Overconfidence is quite common. It can also be pretty dangerous.
The authors note that drivers, motorcyclists, and bungee jumpers commonly overestimate their ability to travel or jump safely and that can resonate beyond themselves: “ … one person’s overconfidence can carry significant consequences for others,” the authors write. “People base important health and financial decisions on advice offered by doctors and lawyers.
This practice seems suspect in light of evidence that both … tend to be overconfident with respect to their job-related knowledge and skills.”
medical errors, car accidents, and legal issues aren’t the only consequences of overconfidence.
The study authors hypothesized that people who overestimate how much better they are than everyone else are less likely to push themselves intellectually.
This is related to what the researchers call the entity theory of intelligence, in which a person believes that intellectual aptitude is concrete and unchanging.