The average American probably believes all these statements, according to David Dunning, a professor of psychology at Cornell University. Dunning asks subjects to estimate their abilities in English grammar, logic and humor, and finds that Americans are surprisingly bad at estimating their own skills, knowledge and experience. And each time, the most inaccurate estimates came from the most inept people. But he thinks exaggerating abilities may be harmful or helpful, depending on the situation. Everybody is wildly overoptimistic about their ability to pull off a successful marriage.
Blue line indicates subjects' assessment of their problem-solving ability.
Red line indicates performance on a test of problem-solving. Self-assessments of ability had essentially nothing to do with actual ability. But overestimating your abilities can be dangerous. A recent study of medical lab technicians found the familiar pattern of inaccuracy on the ability to solve problems, and knowledge of laboratory tests and medical lingo. It suggests that as you gain experience, you gain explanatory power, you come up with stories that explain events in the world.