While en route to present a seminar, I had to change planes in Denver. On arrival in Denver, I checked the departures monitor for my connecting flight. There it was: gate B52 at 3:20 p.m., just as I had expected. It was a short flight on a tiny plane. I had taken many such flights from Denver, and they had all departed from B gates numbered in the 50s.

Having time to kill, I wandered around, periodically rechecking the monitor in case of a gate change. But, no, it was still B52 at 3:20 p.m.

At 2:50 p.m., I moseyed to gate B52. Strangely, the flight information wasn't yet posted, and no service agents were in sight. But, I knew that flights on tiny planes often board right at departure time, so the service agents were surely on their way.

Finally, at 3:00, the flight information was posted. But, it said San Francisco, departing at 4:15 p.m. What? I checked the departure monitor again. It said B52 at 3:20 p.m. How could this be?

And now it was 3:10 p.m. Something was very wrong. Once more, I checked the departure monitor. That's when I saw my departure gate wasn't B52; it was A52! Up until then, the monitor had read B52. I'm sure of it. I'm absolutely positive. But, now it said A52, and I was very far from A52, even at run-like-crazy speed!

To B or not to B
Off I went, hurrying, scurrying, and worrying, doing the airport slalom, swerving around people, veering this way and that, while setting a personal best for inter-terminal travel.

3:11 p.m. ... 3:12 p.m ... 3:13 p.m. ...

Despite huffin' and puffin' regularly at the gym, I quickly became winded. Of course, on the treadmill I don't carry a laptop and carry-on bag.

3:14 p.m. ... 3:15 p.m. … 3:16 p.m. ...

Reaching gate A52 entailed racing through concourse B, rushing down two escalators, taking the train to concourse A (the forty-five-second wait for the train was twice as long as forever), dashing up two long escalators, and speeding to the end of concourse A. Whereupon, at 3:19 p.m., I discovered that my gate wasn't just A52 but A52, door H, downstairs, and at the end of a long corridor.

I gasped my way to door H. It was 3:20 p.m. on the dot. The plane was still there, and I was allowed to board.

Believing is Seeing
I had fallen victim to the "believing is seeing" syndrome. Once my heart rate slowed to a normal thumpety-thump and I reflected on the situation. I realized that when I first looked at the monitor, I saw what I expected to see: a B gate. Gate B52 fit my mental model of how things were, because that's how they'd been in the past. Once I "saw" B52, I kept seeing it each time I checked, even when the facts clearly stated otherwise.

Have you ever been so certain of what you believed to be the truth of a situation that you were blind-as I was-to the reality of the situation?

It turns out there's an entire field of research that focuses on types of blindness in which you see just fine yet miss what's happening right in front of you. One such type of blindness, called change blindness, is being blind to a change that takes place right in front of you. Another type, attentional blindness, results from focusing so intently on one thing that you don't notice something else. See the University of Illinois' Visual Recognition Lab's Web site for videos (some very humorous) that demonstrate these types of blindness.

The most well-known of the experiments in this field is the invisible gorilla experiment. In this experiment, you watch a video of several people, some in white shirts and some in black shirts, tossing two balls around. You're directed to silently count the number of tosses among the people in the white shirts. As they toss the balls around, a gorilla (or at least a confederate dressed as a gorilla) saunters right through the circle of ball-tossers. It stops in the middle, beats its chest, and walks away.

Do you think you'd see the gorilla? Most people say, absolutely, no question about it. And, maybe you would see it. But, about half the people who participate in the experiment are so preoccupied counting the balls that they missed the gorilla. Even people who are forewarned about the gorilla (such as you) sometimes watch the video and don't see it.

Try it yourself at the link above. Even if you see the gorilla, might you have missed it if you didn't know about it, as was the case for the research participants? Much as I wish I could say otherwise, I'd have been among those who didn't see it. I'd have been so focused on counting and so determined to get the count right that I'd have missed the gorilla altogether-just as I missed seeing my gate as A52.

What intrigues me about my departure gate situation is that I wasn't blind due to being distracted by something else; I was blind due to being distracted by my belief about what I'd see. As the research demonstrates, we sometimes see little of what's going on around us and easily miss essential information that's right in front of us. (Yet another reason not to text while driving.)

In preparation for future travels, I'm taking a remedial course in my ABCs.