A little confidence can be a very good thing. But too much confidence may hurt you in the long run: Researchers say overconfident people are less likely to challenge themselves and may therefore miss out on opportunities to learn. Their findings were published this month in the Journal of Experimental Social Psychology

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.”

But 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.

They tested their idea with three studies on college students. In the first study, students completed a questionnaire on their ideas about intelligence. They were asked how strongly they agreed or disagreed with statements like “You have a certain amount of intelligence, and you can't really do much to change it.” Then the students took a 10-question multiple-choice test on a computer. After, the researchers asked the students to estimate on a scale from 0 to 100 how well they thought they did on the test.

The second experiment sought to determine how people who subscribed to the entity theory would allocate their time between easy and difficult tasks. They gave half the participants a fake science article claiming that intelligence is fixed. The other half got an article claiming the opposite. All of the participants were asked to read the article carefully, as though they would be judged on their reading comprehension. The researchers then administered the same 10-question test and again asked the students to guess how well they did.

The third study tested whether the overconfidence of entity theorists could be reduced by making them perform difficult tasks. The students filled out a questionnaire to determine their ideas about intelligence, then took a general-knowledge test consisting of 10 easy questions and 10 harder questions. After the test, some students were asked to review their answers to the hard questions, while the others looked at the easy questions. The researchers added additional tasks like proofreading and naming the color of the text to further increase the difficulty for the hard-question group. All the time, the participants’ computers were tracking how they spent their time and attention.

The three studies confirmed what the researchers had suspected: Entity theorists were both more likely to overestimate their own abilities and less likely to challenge themselves.  

The researchers also found that drawing the students’ attention to growth theory via the fake science article did decrease their overconfidence and increase their openness to learning. These findings have implications for schools, the authors say; if growth theory can be taught, students may be better equipped to learn. 

"By focusing on aspects of the task that were easy and spending as little time as possible on more difficult parts of the task," study lead Joyce Ehrlinger said in a press statement, "fixed theorists felt as if they had performed very well relative to their peers. In contrast, growth theorists weren't threatened by challenging parts of the task and didn't feel the need to bask in the glow of the parts that were easy. This more balanced way of completing the task left growth theorists with a better understanding of how well they did."

Being overconfident is a barrier to intellectual growth, Ehrlinger said: "You have to understand and acknowledge what you don't yet know in order to truly learn. This research suggests that part of why growth mindsets improve learning might be because they lead people to better understand what they do and what they do not know."

This study does have its limits—all of the participants were college students, which likely influenced the results—but the concept is still worth further examination.