THE DILEMMA

Unrealistic optimism—also termed optimistic bias—is the pervasive tendency for people to believe they are less at risk of experiencing negative outcomes and more likely to enjoy positive ones than their peers. Such beliefs appear in health, driving ability, professional skills, and many other domains. Although expressions of unrealistic optimism are quite common, intuition suggests a number of compelling reasons why they might be expected to be inhibited or even extinguished. First, and most obviously, for those who expect to attain positive outcomes, there is a very real possibility that those outcomes will not be attained, and optimistically biased expectations overstate the chances of attaining them. That does not mean any particular prediction is guaranteed to fail. The failure to attain desired outcomes can have obvious social and psychological costs (such as disappointment in one’s efforts, mistrust in one’s ability, or even hostile ridicule for promises unfulfilled) as well as costs associated with any investment of time, effort, or financial resources that had been expended in the failed effort. Moreover, the cumulative effects of continued failure to meet optimistically biased predictions might be expected to have disastrous consequences for people’s abilities to effectively regulate their behavior, as repeated disappointment has been found to compromise people’s ability to set and meet future goals and undermine motivation.

Additional concerns arise if, as many researchers suggest, people use their optimistic expectations as a basis for action. People who have unrealistic expectations about how likely they will be to attain positive outcomes may feel it less necessary to complete actions that are necessary for them to attain these outcomes. Similarly, people who do not expect negative events to happen to them may behave in ways that put themselves in actual danger. Much of the research on unrealistic optimism has been conducted in the domain of health, and many researchers in this area have expressed concern that false belief about personal invulnerability to a variety of health threats may lead people to forgo necessary preventative actions. There is also some concern that overly positive expectations about the consequences of one’s actions may lead people to persist in vain to complete actions for which they are ill-prepared, or to seek outcomes that are impossible to achieve or that are noncontingent on continued efforts. Finally, optimistic social comparisons—in which people believe their own chances of success are greater than the likelihood that other people will succeed—may be especially problematic when accurate understanding of one’s relative chances of success is relevant for particular decisions, such as whether to enter into a competitive market.

The literature reviewed here offered surprisingly little direct evidence for these intuitively plausible concerns about the negative consequences of optimistic biases. It is possible that research relevant to the potentially punishing effects of optimistic biases has not been conducted because these effects seem so intuitively plausible that researchers may find them hardly worth testing. The overall lack of evidence documenting any of the punishing consequences of optimistic bias is nonetheless surprising given that the potential for these consequences is often cited as a reason for why the study of optimistic biases is so important. Moreover, what little evidence there is that speaks to these issues does not consistently reveal adverse effects of optimistic bias. For example, there have been a number of studies in which optimistic expectations were disconfirmed, and disappointment, although expected, had not been found. In one study, heart transplant patients who had initially expressed optimistic expectations were no more discouraged following medical complications than were patients who initially had been less optimistic. The prospective studies reviewed here on optimistic expectations of personal invulnerability and risk-related activity did not confirm the commonsense fear that overly optimistic expectations predict risky behavior. In fact, at least some evidence suggests that the opposite is true: one study found that unrealistic optimism about developing AIDS among HIV-seropositive men was associated with several positive health behaviors and was not associated with any health-compromising behaviors.

This lack of evidence of adverse effects does little to resolve the dilemma of unrealistic optimism. If predictions are unrealistically optimistic, how can they not have negative consequences? Why are people who make unrealistically optimistic predictions not especially vulnerable to disappointment, endangerment, and despair? The very prevalence of evidence showing that people are optimistically biased would seem to indicate that these biases have not been so punished that they have been stricken from our cognitive repertoire. Moreover, many attempts to deliberately reduce optimistic biases have met with limited success. Informing people about risk factors, encouraging comparisons with low-risk standards, or prompting them to list reasons why events might or might not occur often fails to reduce optimistic biases for familiar health hazards. In some cases, interventions that merely list risk-increasing factors can even exaggerate the bias, as health campaigns that emphasize high-risk targets may unintentionally cause people to contrast themselves away from those stereotypical targets, perversely strengthening their sense of invulnerability.

How might optimistic beliefs persist despite potentially disappointing feedback? Ambiguity in self-evaluation offers one explanation. A closely related phenomenon, the above-average effect, illustrates this: on desirable and ambiguous traits (such as leadership ability), the vast majority of people rate themselves as better than average. This happens because when the definition of a trait is ambiguous, individuals can idiosyncratically select the criteria that place themselves in the most favorable light. A “good leader” can be defined as someone who listens well, delegates effectively, or inspires others—whichever dimension the individual happens to excel on. The same process operates in unrealistic optimism about life events: when judging their risk of a negative outcome, people might emphasize their own unique protective practices (e.g., “I exercise differently than most”) or define the outcome in a self-serving way (e.g., “I’m not a real smoker because I only smoke on weekends”). Flexible personal standards can protect a favorable self-image from clear disconfirmation. They do not remove the underlying risk or guarantee protection from disappointment. This mechanism may help explain why general risk information sometimes leaves optimistic comparisons intact: it need not change the criteria people use to judge themselves.