hazard of confidence: the illusion of validity

NYTimes | Many decades ago I spent what seemed like a great deal of time under a scorching sun, watching groups of sweaty soldiers as they solved a problem. I was doing my national service in the Israeli Army at the time. I had completed an undergraduate degree in psychology, and after a year as an infantry officer, I was assigned to the army’s Psychology Branch, where one of my occasional duties was to help evaluate candidates for officer training. We used methods that were developed by the British Army in World War II.

One test, called the leaderless group challenge, was conducted on an obstacle field. Eight candidates, strangers to one another, with all insignia of rank removed and only numbered tags to identify them, were instructed to lift a long log from the ground and haul it to a wall about six feet high. There, they were told that the entire group had to get to the other side of the wall without the log touching either the ground or the wall, and without anyone touching the wall. If any of these things happened, they were to acknowledge it and start again.

A common solution was for several men to reach the other side by crawling along the log as the other men held it up at an angle, like a giant fishing rod. Then one man would climb onto another’s shoulder and tip the log to the far side. The last two men would then have to jump up at the log, now suspended from the other side by those who had made it over, shinny their way along its length and then leap down safely once they crossed the wall. Failure was common at this point, which required starting over.

As a colleague and I monitored the exercise, we made note of who took charge, who tried to lead but was rebuffed, how much each soldier contributed to the group effort. We saw who seemed to be stubborn, submissive, arrogant, patient, hot-tempered, persistent or a quitter. We sometimes saw competitive spite when someone whose idea had been rejected by the group no longer worked very hard. And we saw reactions to crisis: who berated a comrade whose mistake caused the whole group to fail, who stepped forward to lead when the exhausted team had to start over. Under the stress of the event, we felt, each man’s true nature revealed itself in sharp relief.

After watching the candidates go through several such tests, we had to summarize our impressions of the soldiers’ leadership abilities with a grade and determine who would be eligible for officer training. We spent some time discussing each case and reviewing our impressions. The task was not difficult, because we had already seen each of these soldiers’ leadership skills. Some of the men looked like strong leaders, others seemed like wimps or arrogant fools, others mediocre but not hopeless. Quite a few appeared to be so weak that we ruled them out as officer candidates. When our multiple observations of each candidate converged on a coherent picture, we were completely confident in our evaluations and believed that what we saw pointed directly to the future. The soldier who took over when the group was in trouble and led the team over the wall was a leader at that moment. The obvious best guess about how he would do in training, or in combat, was that he would be as effective as he had been at the wall. Any other prediction seemed inconsistent with what we saw.

Because our impressions of how well each soldier performed were generally coherent and clear, our formal predictions were just as definite. We rarely experienced doubt or conflicting impressions. We were quite willing to declare: “This one will never make it,” “That fellow is rather mediocre, but should do O.K.” or “He will be a star.” We felt no need to question our forecasts, moderate them or equivocate. If challenged, however, we were fully prepared to admit, “But of course anything could happen.”

We were willing to make that admission because, as it turned out, despite our certainty about the potential of individual candidates, our forecasts were largely useless. The evidence was overwhelming. Every few months we had a feedback session in which we could compare our evaluations of future cadets with the judgments of their commanders at the officer-training school. The story was always the same: our ability to predict performance at the school was negligible. Our forecasts were better than blind guesses, but not by much.

We were downcast for a while after receiving the discouraging news. But this was the army. Useful or not, there was a routine to be followed, and there were orders to be obeyed. Another batch of candidates would arrive the next day. We took them to the obstacle field, we faced them with the wall, they lifted the log and within a few minutes we saw their true natures revealed, as clearly as ever. The dismal truth about the quality of our predictions had no effect whatsoever on how we evaluated new candidates and very little effect on the confidence we had in our judgments and predictions.

I thought that what was happening to us was remarkable. The statistical evidence of our failure should have shaken our confidence in our judgments of particular candidates, but it did not. It should also have caused us to moderate our predictions, but it did not. We knew as a general fact that our predictions were little better than random guesses, but we continued to feel and act as if each particular prediction was valid. I was reminded of visual illusions, which remain compelling even when you know that what you see is false. I was so struck by the analogy that I coined a term for our experience: the illusion of validity.

I had discovered my first cognitive fallacy.

Decades later, I can see many of the central themes of my thinking about judgment in that old experience. One of these themes is that people who face a difficult question often answer an easier one instead, without realizing it. We were required to predict a soldier’s performance in officer training and in combat, but we did so by evaluating his behavior over one hour in an artificial situation. This was a perfect instance of a general rule that I call WYSIATI, “What you see is all there is.” We had made up a story from the little we knew but had no way to allow for what we did not know about the individual’s future, which was almost everything that would actually matter. When you know as little as we did, you should not make extreme predictions like “He will be a star.” The stars we saw on the obstacle field were most likely accidental flickers, in which a coincidence of random events — like who was near the wall — largely determined who became a leader. Other events — some of them also random — would determine later success in training and combat.

You may be surprised by our failure: it is natural to expect the same leadership ability to manifest itself in various situations. But the exaggerated expectation of consistency is a common error. We are prone to think that the world is more regular and predictable than it really is, because our memory automatically and continuously maintains a story about what is going on, and because the rules of memory tend to make that story as coherent as possible and to suppress alternatives. Fast thinking is not prone to doubt.

The confidence we experience as we make a judgment is not a reasoned evaluation of the probability that it is right. Confidence is a feeling, one determined mostly by the coherence of the story and by the ease with which it comes to mind, even when the evidence for the story is sparse and unreliable. The bias toward coherence favors overconfidence. An individual who expresses high confidence probably has a good story, which may or may not be true.

I coined the term “illusion of validity” because the confidence we had in judgments about individual soldiers was not affected by a statistical fact we knew to be true — that our predictions were unrelated to the truth. This is not an isolated observation. When a compelling impression of a particular event clashes with general knowledge, the impression commonly prevails. And this goes for you, too. The confidence you will experience in your future judgments will not be diminished by what you just read, even if you believe every word. Fist tap Arnach.