The Dunning-Kruger effect is a type of cognitive bias that causes people to overestimate their abilities. In particular, the Dunning-Kruger effect shows that people who know less about a topic or skill tend to overestimate their competence the most. Essentially, the more ignorant you are, the more ignorant you are of your own ignorance.

History of the Dunning-Kruger Effect

The concept of the Dunning-Kruger effect is based on a study in the late 1990s by Drs. David Dunning and Justin Kruger. They asked 65 participants to take a test that would measure their logic, grammar, and sense of humor, and then rate their own perception of their skills.

Those who scored in the bottom 25% showed the largest discrepancy between their actual rating and their predicted rating. Essentially, they were grossly unaware of their own incompetence.

Dunning-Kruger Effect Examples

• A person without any government or public service experience believing they would be a highly effective elected representative
• A student who constantly interrupts and challenges their professor during lectures despite not reading any of the required material
• Someone from a privileged social group feeling qualified to speak for or on behalf of a disadvantaged or oppressed social group despite a lack of shared experiences
• Someone without children openly criticizing a mother for her choice to breastfeed or use formula
• A heckler believing they could be more entertaining on stage without any preparation than the entertainer they paid to see
• A passenger who wants to speak with the pilot to share information they found online about how to land more smoothly

What Is Cognitive Bias?

The Dunning-Kruger effect is just one kind of cognitive bias that affects how we perceive the world. But what is cognitive bias?

Essentially, cognitive bias captures the illogical, often irrational ways we make decisions and move through the world. Although we like to believe we make decisions based on fact and truth, most people make decisions based on a mixture of biases, influences, instincts, and feelings, as well as hard facts. Cognitive biases are shortcuts in our decision-making that we often take without our conscious knowledge.

10 Common Cognitive Biases

In addition to the Dunning-Kruger effect, other common cognitive biases include:

1. Actor-observer bias: Believing your actions are motivated by external factors (e.g., you didn’t turn in your homework because your dog ate it) while believing others’ actions are motivated by internal factors (e.g., your classmate didn’t turn in their homework because they’re inherently lazy)
2. Anchoring effect: Being overly influenced by firsts (e.g., first impressions, first piece of data, first offers, etc.)
3. Availability bias: Using readily available examples that come to mind for your decision-making, thereby giving popular, easily accessible, or commonly repeated data outsized influence (e.g., avoiding traveling by airplane after watching LOST even though your risk of dying in a car accident is much greater than dying in a plane crash)
4. Bandwagon effect: Adopting certain thoughts, feelings, beliefs, or actions in order to go along with a larger group (also known as herd mentality or groupthink)
5. Confirmation bias: Believing only that which already fits with your current beliefs
6. Gambler’s fallacy: Believing that the past frequency of an event has an effect on the probability of that event occurring or recurring in the future (e.g., believing that flipping a coin on its head 10 times makes it more likely that the next toss will land on tails)
7. Hindsight bias: Believing you had greater foresight to predict an event accurately after it has already occurred (e.g., saying you always knew a certain candidate would win an election, even though it was an incredibly close race)
8. Loss aversion: Feeling more pain from loss than pleasure from gain (e.g., paying more attention to gas prices when they increase than when they decrease)
9. Narrative bias: Interpreting the world through story, even when facts are unrelated or do not fit the ultimate narrative (e.g., believing your boss will yell at you or fire you when they unexpectedly request a meeting, while conveniently ignoring the fact that you already exceeded your performance goals for the month and are an exemplary employee)
10. Self-serving bias: Attributing your successes to yourself while spreading the blame for your failures among external factors (e.g., crediting a good test grade to your intelligence and skill while crediting a bad test grade to a lack of sleep, unfair questions, etc.)

What Causes the Dunning-Kruger Effect?

The Dunning-Kruger effect is the result of overconfidence and lack of metacognition, or your awareness and understanding of your thought processes and patterns.

Many people incorrectly believe that the knowledge they currently possess is applicable elsewhere, or that they can pick up new skills and understand new information more easily than others. Your desire to prove that you can “keep up,” so to speak, may tempt you to overestimate your competence in new or unfamiliar areas. It is when we are ignorant that we are most likely to lean on mental shortcuts like cognitive biases.

The Four Stages of Competence

Developed in the late 1960s and early 1970s, the four stages of competence, also known as the hierarchy of competence, show the relationship between awareness and competence and how that affects the learning process. The four stages are:

1. Unconscious incompetence: You’re ignorant of what you don’t know.
2. Conscious incompetence: You’re aware of what you don’t know, but you haven’t taken any steps to learn more.
3. Conscious competence: You’re actively learning and acquiring knowledge about a subject.
4. Unconscious competence: You’ve mastered a subject to the point that you may forget or take for granted how much you truly know.

The Dunning-Kruger effect is strongest in people who are in the first stage of competence: unconscious incompetence. If you don’t know what you don’t know, the Dunning-Kruger effect says you are actually more likely to feel confident in your knowledge (or lack thereof) than others who are at higher stages of competence.

Who Is Affected by the Dunning-Kruger Effect?

Some people mistakenly use the Dunning-Kruger effect as proof that certain groups of people are inherently more ignorant than others. However, the Dunning-Kruger effect applies to everyone. We all have skills or areas of knowledge in which we are completely ignorant, and we are all susceptible to cognitive biases. It is exactly those areas of unconscious incompetence in which we are most likely to prove the Dunning-Kruger effect correct.

Dunning-Kruger Effect vs. Imposter Syndrome

The opposite of the Dunning-Kruger effect is imposter syndrome. Imposter syndrome is characterized by a lack of confidence, regardless of high competence, and may be related to low self-esteem in general. People with imposter syndrome have achieved high levels of mastery of a skill or knowledge area but still doubt their abilities. They may even feel like frauds, despite an overwhelming amount of evidence to the contrary.

How to Overcome Cognitive Biases

Cognitive biases like the Dunning-Kruger effect exist to make our decision-making process feel simpler and more obvious. However, cognitive biases can get in the way of more nuanced thinking and complex decision-making. Here are a few ways to try to challenge your cognitive biases so you can overcome them: