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The American author and aphorist William Feather once wrote that being educated means "being able to differentiate between what you know and what you don't." As it turns out, this simple ideal is extremely hard to achieve. Although what we know is often perceptible to us, even the broad outlines of what we don't know are all too often completely invisible. To a great degree, we fail to recognize the frequency and scope of our ignorance.
In 1999, in the Journal of Personality and Social Psychology, my then graduate student Justin Kruger and I published a paper that documented how, in many areas of life, incompetent people do not recognize - scratch that, cannot recognize - just how incompetent they are, a phenomenon that has come to be known as the Dunning-Kruger effect. Logic itself almost demands this lack of self-insight: For poor performers to recognize their ineptitude would require them to possess the very expertise they lack. To know how skilled or unskilled you are at using the rules of grammar, for instance, you must have a good working knowledge of those rules, an impossibility among the incompetent. Poor performers - and we are all poor performers at some things - fail to see the flaws in their thinking or the answers they lack.
What's curious is that, in many cases, incompetence does not leave people disoriented, perplexed, or cautious. Instead, the incompetent are often blessed with an inappropriate confidence, buoyed by something that feels to them like knowledge.
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Because it's so easy to judge the idiocy of others, it may be sorely tempting to think this doesn't apply to you. But the problem of unrecognized ignorance is one that visits us all. And over the years, I've become convinced of one key, overarching fact about the ignorant mind. One should not think of it as uninformed. Rather, one should think of it as misinformed.
An ignorant mind is precisely not a spotless, empty vessel, but one that's filled with the clutter of irrelevant or misleading life experiences, theories, facts, intuitions, strategies, algorithms, heuristics, metaphors, and hunches that regrettably have the look and feel of useful and accurate knowledge. This clutter is an unfortunate by-product of one of our greatest strengths as a species. We are unbridled pattern recognizers and profligate theorizers. Often, our theories are good enough to get us through the day, or at least to an age when we can procreate. But our genius for creative storytelling, combined with our inability to detect our own ignorance, can sometimes lead to situations that are embarrassing, unfortunate, or downright dangerous - especially in a technologically advanced, complex democratic society that occasionally invests mistaken popular beliefs with immense destructive power (See: crisis, financial; war, Iraq). As the humorist Josh Billings once put it, "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." (Ironically, one thing many people "know" about this quote is that it was first uttered by Mark Twain or Will Rogers - which just ain't so.)
Because of the way we are built, and because of the way we learn from our environment, we are all engines of misbelief. And the better we understand how our wonderful yet kludge-ridden, Rube Goldberg engine works, the better we - as individuals and as a society - can harness it to navigate toward a more objective understanding of the truth.
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But something curious started happening as we began to look at the people who did extremely badly on our little quiz. By now, you may be able to predict it: These people expressed more, not less, confidence in their performance. In fact, people who got none of the items right often expressed confidence that matched that of the top performers. Indeed, this study produced the most dramatic example of the Dunning-Kruger effect we had ever seen: When looking only at the confidence of people getting 100 percent versus zero percent right, it was often impossible to tell who was in which group.
Why? Because both groups "knew something." They knew there was a rigorous, consistent rule that a person should follow to predict the balls' trajectories.