Heuristic Processing &
Attitude Change
The Two Routes to Persuasion
•High
ability
and motivation
•Source
•Systematic
processing
•Message •Audience
•Persuasio
•Low
ability
and motivation
•Heuristic
processing
2
Heuristic Processing



Heuristic: a mental shortcut
that allows people to solve
problems and make
judgments quickly and
efficiently.
These rule-of-thumb
strategies shorten decisionmaking time and allow people
to function without constantly
stopping to think about their
next course of action.
May lead to inaccuracy &
biases
3
Heuristic Processing in Attitude Change


Use superficial cues to assess the validity of
message
Heuristics:
–
–
–
–
–
–
Social Proof: Everyone is doing it so it must be right
Authority: Important people are doing it so it must be right
Liking: People who I like are doing it
Commitment and Consistency: I’ve done it in the past
Reciprocity
Scarcity
4
Social proof
•
We don't have direct
knowledge about many facets
of the world
• We rely upon the visible
behavior of others to form our
own beliefs about what is
correct, right, or appropriate
• Phenomenon strongest
•
•
•
When the world is uncertain or the
stimulus is ambiguous
When the source is expert
When the source is similar to us
5
Choosing a restaurant
6
Why: Wisdom of Crowds Often Works
•High
school dating
network:
•
How many
males (blue?)
7
Hiking paths
8
Netflix
9
It really works: Bellcore Movie Critic
Best algorithms with lots of data get r ~.73 accuracy
10
The drawing power of crowds
11
The drawing power of crowds
•Who
looks up in a city street depends on how many others
are looking
Drawing power of c rowds
90
up
85.7
Percentage of
passersby who look
80
78.6
76.1
70
63.4
60
58.4
50
42.4
40
30
20
10
0
0
0
1
2
3
5
Size of the precipitating group
10
15
12
Signage with social proof

Reuse your towel sign in hotels
–
Control: “HELP SAVE THE
ENVIRONMENT. You can show
your respect for nature and help
save the environment by reusing
your towels during your stay.”
–
Social proof: “JOIN YOUR
FELLOW GUESTS IN HELPING
TO SAVE THE ENVIRONMENT.
Almost 75% of guests who are
asked to participate in our new
resource savings program do
help by using their towelsmore
than once. You
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Boost in compliance with social
proof

25% increase in reuse with
social proof message

Stronger effects when the
reference group was similar:
Guests in your room
14
NPS signs to reduce theft in Petrified Forest
Norm type
Message text
% stealing
Injunctive-positive
Please leave petrified wood in the park
5.33%
Injunctive-negative
Please don’t remove the petrified wood
from the park
1.67%
Descriptive-positive
The vast majority of past visitors have left 5.00%
the petrified wood in the park, preserving
the natural state of the Petrified Forest’
Descriptive-negative
Many past visitors have removed the
petrified wood from the park, changing
the state of the Petrified Forest
•
•
7.92%
Explicitly asking people to do the right thing (injunctive-positive) &
showing them that others do (descriptive-positive) have similar
effects
Explicitly asking people to refrain from wrong behavior (injunctivenegative) & showing them that others bad behavior (injunctivenegative) have oppositive effects
15
Effects can be powerful:
E.g., Broken window theory of policing


Criminology theory of the norm-setting and signaling
effect of urban disorder and vandalism on serious
crime.
Maintaining and monitoring urban environments to
prevent small crimes such as vandalism & public
drinkinghelps to create an atmosphere of order and
lawfulness, thereby preventing more serious crimes
from happening.
16
Tested in year-long field experiment in
Lowell MA


34 criminal “hotspot” randomly assigned to receive
scrutiny & crackdown on low-level norm violations or
regular policing
Typical interventions
–
Situational cleanup





–
Cleaning and securing vacant lots
Razing abandoned buildings
Improving street lighting
Adding video surveillance
Performing code inspections of disorderly taverns
Disorder prevention (misdemeanor arrests)





Repeat foot and radio car patrols
Dispersing groups of loiterers
Making arrests for public drinking
Arresting drug sellers
Performing “stop and frisks” of suspicious persons.
17
Reductions in citizen service calls
for serious crime
Outcome
%
change
Assault
-34%
Robbery
-42%
Burglary/B&E
-35%
Larceny/Theft
-11%
Disorderly/Nuisance
-14%
Total Calls
-20%
Pvalue
***
*
***
t
**
•Mediation
analysis shows all of the effects of the treatment
come from increases in situational responses &
misdemeanor arrests
18
•Braga, A. A.,
& Bond, B. J. (2008). Policing crime and disorder hot spots:
A randomized controlled trial*. Criminology, 46(3), 577-607.
Even though social proof is generally
reliable, it can lead to major screwups and irrational behavior
Candid Camera
20
Asch Experiments
% subjects
with errors
Control
Experimental
Average %
error (12 trials)
.4%
<1%
75%.0
37.5%
40.0%
35.0%
30.0%
%Errors
25.0%
20.0%
15.0%
10.0%
5.0%
0.0%
1
2
3
4
6
8
16
Number in Majority
21
Information cascades


An information cascade
occurs when people observe
the actions of others and
then make the same choice
that the others have made,
independently of their own
private information signals.
•
•
•
•
•
•
Information cascades used to explain many
powerful economic patterns
1634-1637 Dutch tulip bubble & then crash
Runs on banks
Internet bubble
“Irrational exuberance” 1990s stock market boom &
housing prices
Common, but incorrect medical treatments
Rationale behavior, if you
assume that others are
honest and providing
accurate information
22
In Science
23
What are the necessary conditions for social
proof to be accurate?





Sufficient numbers
Diversity
Sufficient motivation
Independence
Decentralization

Problem conditions
–
–
Non-independence  information cascade
Information cascade occurs when each observer’s
judgment is shared by an increasing large consensus
of others’ judgments
24
Social proof can have
important consequences
Orson Wells: War of the World Broadcast
Mercury Theatre Radio Drama, October 30th, 1938
• Text
of NYTimes report
26
Kitty Genovese Case
Martin Gansberg: 38 who saw murder didn’t
call police (NYT article)
For more than half an hour thirty-eight respectable, law-abiding
citizens in Queens watched a killer stalk and stab a woman in
three separate attacks in Kew Gardens. Twice, the sound of
their voices and the sudden glow of their bedroom lights
interrupted him and frightened him off. Each time he returned,
sought her out and stabbed her again. Not one person
telephoned the police during the assault; one witness called
after the woman was dead. (Gansberg, 1964, p. 1)
Controversy over the accuracy of the original
reports
Fewer than 38 eye witnesses
Some did intervene (e.g., shouting, maybe calling of police)
Manning, R., Levine, M., & Collins, A. (2007). The Kitty
Genovese murder and the social psychology of helping: The
parable of the 38 witnesses. American Psychologist, 62(6),
555.
27
Bystander Intervention Research
Darley & Latané: Research
program to understand Kitty
Genovese murder
•
•
•
•
•
Naive subject alone
Naive subject with two
calm confederates
Three naive subjects
Cumulative proportion reporting
smoke

Smoke study
Subject recruited to a lab
to fill out questionnaires
Smoke seeps into the
study room & eventually
fills it
Social condition
Cumulative proportion of subjects reporting the
smoke over time
100
hypothetical 3 person group
90
80
70
alone
60
50
40
30
3 person group
20
10
subject + 2 confederates
0
0
1
2
3
4
5
Minutes from start of smoke infusion
6
28
Epileptic study
•
Subjects go round robin, introducing themselves. The
victim discusses difficulties adjusting to NYC and admits to
epileptic seizures under pressure. In round two, victim
becomes increasingly incoherent, spluttering that he is
having a seizure and needs help
•
Naive subject is paired with victim only, victim + 1 stranger,
victim + 4 strangers
29
Bystander Intervention Process
•Social
comparison processes
•Notice
•Define
as
emergency
event
•Accept
•Evaluate
personal
•responsibility
costs & rewards
•Select
mode of
intervention
•Implement
intervention
for
action
What is the effect of others’ being present?
•
Increases likelihood of noticing the event
•
Depending on others' demeanor, may decrease the likelihood of
interpreting event as an emergency
•
•
Informal norm of looking "cool" while assessing the situation biases
others to interpret the situation as "cool"
Diffuses responsibility
30
Defense
• Identify
a particular helper
• Be explicit about the nature
of the emergency
• Be explicit about what you
want them to do
31