The Dunning-Kruger Effect

Since my Imposter Syndrome Feelings talk at BSidesNOVA (video here: was 25 minutes, I had to remove some content from what I needed to present. One thing I omitted was the Dunning-Kruger Effect.

A Summary

David Dunning and Justin Kruger conducted a study of college students in 1999. They found that people “tend to hold overly-favorable views of their abilities in many social and intellectual domains.” (

As a senior information security person, I regularly witness this in some junior employees. A person will join a team, gain a certification, learn some techniques and feel extremely competent and confident in their skills and abilities. What they don’t realize is that they are just scratching the surface of the industry and their estimation of their competence is over-inflated.

Conversely, I’ve found that many people that have been in a career for years, under-estimate their skills and abilities because they understand that there is a huge body of knowledge that they don’t know.

An Example

Think of it like this: if a person has only ever seen and heard the English language, they don’t know that there are many other languages on this planet. A person with this narrow perception may believe that they have become an expert in languages because they don’t understand there are others out there to learn.

Now picture a person that is a world-traveler; someone that regularly visits foreign lands. Perhaps they also learned English and are as competent as the person previously described. They may have also learned some of the other languages during their travels making them linguistically more diverse. But because this, more-seasoned person knows there are many more languages in the world, they decrease their confidence in their linguistic abilities.

A Graph

Dunning and Kruger’s research has been translated into the graph below. The horizontal axis is wisdom (what you know) and the vertical axis is confidence in your abilities. It illustrates how someone with little wisdom has high confidence until they reach the top of Mount Stupid where they learn that there is so much more to learn. That can cause negative feelings (valley of despair) since the person who thought they were an expert, found out they are not one. As they learn more and gain confidence over time (slope of enlightenment) they eventually reach a level of confidence that matches the knowledge or wisdom they have gained.


(Picture from, February 25, 2017.)

Another Example

When I was in high school I took an anatomy and physiology (A&P) class. I loved it and performed very well in the class. I knew the bones and muscles and body processes and felt like an expert…after-all, I knew more than some of my peers that hadn’t taken the class. I had summitted my “Mount Stupid”.

I then went to college where I again took A&P. I strutted into that classroom 100% confident in my knowledge and that the course would be simple since I knew it all already. I rapidly discovered that there were several layers of deeper material that were not covered in my high school course. For example, I knew about muscles and could name most all of them but I didn’t know about sarcomeres and how they contracted. My confidence in my knowledge plunged to the “valley of despair” because I knew there was more to learn.

Time passed and, as I took other science courses (neurobiology, organic and inorganic chemistry, and physics), I entered into those classes with humility expecting that there would always be more to learn. That was my “slope of enlightenment”.

A Conclusion

If you are a junior person:

  • recognize that it takes time to learn what the entire body of knowledge that you could learn is
  • recognize that you are not an expert and it will take time and effort to become one
  • recognize you can always learn more or “go deeper” in any subject
  • respect those that have been in the field longer than you as they may have broader and deeper knowledgebases than you
  • understand that senior people may have a more-accurate view of the total body of knowledge in your field
  • be humble

If you are a more-experienced person in the “valley of despair”:

  • understand that have skills and knowledge
  • track your progress and what you have learned
  • know you are probably under-estimating your skills and knowledge because you know there is more to learn
  • help newcomers understand that they can always learn more and motivate them to do so

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