A cartoon from Jon Wilkins at the Santa Fe Institute, no less.
(Yeah, I know — it’s not big. Click the image, go see a bigger version at Wilkins’s site.)
Kruger, J., & Dunning, D. (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), 1121-1134 DOI: 10.1037/0022-35188.8.131.521
Earlier flotsam in Millard Fillmore’s Bathtub: “Quote of the moment: Bertrand Russell on the Dunning-Kruger Effect, 64 years prescient”