Risks or threats which are not taken seriously may nonetheless be real. Underestimating the consequences of any risk can lead to dangerous situations.
Risk perception fascinates psychologists, but infuriates those concerned with making the world a safer place. There are often large discrepancies between the risk experts worried about and those lay people were most concerned about. Thus radiation from nuclear power plants is probably feared too much by lay people whereas radon seeping into basements or X-rays are probably feared too little. Although people in rich countries live longer than ever, they are more fearful than their ancestors were about threats to their health from the world around them. One reason is mistrust of technology; another is mistrust of scientists, who have too often claimed that a process or substance is safe, and then changed their minds.
Society evaluates risks in an inconsistent manner partly because the perception of a given risk is influenced by many factors. The greater the number and seriousness of these factors, the greater the likelihood of public concern about the risk, regardless of the scientific data. When officials dismiss such concerns as misguided, they stir anger and distrust. One influence is what psychologists call "outrage factors", which can make people feel that even small risks are unacceptable. Another is that risks which are unfairly shared seem more hazardous. Airplane accidents are feared out of all proportion to the number of accidents per mile travelled, whereas the continuing level of road accidents is accepted as a routine aspect of travel. Natural risks are less threatening than man-made ones, although at the same time risks that are associated with catastrophes are especially frightening. Familiar risks, like smoking, are less frightening than the unfamiliar; invisible risks more scary than visible. Risks from exotic technologies create more dread that do those involving familiar ones: a heavy beer drinker may refuse to eat a genetically engineered tomato. And people are also willing to inflict on themselves much greater risks than they are prepared to have imposed upon them: skiing is roughly 1,000 times more likely to cause ill health than food preservatives.
The beginning of the 1993 school year was delayed in some New York City schools because some parents were distressed to hear that in some schools asbestos was flaking and exposed. This despite public health officials explaining that the risk of dying from exposure to asbestos was less than the likelihood of getting hit by lightning and that the children were probably at greater risk from playing in the streets during the week the schools were closed to fix the asbestos.
It is not clear that knowledge or ignorance of technical facts drives risk estimation, or that risk estimation is the central factor in public risk perception. It is even less clear whether providing citizens with technical risk information will alter their perceptions of risk or their views of how well government agencies are protecting the environment.
Experts often argue that laypeople are too prone to seek certainty, while greater knowledge leads to understanding that certainty does not exist.