Unit 6: Risk, Exposure, and Health // Section 8: Risk Perception
Expert assessments and public perceptions of risk are not always the same. Decision makers need to understand factors that influence how people understand and interpret risk information for several reasons. First, public concerns may influence research and development priorities, such as which chemicals to analyze in toxicity studies. Second, individual behavior choices are guided by risk avoidance, so if experts want people to avoid certain risks, they need to understand whether the public sees those actions as dangerous. If the public views a risky activity as benign, officials may have to develop public-education campaigns to change those perceptions. Current examples include labels warning about health risks on cigarette packages and alcoholic beverage containers.
Behavioral and social scientists have compared risk perceptions among many different groups, including scientists' views compared to those of laypersons, men compared to women, and differences among diverse ethnic and economic groups. One finding is that the general public overestimates the prevalence of some risks (such as those lying above the straight line in Fig. 14) and underestimates others (those lying below the line).
Figure 14. Relationship between judged frequency and actual number of deaths per year
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Source: © Scope Report 27 - Climate impact assessment, Chapter 16, Figure 16.5, ed. by RW Kates, JH Ausubel, and M Berberian. J Wiley & Sons Ltd, UK (1985). Adapted from: Slovic et al. Rating the risks. Environment, 21(3) 14-39 (1979).
Laypeople judge risks differently from technical experts because they give greater weight to factors such as the potential for catastrophic damage, the likelihood of threats to future generations, and their own sense of whether they can control the risk. This can be seen in Table 4, which shows how technical experts and several sets of laypeople ranked the risk from a list of activities and technologies. Note, for example, that the expert group was much less worried about nuclear power but more worried about x-rays than laypeople. Both involve radiation exposure, but x-rays may have seemed less risky to the non-specialists because the scale of an x-ray is much smaller than a nuclear reactor accident and because people usually have a choice about whether to undergo x-rays.
|Activity or technology||League of Women Voters||College students||Active club members||Experts|
|General (private) aviation||7||15||11||12|
|Electric power (nonnuclear)||18||19||19||9|
|High school/college football||23||26||21||27|
Other factors can influence how both experts and laypeople perceive risks. Paul Slovic and other behavioral researchers have found that many Americans stigmatize certain industries, especially nuclear power and chemicals, which are widely viewed as repellent, disruptive, and dangerous. Conversely, scientists who work for industry tend to see chemicals as less threatening than do government and academic researchers (a phenomenon called affiliation bias). Ultimately, they argue, all groups bring their own assumptions to bear on discussions of risk.
Communicating risk information to the public is an important part of risk management. In the early decades of environmental regulation, public communication often took what critics called the "decide, announce, defend" approach: agencies developed policies and released their final results to the public and regulated industries. But since risk analysis involves many uncertainties, assumptions, and judgments, it requires policy makers to explain clearly how decisions are reached—especially if the issue involves risks that laypeople perceive differently from scientific experts.
Often effective risk communication means involving the public in the decision process, not just informing people at the end. Public involvement in risk decisions can take many forms. In early planning stages, it can help regulators identify the issues that citizens care most about, how much risk they will tolerate, and what they view as acceptable mitigation costs. Stakeholders may also take part in implementing decisions. For example, the Defense and Energy Departments have formed community advisory boards to help make decisions about cleaning up contaminated military bases and nuclear weapons production sites.