News Release

October 28, 2005
For Immediate Release
Read the Report

Contact: David Dunning
Chip Heath
Jerry Suls

'Know Thyself' — Easier Said Than Done

Benjamin Franklin wrote in his 1750 Poor Richard's Almanac that "There are three things extremely hard: steel, a diamond, and to know one's self." The problem of achieving accurate self-knowledge hasn't gotten any easier in 250 years; and, as shown in a new research report, there are major real-world consequences to this very human attribute.

In "Flawed Self-Evaluation: Implications for Health, Education, and the Workplace," investigators David Dunning (Cornell), Chip Heath (Stanford), and Jerry M. Suls (University of Iowa) summarized current psychological research on the accuracy (or rather inaccuracy) of self-knowledge, across a wide range of studies in a range of spheres. Their report is published in the December 2004 issue of Psychological Science in the Public Interest, a journal of the American Psychological Society.

A consistent and sobering picture emerged from the team's analysis: On the job, at school, or even in managing our own health, it is as though we all live in Garrison Keillor's fictional Lake Wobegon, "where all the children are above average." People's opinions of themselves, their abilities, and their health outlooks are generally skewed quite strongly in a positive direction.

Such errors in self-assessment can have serious consequences, for example in how people manage their own health. People generally underestimate their own susceptibility to serious health risks like high blood pressure, cancer, or food poisoning — partly because they overestimate how different they are from the norm in terms of behaviors that might put them at risk. This can influence the steps people take — or don't take — to prevent or treat such problems. On the other side of the health equation, doctors (being people too) overestimate their competence to treat problems outside their areas of specialization.

A similar overconfidence is found in education at all levels. Students and people undergoing professional training show a strong tendency to overestimate their mastery of new knowledge and skills, and teachers and peers are generally much better able than a student is to accurately predict the student's performance on tests.

The work world is full of overconfidence and flawed self-knowledge as well. Employees underestimate how long they will take to complete tasks. And CEOs and entrepreneurs are famously (sometimes disastrously) overconfident in making business decisions, particular when venturing into unfamiliar territory such as a business startup or an acquisition — a problem the authors called "the problem of the new."

Although a degree of self-deception may be just part of human nature, individuals aren't completely to blame for their lack of accurate self-knowledge, according to Dunning. There are social and institutional barriers to self-knowledge, such as the difficulty of giving honest critical feedback in workplace settings, as well as to the simple fact that people don't have access to the full range of human competence and skill against which to evaluate their own. Also, in many areas, what people are striving for — excellence — is ill-defined.

Read the Report. For more information, contact David Dunning at, Chip Heath at, or Jerry Suls at

Psychological Science in the Public Interest provides definitive assessments of topics where psychological science may have the potential to inform and improve the lives of individuals and the well-being of society. The American Psychological Society represents psychologists advocating science-based research in the public's interest.