ahem, Trump.......

The bias is not necessarily innate. Reading through a link on Wikipedia, there seems to be cultural differences between how people access their abilities and how they respond to success and failure. Of course, American culture tends to produce people who are overconfident, given the anti-intellectualism and faux intellectualism this country seems to specialize in:

http://www.apa.org/monitor/feb03/overestimate.aspx

I also find that people, in general, tend to be overconfident in their abilities to access facts properly. This is why you have broken clocks being right twice a day and inverse broken clocks being wrong twice a day. One of the areas I like looking into is epistemic peer disagreement- how we should respond regarding our beliefs when we encounter a person who, for all intents and purposes, is your equal on a subject. Philosophers especially fall victim to ignoring the fact that the person whose position they consider so erroneous has the same level of education and read the same essays; it never occurs to people that they might be the wrong party involved, not their opposition.

American culture tends to produce people who are overconfident, given the anti-intellectualism and faux intellectualism this country seems to specialize in — Chany

While I agree with you in principle, I think it is the other way around. In the USA, lower-class culture teaches children that intelligent and educated people are elitist and untrustworthy, so as adults they tend to believe themselves more successful than they are. There is a paradox, though, that people who wrongly believe their skills in language and maths to be higher are putting themselves in the class they despise. More interesting is the reverse tendency for skilled people to underestimate their abilities, which seems less explicable in cultural terms. It seems more explicable that people with more knowledge have a better idea of the limits of knowledge.

American culture tends to produce people who are overconfident, given the anti-intellectualism and faux intellectualism — Chany

I don't think it is especially American but rather globalisation has enabled faux-individuality where everyone has found a superficial happiness in the delusional belief that they are individuals when they actually blindly move in masses and when more people approve a particular behavioural trend, the more legitimate it appears despite lacking the attributes and hard work that comes with attaining anything worthy, thus is spawned overconfidence. People actually believe that having a quantity of likes toward pictures that they post of themselves implies worthiness and we have formed nothing but a narcissistic society.

Thanks for adding that it might not be innate, it could have been an error on my part. It seems undeniable that culture does play a great role.

[Trump] is thus the all-time record-holder of the Dunning-Kruger effect, the phenomenon in which the incompetent person is too incompetent to understand his own incompetence. Trump thought he’d be celebrated for firing James Comey. He thought his press coverage would grow wildly positive once he won the nomination. He is perpetually surprised because reality does not comport with his fantasies. — David Brooks

When the World is Led by a Child

He is perpetually surprised because reality does not comport with his fantasies. — David Brooks

I doubt he is. I think reality conforms to the way he sees it. What he disagree with shall be denoted as fake news. Or he has some alternative facts.