1
Q
what makes nudging powerful?
A
- randomised controlled trails (RCTs)
- A/B testing
2
Q
social influence
A
- Six principles of influence:
1. Reciprocation
2. Social proof
3. Liking
4. Authority
5. Commitment & self-consistency
6. Scarcity - Related terms:
Persuasion, Conformity, Compliance, Obedience
3
Q
why is reciprocation so powerful?
A
- No human society that doesn’t
reciprocate (Gouldner, 1960) - Allows us to give and not lose
- Allows division of labour,
trading, expertise, efficient
social groups
4
Q
reciprocation- cont
A
- Compliance experiment Regan 1971 JESP
- supposedly about “art appreciation”
- a confederate “bought” the participant a Coke (or not)
- At the end, the confederate asked participants to buy
raffle tickets so he could win a competition. - 2x tickets bought in Coke condition compared to
baseline
5
Q
reciprocation
A
- Compliance experiment Regan 1971 JESP
- In 1971, a coke cost 10 cents …. but the average
number of tickets bought in Coke condition was 2
tickets, which was worth 50 cents. - 400% return on investment!
6
Q
reciprocation- powerful
A
- Very powerful
- people gave more money to the confederate when they liked him better
(confederate either behaved nice or mean to third person) - BUT only when he didn’t buy them a coke Regan 1971 JESP
- when he bought them a coke, people reciprocated regardless of liking
- Note that the gift giver chooses
both the gift and the favour - principle behind free samples:
7
Q
reciprocation: enforcing
A
- Enforces uninvited debt
- people give even when they don’t want to (e.g. no one turned down
the free Coke) - makes sense, if rule evolved to help maximise group cohesion i.e.
people can give without loss
Charities use this
technique:
3x more donations
British Red Cross, reported in the
Guardian, 2014
8
Q
- Reciprocal concessions
A
- Door-in-Face technique: obligation to make a concession to
someone who has made a concession to you Cialdini et al 1975, JPSP
3x as many people agree
to chaperone juvenile
delinquents to the zoo
after declining larger
favour Cialdini et al 1975, JPSP
9
Q
social proof: the big mistake
A
- Injunctive norms (what we’re supposed to do)
- Descriptive norms (what most people do)
- Study looked at people removing petrified wood from a National Park in
Arizona Cialdini et al 2006, Social Influence - Compared the effectiveness of different messages set along visitor paths
- Dropped petrified wood along the paths (to measure how much wood was
taken by visitors)
10
Q
social proof: the big mistake
A
- Injunctive norms (what we’re supposed to do)
- Descriptive norms (what most people do)
- “Many past visitors have removed petrified wood” (Negative) descriptive
norm Cialdini et al 2006, Social Influence - “Please don’t remove the petrified wood from the Park, in order to
preserve the natural state of the Petrified Forest” (Positive) injunctive
norm
-> 8% wood removed
-> 1.7% wood removed
11
Q
Social proof: When and why?
A
- When and why do we follow the group?
- Similarity
- We follow people like us:
- in the tax study, “people in the same town” was more effective than
“people in the UK” - in the towel study, “same room” was more effective than “same hotel”
12
Q
social proof: when and why?
A
- When and why do we follow the group?
- When uncertain (informational social influence)
- e.g. bystander effect, Kitty Genovese murder (35 mins and 38 people who
didn’t do anything) - pluralistic ignorance -
“smoke” experiment Latene & Darley 1968, JPSP - 75% people reported the smoke
when on own - 10%, when confederates didn’t move
13
Q
liking: why do we like others
A
- physical attractiveness
- similarity
- cooperation and synchrony
- compliments
- personalisation
14
Q
Liking: physical attractiveness
A
Beauty premium:
* more attractive people are paid around 5 to
10 percent more Hameresh & Biddle 1993, Beauty and the Labor Market
* … are viewed as being more socially
competent Eagly et al Psych Bulletin 1991
* … even receive lighter sentences in the
criminal justice system Stewart, J. Applied Psychology 1980
15
Q
A
- Beautiful people are more
persuasive Chaiken JPSP, 1974 - Supports associative learning
(anything associated with beauty
is also perceived as good) - brands exploit the halo effect to
sell products
16
Q
similarity
A
- We like people more when they are
similar to us - “Hippies” study: people asked for a
favour (borrow a dime for a payphone)
by confederates dressed either as
“Hippies” or “Straights” Emswiller et al 1971
Journal of Applied Social Psych. - Favour was granted more often when
confederates’ clothes matched the
participants’
17
Q
A
- We like people more when they are
similar to us - “Hippie” experimenter got more
signatures on a peace petitions at a real
peace rally than “Straight” experimenter
Suedfeld et al 1971 Journal of Applied Social Psych. - Also, more people signed in the Hippie
condition without looking at the petition!
18
Q
Liking: cooperation and synchrony
A
- “Robbers’ Cave” experiment: when the Eagles and Rattlers
were competing over camp resources, hostilities rapidly
increased. Increasing cooperation between the groups
increased liking and in turn, further cooperation Sherif & Sherif 1954 - Mimicry increases liking Chatrand & Bargh 1999, JPSP
- Synchrony in action increases liking Hove & Risen 2009 Social Cognition
- Synchrony increases helping behaviours: participants and
confederate asked to tap along with music (on headphones):
Valdesolo & DeSteno 2011, Emotion - after unsynchronised tapping (different music), 18% of
participants stayed to help confederate with maths tasks - after synchronised tapping (same music), 49% stayed to help
- likelihood of helping was mediated by sense of similarity
19
Q
comliments
A
Liking: compliments
* Robust effect of compliments on liking
* Surprisingly little research on the effect
of compliments on persuasion
* “Tips” studies: compliments lead to
higher tips Seiter 2007 J Applied Social Psychology
‘‘Flattery will get you everywhere’’
Mae West
20
Q
being personal
A
- In general, remembering details about a person is perceived as
an index of how important you think they are Ray et al JPSP 2019 - Remembering names is perceived as a compliment Howard et al 1995
J. Consumer Research - Remembering someone’s name also increases the likelihood that
the person will make a purchase, mediated by the compliment
value Howard et al 1995 J. Consumer Researc
21
Q
Criticisms of experiments
A
- Demand bias? (participants guess hypothesis)
- Mitigated by:
- making sure participants are blind to the experiment
hypotheses and/or the condition - asking at the end what the experiment was
about (funnel debrief) - use between-subjects design
e.g. synchrony studies Hove & Risen 2009 Social Psychology
22
Q
Criticisms of experiments
A
- Experimenter bias? (most times, the experimenters knew the
hypothesis and so could have acted differently) - Mitigated with:
- strict decision criteria for choosing a participant (e.g. Hippie study used
specific times, approach first person who meets criteria: Emswiller et al 1971 Journal of Applied Social
Psych.) - making experimenters blind
- record interactions
- use computer interaction (so completely
scripted) e.g. Grant et al 2010 Basic and Applied Social Psychology
23
Q
Authority
A
- Milgram experiments: people stopped shocks if…
… the experimenter told the participant to stop
(even if the “victim” insisted they continue)
… the experimenter and “victim” switched roles
… with two experimenters who disagreed - doctors study: researchers phoned wards and pretended to be doctors
and asked the nurses to administer a dangerous dose of unauthorised
medication to a specific patient Hofling et al J. of Nervous and Mental Disease, 1966 - in 95% of cases, the nurses went to the medicine cabinet and secured
the medicine (where they were stopped!)
24
Q
authority
A
- Dominance v. credibility
- Credibility: expertise and trustworthiness
25
Expertise
* Expertise: Asked to judge a laundry detergent brand based on review by Yale
chemist or 14 year old boy Smith, DeHouwer, Nosek, PSPB, 2012
* Yale chemist judged as more credible than the boy (i.e. expert, intelligent,
trustworthy)
* Yale review led to greater explicit preference for the laundry brand
* Yale review led to greater implicit brand preference (via Implicit Association Test)
26
Authority: Trustworthiness
Trustworthiness: weakness-before-strength technique
27
trsut in experts
* Study compared behavioural nudges
carried out by experts (scientists)
and government groups Osman et al
Basic and Applied Social Psych. 2018
* Scientists judged more trustworthy
than government groups
* Genuine nudges judged more
ethical and plausible than fictitious
nudges
* Genuine nudges by government
judged less trustworthy than
fictious (implausible) nudges by
scientists!
28
commitment_ cognitive dissonance
* cognitive dissonance theory:
inconsistency among beliefs or
behaviours causes an
uncomfortable psychological
tension Festinger 1957
* So, we act to reduce that tension -
> consistency is preferred
29
foot in the door
* foot-in-the-door technique: start small and build up
* Cancer study: students were phoned up by a researcher and asked
hypothetical question: would they help collect donations for the
‘American Cancer society’ if asked? Sherman et al, JPSP, 1980, Exp3
* Experimental group (plus control group, who hadn’t previously been
contacted) then phoned up by the ‘American Cancer Society’ and
actually asked to help
* 31.3% helped in experimental group v 4.2% in control group
* Fighting cancer is a socially desirable behaviour so people
overpredicted that they would help (47.8% thought they’d help!)
30
contradiction
* foot-in-the-door technique:
start small and build up
* opposite to the door-in-the-
face technique (start big go
small)
* Contradiction??
31
replication
* meta analysis of experimental studies on environmental pledges Lokhorst
et al 2013 Enviroment and Behavior
* commitment was an effective strategy in changing behaviour (moderate
effect size)
* also successful in driving long term behaviour change (small effect size)
* less clear whether commitment was the best intervention
32
why?
* less clear why commitment is effective Lokhorst et al 2013 Enviroment and Behavior
Could be:
* Change in self concept and/or attitudes towards behaviour (“I am the
kind of person who recycles”)?
* Follow social norm (“good to be consistent”)?
33
Commitment: why?
* less clear why commitment is effective Lokhorst et al 2013 Enviroment and Behavior
Could be:
* Change in self concept and/or attitudes towards behaviour (“I am the
kind of person who recycles”)?
* Follow social norm (“good to be consistent”)?
34
scarcity
People want something more when it is:
* time-limited
* rare
* difficult to get
35
optimal conditions
* Consumer preference study Worchel 1975 et al JPSP
* Participants rated the same cookie, either taken from a jar with 2
cookies OR with 10 cookies.
* Cookies in short supply rated as significantly more desirable to eat
and more attractive as an item, and (ns) more costly
* Newly scarce condition: cookie rated as EVEN more attractive, liked,
and costly when it was first shown in a jar of ten, THEN in a jar of
two (instead of always two)
36
information scarcity
* Censorship study: Participants were given a list of tapes,
either told they could listen to all of them; or told that one
was restricted (censored by the ethics board) Worchel 1992
* Censorship increased people’s desire to hear the tape
* Desire especially increased when:
- told others had heard the tape
- deliberately (not accidentally) withheld
- it was personal (only they couldn’t hear it)
37
* Psychological reactance: when people feel that their choices
are heavily constricted, they feel angry and may react by
increasing that behaviour Brehm 1966
* Streisand effect
38
nudging through the enviroment
* ‘Low’ and ‘high’ roads to imitation (nudging) Dijksterhuis et al 2005 J
Consumer Psychology
* ‘Low road to imitation’ -> mimicry
* mimicry of relatively simple, observable behaviour
* ‘High road to imitation’ -> priming
* imitation based on higher-level constructs (e.g. traits, goals,
and stereotypes)
39
Mimicry as a nudge
* perception-behavior link: seeing is doing (i.e. automatic copying;
no need for conscious or deliberate thought) Dijksterhuis et al J Consumer Psych.
2005
* chameleon effect: mimicry happens automatically and
unconsciously Chartrand & Bargh JPSP, 1999
* > monkey see, monkey do
40
Mimicry as a nudge
* perception-behavior link: seeing is doing (i.e. automatic copying;
no need for conscious or deliberate thought) Dijksterhuis et al J Consumer Psych.
2005
* chameleon effect: mimicry happens automatically and
unconsciously Chartrand & Bargh JPSP, 1999
* paper cited 4,817 times!
41
priming as a nudge
* initial activation of a construct leads to activation of other
constructs Carver et al J. Experimental Social Psych. 1983
* types of priming:
* semantic (priming concepts)
* evaluative (priming good/bad appraisals)
* Implicit Association Task
* other individual difference tasks
* initial activation of a construct leads to relevant behaviour Carver et al J.
Experimental Social Psych. 1983
* behavioural priming
42
Behavioural priming: Traits
* Measured shocks delivered (Milgram task) Carver et al J. Experimental Social Psych.
1983 Study 2
* People primed by asking them to unscramble mainly hostile words
(hostile, aggressive, etc.) or neutral words (supposedly a different
experiment)
* People primed with hostility gave more shocks than the control group did
* Subject to demand, but no one guessed the link between the two studies
at debrief (although one person guessed that
they weren’t really delivering shocks)
* Effect size was really small
43
* Priming behaviour with stereotypes
* people primed with “professor” stereotype (asked to write down typical
professor characteristics) performed better on a general knowledge task
than control participants Dijksterhius & van Knippenberg 1998
* people primed with a “football hooligan” stereotype, showed lower general
knowledge than control participants Dijksterhius & van Knippenberg 1998
44
goals
* Priming goals unconsciously Chartrand & Bargh JPSP 1996
* Relied on this effect: people who are asked to form an impression
remember more personal information than people who are asked
to remember the information directly (ironically!)
* priming impression formation goal (using a scrambled sentence
task) also led to better memory compared to priming a memory
goal
45
Behavioural priming: Non-verbal
* Smell: Participants put in room with (hidden) bucket filled with lemon-
scented cleaning water (or control)
* Participants in the bucket condition were more likely to list cleaning
activities as goals for the day (36%) than the control participants (11%)
Holland et al, Psych. Science 2005
46
context
* photo of eyes increased donations to tea/coffee honesty box
relative to photo of flowers Bateson et al 2006 Biology Letters
* 2012 HMRC tax
advert based
on result
* Halpern 2019, Inside the
Nudge Unit
47
Behavioural priming: does it replicate?
* Elderly-walking paradigm failed to replicate:
- with better methods (e.g. infra-red movement sensors) Doyen
et al 2012 PLOS One
- did replicate when experimenter wasn’t blind to condition i.e.
expected the participant to walk slower
- thus experimenter, rather than environment, may have
primed participant
* Professor/hooligan paradigm failed to replicate:
- set of nine studies Shanks et al., 2013 Plos ONE
- multi-lab collaboration, pre-registered report, protocol
validated by original author O’Donnell et al 2018
48
Behavioural priming: does it replicate?
* Eyes-watching paradigm failed to replicate:
- Carbon & Hesslinger 2011, Swiss J. Psychology
- two meta-analyses conclude no effect Northover et al2016 Evolution & Human
Behavior
* Warm-cold impression priming failed to replicate
- Chabris et al 2019, Social Psychology
* Findings from other literatures:
- Behavioural priming at odds with cognitive neuroscience
literature suggesting that priming requires salient stimuli and
top-down attention (factors associated with consciousness)
Doyen et al 2012 PLOS One
49
Behavioural priming: what’s going on?
* Demand bias & experimenter bias
* Under-powered studies: small effects need large
participant samples, most priming studies were run on N = 20
* Effects may just be a type 1 error (i.e. not really there)
* Mistakes in statistical analysis: statistics are hard and mistakes do
happen!
* experimenter and demand bias may instead demonstrate how
powerful social influence is
50
social psych- year 3
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