Cancer Quiz
Risk
Perception
Rank Order
(1-7)
% Major
Cause
Tobbacco
__________
________
High Power Electric Transmission Lines
__________
________
Sunbathing
__________
________
Pollution
__________
________
Asbestos
__________
________
Fat in diet
__________
________
Nuclear power
__________
________
Edvard Munch, 1893
Cancer Specialists vs. Activists on Cancer Threats
Cancer Quiz
100
Rank Order % Major
(1-7)
Cause
PS 175 Students
Rank
(1-7)
% Major
Cause
Tobbacco
1
95
1.2
69%
Asbestos
2
56
3.9
31
Sunbathing
3
54
2.8
44
Fat in diet
4
33
4.0
31
Pollution
5
26
4.1
28
Nuclear power
6
7
6.0
16
High Power Electric
7
0
6.2
10
90
80
70
Percent major threat
Cancer researchers
60
50
40
30
20
10
Scientists
ee
tn
er
s
la
r
A
rin
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er
sw
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ac
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iti
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uc
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nt
s
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ie
t
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os
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h
S
sb
e
A
S
m
ok
in
g
0
Activists
Source: S. Lichter & S. Rothman, Environmental Cancer, table 4.4, 120.
Definition of Risk
• Product of the Probability of Adverse Event and its
Consequences
Risk Calculations
• We can calculate specific risks
– Probability of dying in plane crash on LA - D.C. flight
Risk = (Probability of Event) x (No. Deaths expected)
– Probability of dying from smoking 1 pack a day
Airline Risk = (Prob of plane crash)x(No. Deaths expected)
– Probability of getting lung cancer, throat cancer, …
Smoking risk = (Prob get cancer) x (No. Deaths expected)
• We can express risk in different ways
– e.g., Expected no. of days lost because of threats
1
Estimated Loss of Life in Days
What the Media Say Causes Cancer, 1972-92
600
2500
2250
Source: Paul Slovic, “Informing and Educating the3
Public about Risk.” Risk Analysis 6 (1986): 403-15,
table 2.
2100
Source: Lichter &
Rothman, 143
498
500
2000
Number of stories
400
1500
1300
1100
1000
980
330
300
268 256
222
200
200 194
163
520
500
273 272
139 136 134
129
400
300
207
100
141
95
95
95
90
86
84
82
79
70
66
41
40
39
8
6
6
3.5
2
59
48
44
0.02
41
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Risk Calculations require
knowledge of Probabilities
• We know about tobacco & airline risks
because the gov’t collects data on them
– Lots of medical knowledge comes from
studying causes of death
– Epidemiology is the study of how often
diseases occur in people, with what
consequences
0
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Sometimes Risk Probabilities are
Unknown
• Risk: Based on estimates of probabilities
• Uncertainty: No knowledge of probabilities
– With uncertainty, we are guessing
– “... there are known knowns; there are things we know
that we know. There are known unknowns; that is to
say, there are things that we now know we don't know.
But there are also unknown unknowns – there are
things we do not know we don't know.
– Donald Rumsfeld, Sec. Defense, Feb 15, 2002 on WMD in Iraq
Risk - Uncertainty Continuum
• For complex problems:
• We break problems into steps & calculate
probabilities of failure for each step
– What is the probability of each component
failing?
• Engineers run lab tests and simulations
• They may use judgements when data are ambiguous
Columbia Space Shuttle
Jan 16, 2003
– They combine estimates for an overall risk
2
Columbia Space Shuttle
Jan 16, 2003
Feb. 1, 2003
Kim Jong-un, Chairman of the Workers' Party of Korea and supreme
leader of the Democratic People's Republic of Korea (DPRK)
Risk
Perception
Fear of Flying vs. Fear of Driving
• Which is safer?
• We do not fear
threats because
of statistical
probabilities
• We choose what
to fear
Edvard Munch, 1893
Car Crash Fatalities and Fatalities per 100,000 Vehicle Miles Traveled
Air Crash Fatalities and Fatalities per 100 Million Air Miles Traveled
60000
30
600
50000
25
500
50.000
45.000
40.000
35.000
40000
20
400
30000
15
300
20000
10
200
30.000
25.000
20.000
15.000
10.000
10000
5
100
0
0
0
1899
1901
1903
1905
1907
1909
1911
1913
1915
1917
1919
1921
1923
1925
1927
1929
1931
1933
1935
1937
1939
1941
1943
1945
1947
1949
1951
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
5.000
Deaths
Fatalities per 100 million VMT
0.000
Total fatalities
Fatalities per 100 million aircraft-miles
Source: http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_statistics/html/table_02_09.html
3
Figure 1. Risk Information in the Los Angeles Times
(Perception of) Risk is Constructed
Total Stories
907
Homicide
• Theories assume that people do not have
much risk information (i.e., statistics)
Homicide-Verbal
5
Homicide-Prob Info
4
– How would people find out about risks?
– From their schooling?
Accident
290
Accident-Verbal
• No, because older people would forget or have
outdated info
3
Accident-Prob Info
12
Disease
– From news media?
129
Disease-Verbal
• No, because news media offer little, useful risk
information
–
591
17
Disease-Prob Info
36
0
100
200
300
400
See Sheldon Krimsky & Dominic Golding, eds., Social Theories of Risk; Richard Ellis &
Michael Thompson, Culture Matters; Howard Margolis, Dealing with Risk
500
600
700
800
900
1000
Number of Stories
Source: E. Smith and Bill
Herms
Agenda Setting
Lichter & Rothman
• When the news media cover an issue, people begin
to think about it and think it is important
• We learn risks from the
news media
– News stories about risks tell
us what to fear
• Environmental advocates
point to certain risks (among
many possible risks)
http://www.gallup.com/poll/184193/racism-edges-again-important-problem.aspx;
http://www.washingtonpost.com/sf/investigative/2015/12/26/a-year-of-reckoning-policefatally-shoot-nearly-1000/; http://mappingpoliceviolence.org/
What the Media Say Causes Cancer, 1972-92
What Cancer Specialists Say Causes Cancer
600
100
Source: Lichter &
Rothman, 143
95
90
498
500
80
400
56
Number of stories
60
54
50
330
33
273 272
300
268 256
222
40
200 194
200
33
163
139 136 134
129
59
48
44
41
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D
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Su
nl
79
9
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A
82
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66
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To cal
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A id
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ry an
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La
oi
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20
86
100
17
H
21
od
26
Fo
30
Sm
ok
Percent major threat
70
4
News Coverage of Environmental Risks
• Events are newsworthy if they involve:
– Conflict
• Disasters
• Conflict between people
• Risks to people
– Proximity
• Close stories are more interesting than distant ones
– Novelty& Timeliness
• New stories, not chronic problems
Conflict
Zika is new
http://www.npr.org/section
s/healthshots/2016/05/17/47825128
9/who-should-be-worriedabout-zika-and-whatshould-they-do
CDC Map of Potential Zika Spread
Car Crashes
are not
Proximity
Media, not just News Media
• Journalists focus on cancer claims with
good story-lines
– Human causes = good guy v. bad guy
• Erin Brockovich
– Natural causes = dull story
• Radon, sunlight, background radiation
Psychometric Theory of Risk
Perception
• Proposed by Paul Slovic & colleagues
– Paul Slovic, Baruch Fischoff, and Sara Lichtenstein, “Rating the Risks,”
Environment, 21 (April 1979): 14-20, 36-39.
– Paul Slovic, “Perception of Risk.” Science 1987 Apr 17;236(4799):280-5.
– P. Slovic & E. Weber, “Perception of Risk Posed by Extreme Events.”
• Criticized by others
• Lennart Sjöberg, Bjørg-Elin Moen, Torbjørn Rundmo, “Explaining risk
perception: An evaluation of the psychometric paradigm in risk perception
research.” http://paulhadrien.info/backup/LSE/IS%20490/utile/Sjoberg%20Psychometric_paradig
m.pdf
5
Psychometric Theory: Risk Characteristics
1. Voluntariness of risk: Do people voluntarily
choose risk?
Psychometric Theory: Risk Characteristics
3. Knowledge of risk: To what extent are the
risks known by the persons exposed to the risks
and to science?
Driving
Psychometric Theory: Risk Characteristics
2. Immediacy of effect: Is the risk of death
immediate or likely to occur at some later
time?
Psychometric Theory: Risk Characteristics
4. Control over Risk: If you are exposed to the
risk, to what extent can you, by personal skill
or diligence, avoid death?
Zika
Psychometric Theory: Risk Characteristics
5. Newness: Is the risk new & novel or old &
familiar?
Psychometric Theory: Risk Characteristics
6. Chronic v. Catastrophic: Is this a risk that kills
people one at a time (chronic) or a risk that
kills large numbers of people at once
(catastrophic)?
6
Psychometric Theory: Risk Characteristics
Psychometric Theory: Risk Characteristics
7. Common v. Dread: Is this a risk that people have
learned to live with, or is it one that people have
great fear of--on the level of dread?
8. Severity of Consequences: When the risk from the
activity is realized (e.g., an accident or illness),
how likely is it that the consequence will be fatal?
Pneumonia (Flu) patient
Psychometric Theory: Risk Characteristics
Cultural Cognition Theory
• Simplify the structure of risks (factor analysis):
• Dan Kahan, et al.
• Based on Aaron Wildavsky & Mary
Douglas’s Cultural Values Theory
– 8 Characteristics reduce to 2 general groups:
– (1) Risks unknown to those exposed & to science
– Newness & involuntary exposure are also related
– New name; new measures
– See Aaron Wildavsky and Karl Dake, “Theories of Risk
Perception: Who Fears What and Why.” Daedalus 119
(1990): 41-60.
– (2) Severity of consequences
– Certainty of being fatal
– Dread
– Severity of consequences
– Ability to control contributes to both factors
Communitarianism-Individualism
Scale
Cultural Cognition Theory
Hierarchy
Communitarianism
Individualism
(Items beginning with “I” are reversed)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Egalitarianism
•
•
•
IENJOY People who are successful in business have a right to enjoy their wealth as they see fit.
IFIX If the government spent less time trying to fix everyone’s problems, we’d all be a lot better off.
IGOVWAST Government regulations are almost always a waste of everyone’s time and money.
IINTRFER The government interferes far too much in our everyday lives.
IMKT Free markets—not government programs—are the best way to supply people with the things they need.
INEEDS Too many people today expect society to do things for them that they should be doing for themselves.
INEEDY It’s a mistake to ask society to help every person in need.
IPRIVACY The government should stop telling people how to live their lives.
IPROFIT Private profit is the main motive for hard work.
IPROTECT It’s not the government’s business to try to protect people from themselves.
IRESPON Society works best when it lets individuals take responsibility for their own lives without telling
them what to do.
ITRIES Our government tries to do too many things for too many people. We should just let people take care
of themselves.
SHARM Sometimes government needs to make laws that keep people from hurting themselves.
SLIMCHOI Government should put limits on the choices individuals can make so they don’t get in the way of
what’s good for society.
SNEEDS It’s society’s responsibility to make sure everyone’s basic needs are met.
SPROTECT The government should do more to advance society’s goals, even if that means limiting the
freedom and choices of individuals.
SRELY People should be able to rely on the government for help when they need it
7
Egalitarianism-Hierarchy Scale
Cultural Cognition Theory
(Items beginning with “E” are reversed)
•
•
•
•
•
•
•
•
•
•
•
•
•
• Those who are ‘individualistic’ and
‘hierarchical’ tend to dismiss claims of
environmental risk
HCHEATS It seems like the criminals and welfare cheats get all the breaks, while the average citizen picks up the
tab.
HEQUAL We have gone too far in pushing equal rights in this country.
HFEMININ Society as a whole has become too soft and feminine.
HREVDIS1 Nowadays it seems like there is just as much discrimination against whites as there is against blacks.
HREVDIS2 It seems like blacks, women, homosexuals and other groups don’t want equal rights, they want special
rights just for them.
HTRADFAM A lot of problems in our society today come from the decline in the traditional family, where the man
works and the woman stays home.
HWMNRTS The women’s rights movement has gone too far.
EDISCRIM Discrimination against minorities is still a very serious problem in our society.
EDIVERS It’s old-fashioned and wrong to think that one culture’s set of values is better than any other culture’s
way of seeing the world.
EGAYMAR A gay or lesbian couple should have just as much right to marry as any other couple.
ERADEQ We need to dramatically reduce inequalities between the rich and the poor, whites and people of color,
and men and women.
EROUGH Parents should encourage young boys to be more sensitive and less “rough and tough.”
EWEALTH Our society would be better off if the distribution of wealth was more equal.
EXSEXIST We live in a sexist society that is fundamentally set up to discriminate against women.
– Acknowledging such hazards would threaten the
autonomy of markets and the authority of social
elites.
• Those who are ‘egalitarian’ and
‘communitarian’ take environmental risks
seriously
– They believe unregulated markets are a source of
inequality and, therefore, harmful to society
–
Nanotechnology Study
Quoted from Kahan et al (2009): 87
Kahan et al Nanotechnology Experiment
100
90
86
The potential benefits of nanotechnology include the use of nanomaterials in
products to make them stronger, lighter and more effective. Some examples
are food containers that kill bacteria, stain-resistant clothing, high
performance sporting goods, faster, smaller computers, and more effective
skincare products and sunscreens. Nanotechnology also has the potential to
provide new and better ways to treat disease, clean up the environment,
enhance national security and provide cheaper energy.
While there has not been conclusive research on the potential risks of
nanotechnology, there are concerns that some of the same properties that
make nanomaterials useful might make them harmful. It is thought that some
nanomaterials may be harmful to humans if they are breathed in and might
cause harm to the environment. There are also concerns that invisible,
nanotechnology-based monitoring devices could pose a threat to national
security and personal privacy.
Vaccinations – Safe or Risky?
• What do the theories predict? Which is more
persuasive?
• Psychometric Theory vs. Cultural Cognitions
Benefits > Risks
•
80
Hierarchical
Individualist
70
60
61
50
40
30
23
20
10
Egalitarian
Communitarian
0
No Info.
Hierarchical-Individualist
Info
Egalitarian Communitarian
Cognitive Cognitions
• Individualists don’t like
government orders
“In the current discussion …
conservatives have been
embracing a precious
individual right to shun
inoculation. On Fox News,
Sean Hannity declared that
he wasn't ‘trusting President
Obama to tell me whether to
vaccinate my kids.’”
– Source: Margaret Talbot, “Not Immune.” New
Yorker - February 16, 2015, page 19
8
Psychometric Theory
would say
• Vaccinations are:
1. Not voluntary
4. Not under parents’ control
7. Cause dread
8. Have severe consequences
(potentially)
A Study Showed Mercury
in the Gulf of Mexico near Platforms
Social Construction of Risk
• How are risks socially constructed?
– Small amount of real risk information
– Psychometric influences
– Social influences
• Consider how science works and how the
news media can report and (sometimes)
distort it
Do Offshore Oil Platforms Leak Mercury?
• News media gave study front page coverage
– Mercury poisoning in fish was a concern
– An explosion of news coverage & protests
• Later studies showed that the mercury level was
constant across the Gulf
– Mercury compounds did not match mercury in
drilling mud
– Mercury eventually traced to Midwest smokestacks
A Study Showed Mercury
in the Gulf of Mexico near Platforms
• News media gave study front page coverage
– Mercury poisoning in fish was a concern
– An explosion of news coverage & protests
Science in Practice
• Process begins with individual research study
– A researcher has an idea, a hypothesis
– He/she tests it
– If data overwhelmingly support it, she/he submits
• Later studies showed that the mercury level was
constant across the Gulf
– Mercury compounds did not match mercury in
drilling mud
– Mercury eventually traced to Midwest smokestacks
it for publication
– Peer review (3-6 months)
– Publication
9
Consider Logic of Hypothesis Test
Science in Practice
• After publication: Other researchers replicate
– Different data sets
– Different methods
• We want to be at least 95% certain before we
claim support for our hypothesis
• But 1 time in 20, we produce a “false positive”
• In some cases, studies yield conflicting findings
– Different data, methods may explain results
– But the original study may have been wrong
• So papers with false positives are published
– And papers with false rebuttals are published
• Result: scientific controversy with findings on
both sides
Science-Politics Timelines
Science
Mercury
study
published
Doubts raised.
New study
begins
Activists
Public
Concern demand
action
Congressional
hearings
Data
gathered;
analyzed
Mercury
study 2
published
New laws,
regulations?
Politics
10