Journal of Personality and Social Psychology 1999, Vol. 77, No. 6. ] 121-1134

Copyright 1999 by the American Psychological Association, Inc. 0022-3514/99/S3.00

Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments

Justin Kruger and David Dunning Cornell University

People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 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 their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.

It is one of the essential features of such incompetence that the person so afflicted is incapable of knowing that he is incompetent. To have such knowledge would already be to remedy a good portion of the offense. (Miller, 1993, p. 4)

In 1995, McArthur Wheeler walked into two Pittsburgh banks and robbed them in broad daylight, with no visible attempt at disguise. He was arrested later that night, less than an hour after videotapes of him taken .from surveillance cameras were broadcast on the 11 o'clock news. When police later showed him the sur- veillance tapes, Mr. Wheeler stared in incredulity. "But I wore the juice," he mumbled. Apparently, Mr. Wheeler was under the impression that rubbing one's face with lemon juice rendered it invisible to videotape cameras (Fuocco, 1996).

We bring up the unfortunate affairs of Mr. Wheeler to make three points. The first two are noncontroversial. First, in many domains in life, success and satisfaction depend on knowledge, wisdom, or savvy in knowing which rules to follow and which strategies to pursue. This is true not only for committing crimes, but also for many tasks in the social and intellectual domains, such

Justin Kruger and David Dunning, Department of Psychology, Cornell University.

We thank Betsy Ostrov, Mark Stalnaker, and Boris Veysman for their assistance in data collection. We also thank Andrew Hayes, Chip Heath, Rich Gonzalez, Ken Savitsky, and David Sherman for their valuable comments on an earlier version of this article, and Dov Cohen for alerting us to the quote we used to begin this article. Portions of this research were presented at the annual meeting of the Eastern Psychological Association, Boston, March 1998. This research was supported financially by National Institute of Mental Health Grant RO1 56072.

Correspondence concerning this article should be addressed to Justin Kruger, who is now at the Department of Psychology, University of Illinois at Urbana-Champaign, 603 East Daniel Street, Champaign, Illinois 61820, or to David Dunning, Department of Psychology, Uris Hall, Cornell University, Ithaca, New York 14853-7601. Electronic mail may be sent to Justin Kruger at [email protected] or to David Dunning at [email protected].

as promoting effective leadership, raising children, constructing a solid logical argument, or designing a rigorous psychological study. Second, people differ widely in the knowledge and strate- gies they apply in these domains (Dunning, Meyerowitz, & Holz- berg, 1989; Dunning, Perie, & Story, 1991; Story & Dunning, 1998), with varying levels of success. Some of the knowledge and theories that people apply to their actions are sound and meet with favorable results. Others, like the lemon juice hypothesis of McArthur Wheeler, are imperfect at best and wrong-headed, in- competent, or dysfunctional at worst.

Perhaps more controversial is the third point, the one that is the focus of this article. We argue that when people are incompetent in the strategies they adopt to achieve success and satisfaction, they suffer a dual burden: Not only do they reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realize it. Instead, like Mr. Wheeler, they are left with the mistaken impression that they are doing just fine. As Miller (1993) perceptively observed in the quote that opens this article, and as Charles Darwin (1871) sagely noted over a century ago, "ignorance more frequently begets confidence than does knowl- edge" (p. 3).

In essence, we argue that the skills that engender competence in a particular domain are often the very same skills necessary to evaluate competence in that domain—one's own or anyone else's. Because of this, incompetent individuals lack what cognitive psy- chologists variously term metacognition (Everson & Tobias, 1998), metamemory (Klin, Guizman, & Levine, 1997), metacom- prehension (Maki, Jonas, & Kallod, 1994), or self-monitoring skills (Chi, Glaser, & Rees, 1982). These terms refer to the ability to know how well one is performing, when one is likely to be accurate in judgment, and when one is likely to be in error. For example, consider the ability to write grammatical English. The skills that enable one to construct a grammatical sentence are the same skills necessary to recognize a grammatical sentence, and thus are the same skills necessary to determine if a grammatical mistake has been made. In short, the same knowledge that under- lies the ability to produce correct judgment is also the knowledge

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that underlies the ability to recognize correct judgment. To lack the former is to be deficient in the latter.

Imperfect Self-Assessments

We focus on the metacognitive skills of the incompetent to explain, in part, the fact that people seem to be so imperfect in appraising themselves and their abilities.1 Perhaps the best illus- tration of this tendency is the "above-average effect," or the tendency of the average person to believe he or she is above average, a result that defies the logic of descriptive statistics (Alicke, 1985; Alicke, Klotz, Breitenbecher, Yurak, & Vreden- burg, 1995; Brown & Gallagher, 1992; Cross, 1977; Dunning et al , 1989; Klar, Medding, & Sarel, 1996; Weinstein, 1980; Wein- stein & Lachendro, 1982). For example, high school students tend to see themselves as having more ability in leadership, getting along with others, and written expression than their peers (College Board, 1976-1977), business managers view themselves as more able than the typical manager (Larwood & Whittaker, 1977), and football players see themselves as more savvy in "football sense" than their teammates (Felson, 1981).

We believe focusing on the metacognitive deficits of the un- skilled may help explain this overall tendency toward inflated self-appraisals. Because people usually choose what they think is the most reasonable and optimal option (Metcalfe, 1998), the failure to recognize that one has performed poorly will instead leave one to assume that one has performed well. As a result, the incompetent will tend to grossly overestimate their skills and abilities.

Competence and Metacognitive Skills

Several lines of research are consistent with the notion that incompetent individuals lack the metacognitive skills necessary for accurate self-assessment. Work on the nature of expertise, for instance, has revealed that novices possess poorer metacognitive skills than do experts. In physics, novices are less accurate than experts in judging the difficulty of physics problems (Chi et al., 1982). In chess, novices are less calibrated than experts about how many times they need to see a given chessboard position before they are able to reproduce it correctly (Chi, 1978). In tennis, novices are less likely than experts to successfully gauge whether specific play attempts were successful (McPherson & Thomas, 1989).

These findings suggest that unaccomplished individuals do not possess the degree of metacognitive skills necessary for accurate self-assessment that their more accomplished counterparts possess. However, none of this research has examined whether metacog- nitive deficiencies translate into inflated self-assessments or whether the relatively incompetent (novices) are systematically more miscalibrated about their ability than are the competent (experts).

If one skims through the psychological literature, one will find some evidence that the incompetent are less able than their more skilled peers to gauge their own level of competence. For example, Fagot and O'Brien (1994) found that socially incompetent boys were largely unaware of their lack of social graces (see Bern & Lord, 1979, for a similar result involving college students). Me- diocre students are less accurate than other students at evaluating

their course performance (Moreland, Miller, & Laucka, 1981). Unskilled readers are less able to assess their text comprehension than are more skilled readers (Maki, Jonas, & Kallod, 1994). Students doing poorly on tests less accurately predict which ques- tions they will get right than do students doing well (Shaughnessy, 1979; Sinkavich, 1995). Drivers involved in accidents or flunking a driving exam predict their performance on a reaction test less accurately than do more accomplished and experienced drivers (Kunkel, 1971). However, none of these studies has examined whether deficient metacognitive skills underlie these miscalibra- tions, nor have they tied these miscalibrations to the above-average effect.

Predictions

These shards of empirical evidence suggest that incompetent individuals have more difficulty recognizing their true level of ability than do more competent individuals and that a lack of metacognitive skills may underlie this deficiency. Thus, we made four specific predictions about the links between competence, metacognitive ability, and inflated self-assessment.

Prediction 1. Incompetent individuals, compared with their more competent peers, will dramatically overestimate their ability and performance relative to objective criteria.

Prediction 2. Incompetent individuals will suffer from deficient metacognitive skills, in that they will be less able than their more competent peers to recognize competence when they see it—be it their own or anyone else's.

Prediction 3. Incompetent individuals will be less able than their more competent peers to gain insight into their true level of performance by means of social comparison information. In par- ticular, because of their difficulty recognizing competence in oth- ers, incompetent individuals will be unable to use information about the choices and performances of others to form more accu- rate impressions of their own ability.

Prediction 4. The incompetent can gain insight about their shortcomings, but this comes (paradoxically) by making them more competent, thus providing them the metacognitive skills necessary to be able to realize that they have performed poorly.

The Studies

We explored these predictions in four studies. In each, we presented participants with tests that assessed their ability in a domain in which knowledge, wisdom, or savvy was crucial: humor (Study 1), logical reasoning (Studies 2- and 4), and English gram- mar (Study 3). We then asked participants to assess their ability

1 A few words are in order about what we mean by incompetent. First, throughout this article, we think of incompetence as a matter of degree and not one of absolutes. There is no categorical bright line that separates "competent" individuals from "incompetent" ones. Thus, when we speak of "incompetent" individuals we mean people who are less competent than their peers. Second, we have focused our analysis on the incompetence individuals display in specific domains. We make no claim that they would be incompetent in any other domains, although many a colleague has pulled us aside to tell us a tale of a person they know who is "domain- general" incompetent. Those people may exist, but they are not the focus of this research.

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and test performance. In all studies, we predicted that participants in general would overestimate their ability and performance rela- tive to objective criteria. But more to the point, we predicted that those who proved to be incompetent (i.e., those who scored in the bottom quarter of the distribution) would be unaware that they had performed poorly. For example, their score would fall in the 10th or 15th percentile among their peers, but they would estimate that it fell much higher (Prediction 1). Of course, this overestimation could be taken as a mathematical verity. If one has a low score, one has a better chance of overestimating one's performance than underestimating it. Thus, the real question in these studies is how much those who scored poorly would be miscalibrated with re- spect to their performance.

In addition, we wanted to examine the relationship between miscalibrated views of ability and metacognitive skills, which we operationalized as (a) the ability to distinguish what one has answered correctly from what one has answered incorrectly and (b) the ability to recognize competence in others. Thus, in Study 4, we asked participants to not only estimate their overall perfor- mance and ability, but to indicate which specific test items they believed they had answered correctly and which incorrectly. In Study 3, we showed competent and incompetent individuals the responses of others and assessed how well participants from each group could spot good and poor performances. In both studies, we predicted that the incompetent would manifest poorer metacogni- tive skills than would their more competent peers (Prediction 2).

We also wanted to find out what experiences or interventions would make low performers realize the true level of performance that they had attained. Thus, in Study 3, we asked participants to reassess their own ability after they had seen the responses of their peers. We predicted that competent individuals would learn from observing the responses of others, thereby becoming better cali- brated about the quality of their performance relative to their peers. Incompetent participants, in contrast, would not (Prediction 3). In Study 4, we gave participants training in the domain of logical reasoning and explored whether this newfound competence would prompt incompetent individuals toward a better understanding of the true level of their ability and test performance (Prediction 4).

Study 1: Humor

In Study 1, we decided to explore people's perceptions of their competence in a domain that requires sophisticated knowledge and wisdom about the tastes and reactions of other people. That do- main was humor. To anticipate what is and what others will find funny, one must have subtle and tacit knowledge about other people's tastes. Thus, in Study 1 we presented participants with a series of jokes and asked them to rate the humor of each one. We then compared their ratings with those provided by a panel of experts, namely, professional comedians who make their living by recognizing what is funny and reporting it to their audiences. By comparing each participant's ratings with those of our expert panel, we could roughly assess participants' ability to spot humor.

Our key interest was how perceptions of that ability converged with actual ability. Specifically, we wanted to discover whether those who did poorly on our measure would recognize the low quality of their performance. Would they recognize it or would they be unaware?

Method

Participants. Participants were 65 Cornell University undergraduates from a variety of courses in psychology who earned extra credit for their participation.

Materials. We created a 30-item questionnaire made up of jokes we felt were of varying comedic value. Jokes were taken from Woody Allen (1975), Al Frankin (1992), and a book of "really silly" pet jokes by Jeff Rovin (1996). To assess joke quality, we contacted several professional comedians via electronic mail and asked them to rate each joke on a scale ranging from 1 (not at all funny) to 11 (very funny). Eight comedians responded to our request (Bob Crawford, Costaki Economopoulos, Paul Frisbie, Kathleen Madigan, Ann Rose, Allan Sitterson, David Spark, and Dan St. Paul). Although the ratings provided by the eight comedians were moderately reliable (a = .72), an analysis of interrater correlations found that one (and only one) comedian's ratings failed to correlate positively with the others (mean r = -.09). We thus excluded this comedian's ratings in our calculation of the humor value of each joke, yielding a final a of .76. Expert ratings revealed that jokes ranged from the not so funny (e.g., "Question: What is big as a man, but weighs nothing? Answer: His shadow." Mean expert rating = 1.3) to the very funny (e.g., "If a kid asks where rain comes from, I think a cute thing to tell him is 'God is crying.' And if he asks why God is crying, another cute thing to tell him is 'probably because of something you did.'" Mean expert rating = 9.6).

Procedure. Participants rated each joke on the same 11-point scale used by the comedians. Afterward, participants compared their "ability to recognize what's funny" with that of the average Cornell student by providing a percentile ranking. In this and in all subsequent studies, we explained that percentile rankings could range from 0 (I'm at the very bottom) to 50 (I'm exactly average) to 99 (I'm at the very top).

Results and Discussion

Gender failed to qualify any results in this or any of the studies reported in this article, and thus receives no further mention.

Our first prediction was that participants overall would overes- timate their ability to tell what is funny relative to their peers. To find out whether this was the case, we first assigned each partic- ipant a percentile rank based on the extent to which his or her joke ratings correlated with the ratings provided by our panel of pro- fessionals (with higher correlations corresponding to better perfor- mance). On average, participants put their ability to recognize what is funny in the 66th percentile, which exceeded the actual mean percentile (50, by definition) by 16 percentile points, one- sample /(64) = 7.02, p < .0001. This overestimation occurred even though self-ratings of ability were significantly correlated with our measure of actual ability, r(63) = .39, p < .001.

Our main focus, however, is on the perceptions of relatively "incompetent" participants, which we defined as those whose test score fell in the bottom quartile (n = 16). As Figure 1 depicts, these participants grossly overestimated their ability relative to their peers. Whereas their actual performance fell in the 12th percentile, they put themselves in the 58th percentile. These esti- mates were not only higher than the ranking they actually achieved, paired r(15) = 10.33, p < .0001, but were also margin- ally higher than a ranking of "average" (i.e., the 50th percentile), one-sample t(15) = 1.96, p < .07. That is, even participants in the bottom quarter of the distribution tended to feel that they were better than average.

As Figure 1 illustrates, participants in other quartiles did not overestimate their ability to the same degree. Indeed, those in the

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Figure 1. Perceived ability to recognize humor as a function of actual test performance (Study 1).

top quartile actually underestimated their ability relative to their peers, paired 1(15) = -2.20, p < .05.

Summary

In short, Study 1 revealed two effects of interest. First, although perceptions of ability were modestly correlated with actual ability, people tended to overestimate their ability relative to their peers. Second, and most important, those who performed particularly poorly relative to theirpeers were utterly unaware of this fact. Participants scoring in the bottom quartile on our humor test not only overestimated their percentile ranking, but they overestimated it by 46 percentile points. To be sure, they had an inkling that they were not as talented in this domain as were participants in the top quartile, as evidenced by the significant correlation between per- ceived and actual ability. However, that suspicion failed to antic- ipate the magnitude of their shortcomings.

At first blush, the reader may point to the regression effect as an alternative interpretation of our results. After all, we examined the perceptions of people who had scored extremely poorly on the objective test we handed them, and found that their perceptions were less extreme than their reality. Because perceptions of ability are imperfectly correlated with actual ability, the regression effect virtually guarantees this result. Moreover, because incompetent participants scored close to the bottom of the distribution, it was nearly impossible for them to underestimate their performance.

Despite the inevitability of the regression effect, we believe that the overestimation we observed was more psychological than artifactual. For one, if regression alone were to blame for our results, then the magnitude of miscalibration among the bottom quartile would be comparable with that of the top quartile. A glance at Figure 1 quickly disabuses one of this notion. Still, we believe this issue warrants empirical attention, which we devote in Studies 3 and 4.

Study 2: Logical Reasoning

We conducted Study 2 with three goals in mind. First, we wanted to replicate the results of Study 1 in a different domain, one

focusing on intellectual rather than social abilities. We chose logical reasoning, a skill central to the academic careers of the participants we tested and a skill that is called on frequently. We wondered if those who do poorly relative to their peers on a logical reasoning test would be unaware of their poor performance.

Examining logical reasoning also enabled us to compare per- ceived and actual ability in a domain less ambiguous than the one we examined in the previous study. It could reasonably be argued that humor, like beauty, is in the eye of the beholder.2 Indeed, the imperfect interrater reliability among our group of professional comedians suggests that there is considerable variability in what is considered funny even by experts. This criterion problem, or lack of uncontroversial criteria against which self-perceptions can be compared, is particularly problematic in light of the tendency to define ambiguous traits and abilities in ways that emphasize one's own strengths (Dunning et al., 1989). Thus, it may have been the tendency to define humor idiosyncratically, and in ways favorable to one's tastes and sensibilities, that produced the miscalibration we observed—not the tendency of the incompetent to miss their own failings. By examining logical reasoning skills, we could circumvent this problem by presenting students with questions for which there is a definitive right answer.

Finally, we wanted to introduce another objective criterion with which we could compare participants' perceptions. Because per- centile ranking is by definition a comparative measure, the mis- calibration we saw could have come from either of two sources. In the comparison, participants may have overestimated their own ability (our contention) or may have underestimated the skills of their peers. To address this issue, in Study 2 we added a second criterion with which to compare participants' perceptions. At the end of the test, we asked participants to estimate how many of the questions they had gotten right and compared their estimates with their actual test scores. This enabled us to directly examine whether the incompetent are, indeed, miscalibrated with respect to their own ability and performance.

Method

Participants. Participants were 45 Cornell University undergraduates from a single introductory psychology course who earned extra credit for their participation. Data from one additional participant was excluded because she failed to complete the dependent measures.

Procedure. Upon arriving at the laboratory, participants were told that the study focused on logical reasoning skills. Participants then completed a 20-item logical reasoning test that we created using questions taken from a Law School Admissions Test (LSAT) test preparation guide (Orton, 1993). Afterward, participants made three estimates about their ability and test performance. First, they compared their "general logical reasoning ability" with that of other students from their psychology class by provid- ing their percentile ranking. Second, they estimated how their score on the test would compare with that of their classmates, again on a percentile scale. Finally, they estimated how many test questions (out of 20) they thought they had answered correctly. The order in which these questions were asked was counterbalanced in this and in all subsequent studies.

2 Actually, some theorists argue that there are universal standards of beauty (see, e.g., Thomhill & Gangestad, 1993), suggesting that this truism may not be, well, true.

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Results and Discussion

The order in which specific questions were asked did not affect any of the results in this or in any of the studies reported in this article and thus receives no further mention.

As expected, participants overestimated their logical reasoning ability relative to their peers. On average, participants placed themselves in the 66th percentile among students from their class, which was significantly higher than the actual mean of 50, one- sample r(44) = 8.13, p < .0001. Participants also overestimated their percentile rank on the test, M percentile = 61, one-sample t(44) = 4.70, p < .0001. Participants did not, however, overesti- mate how many questions they answered correctly, M = 13.3 (perceived) vs. 12.9 (actual), t < 1. As in Study 1, perceptions of ability were positively related to actual ability, although in this case, not to a significant degree. The correlations between actual ability and the three perceived ability and performance measures ranged from .05 to .19, all ns.

What (or rather, who) was responsible for this gross miscalibra- tion? To find out, we once again split participants into quartiles based on their performance on the test. As Figure 2 clearly illus- trates, it was participants in the bottom quartile (n = 11) who overestimated their logical reasoning ability and test performance to the greatest extent. Although these individuals scored at the 12th percentile on average, they nevertheless believed that their general logical reasoning ability fell at the 68th percentile and their score on the test fell at the 62nd percentile. Their estimates not only exceeded their actual percentile scores, fs(10) = 17.2 and 11.0, respectively, ps < .0001, but exceeded the 50th percentile as well, fs(10) = 4.93 and 2.31, .respectively, ps < .05. Thus, participants in the bottom quartile not only overestimated themselves but believed that they were above average. Similarly, they thought they had answered 14.2 problems correctly on average—com- pared with the actual mean score of 9.6, r(10) = 7.66, p < .0001.

Other participants were less miscalibrated. However, as Figure 2 shows, those in the top quartile once again tended to underestimate their ability. Whereas their test performance put them in the 86th percentile, they estimated it to be at the 68th percentile and

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Figure 2. Perceived logical reasoning ability and test performance as a function of actual test performance (Study 2).

estimated their general logical reasoning ability to fall at only the 74th percentile, fs(12) = -3.55 and -2.50, respectively,ps < .05. Top-quartile participants also underestimated their raw score on the test, although this tendency was less robust, M = 14.0 (per- ceived) versus 16.9 (actual), r(12) = -2.15,/? < .06.

Summary

In sum, Study 2 replicated the primary results of Study 1 in a different domain. Participants in general overestimated their logi- cal reasoning ability, and it was once again those in the bottom quartile who showed the greatest miscalibration. It is important to note that these same effects were observed when participants considered their percentile score, ruling out the criterion problem discussed earlier. Lest one think these results reflect erroneous peer assessment rather then erroneous self-assessment, participants in the bottom quartile also overestimated the number of test items they had gotten right by nearly 50%.

Study 3 (Phase 1): Grammar

Study 3 was conducted in two phases. The first phase consisted of a replication of the first two studies in a third domain, one requiring knowledge of clear and decisive rules and facts: gram- mar. People may differ in the worth they assign to American Standard Written English (ASWE), but they do agree that such a standard exists, and they differ in their ability to produce and recognize written