Source: Government photo via Wikimedia Commons

There are all kinds of large-scale disasters that get reported in the news. Some of them are the result of natural causes like earthquakes along an active fault line or volcanoes. Others are caused by human activity, like an oil spill from a tanker, or an explosion at a chemical plant.

How do people judge the severity of these disasters?

Whenever people make judgments about how good or bad something is, they take both information and feelings into account. In the case of a disaster, information like the extent of the damage or the number of victims affects the sense of severity. But, people’s feelings also matter. The worse that people feel about a disaster, the more severe they think it was.

This idea was explored in a 2014 paper in the journal Risk Analysis by Michael Siegrist and Bernadette Sutterlin.

They suggested that people are generally more angry and frustrated by disasters that that are caused by people than for disasters that are natural. As a result, they predicted that people would also find human-caused disasters to be more severe than natural disasters.

The studies typically contrasted scenarios in which different groups of participants rated the severity and impact of disasters that were equated for their death toll or other damage, but differed in whether they were caused by natural or human factors. For example, one study compared ratings for a chemical plant explosion that released sulpher dioxide and killed 15 people in a neighboring town to a volcano that released sulpher dioxide and killed 15 people in a neighboring town. Participants felt the plant explosion was more severe than the volcano. A similar result was obtained for a forest fire that was caused either by a lightning strike or by a fire someone lit that of control.

Other studies in this series used similar examples and also measured people’s feelings after reading the scenarios. People found the man-made disasters more upsetting than the natural disasters, and that explained the difference in ratings of severity.

A final set of studies extended this result to look at technology that either feels more natural or more man-made to participants. For example, they compared accidents associated with solar power (which people think of as natural) to accidents associated with nuclear power. People found the accidents associated with nuclear power to be more severe than those associated with solar power. They were also more upset by the accidents associated with nuclear power than those associated with solar power.

Of course, you might think this last result reflects beliefs about how long-lasting the effects of a nuclear accident might be. To remove this explanation, one study examined deaths that occurred in an accident while building either a solar or nuclear power plant. Even in this case, the accident was judged more severe when it was associated with a nuclear power plant than a solar plant.

Many times in this blog I have written about how information about feelings gets incorporated into other judgments. Often feelings help to make judgments more accurate. However, there are cases like this in which fears about human activity can get in the way of assessments of danger and severity.

Findings like this one are important, because public policy decisions are often based on factors that politicians and voters think are important. When those judgments are based on fears, policy decisions may focus on ways to make people feel better about a situation without actually doing anything to solve the underlying problem.

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