Facts and Fears

Summary of Facts and Fears: Understanding Perceived Risk
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

New research suggests that the accepted views on catastrophic loss may need to be revised.  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 (involuntary risks are 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 seems to suggest that in addition to voluntariness, a host of other factors such as knowledge, controllability, etc. need to be factored into risk standards.  Their study 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.  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.