Now a separate post born of my compulsive pedantry. This is not a comment on the theme itself, but simply an unsolicited pseudo-educational PSA / screed / pet peeve, for anyone who might not know much about this topic and is interested. This might allow such folks to be better informed when invoking the Dunning-Kruger effect in discussions outside of the specific ruleset defined here.
Firstly, there is a lot to suggest that the "effect" itself is largely bunk, or at least not consistent enough to be considered anything beyond ... a phenomenon that sometimes occurs, but not necessarily in a universal correlative or causal pattern. This is true for a lot of experiments and studies in the social sciences, and no shade to Dunning and Kruger themselves. It's just that their results are predictably limited and don't (and perhaps can't) account for the breadth of cultural, social, and individual factors at play. It IS, in my opinion, a useful phenomenon, and potential fallcy / bias, to keep in mind if one wants to live what might be called "an examined life," so it's not like I'd throw the baby out with the bathwater on this one. It's good to constantly examine one's own faults and limitations, and doing so can probably make us all wiser, if not necessarily "smarter" or more competent.
Secondly, and this very much complicates and informs the above, the idea that the DK effect is about inherent intelligence is a common misreading. It primarily deals with the discrepancy between one's actual competence and knowledge, as applied to specific and discrete areas, and one's own perception of their competence and knowledge in that discrete field. Might seem like semantics, but this becomes an important distinction when we, collectively and individually, try to examine ourselves and our biases, because it implies, correctly, that nobody, and I mean nobody, is excempt from this so called effect, regardless of how book-smart or street-smart they are - someone could be a Nobel prize winning theoretical physicist and still easily fall prey to it, perhaps even more so, as they are likely to have an overinflated sense of their own general competence based on their other specific achievements. They might, for example, believe that they can quickly and easily figure out how to fix the engine of their car better than a "common" mechanic, or may underplay the challenges of most artistic pursuits and assume that they themselves are inherently capable enough to paint like Sargent or compose like Beethoven ... if only they wanted to ... but, of course, they simply choose not to try ... because they have more important things to do.
Of course, one can have demonstrable proof of their brain's "above average" cognitive speed and processing capacity, and still fall victim to the effect's flipside, which essentially means that they experience severe imposter syndrome, regardless how many awards or accolates they accumulate, regardless of the fact that they are, objectively, the world's foremost expert on X, and teach a course on X at Columbia. This, of course, is a matter for them and their therapist to sort out. However, pretty much all people are equally susceptible to both sides of the cognitive bias, and there are absolutely various cultural and socioeconmic factors at play that have nothing to do with what we'd call "inherent intelligence." There are plenty of people who, due to circumstances outside of their control, end up "underperforming" in a variety of areas, and blaming this entirely on their own perceived lack of competence and intelligence. Similarly, when someone has had everything handed to them their entire life, they are more likely to feel justified in all kinds of internal Dunning-Kruger nonsense, whether they are actually below average, entirely average, or highly intelligent.
And that's just a really long winded way of saying what most people without my particularly awful brain, and yeah, I recognize both the resonance and the irony in this statement, could probably explain in just one short paragraph.
In short, the actual, real world Dunning-Kruger effect has nothing to do with how "smart" or "stupid" anyone is, and is in fact a cognitive-bias that NOBODY gets a pass on and EVERYBODY can be, and likely has been, at one point or another, affected by - it, in itself, is really just a very messy overcomplication of what I'd consider a fairly solid bit of folk wisdom (i.e. hubris is bad ... remember, thou art foolish ... etc.)