Summary of Slovic, P., Fischhoff, B. and Lichtenstein, S. ‘Facts vs. fears: understanding perceived risk.’ Societal Risk Assessment: How Safe is Safe Enough? (Schwing and Albers, eds.) Plenum Press, 1980
Slovic, Fischhoff, and Lichtenstein conduct a study of risk perception.
Perception of risk refers to the acceptance that there is in fact a risk. Acceptability of risk refers to how much the risk can be tolerated; to what level it should be controlled.
Involuntariness
Research suggests that accepted views on catastrophic loss may need revision. A current view, based on a hypothesis forwarded by Starr (1969), says that people tend to demand stricter standards against hazards brought on by involuntary risks (risks one does not take by choice). The hypothesis is that risks that are involuntary are perceived to be less tolerable. Slovic, et. al's study did not intentionally seek to address Starr's hypothesis, but the findings provided an interesting test of it. Their study indicates that in addition to voluntariness, a host of other factors such as knowledge, controllability, etc. need to be factored into risk standards. The stduy further tends to the notion that it may not be involuntariness per se, that drive the call for stricter results, but other conditions closely associated with involuntariness, such as catastrophic results, that drive the call for stricter controls. The involuntary hazards tend to include large-scale catastrophic events such as nuclear power, terrorism, bio-chemical threats.
Levels of acceptability of risk correlates positively with perceived benefits of the risk, in fact more strongly than voluntariness.
Catastrophic Potential
The study suggests that the potential for massive loss could be the driving force - rather than involuntariness - to risk perception and acceptability. If correct, the effect of this driving force is a public unwilling to take risks on things that may have catastrophic consequences but is very likely to occur, especially in light of lack of empirical data. (It only takes one Chernobyl)
Weighing Catastrophes
Controlling risks mean assessing their proibability and severity, both of which are difficult. Since people react more strongly to a single event that causes N fatalities than to many smaller events, each individually causing few fatalities, even though they total N fatalities in all, some have suggested using a weighting factor in formulas that account for this reaction. Experts can't agree: an additional small number of fatalities is large when considered against a small initial set of fatalities, but the same number is less significant when compared to a large number of initial fatalities.
Signal Value
Conclusions
- Perceived is quantifiable and predictable.
- Groups of people differ systematically in their perceptions
- People make mistakes in judging risks.
- Experts are also susceptible to bias.
- The various modes of death possible from risks do not seem to have a significant impact on public vs expert perceptions of risk (???)
- The higher the perceived current level of risk, the larger the required adjustment needed to bring the risk down to acceptable levels.
- g
- The perceived potential for catastrophic loss of life is one of the most important risk characteristics (not involuntariness)
- Evidence does not remove disagreements. Definitive evidence is rare. All other forms of evidence can be skewed to pre-conceived positions.
Further conclusions. The authors conclude that the public can make gross mistakes in perceptions of risk, but then so do experts, so public opinion ought not to be excluded from risk decisions. It is much better to involve the public in risk matters for the purpose of increasing their knowledge in the longer term and since their cooperation is needed for risk management undertakings to succeed.
