1. GEOG 558 Hazards and Risk Management Dr. Chrys Rodrigue
Hazard Perception
GEOG 558
Hazards and Risk Management
Dr. Chrys Rodrigue

2. Hazard Perception
A disaster requires the intersection of an extreme event and people in the way
Let's look at the human side of the equation, moving people into harm's way
Do we perceive a hazard?
Do we cognize its relevance to us?
Do we know how to minimize our exposure?
What motivates us to act on that knowledge? (or not)
What do people actually do in an emergency?

3. Hazards Perception
Lay perceptions differ markedly from risk assessors'
Risk amplification: when the public exaggerates certain hazards
Risk attenuation: trivializing other, sometimes serious hazards
Why is that?

4. Hazards Perception
The ignorant public is a common concern of exasperated experts
The implication is that public input is useless
Testing that hypothesis by comparing laypeople's estimates with experts': contradictory results
Some studies: the greater the knowledge of a hazard, the less the concern about it, but activists are often well-informed (e.g., nuclear power)
Other studies: the greater the knowledge of a local hazard, the more concerned, even outraged the public becomes (e.g., water pollution)

5. Hazards Perception Are the differences in perception random? No.
Laypeople tend to overestimate low probability, but dramatic technological hazards (e.g., nuclear power accidents, plane crashes)
They tend to underestimate high probability hazards that are less dramatic (e.g., car accidents, lifestyle-mediated illnesses)
Less clear cut with natural hazards (though there may be amplification of risks “elsewhere” and attenuation of local hazards

6. Hazard Perception
Exposure is poorly understood by the public, at least in the case of toxic hazards
That is, release = exposure = injury/illness
The multiplicative reduction in risk probabilities at each point in the chain of events producing exposure gets lost, e.g.,
If failure of 3 valves is necessary for a toxic gas release
Each valve has a 0.01 probability of failing in a given year
The probability of a release in that section of pipe is or in a given year

7. Hazards Perception
People often make up their minds about a hazard before hearing all relevant facts and arguments
Short cut to opinions on things far from our training: the opinions of reference groups we trust
Once the pattern gels, new facts are fit into it in such a way as to reïnforce it, never to question it
This reduces cognitive dissonance (the discomfort of holding two mutually exclusive thoughts at once)

8. Hazards Perception
In defense of the public: It may be less irrational and ignorant than it might seem at first blush
Laypeople may be judging hazards along multiple axes, not just the mortality/morbidity axis that professional risk assessors frame their perceptions around

9. Multiple Axes of Hazards Perception
Perceived control:
Less concern if you can choose your exposure
If you cannot, even tiny risks are very upsetting
Familiarity:
Cars, smoking, and local hazards are less upsetting
Nuclear power , food irradiation, and hazards “over there” evoke heightened worry
Fairness: Who gains, who pays?
NIMBY
Environmental justice

10. Multiple Axes of Hazards Perception
Dread: Heightened, even panicky concern
Does the hazard have even a vanishingly tiny but non-0 probability of creating a huge loss of life (terrorism, nuclear accident) or frightening diseases (cancer, AIDS)?
Can it have effects that are passed down the generations (chromosome damage)?
Is it linked with historical incidents of sheer horror (Hiroshima, Nagasaki)?
Trust
Can institutions managing risk or responding to disaster be “trusted” (transparent? authoritative? consistent?)
Trust once lost is almost impossible to recover

11. Hazards Perception
Implications of this work that is more sympathetic to the public:
Perhaps expert opinion is too narrow and unresponsive to the real-world concerns of the people experts are trying to help
This wall between the expert and the layperson could create unanticipated problems in a crisis
It also poses problems for the democratic governance of risk

12. Hazards Perception
Thomas Jefferson, in a letter to William Jarvis, caught this dilemma back in 1821:
I know no safe depository of the ultimate powers of society but the people themselves; and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion.