We are all what psychologists Dacher Keltner and Robert Robinson call naive realists. We intuitively assume that as we see and remember the world, so it is. We assume that others see it as we do (false consensus). And if they obviously don’t, we assume that the bias is at their end.
Our naiveté extends to our self-confidence. The ‘‘cognitive conceit’’ that appears in our judgments of past knowledge (‘‘I knew it all along’’) surfaces again in estimates of our current knowledge and future behavior. We know that we have muffed things in the past, but we’re confident we will do better in the future at meeting deadlines, nurturing relationships, and following that exercise routine. And we certainly don’t lack for confidence in our hunches and judgments.
To explore this ‘‘overconfidence phenomenon,’’ researchers have given people all sorts of factual questions and then asked them to state their confidence: Is absinthe a liqueur or a precious stone? Which is longer, the Panama Canal or the Suez Canal? In the United States, which claims more lives each year, homicide or suicide? The routine result: When tasks are challenging, people are usually more confident than correct. When 60 percent of folks answer a question correctly, they, on average, feel 75 percent sure. Even when people feel 100 percent certain they err about 15 percent of the time. (The answers, by the way, are a liqueur; the Suez, which is twice as long as the Panama; and suicide, which takes nearly twice as many lives.)
Other studies have invited people to answer factual questions with a wide enough range to surely include the actual answer. ‘‘I feel 98 percent certain that the population of New Zealand is more than but less than ’’ or that ‘‘the number of operating nu- clear power plants is more than but less than .’’ Psy-
chologists Daniel Kahneman and Amos Tversky, two Magellans of the mind who specialized in ‘‘debugging human intuition,’’ reported that nearly one-third of the time people’s estimates, made with 98 percent confidence, failed to include the correct answer (3.7 million New Zealanders and 438 plants at the end of 2000). Although very sure of themselves, they were often wrong. Moreover, warnings (‘‘Be honest with yourselves!’’ ‘‘Admit what you don’t know!’’) and admonitions (‘‘Spread out those distributions!’’) hardly reduced the typical over- confidence.
But these are almanac-type questions. Can we more accurately calibrate our confidence in our social intuitions? To find out, psychol- ogist David Dunning and his associates simulated a little game show. They asked Stanford students to guess a stranger’s answer to such questions as, ‘‘Would you prepare for a difficult exam alone or with a small study group?’’ and ‘‘Would you pocket $5 found at a local cam- pus eatery or turn it in?’’ Knowing the type of question, but not the actual questions, the participants were first given a chance to inter- view the target person about academic interests, hobbies, family, aspirations, astrological signs—anything they guessed might be help- ful. Then the target person answered twenty of the two-choice ques- tions while the interviewers predicted the target’s answers and rated their own confidence.
The result? The interviewers were ‘‘markedly overconfident.’’ Al- though they guessed right 63 percent of the time, they felt, on aver- age, 75 percent sure. When guessing their own roommates’ responses to the questions, they became a bit more accurate (68 percent). But their 78 percent confidence again exceeded their accuracy. Moreover, the most confident people tended to be the most overconfident. Over- confidence has also reigned in studies of people’s intuitive lie detec- tion abilities. On average, participants have been 57 percent accurate but 73 percent sure. Again, the most confident people were not more accurate.
So, our judgments are better than chance (two cheers for social intuition) but generally not as good as we think. In the previous chapter we saw that even our self-predictions are imperfect. But can we accurately calibrate our confidence in our self-predictions? To find out, Robert Vallone and his colleagues had university students
predict in September whether they would drop a course, declare a major, elect to live off campus next year, and so forth. Although the students felt, on average, 84 percent sure of these self-predictions, they erred nearly twice as often as they expected. Even when feeling 100 percent sure they erred 15 percent of the time (just as we noted on the almanac questions).
Other studies show that people are similarly overconfident in pre- dicting how they’re going to change—to lose weight, to study harder, to quit smoking, to exercise regularly. For most, the typical pattern is to start well and then to regress to old habits. (One of psychology’s maxims is that the best predictor of future behavior is past behavior, not present intentions.) We then blame ourselves, feel a bit guilty and depressed, and eventually make a new resolution or seek a new self- help program. Change can happen, but it’s most likely for those who realistically appreciate the challenge and the discipline and mental energy required. Without this appreciation, inflated promises and unrealistic expectations breed a ‘‘false-hope syndrome,’’ note Univer- sity of Toronto psychologists Janet Polivy and Peter Herman. This syndrome entails ‘‘disappointment, discouragement, and perception of oneself as a failure.’’
Psychologist Roger Buehler, of Wilfrid Laurier University, and his colleagues report that most students will confidently underestimate how long it will take to complete papers and other major assign- ments. They have much company. Planners routinely underestimate project time and expense (as Bostonians awaiting their new sub- merged highway can verify). In 1969, Montreal Mayor Jean Drapeau proudly announced that a $120 million stadium with a retractable roof would be built for the 1976 Olympics. The roof was completed in 1989; it alone cost $120 million.
At its worst, overconfidence breeds folly (see box) and catastro- phe. It was an overconfident Hitler who invaded the countries of Europe. It was an overconfident Lyndon Johnson who sent the U.S. Army to salvage democracy in South Vietnam. It was an overconfi- dent Saddam Hussein who marched his army into Kuwait. It was an overconfident Slobodan Milosevic who proclaimed that he would never allow peacekeeping troops in Kosovo.