The Dunning-Kruger effect: why and how we overestimate our own abilities

I vividly remember the very first assignment I submitted in my college opinion writing class, which was, notably, also my very first journalism course. I toiled over my paper for hours, and by the time I proudly dropped it on my professor’s desk at the end of a lecture, I was confident her only feedback would be that I was destined for a Pulitzer.

To my surprise, my paper came back to me looking like it had been the test pad in a red pen factory. At the top was an enormous “C-” with a big ol’ circle around it.

Oof. My knee-jerk reaction was to discredit the qualifications of my professor – she was obviously ignorant to my brilliance. I was a smart and capable student, so there was no way I deserved that grade – right?

But now, years later, I realize my professor wasn’t out of line. I was learning for the first time how to structure a compelling written argument – of course, I wasn’t good at it yet! 

It’s a great example of the Dunning-Kruger effect, which occurs when we overestimate our own knowledge or abilities. While majorly humbling, it can happen to anyone, regardless of intelligence or skill level.

What exactly is a cognitive bias?

A cognitive bias is an error in judgment that typically happens subconsciously. People tend to hold onto their personal preferences and beliefs when making judgments and decisions – even if other information threatens or disproves those preconceived notions. 

Cognitive biases are not limitations reserved for the unskilled and inadequate. They happen to all of us, and there are tons of them that can unknowingly sabotage our thought processes. 

When you selectively search for or retain information that supports what you already believe to be true? That’s confirmation bias. When you make a decision based on a recent experience, even if it’s not the best fit? That’s availability bias.

Put simply, our brains use cognitive biases as shortcuts – as ways of processing the overload of information we take in daily. Definitely not a perfect system, but one our brains seem intent on sticking with because it’s our system (we call that one modal bias, by the way).

The Dunning-Kruger effect: What it is and why it happens

So the Dunning-Kruger effect is just one cognitive bias in our brains full of many. The term was first coined by David Dunning and Justin Kruger, both psychologists at Cornell University, in their 1999 paper. 

The psychologists conducted four different studies that each tested participants on humor, grammar, and logic. They didn’t just complete the tests – they were also asked to predict their own performance. The participants who scored in the bottom quartile of the tests had grossly overestimated their own abilities. Their actual performance, on average, put them in the 12th percentile, despite the fact that they self-estimated they’d be closer to the 62nd percentile. That disconnect lives at the heart of the Dunning-Kruger effect.

The typical “sitcom dad” is one trope where you’ll see this particular bias pop up again and again. He refuses to ask for directions on a road trip and gets his family hopelessly lost. He insists he can complete a basic home repair only for chaos (and property damage) to ensue. He’s confident he can cook a family meal, then the frying pan to start on fire. 

But that tired comedy device implies that the Dunning-Kruger effect relates to basic intelligence, that it only happens to the most bumbling and inept among us. In reality, the Dunning-Kruger effect can happen to all of us – including you and me.

“The Dunning-Kruger effect is not about dumb people,” explains Jonathan Jarry, a science communicator with the McGill Office for Science and Society, in an article for McGill University (in which he expresses skepticism that the effect is even a real phenomenon, which we’ll get into a little later). “It’s mostly about all of us when it comes to things we are not very competent at.”

Why does the Dunning-Kruger effect happen?

But why do some of us tend to be so optimistic about our abilities, especially in areas where we should readily recognize that we have limited knowledge and skills? 

In their paper, Dunning and Kruger described it as a “dual burden.” We charge ahead while overestimating our talents, but we also lack the awareness (something Dunning and Kruger called “metacognitive abilities”) to recognize that we’re falling short in the first place.

Basically, you don’t know what you don’t know. Because you’re inexperienced in a particular area, you don’t have the basic information you need to distinguish between a good performance and a bad performance. Think of it like this: If you’re not into wine, you probably can’t tell the difference between a $10 bottle and a $100 bottle.

Another reason we tend to aggrandize our own skills and talents ties to the fact that it can feel shameful to admit that we don’t know something.

What’s the harm in the Dunning-Kruger effect?

We all over-inflate our abilities occasionally. But even so, most of us still have a somewhat realistic grasp on what we’re capable of – you probably aren’t volunteering when somebody on a plane asks for a doctor simply because you’ve watched a few medical dramas.

So is this cognitive bias really all that bad? What’s the harm? Well, Dunning-Kruger does have some potential for fallout, including:

• Poor decision-making: Whether it’s pursuing a career that ultimately isn’t a match for your abilities or volunteering for a project you can’t realistically pull off, that dual burden can trigger some poor decisions.
  
• Mistrust among team members: If your overconfidence becomes a pattern, your co-workers could start to doubt your ability to perform at a high level in any area. A tendency to overpromise and underdeliver erodes teammates’ trust.
  
• Potential danger: Particularly for people in hazardous and high-risk careers, overestimating their skills could pose a danger to themselves and others. 

The Dunning-Kruger effect isn’t all bad, though. A little extra optimism and self-assuredness could be what’s needed for people to achieve goals that might’ve seemed completely unreasonable to others.

Criticisms of the Dunning-Kruger effect

Like any other theory or finding, the Dunning-Kruger effect has been the focus of criticism – with some skeptics pointing to regression to the mean or even a random occurrence to explain the original study’s findings, rather than a real defect in our self-insight. 

But beyond the scholarly hole-poking, perhaps the biggest problem with the way we talk about this bias lies in the undercurrent of shame. Academic explanations are riddled with words like “incompetent,” “ignorant,” and “poor performer,” terms that can understandably trigger some self-consciousness and humiliation. 

As a result, identifying the DUnning-Kruger effect as the cause of someone’s bias can feel like a personal attack, despite the fact that it’s a universal experience – something that can (and will) happen to all of us. 

What can you do about the Dunning-Kruger effect on your team?

On a personal level, aiming to have a higher level of self-awareness is your best antidote to the Dunning-Kruger effect. Asking for feedback, reflecting on past experiences, and questioning your assumptions can give you a more accurate grasp on your strengths and weaknesses. 

If you’re leading a team, there are a few other steps you can take to minimize this bias and root everybody in reality:

• Prioritize psychological safety: A high degree of psychological safety means people feel more comfortable admitting they don’t have the necessary know-how to do something, rather than feeling like they need to “fake it ’til they make it.” 

• Value a variety of skills: As a manager, it’s tempting to zone in on patching up weaknesses on your team. But, focusing on praising, rewarding, and supporting a wide range of strengths might be a better option. Classic research from Gallup found that a strengths-based culture, as opposed to one that fixates only on development areas, increases employee engagement. Plus, people will feel valued for their unique attributes rather than going way beyond their capabilities to get your recognition and approval.
  
• Fuel a growth mindset: A team that has embraced a growth mindset is hungry to learn and improve, and views failures and mistakes as learning opportunities. You can feed this mindset by providing plenty of resources – like mentorship, seminars, books, courses, and other professional development opportunities – for team members to explore and refine their skills.
  
• Give thoughtful and honest feedback: Constructive criticism is hard to hear and sometimes even harder to deliver. But if you keep your lips zipped and let your low performers continue to assume they’re knocking it out of the park, they’ll stay on that same path, blissfully unaware that they’re falling short. 

Aim for awareness, not apprehension

Knowing your brain is basically hardwired to trick you into an inflated self-assessment is a little off-putting. But the goal here isn’t to inspire doubt or hesitation. Rather, understanding the Dunning-Kruger effect and how it might show up in your work and your life will help you build your self-awareness.

And when you have a more pragmatic sense of your actual strengths and weaknesses, you’re able to seek out roles, projects, and situations where you (and the other people on your team) can shine – not struggle.