Dunning-Kruger Effect: What to Know

Medically Reviewed by Melinda Ratini, MS, DO on November 09, 2021
5 min read

Every now and then, you may come across someone who thinks they know more about a topic than others, when they actually have little to no background to support that belief. If so, you may have encountered the Dunning-Kruger effect.

It's when underperformers grossly overestimate their ability to do something. They also lack the awareness to realize their limits and shortcomings. This faulty perception is a type of what psychologists call cognitive bias.

The Dunning-Kruger effect was named after two Cornell University psychologists, David Dunning, PhD, and Justin Kruger, PhD. They coined the term in a paper on their observations of this behavior in 1999.

Cognitive bias is an umbrella term used to describe a reasoning error or flaws in judgement. Your brain may overlook basic things like logic, strategy, and probability. Think of it like a blind spot as you navigate your day-to-day life. Cognitive bias can create gaps in knowledge that go on to affect how you make decisions. This then shapes how you understand the world around you.

Anyone and everyone can have cognitive biases. In fact, most people are unaware they have certain biases ingrained in them. Basically, people with this type don’t know that they are ignorant of their own ignorance.

Over time, this bias-based decision-making can have short- and long-term consequences. It can bleed into important parts of your life, like relationships and work. It may even affect your general world view.

So, what makes some people convinced they’re more qualified or knowledgeable than they really are? In the original study, Dunning and Kruger say they pinpointed two major things that are directly responsible for causing this particular bias.

They are:

Incompetence in a given field or topic. This is the lack of skill or knowledge required to do things that result in the best possible outcome.

Lack of metacognition. Simply put, metacognition is the ability to think about thinking. People with this bias lack the basic knowledge and insight required to realize whether a decision, an opinion, or a belief is correct or not.

Basically, these two things lead to a gap between perceived and actual performance.

To observe this phenomenon, Dunning and Kruger gave students tests of grammar, logical reasoning, and humor. The psychologists found that those who scored in the bottom 25% tended to overestimate their ability and test score. Most predicted their scores to be above the 60th percentile.

On the other hand, those who overperformed -- those in the top 25% of the students -- also incorrectly assessed their final result. Most of these students estimated their scores to be in the 70th- to 75th-percentile range. But most actually scored above the 87th percentile. While this is also not a realistic self-assessment, the researchers found that this group was competent enough to understand how they got a higher score, unlike the low performers. In other words, the gap between perceived and actual performance is smaller.

You can spot the Dunning-Kruger effect among people who:

  • Are poor performers
  • Are overconfident
  • Lack appropriate skills
  • Lack knowledge
  • Lack the ability to be self-aware

It’s important to note that the effect doesn’t happen only to people with a lack of skills or level of education. It can happen to anyone.

In fact, several studies have observed the Dunning-Kruger effect among:

  • College undergraduate students completing an exam
  • Medical students and their ability to self-assess interviewing skills
  • Clerks on their job performance
  • Medical lab technicians on their job expertise and skills

The Dunning-Kruger effect phenomenon isn’t limited to labs and studies. You can see it -- and its consequences -- almost everywhere in the real world.

This includes:

Work. In the work setting, everyone can be prone to overestimating their ability to perform well at their job. But showing too much overconfidence without the necessary evidence to back it up could make it hard to manage expectations among your co-workers and mangers.

The Dunning-Kruger effect can affect many parts of the work environment.

This includes:

  • Recruiting candidates who seem confident but, in reality, are unqualified for the position
  • Pay rises and promotions for employees who may not be top performers. This may lead to jealousy or bitterness among other employees.
  • Tension and conflict that create a toxic environment

To combat this, managers often hold yearly and semi-annual performance reviews to give employees feedback on their work ethic and the quality of their work.

Politics. The Dunning-Kruger effect can have an impact on your knowledge of politics and current affairs. One recent study took a look at its effects on political knowledge and discussion.

The study found that people with little to no knowledge of policy may voice strong opinions. These opinions could have short- and long-term real-life consequences within society.

Some examples include when you see people:

  • Sharing political opinions as facts within personal social media groups
  • Resisting any counter-arguments that may not align with their political beliefs
  • Assessing others’ political knowledge based on their own ideas and beliefs
  • Believing stereotypes about those who don’t have the same political beliefs
  • Being unwilling to listen or discuss politics with actual political experts
  • Holding strong political biases or doubling down on them, especially when they engage with people who don’t share the same views
  • Spreading misinformation that can have dangerous consequences

The study notes that there needs to be more in-depth research done on the Dunning-Kruger effect and its role in politics.

The Dunning-Kruger effect is an unconscious cognitive bias. Most people don’t realize their overconfidence or their overestimation of their skills. This makes it hard to overcome. But it can start with conscious training to improve self-reflection and curb biases.

Here are some tips to overcome your own bias:

  • Understand the nature of your bias. Try to recognize and categorize probable biases. This will allow you to approach your biases in a more open and informed way.
  • Work on improving self-awareness. There are several evidence-based tests available to help you weed out any unconscious biases you may be holding.
  • Share and discuss your biases with others. Lack of skill or knowledge may stop you from recognizing your own limits. But others around you can help point them out and give you a new perspective -- one you may have missed otherwise.
  • Be open to criticism. This is key if you’re aiming to overcome an unconscious bias. It can help you improve on any reasoning errors or flaws in judgment moving forward.

Show Sources


Frontiers in Psychology: “Dunning-Kruger Effect: Intuitive Errors Predict Overconfidence on the Cognitive Reflection Test.”

UCSF Office of Diversity and Outreach: “Strategies to Address Unconscious Bias.”

Political Psychology: “Partisanship, political knowledge, and the Dunning‐Kruger Effect.”

Organizational Behavior and Human Decision Processes: “Why the Unskilled Are Unaware: Further Explorations of (Absent) Self-Insight Among the Incompetent.”

Journal of Personality and Social Psychology: “Unskilled and unaware of it: How difficulties in recognizing one's own incompetence lead to inflated self-assessments.”

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