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date: 19 September 2017

Optimism and Its Associations with Health Behavior and Responses to Health Communication

Summary and Keywords

When individuals are asked whether they will someday own their own home, enjoy a productive career, or develop a myriad of diseases, many are optimistic. Generally, they think they will experience more good than bad outcomes in life and they view themselves as more likely than similar others to experience the good things and less likely than others to experience the bad things. In the area of health behavior and communication, there are three primary types of optimism that have been defined and operationalized: (1) Dispositional optimism is the generalized positive expectancy that one will experience good outcomes. (2) Comparative optimism refers to the belief that one is either more likely than others to experience positive events or less likely than others to experience negative events. (3) Unrealistic optimism refers to an underestimation of one’s actual risk of experiencing some negative event. Although the three types of optimism may be correlated, their associations may be modest. Also, unlike dispositional optimism, which is an individual difference, comparative and unrealistic optimism are often risk perceptions about specific events and therefore can be defined as accurate or inaccurate. For this reason, the latter two types of optimism have sometimes been labeled the optimistic bias. Research on all three varieties of optimism affords opportunities to understand how optimism influences information processing in a health message or one’s behavioral intentions following the message.

Keywords: unrealistic optimism, comparative optimism, trait optimism, health communication, health behaviors, defensive biases, health and risk message design and processing

Introduction

Many theories of health behavior view risk perceptions, or one’s perceived susceptibility to a health threat, as a central factor in behavior motivation (Janz & Becker, 1984; Rogers, 1975; Rosenstock, 1974; Weinstein, 1988). Along with their influence on health behavior, risk perceptions are likely to influence how individuals respond to health information. For example, relative to a woman who believes she has a low risk of developing a disease such as breast cancer, one who believes her risk is high may give more attention to a health message about the cancer such as its risk factors and possible preventive measures (e.g., Dillard et al., 2011; McCaul, Branstetter, Schroeder, & Glasgow, 1996). Because of how significant risk perceptions are to health behavior, health communication interventions often focus on influencing them. Although researchers face several challenges when attempting to influence risk perceptions, optimistic biases may be the greatest. Optimistic biases occur when individuals’ risk perceptions are overly positive yet not in line with reality. These biases have sometimes been called positive illusions (Taylor et al., 1992), and when applied to risk perceptions of negative events, they are extremely prevalent (Weinstein, 1982; Weinstein & Klein, 1996). Optimistic biases have been found in different health domains, from substance abuse and risky sexual activity to risk for chronic diseases, such as cancer and heart disease (e.g., Avis, Smith, & McKinlay, 1989; Clarke, Williams, & Arthey, 1997; Gerrard & Luus, 1995; Gold & Aucote, 2003; Perloff & Fetzer, 1986; Skinner, Kreuter, Kobrin, & Strecher, 1998; Weinstein, 1980; Weinstein & Klein, 1996). In the current chapter, we review the optimistic bias literature, including the different ways the bias has been defined and assessed, as well as its associations with health behavior and its role in responses to health communication.

In the area of health behavior and communication, there are three primary types of optimism that have been defined and operationalized. The first type of optimism reflects individual differences, and has also been called trait or dispositional optimism. Dispositional optimism is defined as a generalized positive expectancy that one will experience good outcomes (Scheier, Carver, & Bridges, 1994). It is typically measured using a scale of optimism/pessimism statements rather than measuring risk perceptions. Two other types of optimism are comparative optimism and unrealistic optimism. Comparative optimism refers to the belief that one is either more likely than others to experience positive events or less likely than others to experience negative events (Radcliffe & Klein, 2002). In comparative optimism, one is asked to compare one’s own risk to another individual’s or group’s risk level. This type of optimism may or may not be inaccurate or unrealistic (Weinstein & Klein, 1996). Unrealistic optimism is a third type of optimism that refers to an underestimation of one’s risk of experiencing some negative event relative to some objectively-derived estimate (Klein & Cooper, 2008; Weinstein & Klein, 1996). For example, to determine unrealistic optimism, one’s risk perception of an event may be compared to his or her actual absolute risk, or his or her actual comparative risk. In these cases, the terms unrealistic absolute optimism or unrealistic comparative optimism, respectively, may be applied (Klein & Weinstein, 1997).

In contrast to dispositional optimism, which is about one’s expectations of general outcomes, comparative and unrealistic optimism relate to expectations of specific events that may occur in the future. For example, people have been asked about their likelihood of owning their own home, being fired from a job, or experiencing different health events or diseases (e.g., Avis et al., 1989; Clarke et al., 1997; Skinner et al., 1998; Weinstein, 1980). Research reveals that across these and other events, people rate themselves as more likely than others to experience the good things and less likely than others to experience the bad things (Weinstein & Klein, 1995). When individuals are inaccurate about their risks, they are optimistically biased. Although dispositional optimism may sometimes be called an optimistic bias (e.g., due to the prevalence of moderate to high scores), it is impossible to define this type of optimism as a form of optimistic bias. This is because people’s general life expectancies cannot be defined as accurate or inaccurate. In this chapter, we will review the ways in which all three types of optimism (dispositional, comparative, and unrealistic) influence health and responses to health communication.

Dispositional Optimism

Dispositional optimism is the generalized positive expectancy that one is likely to experience good outcomes in life (Scheier et al., 1994). This type of optimism is most often measured using the Life Orientation Test (LOT), a 10-item questionnaire that includes statements such as “In uncertain times, I usually expect the best,” and “I'm always optimistic about my future.” Decades of research using the LOT in populations of college students, older adults, and even those who have chronic illnesses suggest that most people are moderately to highly optimistic, with average scores of 25 out of a possible 30 (Carver et al., 1993; for a review, see Carver, Scheier, & Segerstrom, 2010).

After more than 30 years of research on dispositional optimism, researchers have associated the construct with many different outcomes. The earliest work revealed its connections to psychological constructs such as self-esteem, anxiety, and neuroticism. For example, Scheier and Carver showed that as individuals scored higher on the LOT, they scored higher on measures of self-esteem and lower on measures of trait anxiety and neuroticism (Scheier & Carver, 1987; Scheier, Carver, & Bridges, 1994). In the 1990s, research linked higher scores on the LOT with reports of fewer daily physical symptoms (Scheier & Carver, 1992) as well as faster recovery following cardiac bypass surgery (Fitzgerald, Tennen, Affleck, & Pransky, 1993; Scheier & Carver, 1992). The most recent reviews on dispositional optimism suggest that it is beneficial to health across a number of domains, including cardiovascular risk, immune function, risk of cancer, risks related to pregnancy and infant health, and pain (for reviews, see Carver & Scheier, 2014; Rasmussen, Wrosch, Scheier, & Carver, 2006; Rasmussen, Scheier, & Greenhouse, 2009). Research has also linked dispositional optimism to the ultimate health outcomes of survival and mortality (Allison, Guichard, Fung, & Gilain, 2003; Carver & Scheier, 2014; Giltay, Geleijnse, Zitman, Hoekstra, & Schouten, 2004; Rasmussen et al., 2009).

Part of the reason that dispositional optimists may enjoy these health benefits is that their optimism leads them to deal more effectively with life stressors. For example, researchers have found that dispositional optimism is associated with being more likely to use problem-focused rather than avoidant coping when facing real-life health problems such as diagnoses of chronic illness (for reviews, see Nes & Segerstrom, 2006; Wrosch & Scheier, 2003). Along with applying more positive coping strategies in dealing with health-related stressors, optimists may use these strategies in dealing with other stressors, like those surrounding social relationships. Recent research reveals that optimists work harder at nurturing and maintaining social relationships and that they also respond more adaptively to relationship crises (Carver & Scheier, 2014). Biological indicators have also been studied. Researchers find that those who score high on measures of dispositional optimism also show less inflammatory biomarkers and a lower cortisol response when faced with these stressors (Carver & Scheier, 2014).

Along with coping strategies, research shows that when feeling stressed, optimists may be less likely to engage in unhealthy behaviors like smoking, using illicit drugs, or drinking alcohol (Nes & Segerstrom, 2006; Wrosch & Scheier, 2003). It should be noted that there is a broader finding that regardless of stress, compared to pessimists, optimists are less likely to smoke and more likely to have healthy diets or attempt to improve their diets (Giltay, Geleijnse, Zitman, Buijsse, & Kromhout, 2007; Hingle et al., 2014; Steptoe et al., 1994; Steptoe, Wright, Kunz‐Ebrecht, & Iliffe, 2006). Together this research suggest that dispositional optimism may be a health-protective resource for people, including helping them to cope more effectively when they are in the crux of stressful experiences and leading them to engage in healthier behaviors on a general basis.

Along with dispositional optimism’s connections to physical health, stress and coping, and health behaviors, researchers have examined how the construct relates to individuals’ responses to health information. Providing individuals with personally relevant health information may be an early first step toward influencing health behavior motivation. Research reveals that dispositional optimism may predispose people to respond in particular ways to messages about their health. For example, a number of studies have found that higher scores on dispositional optimism tends to be associated with giving more attention to threatening health information, particularly when the information is self-relevant—i.e., one engages in the behavior of which the information is focused (e.g., Aspinwall & Brunhart, 1996; Aspinwall & Richter, 2001). In one study, optimists who used vitamins paid more attention to negative information about vitamin use than to positive or neutral information about it. They also recalled more of the information and showed evidence of greater elaborative processing (Aspinwall & Brunhart, 1996). In another study, researchers found that dispositional optimists who tanned were more likely than their pessimistic counterparts to recall risky information about tanning (Aspinwall & Brunhart, 2000). Similar findings have been observed for optimists and personally relevant information about exercise (Abele & Gendolla, 2007).

Along with paying greater attention to risk information, those high in dispositional optimism may show less defensiveness to personally relevant, threatening information. Defensiveness can be a common response to threatening information (Ditto & Lopez, 1992; Jemmott, Ditto, & Croyle, 1986; Leffingwell, Neumann, Leedy, & Babitzke, 2007; Liberman & Chaiken, 1992; Rothman & Schwarz, 1998; Sherman & Cohen, 2002), and it involves different strategies to protect the self from psychological harm. The strategies are varied and can range from minimizing threatening information (e.g., downplaying the seriousness or importance or viewing it as less credible) to increasing one’s beliefs in the prevalence of the behavior (“everyone does it”) or increasing one’s own intentions to do the behavior (e.g., reactance) (for a review, see Croyle, Sun, & Hart, 1997; also Croyle, Sun, & Louie, 1993; Goldstein, 1991; Klein, 1996; Liberman & Chaiken, 1992). Recently, affective responses have also been argued to be a proxy for defensiveness (Geers, Wellman, & Fowler, 2013; Zhao, Huang, Li, Zhao, & Peng, 2015). Some of these defensive strategies have been associated with dispositional optimism. For example, Geers and colleagues found that higher levels of dispositional optimism were associated with being more likely to view personally relevant risk information as credible and important (Geers et al., 2013). Higher dispostional optimism has also been associated with being more certain about risk information, regardless of varying formats of information presentation (Han et al., 2012). Recent research has also found that people who score higher on dispositional optimism tend to have more positive and less negative affective responses to health information that is self-threatening (Geers et al., 2013; Zhao et al., 2015).

Importantly, not all studies have found these associations between dispositional optimism and responses to health messages. For example, one study showed that compared to pessimists, optimists tend to fixate less on negative or threatening stimuli (e.g., Isaacowitz, 2005). In this study, the researchers used eye-tracking software and found that college students who were more optimistic looked less at images of melanoma compared to their more pessimistic peers. The finding held even after adjusting for anxiety, personality, and demographics (Isaacowitz, 2005). In another study, researchers found that dispositional optimists showed an (unconscious) attentional preference for positive information, but this study was not in a health context (Segerstrom, 2001). However, other studies have found null associations between dispositional optimism and attention to health-related information (e.g., Luo & Isaacowitz, 2007; Radcliffe & Klein, 2002).

In sum, the above research on dispositional optimism suggests that it can be associated with many health outcomes and can shape how individuals process and use risk information, which could further influence health outcomes. We now turn to two other types of optimism that have also been shown to relate to health: comparative and unrealistic optimism. These forms of optimism differ from dispositional optimism in that they represent expectations about specific events for which actual risk levels can be estimated. Therefore, these types of optimism can be defined as accurate or inaccurate, which has implications for how they are studied and for their relations to health communication. Not only can we determine if individuals’ risk perceptions are in line with reality, but we can also examine the consequences of realistic or unrealistic risk perceptions (e.g., including the optimistic bias). We begin with comparative optimism, including how it has been operationalized, its links to physical health and health behaviors, and its role in individuals’ responses to health communication.

Comparative Optimism

Comparative optimism is when individuals have optimistic expectations about the likelihood of events occurring for them compared to their expectations about the likelihood of those events occurring for others (Radcliffe & Klein, 2002; Rose, 2012). For example, individuals who are comparatively optimistic would rate their risk of a negative event as lower than others’ risk of the same event. The “others” may be one individual or a group of individuals who may be further defined as similar to the individual (e.g., in race, sex, and age characteristics) or dissimilar (Klein, 1997, 2002). Comparative optimism has been assessed at the group and individual levels, although the group level is much more common. It can be assessed directly by asking, “What are your chances of experiencing X compared to a similar other?” If a group or individual rates risk as below the scale midpoint (i.e., average), they are defined as comparatively optimistic. Comparative optimism can also be assessed indirectly by asking individuals about both their own chances of experiencing some event, as well as another’s chances of experiencing the same event. If the individual rates his or her risk lower than the similar other, he or she is defined as comparatively optimistic.

Much research has examined comparative optimism using the direct and indirect methods described above. Thanks to this research we now know that people show comparative optimism for many events, both positive and negative. For example, they are comparatively optimistic about their likelihood of graduating from college, owing their own home, becoming divorced, or being fired from a job (Weinstein, 1980). Research also shows comparative optimism for a wide range of health events including experiencing a heart attack, contracting HIV or other sexually transmitted diseases, having an unwanted pregnancy, becoming ill, developing several types of cancer, and many more (e.g., Avis et al., 1989; Clarke et al., 1997; Gerrard & Luus, 1995; Gold & Aucote, 2003; Helweg-Larson & Shepperd, 2001; Perloff & Fetzer, 1986; Pahl, Harris, Todd, & Rutter, 2005; Skinner et al., 1998; Strecher, Kreuter, & Kobrin, 1995; Weinstein, 1980, 1987, 1998; Weinstein & Klein, 1996). This optimism holds across different genders, ages, education levels and occupations (Weinstein, 1987).

Like dispositional optimism, comparative optimism has also been linked to health behaviors. But unlike dispositional optimism, comparative optimism may actually deter engagement in healthy behaviors, particularly for events that are perceived as within one’s personal control, or events or consequences with which they have little experience (Helweg-Larsen, 1999; Klein & Helweg-Larsen, 2002; Rimal & Real, 2003; Weinstein, 1984; Weinstein & Klein, 1995). Consider smokers, for example. Several studies have documented that smokers as a group exhibit comparative optimism (e.g., Borrelli, Hayes, Dunsiger, & Fava, 2010; Masiero, Lucchiari, Pravettoni, 2015; McCoy et al., 1992; Weinstein, Slovic, & Gibson, 2004; Williams & Clarke, 1997). For example, fewer than half of current smokers consider themselves to be at higher risk than former smokers or nonsmokers for smoking-related illnesses such as heart disease and cancer (Ayanian & Cleary, 1999; Halpern-Felsher Biehl, Kropp, & Rubinstein, 2004; McCoy et al., 1992; Weinstein, Marcus, & Moser, 2005)! Among smokers who do perceive themselves to be at higher risk than nonsmokers, they are still comparatively optimistic about their disease risk compared to other smokers (Arnett, 2000; Peretti-Watel et al., 2014; Strecher et al., 1995; Weinstein, 1998; Weinstein et al., 2005). Smokers who underestimate their risk relative to other smokers may be less motivated and have lower intentions to quit (e.g., Borrelli et al., 2010; McCoy et al., 1992). Outside of a smoking context, comparative optimism has been linked to other risky health behaviors, such as excessive alcohol consumption (Dillard, Midboe, & Klein, 2009), hazardous driving behavior (Deery, 1999; Martha, Laurendeau, & Griffet, 2010), lower intentions to lose weight (Klein, 2002), and engagement in other lifestyle behaviors that increase risk for disease (Wendt, 2005). Comparative optimism has also been associated with nonadherence to cancer screening guidelines (Aiken et al., 1994; Clarke et al., 2000; Katapodi, Dodd, Lee, & Facione, 2009; Lipkus, Lyna, & Rimer, 2000; Wong, 2009). In research on breast cancer, studies have also associated comparatively optimistic risk perceptions with little interest in learning more about medicines that could potentially lower one’s objective risk of the disease (e.g., Dillard et al., 2011; Fagerlin, Zikmund-Fisher, & Ubel, 2007).

Although the above research suggests that comparative optimism is associated with more risk behaviors than health behaviors, the relationship is not entirely conclusive. This is because research has not always found comparative optimism to have such associations. For instance, some studies find that the majority of women actually overestimate their risk for breast cancer (Black, Nease, & Tosteson, 1995; Buxton et al., 2003; Davids et al., 2004; Gail & Costantino, 2001). In another study, individuals who were comparatively optimistic about their health but also worried about their health had the greatest exercise intentions (Portnoy, Kaufman, Klein, Doyle, & de Groot, 2014). In an intervention study that was aimed at reducing comparative optimism in risk perceptions of colorectal cancer, researchers found that cancer screening intentions were actually highest among participants who learned they had a lower-than-average risk (Lipkus & Klein, 2006).

Some of these inconsistencies in the literature regarding comparative optimism being associated with risky or healthy behavior may reflect a greater tendency to be comparatively optimistic when the causes of disease are influenced by one’s own actions compared to when they are heritable or environmental (Gerend, Erchull, Aiken, & Maner, 2006; Weinstein, 1984). In other words, comparative optimism and its behavioral consequences may depend on the characteristics of health events or beliefs surrounding the health events. In general, future work is needed to elucidate the situational, behavioral, and psychosocial factors that moderate the associations between comparative optimism and health behavior (e.g., Carver & Scheier, 2014; Dillard et al., 2009; Klein, Geaghan, & MacDonald, 2007; van der Pligt, 1998; Weinstein & Klein, 1996). Importantly, there are also measurement issues that may be related to the inconsistencies in the literature. For example, comparative optimism has often been assessed at the group level in which a group of individuals are defined as comparatively optimistic based on the mean of the sample. While this type of optimism was once called unrealistic optimism (Weinstein, 1980), this would be incorrect as some individuals within the sample may actually be accurate in their optimism (Klein & Cooper, 2008).

Along with health behavior, researchers have examined the association between comparative optimism and individuals’ responses to a health communication. This research has revealed that comparative optimism appears to be associated with defensive responding to health information. For example, a number of studies show that comparative optimism is associated with minimizing the importance of health information (e.g., Dillard et al., 2011; Trelor & Hopwood, 2008; Wiebe & Black, 1997). Comparative optimism has also been associated with less negative affect after reviewing unpleasant health-related feedback (Geers et al., 2013). Affective responses elicited by health risk communications may be particularly important given the growing body of literature suggesting that one’s current emotional state influences perceived risk as well as behavioral responses to these risks (Ferrer, Klein, Lerner, Reyna, & Keltner, 2014; Lench & Levine, 2005; Lerner & Keltner, 2001). To the extent that comparative optimists experience different affective reactions to a health message, this may predispose other responses like their attention to the message or their plans to follow the behavioral recommendation.

Importantly, how comparative optimism influences information processing and subsequent behavior following a health message could depend on one’s level of dispositional optimism. In one study, among those high in dispositional optimism, those who were comparatively optimistic about their risk for cardiovascular disease reported a smaller increase in knowledge following a lecture about this health threat (Davidson & Prkachin, 1997; note that this study used the term unrealistic optimism, but for reasons discussed, we have classified it as comparative optimism.). This was compared to those high in dispositional optimism but low on comparative optimism. In another study, for participants who were dispositionally optimistic, negative dental health feedback was perceived as less credible and more threatening if the individuals also held comparatively optimistic risk perceptions (Geers et al., 2013). Other research has shown that the combined effects of high comparative and high dispositional optimism can alter information processing strategies such that these individuals tend to minimize looming threats and fail to seek additional information about them (Fowler & Geers, 2015). On the other hand, when low comparative optimism is combined with high dispositional optimism, this may create the perception that one is at risk, but is also capable of coping with the threat, which may then positively influence the processing and use of health risk information (Shepperd, Waters, Weinstein, & Klein, 2015).

Comparative Optimism Versus Unrealistic Optimism

Perceiving one’s risk to be lower than that of others reflects comparative optimism; for it to also reflect the third type of optimism, unrealistic optimism, these perceptions must be defined as an inaccurate or optimistically biased perception of one’s actual level of risk. Despite this important difference, these two types of optimism have been (and sometimes still are) used as interchangeable terms or indicative of each other in the literature. For instance, most investigations of comparative optimism have been done at the level of the group, not the individual. When a group of individuals are asked to rate their risk for an adverse outcome, and they rate their risk (i.e., the mean of the group) as less than average or below the midpoint of the scale, the group is labeled unrealistically optimistic. While this may seem reasonable, assuming there is a normal distribution, the fact is that there will be some group members who actually have a lower-than-average risk (Klein & Cooper, 2008; Kreuter & Stretcher, 1995). Because these individuals are not actually unrealistically optimistic but instead realistic in their optimism, categorizing them along with the biased individuals is a problem. This situation is an example of how comparative optimism may incorrectly be labeled as unrealistic optimism.

There are times when comparative optimism can indicate unrealistic optimism. For example, researchers have compared participants’ comparative risk perceptions to their actual comparative risks (e.g., based on their risk factors relative to comparative peers’). In this situation, because both the risk perceptions and the risk estimates are on comparative scales, this optimism might best be labeled unrealistic comparative optimism (Klein & Weinstein, 1997). When an individual’s risk perceptions are compared to his or her actual risks (whether they are actual comparative risks or actual absolute risks), researchers are examining optimism at the individual level, and this is considered the rigorous “gold standard” approach to defining unrealistic optimism (Klein & Cooper, 2008). We next describe unrealistic optimism as it has been measured in this way, and its connections to health and how it may influence responses to health communication.

Unrealistic Optimism

Unrealistic optimism occurs when someone believes his or her risk for some negative event is lower than it truly is. Unrealistic optimism is an inaccuracy, in the form of underestimation, of risk. Someone may underestimate their actual comparative risk (unrealistic comparative optimism) or their actual absolute risk (unrealistic absolute optimism; Klein & Weinstein, 1997). Research suggests that unrealistic optimism is related, but conceptually distinct from other factors, such as defensive pessimism and fatalism (Taylor et al., 1992). When defining unrealistic optimism, researchers have operationalized it as both continuous and categorical in nature. This section synthesizes the work across these delineations.

Unrealistic optimism can be about positive events in which one believes his or her likelihood of some positive event is actually higher than it truly is. However, most research has focused on negative events. Researchers have argued that the best way to assess unrealistic optimism is to use objective risk measures (Klein & Cooper, 2008). For example, individuals’ perceived risks can be compared to an ad hoc or epidemiologic risk index created from individual risk factors (e.g., Dillard, McCaul, & Klein, 2006; Gerrard & Warner, 1994; Kreuter & Stretcher, 1995; Radcliffe & Klein, 2002). Researchers have also used past or current behavior or risk status, as well as future occurrences, as a proxy for actual risk (e.g., Dillard et al., 2009; Klein et al., 2007; Taylor & Brown, 1988, 1994; Taylor et al., 1992).

Several studies have assessed unrealistic optimism using the methods described above. Given that positive health behaviors are often motivated by increased perceptions of threat or risk (e.g., Rogers, 1975; Rosenstock, 1974), it is perhaps not surprising that the research has revealed that unlike dispositional optimism, unrealistic optimism is not associated with preventive health behaviors (for an exception, see Taylor et al., 1992). Instead, unrealistic optimism tends to look similar to comparative optimism in its associations with health behavior. For example, unrealistic optimism has been found to be associated with engaging in risky behaviors, including alcohol consumption, smoking, and unprotected sex (Ayanian & Cleary, 1999; Gerrard & Warner, 1994; Radcliffe & Klein, 2002; Skinner et al., 1998; Wiebe & Black, 1997). In one study, Dillard and others compared smokers’ ratings of their risk for lung cancer to an objective risk estimate calculated based on their age, number of years smoked, and number of cigarettes smoked per day (Dillard et al., 2006). They found that the majority of smokers could be categorized as unrealistically optimistic. Moreover, compared to smokers whose risk estimates met or exceeded their objectively measured risks, those who were unrealistically optimistic were more likely to agree with statements such as, “lung cancer depends mostly on genes” and “there’s no harm if someone smokes only a few years.” Endorsing these myths about smoking may help smokers rationalize a continuation of smoking behavior. Indeed, the unrealistic optimists in this study were also less likely to plan to quit smoking in the next few years. In another study, Klein and colleagues asked college students to estimate their risk of having unplanned sexual activity as a consequence of consuming alcohol and compared these risk perceptions with whether they actually engaged in unplanned sex (Klein et al., 2007). Compared to students who accurately estimated their risk, unrealistically optimistic students (i.e., those who had sex, despite estimating their chances of doing so were low) reported higher levels of alcohol consumption at future time points. Interestingly, this study showed that unrealistic optimism in one risk context (sexual activity) could carry over to influence risky behavior in a different context (alcohol consumption).

Along with their likelihood of engaging in risky behaviors like smoking and drinking alcohol, people’s unrealistic optimism for diseases such as breast cancer and heart disease (Dillard et al., 2011; Radcliffe & Klein, 2002) seems to have implications for adhering to cancer screening recommendations or behaving in other ways to reduce these diseases (Ayanian & Cleary, 1999; Skinner et al., 1998; Waters et al., 2007). For example, unrealistic optimism has been associated with care-seeking delays in response to illness symptoms, thereby compromising the effectiveness of medical care (Jones, 1990). One study has even linked unrealistic optimism about one’s risk of heart disease to higher levels of subclinical markers of atherosclerosis (Ferrer, et al., 2012).

Unrealistic optimism also appears to reduce the influence of risk-related health information, although much less research exists in this domain relative to dispositional optimism. Studies have found that compared to unrealistic pessimists or those who are accurate in their risk perceptions, unrealistic optimists are more likely to reject or minimize threatening information, deny its personal relevance (Dillard et al., 2011; Trelor & Hopwood, 2008; Wiebe & Black, 1997), and fail to apply it to their own lives (Gerrard et al., 1991; Weinstein, 1998). Unrealistic optimism at the individual level has also been associated with lower attention and poorer processing of risk information. In one study, Wiebe and Black (1997) asked sexually active college students about their risk of becoming pregnant or contracting a sexually-transmitted disease. The researchers estimated the students’ actual risks based on their prior sexual behaviors (e.g., frequency of sexual activity and percent of time they used condoms). Findings indicated that compared to those students who had accurate risk perceptions, those who were unrealistically optimistic were less interested in information about their personal risk, and viewed the information as less personally relevant. In a different health context and with different types of participants, Radcliffe and Klein (2002) asked older adults to estimate their risk of a heart attack, and then used a risk algorithm to estimate the adults’ actual risks. Findings showed that compared to those who were accurate or pessimistic in their risk perceptions, unrealistic optimists were less worried about their risk of a heart attack, had less current knowledge about risk factors, and remembered less following an essay about risk factors.

These responses to health information also extend to behavior or behavior plans. For example, after receiving information about their risk for colorectal cancer, unrealistic optimists reported less interest in colorectal cancer screening compared to realistic participants (Klein et al., 2010). In another study, women who were at an increased risk of breast cancer were given a decision aid about tamoxifen, which is a medication that can reduce some women’s risk of the disease (Dillard et al., 2011). Following the decision aid, compared to women who viewed their risk accurately, those who were unrealistically optimistic were less likely to report they would talk to their doctor about tamoxifen or take it in the next few months.

Are There Positive Effects of Optimistic Biases?

While the research above paints a consistent picture of negative associations with optimistic biases, including both comparative optimism and unrealistic optimism, historically the adaptiveness of the optimistic bias has been debated (Colvin & Block, 1994; Robins & Beer, 2001; Taylor & Brown, 1988, 1994). In fact, some researchers have argued that optimistic biases are beneficial –they are part of a set of “positive illusions” that individuals hold that serve to promote psychological and physical health (Taylor & Brown, 1988). The seminal study responsible for this viewpoint was conducted by Taylor and colleagues (1992). These researchers asked gay men, who were HIV-positive, about their risk perceptions and worries about developing AIDS. They defined unrealistic optimism as having an increased risk for developing AIDS (due to testing positive for HIV), but viewing one’s chances of developing the disease as low. They found that the unrealistic optimists reported more worry and concern about developing AIDS and they were more likely than those who were not optimistic to practice behaviors like having fewer partners and frequently using condoms. Although other studies in the 1990s (e.g., Aspinwall & Brunhart, 1996; Aspinwall et al., 1991; van der Velde, Hooykaas, & van der Pligt, 1992) also claimed beneficial effects of unrealistic optimism, they did not measure it at the individual level. Although this study by Taylor and colleagues (1992) goes against the recent findings, it is possible that in the unique situation of coping with an HIV diagnosis, unrealistic optimism led participants to engage in more positive coping skills. The findings echo the need for more research on unrealistic optimism and its implications under different conditions, including different health threats or diseases.

Future Directions

More research is needed on how unrealistic optimism can be reduced. The idea that an optimistic bias may represent a type of defensive or self-protective strategy fits with research on which types of interventions have been found to reduce the bias. For example, studies attempting to correct unrealistic optimism show that informational strategies are often unsuccessful (Weinstein & Klein, 1995). However, strategies that bolster the self-concept may reduce the bias. For example, allowing individuals to reinforce their positive self-views via a self-affirmation has been shown to reduce defensiveness to threatening health information (e.g., Sherman, Nelson, & Steele, 2000; see McQueen & Klein, 2007 for a review). In one study, Klein and colleagues examined individuals’ unrealistic optimism about the likelihood of developing colon cancer (Klein et al., 2010). They found that compared to those individuals who were accurate in their risk perceptions, unrealistic optimists who completed a self-affirmation task reported greater intentions to have a screening. The findings of this study provide support for the general idea that unrealistic optimists may feel threatened by risk information and are motivated to respond defensively (e.g., Radcliffe & Klein, 2002; Wiebe & Black, 1997). If a self-affirmation intervention is used with individuals who are unrealistically optimistic, they may feel less threatened and become more open to reducing risky behaviors or beginning healthy ones.

Although bolstering the self-concept may effectively reduce an optimistic bias and its consequences for behaviors (e.g., Klein et al., 2010), more studies are needed to replicate these effects. In fact, more research connecting unrealistic optimism to defensive strategies such as biased information processing or counter-arguing of personally relevant information are needed. Other interventions to reduce the bias, such as providing information about peers’ risky behavior, or asking individuals to rate peers’ risks in close proximity to one’s own risk, has shown promise in reducing comparative optimism (e.g., Klein, 1996; Rose, 2012; Weinstein, 1983). However, studies are needed on this possible strategy to reduce unrealistic optimism.

Future research is also needed to examine how the different types of optimism interact. Clearly, dispositional optimism is distinct from comparative optimism and unrealistic optimism. While dispositional optimism is associated with more healthy behaviors and less risky behaviors as well as enhancing the processing of personally relevant health information, comparative optimism and unrealistic optimism would seem to have the opposite associations. Although a few previous studies have investigated how dispositional optimism may interact with different levels of risk perceptions (e.g., Geers et al., 2013; Taber et al., 2015), the perceptions have not been defined in terms of individual-level bias. Research on comparative optimism and unrealistic optimism should always include a measure of dispositional optimism. It is possible that for some people and for some health threats, different types of optimism may outperform the others in influencing behaviors and responses to health communication.

To date, only a handful of studies have assessed unrealistic optimism at the individual level in which an individual’s actual risk is compared to his or her perceived risk. More studies are needed to define unrealistic optimism this way, including both comparing risk perceptions to actual absolute risks or actual comparative risks (Shepperd et al., 2013). Also, the studies that have been done have mostly focused on relating unrealistic optimism at the individual level to healthy or risky behaviors or intentions. More studies are needed on how these different ways of defining unrealistic optimism at the individual level are associated with other variables such as processing of a health message or behavior intentions following a message. Previous research examining these types of varaibles has mostly been done with dispositional optimism or comparative optimism that may or may not be unrealistic.

One specific question for future research is to what extent is unrealistic optimism a tendency or charateristic way of thinking about risk perceptions for all or most negative events? Researchers have developed a scale that assesses optimistic bias tendencies (Thompson, Robbins, Payne, & Castillo, 2011), but more studies are needed to examine this scale and the general idea. If some individuals have a tendency to think about their risk for any negative event as less than similar others or lower than their actual risks, then this optimism begins to look similar to dispositional optimism, only without the positive associations. And how might an optimistic bias tendency influence people’s responses to health risk messages? If there are individuals who have an optimistic bias tendency, health messages may be a mostly ineffective means of health or risk communication for this group.

Another question for future research is, how might emotions interact with the optimistic bias? Robins and Beer (2001) proposed that optimistic biases may serve important emotion-regulation purposes. Some research has connected unrealistic optimism or comparative unrealistic optimism to lower worry and anxiety (e.g., Dillard et al., 2011; Rose, 2012; Helweg-Larson & Shepperd, 2001; Lipkus & Klein, 2006; Weinstein, 1982). If unrealistic optimism makes people feel less worry or anxiety in response to health messages that warn them of personal risk, it may protect them emotionally. But, research would suggest that some level of worry or anxiety is necessary to motivate behavior, including preventive ones like cancer screening (e.g., McCaul et al., 1996; McCaul, Schroeder, & Reid, 1996; Moser, McCaul, Peters, Nelson, & Marcus, 2007). Generally, more studies are needed to examine which emotions may be associated with unrealistic optimism and whether they may moderate the associations with health behavior and responses to health messages. Positive emotions may also influence or be influenced by optimistic biases (e.g., Helweg-Larson & Shepperd, 2001). If individuals experience pleasant moods when they are thinking about their risk, or rating others’ risks, this mood could influence how they process a message. For example, some research shows that positive moods can decrease systematic processing of threatening health information (Wegener, Petty, & Smith, 1995).

Although research has documented associations between the optimistic bias and health behavior using both cross-sectional and longitudinal designs, more experimental research is needed, particularly with more diverse samples in terms of race/ethnicity and socioeconomic status. Although experimental research that actually manipulates an optimistic bias would be difficult (and likely have to concern a hypothetical or fictitious health threat), manipulating different factors to determine what leads to the optimistic bias would be insightful. One question for future experimental research is whether unrealistic optimism is more likely to be influenced by perceived risk or worry. Both of these constructs have been associated with the optimistic bias in past studies (e.g., Helweg-Larson & Shepperd, 2001; Lipkus & Klein, 1996), but examining their independent influences (for a review, see Ferrer, Portnoy, & Klein, 2013) may provide insight into the broad question of whether unrealistic optimism is a cognitive or motivational strategy. If unrealistic optimism is motivational as research to date would suggest, then one would expect it will be more likely to be influenced by manipulations of worry rather than perceived risk.

Conclusion

Long ago, Freud (1928) argued that optimism was fundamental to the human condition. Empirical research would clearly support his statement—most people are highly optimistic according to dispositional measures (Carver et al., 2010; Carver & Scheier, 2014) and when examining people’s risk perceptions for an optimistic bias, individuals are more likely to be unrealistically optimistic than pessimistic or accurate (e.g., Dillard et al., 2006, 2009), and comparative optimism is also common (Weinstein, 1987; Weinstein & Klein, 1996). Freud (1928) also argued that optimism represented denial and therefore poor psychological health. Although a few studies have found that unrealistic optimism is associated with positive psychological and physical health (e.g., Taylor et al., 1992), a greater number have instead found harmful effects of this optimism, at least when it comes to risky behavior and responses to health-related feedback (Dillard et al., 2006, 2009; Radcliffe & Klein, 2002; Wiebe & Black, 1997).

One way to reconcile the inconsistency of whether the optimistic bias leads to good or bad outcomes is to consider the distinction between psychological and physical health (Klein & Cooper, 2008). As for psychological health, optimism—whether dispositional, comparative, or unrealistic—may allow individuals to maintain or enhance a positive view of themselves (Weinstein, 1989). The desire to see oneself positively is a fundamental human motivation (Sedikides & Gregg, 2008; Sedikides & Strube, 1995). But although optimism may protect individuals psychologically, if it leads them to engage in risky behaviors, forgo preventive behaviors, or minimize or outright deny personally relevant health information, their physical health will eventually pay the price.

Further Reading

Aspinwall, L. G., & Brunhart, S. M. (1996). Distinguishing optimism from denial: Optimistic beliefs predict attention to health threats. Personality and Social Psychology Bulletin, 22(10), 993–1003.Find this resource:

Carver, C. S., & Scheier, M. F. (2014). Dispositional optimism. Trends in Cognitive Sciences, 18(6), 293–299.Find this resource:

Davidson, K., & Prkachin, K. (1997). Optimism and unrealistic optimism have an interacting impact on health-promoting behavior and knowledge changes. Personality and Social Psychology Bulletin, 23, 617–625.Find this resource:

Dillard, A. J., Ubel, P. A., Smith, D. M., Zikmund-Fisher, B. J., Nair, V., . . . Fagerlin, A. (2011). The distinct role of comparative risk perceptions in a breast cancer prevention program. Annals of Behavioral Medicine, 42, 262–268.Find this resource:

Fagerlin, A., Zikmund-Fisher, B. J., & Ubel, P. A. (2007). If I’m better than average, then I’m ok? Comparative information influences beliefs about risk and benefits. Patient Education and Counseling, 69, 140–144.Find this resource:

Geers, A. L., Wellman, J. A., & Fowler, S. L. (2013). Comparative and dispositional optimism as separate and interactive predictors. Psychology and Health, 28(1), 30–48.Find this resource:

Radcliffe, N. M., & Klein, W. M. P. (2002). Dispositional, unrealistic, and comparative optimism: Differential relations with the knowledge and processing of risk information and beliefs about personal risk. Personality and Social Psychology Bulletin, 28(6), 836–846.Find this resource:

Rasmussen, H. N., Scheier, M. F., & Greenhouse, J. B. (2009). Optimism and physical health: A meta-analytic review. Annals of Behavioral Medicine, 37(3), 239–256.Find this resource:

Rose, J. P. (2012). Debiasing comparative optimism and increasing worry for health outcomes. Journal of Health Psychology, 17, 1121–1131.Find this resource:

Shepperd, J. A., Waters, E. A., Weinstein, N. D., & Klein, W. M. P. (2015). A primer on unrealistic optimism. Current Directions in Psychological Science, 24(3), 232–237.Find this resource:

Weinstein, N. D., & Klein, W. M. (1996). Unrealistic optimism: Present and future. Journal of Social and Clinical Psychology, 15, 1–8.Find this resource:

Weinstein, N. D., Marcus, S., & Moser, R. P. (2005). Smokers’ unrealistic optimism about their risk. Tobacco Control, 14, 55–59.Find this resource:

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