1995: Justin Kruger and David Dunning illustrated their article “Unskilled and Unaware of It” with the example of McArthur Wheeler, who robbed two Pittsburgh banks in broad daylight with no obvious attempt at disguise. When arrested shortly afterwards, Wheeler expressed surprise that the lemon juice he had rubbed on his face had failed to make him invisible to surveillance cameras. Why lemon juice? Because lemon juice can be used as invisible ink, so, as any fool knows, rubbing it on the skin obviously makes one’s features invisible. In their article in the Journal of Personality and Social Psychology, Kruger and Dunning argued that, not only are the McArthur Wheelers of this world incompetent, but their incompetence means that they don’t realize they are incompetent.
Source: Journal of Personality and Social Psychology, December 1999