Before we jump in,
Research shows that 93% of Americans think they are better drivers than average. But not all of us can be above average, right? This is a classic example of the Dunning-Kruger effect.
In 1995, McArthur Wheeler walked into two Pittsburgh banks and robbed them in broad daylight, with no visible attempt at disguise. He was arrested later that night, less than an hour after surveillance photos of him were broadcast on the 11 o'clock news. When police showed him the surveillance tapes, Wheeler stared in disbelief. "But I wore the juice," he mumbled.
Apparently, Wheeler believed that rubbing lemon juice on his face would render him invisible to video cameras. After all, lemon juice is used as invisible ink, so why wouldn't it work on his face?
This bizarre case caught the attention of David Dunning, a Cornell psychology professor who, along with his graduate student Justin Kruger, saw in Wheeler's story something more than a tale of a spectacularly ill-informed criminal. They wondered: Could it be that Wheeler was too incompetent to recognize his own incompetence?
To test this hypothesis, Dunning and Kruger designed a series of experiments. In one study, they asked undergraduate students to rate their logical reasoning skills, grammatical skills, and humor. The students were then asked to take a test in each of these areas, and also to estimate how well they performed on the test compared to other students.
The results were striking. Students who scored in the bottom quartile on the tests grossly overestimated their own performance. Those in the 12th percentile of logical reasoning ability, for instance, estimated that they were in the 68th percentile. Meanwhile, students who scored highest often underestimated their performance.
Dunning and Kruger had discovered a cognitive bias in which people with limited knowledge or competence in a given intellectual or social domain greatly overestimate their own knowledge or competence in that domain relative to objective criteria or to the performance of their peers.
The only true wisdom is in knowing you know nothing — Socrates