When news came Friday that there had been a bloody attack in Norway, many people assumed that it was done by Islamic terrorists of some sort. Those assumptions produced the kind of hate-filled displays such as the one you see at the right. If the copy is too small to read, it says:

“MUSLIMS ATTACK PEACEFUL NORWAY: WAKE UP CALL FROM HELL! Once again proof that appeasement does not work! The time has come to declare World War III on Islam. The only good Muslim is a dead Muslim.”

(The complete page is still online as I write this, but it might disappear.)

As it turns out, the attacks were actually carried out by a self-described conservative Christian Norwegian with blond hair and blue eyes. This sort of spoils the script for those who are eager to blame everything in the world on the people they hate.

The world is a far more complex place than many people realize. It seems that most people have a script in their heads about the way the world works. Their confirmation bias makes them only see the things that fit their script. The rest is simply ignored, as though it doesn’t exist. It’s bizarre, but it seems to be part of human nature.

One of the most useful books I’ve read in the last five years is “Mistakes Were Made (But Not by Me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts,” by psychologists Carol Tavris and Elliot Aronson. In it, the authors explain — in very readable language and with examples that are painfully familiar to many of us — why we do some of the things we do in parts of our lives ranging from politics to romance.

The idea is simple. We tend to cling dearly to the things we already believe, even if we’re not conscious of how closed-minded we’re being. When we’re presented with facts that seem to conflict with what we believe, we experience cognitive dissonance, which is a fancy way of saying that we’re uncomfortable because we’re aware on some unconscious level that contradictory things can’t both be true.

This isn’t a conscious process, but when the brain is faced with such dissonance, it has to find a way out of the dilemma, so it tends to find other facts or opinions that allow it to ignore the information that contradicts what it already believed. For instance, for the people who believe that terrorists are inevitably Muslims, they jumped to the conclusion that the Norwegian attackers were Muslim. When they found out otherwise, the rational thing to have done would have been to ask why they made an assumption without facts. But since the belief is so strong in them that “terror attacks equal Muslims,” they instead leap to some form of, “Well, this was an exception, but what I thought was right anyway, because it’s almost always true.”

In this way, people can face evidence that contradicts what they believe over and over again, but their brains are motivated to find explanations about why they’re still right anyway.

Some of the people who hold these assumptions about Muslims and who jumped to the conclusions Friday are busy making excuses today, but most of them are silent and have moved on to other subjects. Still others are racing to delete evidence of their wrong assumptions. For instance, take a look at the Google search result at the bottom of this column. The headline Friday at that blog — which has “Reviving Common Sense” as its slogan — read, “Norway Under Muslim Attack.” Strangely, if you go to that page now, it just says, “ERROR 404 – NOT FOUND.” In other words, the page has been deleted to hide their gross error. (If you look at the site’s main page, you’ll see that it now makes no mention of the Friday attacks.)

It’s true that many of the people in the world today who are killing innocent people to achieve their political or social goals are Muslim, but it’s just as true that many people have done the same thing throughout history in many names. At various times, they’ve been Christians and Jews and Hindus and Muslims and atheists and just about any other group you could name. We need to condemn all of those who initiate violence, but we don’t need to turn it into an excuse to hate entire religions or the people who follow those religions.

I have serious disagreements with Muslims about theological truth. As a Christian, I believe that Jesus is the Son of God and is the only way to know God. They believe I’m wrong. I disagree with their beliefs. But there’s no reason for us to hate each other over our spiritual disagreements — and there’s certainly no reason for me to hold my Muslim friends responsible for the actions of other Muslims, any more than it would make sense for anyone to hold me responsible for the murders committed by one conservative Christian nutcase who killed a bunch of people in Norway Friday.