Bank robbers carried out such a stupid act scientists used it as research for new condition

Two robbers had a plan to rob banks and not be caught on CCTV, by using lemon juice to appear invisible in front of cameras

It was a crime considered so “stupid” it prompted psychologists to study the criminals involved for anomalies, leading to the discovery of a cognitive effect that explained their behaviour.

In 1995, McArthur Wheeler and Clifton Earl Johnson carried out multiple bank robberies in the Greater Pittsburgh area, in the United States.

What set this crime apart from regular heists was the fact that the two criminals walked into the bank branches – the Swissvale branch of Mellon Bank, Parkvale Savings Bank and Fidelity Savings Bank in Brighton Heights – holding semi-automatic handguns and showing their faces, with no attempts made to cover cameras or disguise their identities.

Instead, the two men had applied lemon juice to their faces, which they thought would make them unidentifiable.

According to Wheeler, Johnson had told him that lemon juice was one of the essential ingredients in invisible ink, which meant that, if applied directly to one’s skin, it would make one invisible on camera.

But they didn’t blindly believe that theory – the two robbers put their invisible ink to the test by smearing lemon juice all over Wheeler’s face and then having the man take a Polaroid picture of himself. The print got developed a few minutes later, and Wheeler was nowhere to be found in the image – something the police credited to either him just failing to aim the camera at his own face, or a faulty film.

Convinced they would undoubtedly be invisible and undetectable on camera, Wheeler and Johnson went through with the plan. The only thing that went wrong, according to them, was that the lemon juice made their eyes sting the whole time while they were robbing the banks.

Unexpectedly to both of them, their faces were, in fact, easily recognisable and captured on CCTV. It wasn’t long before the police tracked down and arrested Wheeler and Johnson.

When they were captured, Wheeler reportedly looked at the pictures that showed him robbing a bank at gunpoint and exclaimed, “But I wore the lemon juice. I wore the lemon juice!”

Johnson got a prison sentence of five years for testifying against Wheeler, who, in turn, was locked up for over 24 years.

The robberies were documented on the 1996 World Almanac, which prompted Cornell University social psychology professor David Dunning to grow interested in studying the men’s thought process.

His findings were, as published in the Pittsburgh Post-Gazette, that “If Wheeler was too stupid to be a bank robber, perhaps he was also too stupid to know that he was too stupid to be a bank robber – that is, his stupidity protected him from an awareness of his own stupidity.”

Alongside graduate student Justin Kruger, Dunning coined the Dunning-Kruger effect, which explains a cognitive bias that leads people to give overly positive assessments of their own ability.

In Wheeler and Johnson’s case, he said: “When people are incompetent in the strategies they adopt to achieve success and satisfaction, they suffer a dual burden: Not only do they reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realise it. Instead, like Mr Wheeler, they are left with the mistaken impression that they are doing just fine.”