Risk perception factors profoundly affect the ability of people to make informed decisions about risk‐related issues. Table 3.6 contains a list of the 20 most important risk perception factors. Each factor is described in more detail below.
1 Trust in responsible authorities and institutions: People are often more concerned about activities or actions where the responsible assessor or manager is perceived to be untrustworthy (e.g., individuals, organizations, or institutions that have a clear conflict of interest) than they are about activities or actions where the responsible assessor or manager is perceived to be trustworthy (e.g., trust in first responders, such as fire department personnel).
2 Voluntariness: People are often more concerned about activities and actions that are perceived to be involuntary, coerced, or imposed on them (e.g., exposure to chemicals or radiation from an accident at an industrial facility) than about activities or actions that are perceived to be voluntary or chosen (e.g., smoking, sunbathing, talking on a cellphone while driving, or mountain climbing).
3 Scope/catastrophic potential: People are typically more concerned about activities and actions perceived to be cataclysmic and where harm, fatalities, and injuries are grouped in time and space (e.g., harm, fatalities, and injuries resulting from a major release of toxic chemicals or radiation) than about activities or actions where harm, fatalities, and injuries are scattered, occur over a long period, or are random in time and space (e.g., automobile accidents).
4 Familiarity/exotic: People are typically more concerned about activities or actions perceived to cause harm and perceived to be unfamiliar (e.g., leaks of chemicals or radiation from waste disposal facilities; outbreaks of unfamiliar infectious diseases such as Zika, West Nile Virus, and Ebola) than about activities or actions that are familiar and routine (e.g., household accidents).
5 Understanding/visibility: People are often more concerned about activities or actions perceived to be characterized by invisible or poorly understood exposure mechanisms or processes (e.g., long‐term exposure to low doses of toxic chemicals or radiation) than about activities or actions perceived to be characterized by visible and apparently well‐understood exposure mechanisms or processes (e.g., pedestrian accidents or slipping on ice).
6 Uncertainty: People are often more concerned about activities or actions that are perceived to cause harm and are perceived to have unknown causes or uncertain risks (e.g., mysterious outbreaks of illnesses; risks from a radioactive waste facility designed to last 20,000 years) than about activities or actions that are perceived to cause harm and that are perceived to have known causes and for which there are relatively certain risk‐related data (e.g., actuarial data on automobile accidents).
7 Controllability (personal): People are often more concerned about activities or actions that are perceived as outside their control (e.g., flying in an airplane; exposure to releases of toxic chemicals or radiation from an accident at an industrial facility) than about activities or actions that are perceived to be under their personal control (e.g., driving an automobile or riding a bicycle).
8 Effects on children: People are often more concerned about activities or actions that are perceived to adversely affect children or specifically put children in the way of harm or risk (e.g., asbestos in school buildings; milk contaminated with radiation or toxic chemicals; children’s food contaminated with pesticide residues; pregnant women exposed to radiation or toxic chemicals) than about activities or actions engaged in by adults and that are not perceived to specifically put children in the way of harm or risk (indoor air pollution in office buildings).
9 Effects manifestation: People are often more concerned about risks that have delayed effects (e.g., the development of cancer after exposure to low doses of chemicals or radiation) than about risks that have immediate effects (e.g., poisonings).
10 Effects on future generations: People are often more concerned about activities or actions perceived to pose significant risks to future generations (e.g., genetic effects related to exposure to toxic chemicals or radiation) than activities or actions perceived to pose no special significant risks to future generations (e.g., skiing accidents).
11 Victim identity: People are often more concerned about activities or actions that are perceived to cause harm and that impact identifiable victims or a named person (e.g., a worker exposed to high levels of toxic chemicals or radiation; a child who has fallen in a well) than about risks that are statistical and impact persons that are nameless or faceless (e.g., statistical deaths related to automobile accidents).
12 Pleasurable/Dreaded: People are often more concerned about activities or actions that are perceived as unpleasant, dreaded, or evoke a response of fear, terror, or anxiety (e.g., exposure to radiation or chemicals that can cause cancer or birth defects) than to activities or action risks that are perceived to be pleasurable, not especially dreaded, or do not evoke a special response of fear, terror or anxiety (e.g., using recreational drugs, common colds, or household accidents).
13 Awareness/Media attention: People are often more concerned about activities or actions that are perceived to cause potential harm and for which there is high public awareness and media attention (e.g., cancer, airplane crashes, hazardous waste sites, accidents at industrial or nuclear power facilities) than about activities or actions that are perceived to cause harm but for which there are little awareness and media attention (e.g., on‐the‐job accidents).
14 Fairness: People are often more concerned about activities or actions that are perceived to be characterized by an inequitable or unfair distribution of risks, costs, and benefits (e.g., inequities related to the siting of waste disposal or industrial facilities) than about activities or actions perceived to be characterized by an equitable distribution of risks, costs, or benefits (e.g., flu vaccination).
15 Benefits: People are often more concerned about activities or actions that are perceived to have unclear, questionable, or diffused benefits (e.g., waste disposal facilities) than about activities or actions that are perceived to have obvious benefits (e.g., elective surgery).
16 Reversibility: People are often more concerned about activities or actions that are perceived to have potentially permanent adverse outcomes or effects (e.g., nuclear war) than about activities or actions perceived to have potentially reversible adverse outcomes or effects (e.g., injuries from most sports or household accidents).
17 Personal stake: People are often more concerned about activities or actions that they perceive place them, or their families or friends, personally and directly in the way of harm or risk (e.g., living near an industrial facility with potentially hazardous air emissions) than about activities or actions that do not place them or their families and friends personally and directly in the way of harm or risk (e.g., disposal of hazardous waste in remote places).
18 Nature of evidence: People are often more concerned about activities or actions that are based on risk assessments from human studies (e.g., risk assessments based on adequate exposure data of humans) than about activities or actions based on risk assessments from nonhuman studies (e.g., laboratory studies of the effects of potentially hazardous chemicals using mice or rats).
19 Morality: People are often more concerned about activities or actions that are perceived to violate culturally based principles of morality and ethics (e.g., raising the price of a life‐saving prescription drug to a very high level) than about activities or actions that are perceived to be consistent with culturally based principles of morality and ethics (e.g., lying about the nationality or ethnicity of a child to protect the child from those who want to do harm because of child’s nationality or ethnicity).
20 Human vs. natural origin: People are often more concerned about activities and actions that are perceived to cause harm and are