On 19 April 1995, McArthur Wheeler robbed two banks in Pittsburgh. Knowing that lemon juice can be used as a simple invisible ink, he smeared his face with it before the robberies, believing the juice would make his features invisible to the security cameras …
This ‘illusion of competence’ is known as the Dunning-Kruger effect, a cognitive bias that describes the difficulty we all have in assessing our own abilities. Psychologists David Dunning and Justin Kruger explain that poor performers tend to over-estimate their own ability, while experts tend to over-estimate the ability of others.
It’s important to understand that in most cases, the Dunning-Kruger effect happens as a result of incomplete or incorrect information, not ignorance or stupidity. Before carrying out the robberies, McArthur Wheeler tested his theory with a Polaroid camera, which returned a blank image. Exactly why is a mystery, but he was reportedly shocked to clearly see his face when shown security footage by police after his arrest – he genuinely thought the lemon juice would make his features invisible.
This is relevant for two reasons. Firstly, when assessing ourselves, Dunning-Kruger only happens when we think our information is correct. If we are uncertain, then our doubt allows us to say “I don’t know”. This means we should be wary of certainty. Secondly, when we think others may be experiencing Dunning-Kruger, while they might appear stupid to us, we need to remember that they are probably acting in good faith.
The other end of the scale is what happens when we do have knowledge. In this case, we are generally pretty good at assessing our own level of expertise – but we tend to over-estimate how much other people know. We assume that because we find something easy everyone else does too, which can lead us to doubt ourselves.
This uncertainty may come from realising we know absolutely nothing about a given subject – but it also happens when we have enough understanding to recognise where the gaps in our knowledge are. Whether in ourselves or others, this awareness of uncertainty should be seen as a positive, and should not devalue the knowledge we do possess. We should also pay attention when someone else is uncertain, because perhaps they can see a bigger picture than we can.
There are two main ways to avoid falling into the Dunning-Kruger trap. The first is being open to feedback, and the second is to be continually learning. In the words of David Dunning himself:
“The trick is to be your own devil’s advocate: to think through how your favoured conclusions might be misguided; to ask yourself how you might be wrong, or how things might turn out differently from what you expect.”