the period when we evolved can be counterproductive now.

This is especially interesting if you're thinking about how people make group decisions. If we think with our emotions, we may be twice removed from reality. In a sense, identifying with your country is patriotism - yet it makes it easy to fall into the trap of thinking about international relations as we do individual relations. Worse yet, our individual emotions are restrained by the experience and knowledge of a lifetime, where our gut reactions to individual relations are not.

Suppose you get really angry at your boss, and you want to hit him. You might be bigger and stronger than him, and pretty much convinced you could beat him up. The anger urging you on might have made sense a million years ago - displaying your physical dominance should persuade him to yield to you in competition for food or mates. If the rest of the group sided against you with him it might not be a good idea, but it was a serious possibility, and the adrenaline surge preparing you for that course of action was favored by natural selection. In the modern world, a lifetime of knowledge reminds you that the almost certain result is that he will call the police.

When our nation is tormented by terrorists who seem impossible to root out, who seem to enjoy irrational popular support among certain groups, the anger, the urge to lash out, is still there. Of course, if your boss had actually tried to kill you and you could prove it you could call the police. In the international arena the solution is much less easy to see - if it weren't, perhaps reason would overcome emotion and we would do the obvious thing, but there is no obvious thing.

I have read many arguments favoring the invasion of Iraq - both before and after the fact. I still believe that fear and anger were a key to the decision, as was the desire for a simple and viscereal triumph. I hope the cost of these is not too high.