19 April 1995. Pittsburgh. Pennsylvania. McArthur Wheeler decided to rob two savings banks. He had an infallible plan.

Since lemon juice can be used to write invisible letters which are only revealed when the letter is heated, by smearing lemon juice on his face, McArthur was certain that he would be invisible to the security cameras. He even tested it by taking a selfie with a polaroid, which for some reason came out blank. When he was caught by the police after being identified by reviewing the security footage, his comment was: “But I was wearing the Juice!”

Psychologists Dunning and Kruger studied this case and arrived at the conclusion that the less competent an individual is at a specific task, the more likely they are to inflate their self-appraised competence in relationship to that task. This phenomenon is today known as the Dunning-Kruger effect.

We can see examples of the Dunning-Kruger effect in :

• Shows like American Idol where we see people who clearly can’t sing, who are surprised and complain when they get rejected.
• Nobel prize winning economists losing $4.6Bn in 4 months in Long-Term Capital Management.
• Billionaire businessmen running for president of the USA
• Amateur investors losing money in bitcoin investments

To some degree we all suffer the Dunning-Kruger effect. It is wise to acknowledge this and be self-critical when evaluating the work of others.