“Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it.” — Kruger and Dunning, 1999
What’s it about?
This paper is the basis of what is now called the Dunning-Kruger Effect. This is the phenomenon where people tend to grossly overestimate their abilities, especially when they are objectively incompetent at a particular task. Conversely, people of high competence tend to underestimate their ability.
Why does it matter?
Not everyone can be ‘above average.’ After all, by definition, half of people must be below average. Yet, most people consider themselves above average, at least for cognitive tasks (for example: recognizing humor, using logic, and writing with correct grammar). This can result in some pretty serious mistakes. Thus, it’s important to demonstrate that this phenomenon exists, and to explore what causes it.
Why did I read this?
The Dunning-Kruger Effect has been splashed all over social media because of this unfortunate tweet:

Many claim this as an example of the Dunning-Kruger Effect. After all (as Kruger and Dunning, 1999 point out), a real genius tends to underestimate his or her ability.
There have been many rebuttals and angry messages, but this one is my favorite:
IM A HORSE THAT LEARNED TO TYPE
I THINK THAT MAKES ME A STABLE GENIUS https://t.co/OC1HrxPyeN
— Roy Moore’s Horse (@RoyMooresHorse) January 6, 2018
Also, if you want to download the original paper, but find that it’s behind a paywall, click this link. I found a PDF copy online. Shhh.