Dunning-Kruger effect

"The less I am qualified, the more I overestimate my competence. The more I am qualified, the more I underestimate my competence."

Definition

Our competence in a given field has a curious influence over the degree of confidence we feel about our capacities. This is what characterises the Dunning-Kruger effect: in a great variety of fields, less-qualified people have a tendency to overestimate their ability or knowledge compared to their peers, whereas more-qualified people tend to underestimate theirs [1]. Although overconfidence is a normal attribute of the human species [2], in any given field it is more evident among people who are less expert in it. They are not aware of their low level of competence. Ironically, this trend reverses for those who are experts in the field: more competent people tend to underestimate their skills compared to others. This psychological phenomenon, which has been demonstrated many times, affects all of us in the specific areas of knowledge in which we are the most or the least proficient.

Example

Failing an exam when we were certain we had excelled, or on the contrary performing brilliantly when we feared for the worst are examples of how we are unaware of our real capacities. In one study, students who had obtained the worst grades left the examination thinking that their performance had been better than the majority of their colleagues. At the other end of the spectrum, students with the highest grades underestimated their grade compared to others [3].

Explanation

Failing an exam when we were certain we had excelled, or on the contrary performing brilliantly when we feared for the worst are examples of how we are unaware of our real capacities. In one study, students who had obtained the worst grades left the examination thinking that their performance had been better than the majority of their colleagues. At the other end of the spectrum, students with the highest grades underestimated their grade compared to others [3].

Consequences

Failing an exam when we were certain we had excelled, or on the contrary performing brilliantly when we feared for the worst are examples of how we are unaware of our real capacities. In one study, students who had obtained the worst grades left the examination thinking that their performance had been better than the majority of their colleagues. At the other end of the spectrum, students with the highest grades underestimated their grade compared to others [3].

Thoughts on how to act in light of this bias

  • Take into consideration others’ honest opinions about our competence

  • Continue to educate ourselves and cultivate knowledge

  • Be our own devil’s advocate: always take into consideration that you may be wrong

How is this bias measured?

This effect is most often measured by administering tests on a particular subject to groups of participants. Before seeing the results, participants are asked to evaluate their own results and to position their performance relative to their peers (for example, I performed better than 80% of the other participants). The researchers then compare the real performance of the participants to their perceived performance relative to others. The Dunning-Kruger effect is represented by the error in prediction among the participants with the worst results on the test and among those with the best results [4].

This bias is discussed in the scientific literature:

This bias has social or individual repercussions:

This bias is empirically demonstrated:

References

[1] Kruger, Justin & 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. https://doi.org/10.1037/0022-3514.77.6.1121 


[2] Johnson, Dominic D. P. & James H. Fowler (2011). The evolution of overconfidence. Nature, 477(7364), 317–320. https://doi.org/10.1038/nature10384 


[3] Dunning, David, Kerri Johnson, Joyce Ehrlinger & Justin Kruger (2003). Why people fail to recognize their own incompetence. Current Directions in Psychological Science, 12, 83-86. https://doi.org/10.1111%2F1467-8721.01235


[4] Ehrlinger, Joyce, Kerri Johnson, Matthew Banner, David Dunning & Justin Kruger (2008). Why the Unskilled Are Unaware: Further Explorations of (Absent) Self-Insight Among the Incompetent. Organizational Behavior and Human Decision Processes, 105(1), 98–121. https://doi.org/10.1016/j.obhdp.2007.05.002 


[5] Dunning, David, Chip Heath & Jerry. M. Suls (2004). Flawed Self-Assessment: Implications for Health, Education, and the Workplace. Psychological Science in the Public Interest, 5(3), 69–106. https://doi.org/10.1111/j.1529-1006.2004.00018.x

Tags

Individual level, Availability heuristic, Need for self-esteem

Related biases

Author

Trisha Rani Saha, B.Sc. is studying cognitive neurosciences at the Université de Montréal. 

Translated from French to English by Kathie M. McClintock.

How to cite this entry

Rani Saha, T. (2020). Dunning-Kruger Effect, trans. K. McClintock.  In E. Gagnon-St-Pierre, C. Gratton, & E. Muszynski (Eds). Shortcuts: A handy guide to cognitive biases Vol. 2. Online: www.shortcogs.com

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