Dunning–Kruger effect

The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than average. This bias is attributed to a metacognitive inability of the unskilled to recognize their mistakes.

Actual competence may weaken self-confidence, as competent individuals may falsely assume that others have an equivalent understanding. Kruger and Dunning conclude, "the miscalibration of the incompetent stems from an error about the self, whereas the miscalibration of the highly competent stems from an error about others".

Historical references

Although the Dunning–Kruger effect was put forward in 1999, David Dunning and Justin Kruger have quoted Charles Darwin ("Ignorance more frequently begets confidence than does knowledge") and Bertrand Russell ("One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision") as authors who have recognised the phenomenon. Geraint Fuller, commenting on the paper, notes that Shakespeare expresses similar sentiment in As You Like It ("The fool doth think he is wise, but the wise man knows himself to be a fool." (V.i)). Thomas Hobbes also notably referenced what later became the Dunning-Kruger effect in his magnum opus Leviathan: "For such is the nature of men, that howsoever they may acknowledge many others to be more witty, or more eloquent, or more learned; Yet they will hardly believe there be many so wise as themselves: For they see their own wit at hand, and other mens at a distance."

Hypothesis

The hypothesized phenomenon was tested in a series of experiments performed by Justin Kruger and David Dunning, both of them of Cornell University. Kruger and Dunning noted earlier studies suggesting that ignorance of standards of performance is behind a great deal of incompetence. This pattern was seen in studies of skills as diverse as reading comprehension, operating a motor vehicle, and playing chess or tennis.

Kruger and Dunning proposed that, for a given skill, incompetent people will:

1. tend to overestimate their own level of skill;
2. fail to recognize genuine skill in others;
3. fail to recognize the extremity of their inadequacy;
4. recognize and acknowledge their own previous lack of skill, if they are exposed to training for that skill

Dunning has since drawn an analogy ("the anosognosia of everyday life") to a condition in which a person who suffers a physical disability because of brain injury seems unaware of or denies the existence of the disability, even for dramatic impairments such as blindness or paralysis.

Supporting studies

Kruger and Dunning set out to test these hypotheses on Cornell undergraduates in various psychology courses. In a series of studies, they examined the subjects' self-assessment of logical reasoning skills, grammatical skills, and humor. After being shown their test scores, the subjects were again asked to estimate their own rank, whereupon the competent group accurately estimated their rank, while the incompetent group still overestimated their own rank. As Dunning and Kruger noted,

Across four studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although test scores put them in the 12th percentile, they estimated themselves to be in the 62nd.

Meanwhile, people with true ability tended to underestimate their relative competence. Roughly, participants who found tasks to be relatively easy erroneously assumed, to some extent, that the tasks must also be easy for others.

A follow-up study, reported in the same paper, suggests that grossly incompetent students improved their ability to estimate their rank after minimal tutoring in the skills they had previously lacked—regardless of the negligible improvement in actual skills.

In 2003, Dunning and Joyce Ehrlinger, also of Cornell University, published a study that detailed a shift in people's views of themselves when influenced by external cues. Participants in the study (Cornell University undergraduates) were given tests of their knowledge of geography, some intended to positively affect their self-views, some intended to affect them negatively. They were then asked to rate their performance, and those given the positive tests reported significantly better performance than those given the negative.

Daniel Ames and Lara Kammrath extended this work to sensitivity to others, and the subjects' perception of how sensitive they were. Other research has suggested that the effect is not so obvious and may be due to noise and bias levels.

Dunning, Kruger, and coauthors' 2008 paper on this subject comes to qualitatively similar conclusions to their original work, after making some attempt to test alternative explanations. They conclude that the root cause is that, in contrast to high performers, "poor performers do not learn from feedback suggesting a need to improve."

Studies on the Dunning–Kruger effect tend to focus on American test subjects. A study on some East Asian subjects suggested that something like the opposite of the Dunning–Kruger effect may operate on self-assessment and motivation to improve.

Awards

Dunning and Kruger were awarded the 2000 Ig Nobel Prize in Psychology for their report, "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments".

See also

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