Justin Kruger’s research while affiliated with University of Illinois Urbana-Champaign and other places

Previous work on the Dunning–Kruger effect has shown that poor performers often show little insight into the shortcomings in their performance, presumably because they suffer a double curse. Deficits in their knowledge prevent them from both producing correct responses and recognizing that the responses they produce are inferior to those produced by others. Krajč and Ortmann (2008) offered a different account, suggesting instead that poor performers make performance estimates with no more error than top performers. Floor effects, coupled with the assumption of a backwards-J performance distribution, force their self-evaluations errors to be frequently positive in nature. Krajč and Ortmann, however, offered no empirical data to test their “signal extraction” account. In three studies, we assessed their theoretical model by examining whether (1) the data producing the Dunning–Kruger effect fit the statistical assumptions considered by Krajč and Ortmann necessary to produce it, and (2) to see if their framework reproduced Dunning–Kruger errors in a data set that fit their statistical assumptions. We found that the Krajč–Ortmann framework failed to anticipate self-evaluative misperceptions on the part of poor performers, but that it does much better at accounting for misperceptions among top performers. Paradoxically, the model suggests that Kruger and Dunning (1999) may have underestimated the accuracy of top performers, even though their account asserts such accuracy.

People often hold inflated views of their performance on intellectual tasks, with poor performers exhibiting the most inflation. What leads to such excessive confidence? We suggest that the more people approach such tasks in a "rational" (i.e., consistent, algorithmic) manner, relative to those who use more variable or ad hoc approaches, the more confident they become, irrespective of whether they are reaching correct judgments. In 6 studies, participants completed tests involving logical reasoning, intuitive physics, or financial investment. Those more consistent in their approach to the task rated their performances more positively, including those consistently pursuing the wrong rule. Indeed, completely consistent but wrong participants thought almost as highly of their performance as did completely consistent and correct participants. Participants were largely aware of the rules they followed and became more confident in their performance when induced to be more systematic in their approach, no matter how misguided that approach was. In part, the link between decision consistency and (over)confidence was mediated by a neglect of alternative solutions as participants followed a more uniform approach to a task. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Consumers often choose how quickly to consume things they enjoy. The research presented here demonstrates that they tend to consume too rapidly, growing tired of initially well-liked stimuli such as a favorite snack (experiments 1 and 4) or an enjoyable video game (experiments 2 and 3) more quickly than they would if they slowed consumption. The results also demonstrate that such overly-rapid consumption results from a failure to appreciate that longer breaks between consumption episodes slow satiation. The results present a paradox: Participants who choose their own rate of consumption experience less pleasure than those who have a slower rate of consumption chosen for them.

People commonly believe they have contributed more to collaborative tasks than others give them credit for. We distinguish between two types of contributions – additions (such as adding words to a co-authored paper) and deletions (such as removing extraneous words) – and show that individuals are especially prone to receive less credit from others than they believe they deserve when their contributions consist of taking something away rather than adding something. Participants who shortened some writing believed they improved it just as much as did participants who lengthened some, but were seen by others as having contributed less. Although one can hardly fail to notice one's own deletions, these contributions – like any contributions that, by their very nature, leave little trace of themselves – are easy for others to overlook.

Is variety of the spice of life? The present research suggests that the answer depends on the rate of consumption. In three experiments, we find that, whereas a variety of stimuli is preferred to repetition of even a better-liked single stimulus when consumption is continuous, this preference reverses when the satiation associated with repetition is reduced by slowing down the rate of consumption. Decision makers, however, seem to under-appreciate the influence of consumption rate on preference for (and satisfaction with) variety. At high rates of consumption, they correctly anticipate their own, high, desire for variety, but at low rates of consumption people tend to overestimate their own desire for variety. These results complicate the picture presented by prior research on the ``diversification bias'', suggesting that people overestimate their own desire for variety only when consumption is spaced out over time.

Consumers frequently consume items to the point where they no longer enjoy them. In a pilot study and two experiments spanning three distinct classes of stimuli, we find that people can recover from this satiation by simply recalling the variety of alternative items they have consumed in the past. And yet, people seem to exhibit "variety amnesia" in that they do not spontaneously recall this past variety despite the fact that it would result in a desirable decrease in satiation. Thus, rather than satiation being a fixed physiological process, it appears that it is at least partially constructed in the moment. We discuss some of the theoretical implications of these findings and provide some prescriptive measures for both marketers and consumers. (c) 2009 by JOURNAL OF CONSUMER RESEARCH, Inc..

We question a central premise upon which the target article is based. Namely, we point out that the evidence for "positive illusions" is in fact quite mixed. As such, the question of whether positive illusions are adaptive from an evolutionary standpoint may be premature in light of the fact that their very existence may be an illusion.

Individuals are frequently forced to make decisions from among undesirable choice-sets. Raise taxes or cut social services? Lay off workers or go bankrupt? Go deep in debt or forgo a college education? The research presented here suggests that in such situations, decision-makers are often evaluated negatively regardless of the choice they make. In Experiment 1, participants read about a judge deciding which of two seemingly unfit parents to award sole custody in a real-life divorce case. In Experiment 2, participants were led to believe that their partner in the experiment was forced to pick one of two unpleasant tasks for the participant to perform. In both cases, the decision and decision-maker were evaluated negatively regardless of the alternative chosen–and regardless of the fact that they were the only options in the choice-set. Discussion focuses on the source, scope, and consequences of this phenomenon.

Prior research has found that people tend to overestimate their relative contribution to joint tasks [e.g., Ross, M., & Sicoly, F. (1979). Egocentric biases in availability and attribution. Journal of Personality and Social Psychology, 37, 322-336]. The present research investigates one source of this bias, and in doing so, identifies an important moderator of the effect. Three studies demonstrate that when people estimate their relative contribution to collective endeavors they focus on their own contribution and give less consideration to the contribution of their collaborators. This can cause overestimation for tasks in which total contributions are plentiful, but underestimation for tasks in which total contributions are few--despite the fact that both tasks reflect positively on the person who performs them. These results extend Ross and Sicoly's (1979) original analysis of bias in responsibility judgments, but also suggest that the tendency to overestimate one's relative contribution to collaborations is not as ubiquitous as once thought.

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 the participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities. (PsycINFO Database Record (c) 2012 APA, all rights reserved)