I grew up with a habitual overclaimer. He wildly exaggerated his expertise, at times claiming knowledge of things he couldn't possibly know -- people, events, ideas that simply do not exist. Being unfamiliar with overclaiming, I just called him a liar.
I couldn't have known the word "overclaimer," nor the concept. The word didn't exist and is only used today in the world of psychological science. Even so, we're all familiar with these people who feel the need to overestimate what they know about the world. What underlies such assertions of impossible knowledge?
A team of researchers at Cornell University--Stav Atir, Emily Rosenzweig and David Dunning--have a theory about overclaiming, one that they decided to test in a series of studies. They had the idea that people's perceptions of their own knowledge of specific domains--biology, personal technology, sculpture--might play a role in overclaiming expertise in that domain. So for example, if I believe my understanding of biology is excellent, and you are a little shaky on the field, I will be more likely to claim knowledge about biology--even nonexistent biological concepts.
The scientists decided to test this connection in the area of personal finance--a domain where a distorted sense of one's expertise could lead to devastating results. They first asked about 100 men and women to rate their general knowledge of personal finance, and to compare themselves with the average American. Then they asked the subjects to rate their knowledge of specific terms related to personal finance. But here's the rub: Only some of these terms were real--"fixed-rate mortgage," "home equity," and so forth. The others were nonexistent terms invented by the scientists--"pre-rated stocks," for example, or "annualized credit."
The results were intriguing. The more that people viewed themselves as knowledgeable about personal finance, the more they claimed impossible knowledge of made-up concepts. This remained true whether the subjects were genuinely knowledgeable about finance or not.
The Cornell scientists ran several other versions of this same basic experiment, illuminating some nuances of overclaiming. In one, they showed that overclaiming is domain-specific--that is, if I see myself as an expert on personal computers but not Renaissance art, I will only claim impossible knowledge in the area of personal computers. Interestingly, even warning subjects about the bogus concepts ahead of time did not diminish the effect. This suggests, importantly, that self-perceived knowledge prompts mistaken claims of impossible expertise--not dishonest claims.
The scientists also demonstrated a clear causal link between self-perceptions and overclaiming. They experimentally enhanced only some subjects' self-perceived knowledge of North American geography and then tested them on both real and made-up places. Those with overblown perceptions of their general knowledge of North America were much more likely to claim specific familiarity with nonexistent places like Lake Othello, Wisconsin, and Cashmere, Oregon.
These findings, taken together and reported in a forthcoming issue of the journal Psychological Science, suggest that the seemingly straightforward task of assessing one's knowledge may not be so straightforward after all. It seems that people do not simply consult a mental index that catalogues their knowledge. Instead, they draw on pre-existing self-perceptions to decide what they do--or should--understand about the world.
Follow Wray Herbert's reporting on psychological science in The Huffington Post or on Twitter at @wrayherbert.