The Surprising Impact of the Dunning-Kruger Effect on our Lives
The Dunning-Kruger Effect is a cognitive bias that affects every one of us at different levels. Picture a flush toilet. Are you smart enough to understand how it works? Most of our minds will fool us to think that we know how it works, but research by Dunning and Kruger tells us otherwise.
The Dunning-Kruger Effect postulates that the lack of knowledge in a particular domain not only has the consequences that come from its incompetence but also robs the person the ability to recognize their inability or genuine ability in others.
To fully understand the toilet, one has to have multidisciplinary knowledge because every invention is built upon by others to make it more efficient. Here are a couple of questions related to the toilet that can help you assess your knowledge.
- How does the toilet sense to stop adding water to the tank once the toilet is flushed? If you do, how is the float ensure that the water is at the correct level?
- Did you know that the toilet has a trap before proceeding to the main drain?
- Did you know the toilet has two valves (fill and flush valves)? Do you know what they do?
- Does a toilet work like a suction (not letting the water out above a certain height off the ground)?
- Did you know how the flushing process works as a whole from pressing the handle to the water draining to the sewage?
Unless you did plumbing or you are really smart, you learned something new today.
The Illusion of Explanatory Depth
According to Dunning and Kruger, most people who overly estimated their abilities fell on the lower percentiles, while those who understood it enough to know their gaps in knowledge rated themselves lower. The flush toilet experiment was conducted by Rozenblit and Keil to prove the illusion of explanatory depth. Subjects who said they knew how toilets worked had a test to measure their intelligence. The results were consistent.
It is easy to look up information online to get what something means but people usually mistake the existence of this community information as individual knowledge.
Another reason for this illusionary perception of understanding may come from knowledge adjacency — which is the inability to differentiate between knowing the name of something and understanding what it is. In this technological era, it is easy to look up information online to get what something means, but people usually mistake the existence of this community information as personal knowledge.
To mitigate this, use objective criteria to measure your understanding. It was discovered that those who know a subject were fairly accurate than those who did not but tend to underestimate themselves. The reason is that they lacked the data for comparison. Getting scores on a test that measures your ability is a great way to gauge your level but isn’t often enough. The person can now use the test results to optimize their self-evaluation and reduce the error that comes from it.
When low scorers receive evaluations of their understanding, it does not seem to change their perception of themselves and, in some cases, can increase their self-efficacy. Training on spotting this bias proved more effective as people who received education on how to place their understanding could work on them.
So, the next time someone comes up to you and asks whether you know how airplane pressure works, have a deep reflection on whether you understand the physics and biology of why you can hold your breath on land for minutes but only a few seconds on a falling plane.
Kruger, Justin & Dunning, David. (2000). Unskilled and Unaware of It: How Difficulties in Recognizing One’s Incompetence Lead to Inflated Self-Assessments. Journal of Personality and Social Psychology. 77. 1121–34. 10.1037//0022–3518.104.22.1681.
Rozenblit, L., & Keil, F. C. (2002). The misunderstood limits of folk science: An illusion of explanatory depth. Cognitive Science, 26, 521–562.