Don’t know, but found it to be true anecdotally and heard others say the same.
Jason Toff

It’s called the Dunning–Kruger effect (

TL;DR: Capable people tend to know how much they don’t know and it negatively affects their confidence. Incapable people are more unaware and tend to act overly confident. The dark side of this effect is that observers tend to associate confidence with capability, when in fact they are often inversely proportional.