The Illusion of Explanatory Depth

I am utterly fascinated by the concept of metacognition — how we evaluate and measure our own skills and abilities. This is the main idea underlying the Dunning-Kruger curve, the tendency for those with lower levels of  competency to wildly over-estimate their own skill levels.

This impacts everything and everyone, from policymakers to entrepreneurs to most especially, investors.

There is a related concept I referenced earlier this month called “The Illusion of Explanatory Depth.” It is the intriguing idea that we think we actually know much more about things — and can easily explain them — when in fact we do not.

We know how to get the information; we know who to call to fix a toilet when it breaks — but (most of us) do not ourselves actually know how these things work or (and this is the key) have the ability to explain them.

Stephen Dubner discussed the idea of Illusion of Explanatory Depth in a recent episode of Freakonomics: “Think of something you have a really strong opinion about. . . Now think about why you have such a strong opinion. How well do you think could you explain your position?”

If you want an even simpler example, could you explain how a toilet or zipper or ballpoint pen or bicycles work? Can you describe how pencils are manufactured?  You probably think you understand these things, but once you try to explain the specifics, you might find you falter and understand less than you previously imagined.

Here is professor Steven SLOMAN, a cognitive psychologist at Brown University:

If you’re forced to give an explanation, you have to really understand, and you have to confront the fact that you might not understand. Whereas when you give reasons, then you do what people do around the Thanksgiving dinner table. They talk about their feelings about it, what they like, what they don’t like.”

This is why Nobel winning physicist Richard Feynman suggested “If you want to master something, teach it.” Dr. Mortimer J. Adler, founder of the Institute for Philosophical Research, was even more blunt: “The person who says he knows what he thinks but cannot express it usually does not know what he thinks.”

The illusion allows people to believe they know more than they do. I suspect the reason for this can be described as being “Knowledge Adjacent.” Feynman also observed “I learned very early the difference between knowing the name of something and knowing something.”

Consider how often we do not know the answer to specific detailed questions — for example about how things like zippers or ballpoint pens work, but we do know how to find those answers. Knowledge Adjacency seems to be is a misleading form as a form of intelligence and understanding. We confuse what our community collectively knows with our own individual understanding.

This leads to a form of misperception, that creates a false belief that we know more than they actually do.

Now apply this to social media and the internet.

We are surrounded by other people, and dependent upon their abilities and expertise. This is true whether it is an Uber driver or a medical doctor or home builder. We enjoy massive technological advancements, not because we can build an iPhone or an index the internet ourselves, but because we know how to Google and where to buy a phone.

Knowledge is distributed widely in our society. We err when we believe this is our own understanding.




Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments.
Justin Kruger and David Dunning, Cornell University
Journal of Personality and Social Psychology, 77(6), 1121-1134  (December 1999)

How to Change Your Mind (Ep. 379)
Stephen J. Dubner
Freakonomics, May 29, 2019


How to Change Your Mind (August 7, 2019)



More of the Dubner/Sloman discussion after the jump…