Questions to reflect on
- Why can people with little knowledge sometimes sound so certain?
- Why can more knowledge actually make someone see more nuances and exceptions?
- Does a lot of self-confidence mean someone is an expert?
- Can experts also misjudge themselves?
- Why do I sometimes only realize how much I don’t know after I’ve dug deeper into something?
- How can I recognize the limits of my own knowledge?
- And is it actually true that ignorant people always think they’re experts?
What is the Dunning-Kruger effect?
The Dunning-Kruger effect is named after psychologists Justin Kruger and David Dunning. In their original 1999 study, they examined how well people could assess their own performance on tasks involving humor, grammar, and logical reasoning.
The participants who objectively scored the lowest tended, on average, to overestimate their own relative performance by a considerable margin. Kruger and Dunning suggested that part of the explanation lay in metacognition: to recognize your own mistakes, you sometimes need the same knowledge that is required to do the task well.
For example:
I still know very little
about a subject
↓
I also lack the knowledge
to recognize my own
mistakes
↓
My self-assessment
can be inaccurateBut that does not imply:
little knowledge
=
very much
self-confidenceThat is a popular simplification of the original research.
What did Dunning and Kruger originally find?
In their well-known studies, participants in the lowest quartile objectively scored around the 12th percentile on average, while they themselves placed their performance at about the 62nd percentile.
So the striking thing was mainly the gap between actual performance and self-assessment.
That is something different from saying that all of these participants thought they were brilliant.
For example, someone might think:
“I think I’m pretty good at this.”
while their actual performance is much lower.
A much more gifted participant might think:
“I’m pretty good at this.”
and still have more self-confidence than the beginner.
Dunning-Kruger is mainly about:
actual performance
↕
self-assessment
not simply about:
“dumb people
are very sure of themselves”That distinction is important.
Why can self-assessment be difficult?
To judge whether you’ve done something well, you often need to know what “good” looks like.
Suppose you barely speak Spanish.
You write:
Yo gusto comer.
It may sound perfectly fine to you.
Someone with more knowledge immediately sees that something is grammatically wrong.
So the knowledge needed to make a good sentence also helps you recognize when a sentence is not good.
That was an important part of Kruger and Dunning’s original explanation.
Skill helps with:
doing something well
+
judging
whether you’re doing it wellPsychologists call this ability to assess your own thinking, knowledge, or performance metacognition.
But the scientific story has become more complicated
Since 1999, a lot of research has been done on the Dunning-Kruger effect.
That has led to an important debate.
Various researchers have pointed out that the classic Dunning-Kruger graph can partly arise from statistical phenomena such as regression to the mean, measurement error, and the way participants are divided into groups or quartiles.
A 2020 study, for example, concluded that the classic method of measuring the effect may be strongly biased and found little support for a meaningful Dunning-Kruger effect for intelligence using other analytical methods.
A 2022 study went even further. In that study, poorer performers were on average actually less confident than better performers. The researchers concluded that the classic pattern was largely caused by statistical regression and found no support for the original double burden explanation in their task.
And in 2024 research on creativity, no strong support was found for a general Dunning-Kruger effect either.
So today, a more cautious explanation is better:
Original research:
low performance
+
inaccurate self-assessment
+
possible metacognitive cause
Later research:
some of it may be real
but part of the
classic pattern may also
be statisticalSo the Dunning-Kruger effect is not a simple law of nature that works exactly the same everywhere.
Beginners are not automatically overconfident
A widely shared image on the internet often shows a huge spike:
“Mount Stupid”
in which someone, after gaining a little bit of knowledge, becomes extremely confident, then ends up in a valley of despair and eventually slowly builds wisdom.
That pattern is often linked to the Dunning-Kruger effect, but it is not the graph from Kruger and Dunning’s original research.
The original study therefore did not prove:
“Every beginner thinks they’re an expert after five minutes.”
Beginners can also be uncertain.
Some people underestimate themselves.
Other people overestimate themselves.
And experts can also make mistakes in judging themselves.
More knowledge can make it clear how much there is still to know
Although the popular Dunning-Kruger graph is oversimplified, it is very recognizable that deeper understanding reveals new complexity.
For example, someone reads one article about a legal issue and thinks:
“Surely this is very simple?”
A lawyer with twenty years of experience may say:
“It depends.”
“There is an exception.”
“In this situation, different case law applies.”
“Without the case file, I can’t give a responsible answer to that.”
Little information
“It seems simple”
↓
More knowledge
“It turns out there are exceptions,
conditions and uncertainties”That caution does not automatically mean the expert knows less.
Sometimes it is actually the result of a better understanding of where the limits of one’s own knowledge lie.
But even this is not a hard rule. Experts can also be overconfident. Research has even shown that, under certain circumstances, expertise can be accompanied by an illusion that one can explain something better than is actually the case.
Confidence and expertise are not the same thing
We often use confidence unconsciously as a clue to expertise.
Someone says:
“I’m one hundred percent sure this is how it is.”
That sounds more convincing than:
“Based on what we know now, this seems most likely, but there are limitations.”
But the first person does not necessarily know more.
Research on confidence and performance shows that confidence can contain some information, but it by no means lines up perfectly with actual accuracy. For example, a large meta-analysis of 213 datasets found only a modest relationship between average confidence and actual accuracy.
SOUNDING SURE
≠
BEING AN EXPERT
SOUNDING CAUTIOUS
≠
KNOWING LITTLEThe content of the argument remains more important than the force with which someone presents it.
And what about experts?
A degree or years of experience do not make someone infallible.
Self-assessment can also be limited among professionals. A systematic review of physicians, for example, found that self-assessments did not always align well with external measures of competence.
Across different domains, the relationship between how good people think they are and how well they objectively perform is only moderate on average. A review of 22 meta-analyses found an average correlation of about 0.29.
So:
Beginner
can misjudge
themselves
Expert
can misjudge
themselves
Everyone needs
feedback and evidenceExpertise remains important.
But expertise and perfect self-knowledge are not the same thing.
Why is “I don’t know” valuable?
With complicated topics, there is sometimes not enough information to give a strong answer.
Then:
“I don’t know.”
is not a weakness.
It can actually mean that someone recognizes the line between knowledge and speculation.
That ties into the concept of intellectual humility (intellectual humility). An important part of that is being able to acknowledge that your beliefs and knowledge can be limited or fallible. Researchers describe this as a metacognitive awareness of the limits of one’s own knowledge.
“I know it”
“I suspect it”
“There is evidence for this”
“I don’t know yet”These are four different statements.
Good thinking means not confusing them with one another.
Example from everyday life
Someone reads a few articles in one weekend about a complicated legal dispute.
After that, he says:
“The judge only has to apply this article of the law. Done.”
A lawyer says:
“That statute is relevant, but there are exceptions, earlier rulings, and facts from the case file that determine how it is applied.”
The beginner does not have to be stupid.
He simply may not yet have enough knowledge to see which information is missing.
“I see one rule”
versus
“I see the rule,
exceptions,
case law
and missing facts”But even the lawyer must be able to provide arguments and sources. The label expert is no substitute for evidence.
The internet makes confident expertise easy
Online, someone can gather a great deal of information about a topic within a few hours.
That is valuable.
But there is a difference between:
having read information,
understanding information,
being able to assess its quality,
and having professional or scientific expertise.
This applies, for example, to law, psychology, medicine, history, theology, and statistics.
A few articles can give someone a good first impression.
They do not automatically make someone an expert.
Finding information
↓
is not automatically
assessing information
↓
is not automatically
expertiseAt the same time, a non-expert has the right to ask questions of experts. Critical thinking does not mean you are only allowed to believe experts.
How can this happen within close-knit belief communities?
Within any community, simple and confident explanations can be appealing.
This can happen within religious communities, online groups, professional circles, and groups of former members.
When many people around you use the same explanation, it can start to feel familiar and complete.
However, the Dunning-Kruger effect should not be used as a convenient explanation:
“They know little, so they think they know everything.”
The concept is too nuanced scientifically for that.
A better approach is:
Not:
“How confident does he sound?”
But:
“What exactly is he basing
this on?”How can this be recognizable around Jehovah’s Witnesses?
Both Jehovah’s Witnesses and former Jehovah’s Witnesses can be very convinced of their conclusions.
An active Witness may have extensive knowledge of JW publications and the organization’s own Bible interpretation.
A former Witness may have studied a great deal of critical literature, historical documents, or personal accounts.
But familiarity with one set of sources does not automatically make someone an expert on every related subject.
For example:
Biblical studies require specific expertise.
Historical research requires source criticism and context.
Medical topics require medical expertise.
Psychological concepts require psychological knowledge and research.
This applies to both sides.
“I’ve read a lot
about this”
may be true
without:
“That means I’m
an expert in this field”
also being trueThat is why it is more useful to look at sources, arguments, and relevant expertise than at group membership.
Psychology also cannot determine from someone’s self-confidence whether their religious conclusion is true or false.
Do not use Dunning-Kruger as an insult
Online, Dunning-Kruger is often used as a polite way of saying:
“You’re too stupid to understand that you’re stupid.”
That is not a careful use of the concept.
You cannot diagnose someone’s intelligence or expertise from a single confident remark.
And when two people disagree, you cannot simply label the one you believe is wrong with Dunning-Kruger.
“You are very sure
and I think you are
wrong”
≠
evidence of
Dunning-KrugerA much better response is:
“What arguments and sources support your conclusion?”
How do you know whether someone is an expert?
Self-confidence is therefore insufficient.
It is better to look at several indicators:
Does the person have relevant training or demonstrable experience?
Do they work in the field they are making claims about?
Can they provide reliable sources?
Do they distinguish between facts and interpretations?
Can they explain where uncertainty exists?
Do they adjust their opinion when solid evidence requires it?
Do other experts recognize their expertise?
No single point guarantees that someone is right.
But together they tell you more than just:
“He sounds very convincing.”
What do I actually know myself?
The concept is most useful when you do not use it to judge others, but as a prompt to examine your own knowledge.
Ask:
How do I know this?
Where did I get this information?
Have I seen the original source?
How much have I actually studied this topic?
What expertise is needed to assess this properly?
Which parts do I still not understand?
What would someone who knows a lot more about this add to my explanation?
A simple framework can help:
WHAT DO I KNOW?
Well supported
WHAT DO I THINK?
My interpretation
WHAT DO I SUSPECT?
Still uncertain
WHAT DON'T I KNOW?
Still to be exploredThat last category is not a shortcoming.
Every expert has one.
Intellectual humility is not the same as uncertainty
Intellectual humility does not mean:
“My opinion is probably worthless.”
Nor does it mean:
“Everyone is equally right.”
Rather, it means:
“I have reasons
for my conclusion
but I may be
missing something
and good evidence
can change
my mind”So you can be both confident and intellectually humble at the same time.
For example:
“Based on the available evidence, I think this is the best explanation. But I’m open to better evidence.”
That is different from constantly doubting yourself.
What can you do with this?
Don’t use your own confidence as evidence.
When you feel very certain about something, ask:
“What am I basing this certainty on?”
For complex topics, look for expertise and multiple reliable sources.
Ask experts not only for their conclusion, but also:
How do we know this?
What do we agree on?
What is still being debated?
What limitations does this evidence have?
And give yourself permission to say:
“I don’t know enough about that yet.”
Not knowing
↓
research
↓
understanding more
↓
seeing new questions
is not failure
it is learningQuestions to reflect on
Which topics might I speak about more confidently than my knowledge justifies?
How do I know what I think I know?
Have I mostly read summaries, or have I also checked original sources?
What education or expertise is needed to assess this topic properly?
Can I explain what the main uncertainties are?
Do I sometimes confuse someone’s confidence with expertise?
Do I sometimes distrust an expert precisely because they express themselves more cautiously?
Can I acknowledge that someone I disagree with may have more expertise than I do on a certain point?
Can I say “I don’t know” without feeling inferior because of it?
What information could change my current judgment?
And perhaps the most important one:
Do I know this?
Do I think this?
Or do I mostly think
that I know it?Summary
The Dunning-Kruger effect originally refers to research in which low-performing participants significantly overestimated their own performance. Kruger and Dunning partly explained this through a metacognitive problem: some of the knowledge needed to perform a task well is also needed to recognize your own mistakes.
But the popular idea:
“The less someone knows, the more certain they are.”
is too simplistic.
Later studies have shown that statistical effects can explain a large part of the classic pattern, and some recent studies find little or no support for the strong original interpretation.
So it is better to remember:
Confidence
≠
expertise
Expertise
≠
infallibility
“I don’t know”
≠
ignoranceThe most useful insight is not that other people don’t know what they don’t know.
It is that all of us have limits to what we know and to how well we can judge those limits.
Sources and further reading
Justin Kruger & David Dunning (1999), Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments, Journal of Personality and Social Psychology, 77(6), 1121–1134. The original study on which the Dunning-Kruger effect is based.
Gilles E. Gignac & Marcin Zajenkowski (2020), The Dunning-Kruger effect is (mostly) a statistical artefact: Valid approaches to testing the hypothesis with individual differences data, Intelligence, 80, 101449. A critical analysis showing that classic methods used to demonstrate the effect are sensitive to statistical bias and that their data found little support for a meaningful effect.
Robin Kramer e.a. (2022), Skill and self-knowledge: empirical refutation of the dual-burden account of the Dunning-Kruger effect. A Registered Report in which the classic Dunning-Kruger pattern was largely explained by performance scores and statistical regression; poor performers in this study were not more confident than good performers.
John R. Magnus & Anatoly A. Peresetsky (2022), A Statistical Explanation of the Dunning-Kruger Effect. Provides a statistical explanation by which the well-known pattern can arise without having to accept the original psychological explanation.
Izabela Lebuda e.a. (2024), No strong support for a Dunning–Kruger effect in creativity, Scientific Reports, 14, 11883. Research that found no strong support for the effect in creative abilities and discusses the statistical debate surrounding classic Dunning-Kruger analyses.
Ethan Zell & Zlatan Krizan (2014), Do People Have Insight Into Their Abilities? A Metasynthesis. An analysis of 22 meta-analyses showing that the correspondence between self-assessment and objective performance is on average only moderate and strongly depends on the domain and the measurement method.
Matthew Fisher & Frank C. Keil (2016), The Curse of Expertise: When More Knowledge Leads to Miscalibrated Explanatory Insight. Shows that expertise can also, under certain circumstances, go hand in hand with overestimating one's own understanding.
Mark R. Leary e.a. / overview of intellectual humility, Nature Reviews Psychology (2022). Discusses intellectual humility as recognizing the limits of one's own knowledge and beliefs, and the possible benefits of that for thinking and decision-making.
