1995, Pittsburgh, USA. MacArthur Wheeler breaks into a bank for a robbery. But strangely, he acts with his face uncovered… and smells very strong lemon! Easily identified thanks to surveillance cameras, he is arrested the same evening.

So why didn’t Wheeler cover his face like all robbers do?

Wheeler thought having a great idea: lemon juice could serve as invisible ink to write secret messages, therefore it could be used to become invisible to the cameras if he would spray his face.

This piece of news intrigues two psychologists, Daniel Dunning and Justin Kruger: how can people be so sure of themselves when they obviously know nothing?

To find an answer, the two psychologists set up a small experiment. They submit tests (humorist, grammatical, and logical reasoning) to groups of people and then ask them to self-assess. As a result, the people who have failed their tests the most are also those who feel they have done the best.

This is the “Dunning-Kruger effect“, also called the overconfidence effect: when you are not competent in a field, you do not recognize this incompetence and you are even strongly tempted to overestimate your own abilities!

Wheeler the robber, who thought being an expert in becoming invisible, was probably a victim of this psychological bias which can also do damage in other fields. For example, if in the workplace, very self-confident incompetents get promoted instead of competent but more discreet colleagues, this can generate stress, a sense of injustice and demotivation within a team.

In short, it can make relationships between colleagues as acid as lemon!

How many overconfident people have you met?

yellow lemon fruit on yellow surface
Lemon – Photo by Cup of Couple on Pexels.com