As I was taking my afternoon break, I listened to This American Life on the local PBS station, KMUW. One segment of that program reminded me of a study, the results of which seem applicable to some of the candidates for higher office in the USA. Immediately, I Googled "Dunning-Kruger" effect to find the write-up in Wikipedia. The first couple of paragraphs follow, below.
The Dunning–Kruger effect is a cognitive bias in which relatively unskilled persons suffer illusory superiority, mistakenly assessing their ability to be much higher than it really is. Dunning and Kruger attributed this bias to a metacognitive inability of the unskilled to recognize their own ineptitude and evaluate their own ability accurately. Their research also suggests corollaries: highly skilled individuals may underestimate their relative competence and may erroneously assume that tasks which are easy for them are also easy for others.
The bias was first experimentally observed by David Dunning and Justin Kruger of Cornell University in 1999. They postulated that the effect is the result of internal illusion in the unskilled, and external misperception in the skilled: "The miscalibration of the incompetent stems from an error about the self, whereas the miscalibration of the highly competent stems from an error about others."
1. Kruger, Justin; Dunning, David (1999). "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments". Journal of Personality and Social Psychology 77 (6): 1121–34.