What is the Dunning-Kruger Effect and Why it Matters

By Danielle Dahl | Published December 7, 2022

The Dunning-Kruger effect is a psychological term for a type of cognitive bias.

It means that people with limited knowledge or competence in an intellectual or social domain overestimate their own knowledge.

They believe their competence in that domain is equal to that of the experts, instead of their peers or other people.

In short, it means they think they know the same about complex subjects as the people who are experts in the field.

Tell us about a time you encountered the Dunning-Kruger effect in the comment section below.

What can we learn about this psychological phenomenon?

The term is named after psychologists David Dunning and Justin Kruger, the researchers who studied this phenomenon.

They explain the effect by stating that “the metacognitive ability to recognize deficiencies in one’s own knowledge or competence requires that one possess at least a minimum level of the same kind of knowledge or competence, which those who exhibit the effect have not attained.”

People are often in denial of their deficiencies and assume that they are not deficient.

This allows people to form opinions they believe to be reasonable and believe they are making informed decisions.

Before diving into some examples of this, let’s look a little more at how the Dunning-Kruger effect was studied.

Research studies by David Dunning and Justin Kruger

In 1999, Dunning and Kruger published a research study titled: Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments.

Over the course of the study, Dunning and Kruger tested the abilities of four groups of young adults.

They were specifically interested in three domains:

humor
logic (reasoning)
grammar

The study cites the case of McArthur Wheeler.

He robbed banks in bright daylight with no disguise and was subsequently caught after the airing of the local news… which broadcasted his face from the security footage.

When he was brought to the police station, he was astounded that they caught him because “he used the juice.”

Just what was he talking about?

Apparently, he believed that rubbing his face with lemon juice would render it invisible to the cameras.

They use his story to illustrate three theories:

Success and satisfaction depend on knowledge, wisdom, or savvy in knowing which rules to follow and which strategies to pursue
People differ widely in the knowledge and strategies they apply in these domains
When people are incompetent in the strategies they adopt to achieve success and satisfaction, they suffer a dual burden of reaching erroneous conclusions and making unfortunate choices. Then their incompetence robs them of the ability to realize it.

Related Gettin’ Real With Happiness

The methods and results of the Dunning-Kruger study

They conducted their study on four groups, in which they presented participants with tests that assessed their ability in a domain in which knowledge, wisdom, or savvy was crucial: humor (Study 1), logical reasoning (Studies 2 and 4), and English grammar (Study 3).

Researchers asked participants to assess their ability and test performance.

Dunning and Kruger hypothesized that in each study, participants would overestimate their ability and performance relative to objective criteria.

A more nuanced prediction posited that those who proved to be incompetent, by scoring in the bottom quarter of the distribution, would be unaware that they had performed badly.

When testing humor, which the researchers believed required knowledge of the tastes and reactions of other people, they asked participants to determine which jokes were funny.

They compared these with the answers from professional comedians.

Those who did not score well “grossly overestimated their ability relative to their peers.”

The results were similar for logical reasoning and grammar.

People who did not score well in either subject overestimated how well they did.

Interestingly, researchers also noted that those in the top quartile underestimated themselves.

Why the Dunning-Kruger effect matters now more than ever

We live in a world where the average person can access all kinds of information in seconds.

A simple Google search will answer just about any question you ask it.

The results will be based on how you ask the question.

For instance, try this simple exercise.

Google something like “Why having a dog is good for you.”

You will get all kinds of information from various sources about the benefits of owning a dog.

Now, Google “Why having a dog is dangerous.”

Suddenly, there is as much information about why you should not have a dog.

This is another type of cognitive bias known as confirmation bias.

Basically, this means that we seek information that agrees with our preconceived notions.

This can get dangerous when we apply it to things like self-diagnosis, research on complex subjects, and current events.

We have seen the Dunning-Kruger effect in action quite a lot over the past few years.

At the onset of the pandemic, my Facebook feed was filled with people who hadn’t graduated high school or couldn’t write competent sentences, trying to explain things like virology and vaccines.

Suddenly, we had to defend science!

People with decades of education and real-life experience studying, researching, and understanding things like viruses were not believed.

It became apparent the Dunning-Kruger effect was spot on.

Other examples of the Dunning-Kruger effect

Each of us is guilty of exhibiting this type of behavior in certain situations.

I have a bad habit of Googling my symptoms before seeing the doctor.

To be fair, I have a few college degrees and am working on a Ph.D.

I would argue that I am fairly intelligent and can understand complex written words—like medical studies.

However, I am not a doctor of medicine.

I took an intro to biology and an anatomy class or two.

I am not an expert.

However, I go to the doctor armed with “knowledge” and thoughts about what is wrong with me.

Nine out of ten times, I am completely off base.

Why do we all suddenly not trust experts?

Trust in experts has been wavering for a while now.

Part of the problem is the way we communicate science.

Scientific journal articles are nuanced and cautious in their claims.

The entire study is filled with so much information that the public is unaware of.

Instead, they get headlines and memes that ignore nuance and uncertainty.

Trust the science has become something we have to preach

Science is all about a theory and then rejecting or failing to reject a null hypothesis.

For example, if your hypothesis was, “The Earth is round,” you would conduct a study based on that assumption.

You would reject the null hypothesis if you found scientific evidence that supported the Earth being anything other than round.

You could conclude the Earth was not round.

Now, it gets a little tricky when the evidence supports your hypothesis.

Here you are doing a study on the shape of the Earth, and you have a plethora of verifiable and repeatable evidence that supports the Earth being round.

However, you do not technically prove the Earth is round.

Your study would just not be able to reject the null hypothesis.

Over time, the not rejected hypothesis can become standard practice and be accepted as fact.

However, new technological advances, events, and understandings might someday find evidence that is cause to reject a hypothesis that has been accepted.

For instance, humans thought the Earth was flat for a long time.

Then scientific methods disproved that, and other research supported that the Earth was round.

That science has disproved things we believe to be true because science showed it was true in the first place often leads people to think that science was wrong.

And therefore, science is untrustworthy, so we must know more (Dunning-Kruger effect).

Yet, that is not true.

It is just how science works.

We only know what we know until we learn something new.

Science is not wrong—it is just constantly evolving.

Experts exist for a reason

It is not about proving a theory to be correct.

Rather, it is about being unable to prove your theory is incorrect.

It is complicated—which is why we have experts.

Medicine is complicated, which is why we have experts (doctors).

Aviation is complicated, which is why we have experts (pilots).

Teachers, mechanics, accountants, and other various experts are there for a purpose.

Yet here are most of us cutting our hair, fixing our cars, and doing our taxes.

Sure, most of us can use a tax software service and plug in the information.

However, when our finances get complicated, and tax law becomes a bigger concern, we should recognize that we might need someone else to help.

Regardless of how educated, smart, or capable we believe we are—we do not know more than the experts.

Sadly, as the Dunning-Kruger effect study showed us… the people who are the most incompetent do not recognize that they need this help.

They overestimate their understanding of a subject and feel as if their efforts have made them just as capable as the experts.

How can we overcome our tendency toward the Dunning-Kruger effect

We can do a few things to curb the tendency to think we know everything we need to (and more than others).

First, take time to reflect.

Deciding quickly is sometimes necessary, but most always, we can at least take a few moments.

This is enough time to reflect on similar decisions we have made in the past and evaluate anything that went wrong last time.

By reflecting, we can avoid similar pitfalls and make even better decisions.

Next, recognize that no one knows everything and that learning is an opportunity to move forward.

Combat the Dunning-Kruger effect

Don’t be afraid to ask questions.

Asking a question or asking for help can help you do better and learn more that can help you move forward.

Challenging our beliefs and revisiting them is a great way to help foster growth.