Joseph T. Hallinan - Why We Make Mistakes: How We Look Without Seeing, Forget Things in Seconds, and Are All Pretty Sure We Are Way Above Average

T here are all kinds of mistakes. There's real estate you should have bought and people you shouldn't have married. There's the stock that tanked, and the job that didn't work out, and that misguided attempt to save a few bucks by giving yourself a haircut.

And then there are the errors of other people. As a newspaper reporter for more than two decades, I have made a small (and arguably perverse) hobby of collecting stories about these, tearing out the more memorable ones and tucking them into a manila folder I had labeled Mistakes.

My favorite was torn from page 34 of my hometown paper, the Chicago Sun-Times. The story involved an incident that occurred a few years ago in the village of St. Brides, in South Wales. According to the Associated Press, a mob of vigilantes attacked and vandalized the office of a prominent children's doctor there.

Why attack the office of a prominent children's doctor?

Because, according to police, the vigilantes had confused the word pediatrician with the word pedophile.

The doctor involved, Yvette Cloete, was forced to flee her home, which had been spray painted with the word paedo an abbreviation for the British spelling of paedophile. Afterward, she gave an interview to the local paper.

I suppose, said Dr. Cloete, I'm really a victim of ignorance.

She was, of course. And so are we. We all know the clich To err is human. And this is true enough. When something goes wrong, the cause is overwhelmingly attributed to human error: airplane crashes (70 percent), car wrecks (90 percent), workplace accidents (also 90 percent). You name it, and humans are usually to blame. And once a human is blamed, the inquiry usually stops there. But it shouldn'tat least not if we want to eliminate the error.

In many cases, our mistakes are not our fault, at least not entirely. For we are all afflicted with certain systemic biases in the way we see, remember, and perceive the world around us, and these biases make us prone to commit certain kinds of errors. Right-handed people, for instance, tend to turn right when entering a building, even though that may not afford the best route to take. And most of us, whether left- or right-handed, show an inordinate preference for the number 7 and the color blue. We are also so swayed by our initial impressions of things that we are reluctant to change our first answer on a test; yet many studies have shown we would be better off if we did exactly this.

Most of us show an inordinate preference for the number 7 and the color blue.

Our expectations can shape the way we see the world and, often, the way we act in it as well. In one case, people encountered an unknown man and were later told his occupation. When they were told that the man was a truck driver, they said he weighed more; when they were told he was a dancer, they said he weighed less. In another case, half the people in a restaurant were told their complimentary glass of cabernet sauvignon that night came from California; the other half were told their wine came from North Dakota. Not only did the North Dakota group eat less of their meals, but they headed for the doors more quickly. Even presumably stolid people, like farmers, show the same propensity. Farmers who believe in global warming, for instance, have been shown to remember temperatures as being warmer than those recorded in statistical tables. And what about farmers who do not believe in global warming? They remembered temperatures that were colder than those in the record books.

What's important about these examples is not that we think a trucker is fatter than a dancer or that temperatures are warmer than they used to be (unless, of course, you like to bet on these kinds of things). What's important is that these effects occur largely outside of our consciousness; we're biasedwe just don't know we're biased. Some of these tendencies are so strong that even when we do know about them, we find it hard to correct for them. A practical example involves the power of first impressions. Nearly eighty years of research on answer changing shows that most answer changes are from wrong to right, and that most people who change their answers usually improve their test scores. One comprehensive review examined thirty-three studies of answer changing; in not one were test takers hurt, on average, by changing their answers. And yet, even after students are told of these results, they still tend to stick with their first answers. Investors, by the way, show the same tendencies when it comes to stocks. Even after learning that their reason for picking a stock might be wrong, they still tended to stick with their initial choice 70 percent of the time.

Biases like these seem to be deeply ingrained in us. Many of the qualities that allow us to do so many things so well contain flip sides that predispose us to error. We happen to be very good, for instance, at quickly sizing up a situation. Within a tenth of a second or so after looking at a scene, we are usually able to extract its meaning, or gist. The price we pay for this rapid-fire analysis is that we miss a lot of details. Where the problem comes in is that we don't think we've missed anything: we think we've seen it all. But we haven't. An obvious example comes from Hollywood. Movies are typically made on film composed of individual frames that are exposed at a rate of twenty-four frames per second. But when the film is projected onto a screen, we don't see still pictures; we see motion pictures. This is a good error, of course, and we don't mind making it; in fact, we usually enjoy it. But a similar visual error, committed by the doctor who looks at our X-rays for signs of cancer or the airport security agent who looks for bombs in our luggage, can have deadly consequences. And, as we'll see, they miss quite a lot of what they're looking for.