Writing at Pacific Standard, psychologist David Dunning — one of the social psychologists who first documented this type of cognitive bias — describes it in more detail:
In many areas of life, incompetent people do not recognize — scratch that, cannot recognize — just how incompetent they are, a phenomenon that has come to be known as the Dunning-Kruger effect. Logic itself almost demands this lack of self-insight: For poor performers to recognize their ineptitude would require them to possess the very expertise they lack. To know how skilled or unskilled you are at using the rules of grammar, for instance, you must have a good working knowledge of those rules, an impossibility among the incompetent. Poor performers — and we are all poor performers at some things — fail to see the flaws in their thinking or the answers they lack. What’s curious is that, in many cases, incompetence does not leave people disoriented, perplexed, or cautious. Instead, the incompetent are often blessed with an inappropriate confidence, buoyed by something that feels to them like knowledge. Continue reading.