An eye for an eye is a subjective game.

Suggests Daniel Gilbert, the Harvard psychologist, in an op-ed in today's NYT. Here's a study he describes:

The researcher began the game by exerting a fixed amount of pressure on the first volunteer’s finger. The first volunteer was then asked to exert precisely the same amount of pressure on the second volunteer’s finger. The second volunteer was then asked to exert the same amount of pressure on the first volunteer’s finger. And so on. The two volunteers took turns applying equal amounts of pressure to each other’s fingers while the researchers measured the actual amount of pressure they applied.

The results were striking. Although volunteers tried to respond to each other’s touches with equal force, they typically responded with about 40 percent more force than they had just experienced. Each time a volunteer was touched, he touched back harder, which led the other volunteer to touch back even harder. What began as a game of soft touches quickly became a game of moderate pokes and then hard prods, even though both volunteers were doing their level best to respond in kind.

So they were upping the pressure 40%? How disturbing is that? Maybe the "eye for an eye" rule already incorporated the realistic prediction that people carrying out retribution would go over the mark. And maybe they should. There are lots of people who would be only too happy to punch you in the face if they had the assurance that all you'd ever do would be to give them one equal punch. But what discord the first puncher causes! How is one equal punch back fair? There's a guy at the next table in the café where I'm writing this. If I waltzed over and slapped him in the face, I'd be shattering the whole social order. Slapping me back is hardly sufficient. The lesson is: Don't start it, because even fair-minded people will pay you back with some extra punishment that you richly deserve for breaching the peace.

Well, that's what crossed my mind. Gilbert's conclusion is much mellower:

Research teaches us that our reasons and our pains are more palpable, more obvious and real, than are the reasons and pains of others. This leads to the escalation of mutual harm, to the illusion that others are solely responsible for it and to the belief that our actions are justifiable responses to theirs.

None of this is to deny the roles that hatred, intolerance, avarice and deceit play in human conflict. It is simply to say that basic principles of human psychology are important ingredients in this miserable stew. Until we learn to stop trusting everything our brains tell us about others — and to start trusting others themselves — there will continue to be tears and recriminations in the wayback.

Hey, why should I trust the bastard who hits me out of the blue?

I know Jesus said "Turn the other cheek." I remember right after 9/11, a friend say to me -- with great enthusiasm -- that a brilliant response would be to do nothing at all, to turn the other cheek. The Muslim world would be awed into profound admiration of us and everything would just topple into place.