A Heuristics Approach to Understanding Cancer Risk Perception: Contributions From Judgment and Decision-Making Research Ellen Peters, Ph.D. Decision Research, Eugene, Oregon and University of Oregon Kevin D. McCaul, Ph.D. North Dakota State University Michael Stefanek, Ph.D. and Wendy Nelson, Ph.D. National Cancer Institute ABSTRACT uncertainty, patient understanding of risk is a critical part of the Background: The likelihood judgments that people make decision-making process (3–5). For example, a man who elects about their risks for cancer have important implications. At the to screen for prostate cancer by having a prostate-specific anti- individual level, risk estimates guide protective actions, such as gen test would need to weigh the potential positive and negative cancer screening. However, at the extremes, exaggerated risk outcomes of the test (e.g., cancer detection, unnecessary anxiety judgments can also lead to anxiety that degrades quality of life from a detected cancer whose best treatment is watchful wait- or to aggressive self-protective actions that are unwarranted ing) with the likelihood of each outcome. At a policy level, risk given the objective risks. At the policy level, risk judgments may judgments may reflect societal perceptions of cancer prevention serve as an indicator of societal perceptions of the “war” and control efforts. For example, news reports describing ele- against cancer. Using risk judgments, the public expresses its vated rates of cancer in Long Island, NY, or Marin County, CA belief about whether we are winning. Purpose: We present theo- (so-called cancer clusters) may be interpreted to mean that we retical perspectives from judgment and decision making, illus- are losing the “war on cancer” even though the objective exis- trate how they can explain some of the existing empirical find- tence of these cancer clusters remains an open question (6). ings in the cancer risk literature, and describe additional People do not always have a clear understanding of the risks predictions that have not yet been tested. Conclusions: Overall, of cancer, or of the likelihood of various outcomes of cancer we suggest that theories from the judgment and decision-making screening tests and treatments (7). For example, with genetic perspective offer a potentially powerful view for understanding testing, people tend to overestimate their risk of cancer and un- and improving risk judgments for cancer and other diseases. derestimate the risks associated with genetic testing itself, such as the stigma associated with testing positive for a cancer sus- (Ann Behav Med 2006, 31(1):45–52) ceptibility gene (8,9). In extreme cases, exaggerated risk judg- ments can lead to anxiety that degrades quality of life and causes INTRODUCTION excessive vigilance and self-protective behaviors as well as un- The judgments people make about their risk or statistical warranted, aggressive medical treatments (e.g., prophylactic probability of developing cancer (i.e., their risk perceptions) mastectomy in the absence of a family history or genetic vulner- have important implications for cancer prevention, screening, ability to breast cancer) (10,11). and treatment. At an individual level, risk perceptions can guide People estimate risk in a variety of ways. For example, they protective actions, such as screening for cancer or quitting may make risk judgments based on intuition, a recent experi- smoking (1,2). Risk perceptions are also relevant to medical de- ence, a vivid memory, or a sound bite on the news. Others may cisions that cancer patients make, especially when no consensus approach risk estimation more systematically and analytically, exists on the standard of care or best course of action to take. Be- basing their risk estimates on “hard data.” When facing uncer- cause cancer patients make many decisions under conditions of tain situations and complex decisions, people tend to rely on mental shortcuts to simplify the decision-making process and thus reduce its cognitive demands and psychological stress. This work was supported by grants from the National Science Founda- The purpose of this article is to summarize how the judg- tion (0111941 and 0241313) to Dr. Ellen Peters and from the National ment and decision-making literature can help us understand Cancer Institute (K05 CA92633) to Dr. Kevin McCaul. how and why people underestimate or overestimate cancer risk. Specifically, we examine heuristics, the mental shortcuts or We thank Paul Slovic and Stephanie Hess for helpful comments on the “rules of thumb” that decision makers consciously or uncon- article and Stephanie Hess for helping with the literature search. sciously employ to make judgments of uncertainty. We review Reprint Address: E. Peters, Ph.D., Decision Research, 1201 Oak Street, four heuristics—affect, representativeness, availability, and an- Suite 200, Eugene, OR 97401. E-mail: [email protected] choring and adjustment—and speculate how each may contrib- © 2006 by The Society of Behavioral Medicine. ute to risk judgments about cancer. 45 46 Peters et al. Annals of Behavioral Medicine HEURISTICS, JUDGMENT, AND cision making; instead, they are critical for accuracy and effi- DECISION-MAKING RESEARCH ciency. According to the affect heuristic, all of the images in a The psychological study of judgment and decision making person’s mind are marked to varying degrees with affect, and it attempts to understand how decision makers process information is this “affect pool” that people consult when called on to make to form judgments (defined as beliefs or evaluations; e.g., a risk certain judgments (21). Relying on affective impressions can be perception) and make decisions (defined as a choice among two simpler and more efficient than using deliberative processes, or more options; e.g., a choice among treatments). Three general such as weighing the pros and cons of a situation or retrieving rel- themes guide research on judgment and decision making. The evant examples from memory, especially when the required judg- first is that people have limited resources to deal with the numer- ment or decision is complex or mental resources are limited. ous decisions and overwhelming quantity of information that The affective and experiential nature of risk perception is they face daily. People are limited by time, their cognitive and particularly relevant to health domains such as cancer, given the computational abilities at the moment of choice, and their envi- affect that cancer arouses. People who have personally experi- ronment. The second theme states that because people often do enced cancer are likely to have developed stronger and more ac- not know what they value or prefer, they tend to construct judg- cessible affective reactions to the disease compared with people ments “on the spot” when asked to make a particular judgment or who lack personal experience. According to the affect heuristic, decision.Consequently,valuesandpreferencesmaybelabileand individuals then will use these feelings as a cue to determining sensitive to the way in which choices are framed (12). The third their own risk, with the stronger feelings being associated with theme states that people process information using two distinct enhanced personal risk estimates. Although they did not assess modes of thinking: deliberative and experiential (13–15). feelings specifically, Fiandt, Pullen, and Walker (22) found evi- Whereasthedeliberativemodeisanalytical,reasonbased,verbal, dence consistent with the affect heuristic in that women who had and relatively slow, the experiential mode is automatic, associa- a family member or a friend with cancer used their experience as tive, and fast. The experiential mode of thought relies on affect a cue for increased risk perceptions. and categorical thinking (e.g., stereotypes) and functions to high- Experimental studies have shown that attention to salient light important information. Depending on the situation and na- affective cues can lead to neglect of probabilistic information ture of the decision, people may rely more heavily on one system. (23). These findings may explain why some women fail to be- For example, whereas a medical professional’s understanding of lieve accurate numerical risk information about breast cancer, risk as statistical probability may be more heavily influenced by overestimate their risk, and experience undue cancer distress the deliberative system, lay understanding may rely more on ex- (24). Because cancer is a dreaded disease, the strong negative af- periential ways of knowing (16). fect that it elicits may create insensitivity to its (often relatively The deliberative and experiential modes of thinking have low) objective risk. For example, Kraus, Malmfors, and Slovic important implications for how people judge and decide. Al- (25) found that, even though expert toxicologists were able to though people in Western cultures tend to believe that more de- accurately assess the risk of cancer posed by different levels of liberation will always produce better decisions, evidence sug- exposure to a toxic agent, the public tended to believe that any gests that, in some contexts, deliberation disrupts affective and level of exposure was risky. Because the possibility of cancer intuitive processes in decision making and reduces postchoice will likely remain after testing and monitoring, affective reac- satisfaction (e.g., 17). Research suggests that intuitive processes tions to it will also remain, and risk perceptions may not