12/09/14 09. September 2014
Nudge
PELLE GULDBORG HANSEN, BEHAVIOURAL SCIENTIST, PH.D. / CBIT, ROSKILDE UNIVERSITY
DIRECTOR OF ISSP – THE INITIATIVE FOR SCIENCE, SOCIETY & POLICY
MEMBER OF THE PREVENTION COUNCIL, DANISH DIABETIC ASSOCIATION
CHAIRMAN OF THE DANISH NUDGE NETWORK
HEAD OF INUDGEYOU TEAM
The smaller the piece the healthier consumption – a choice architectural experiment in behavioral nutrition
Hansen PG; Skov LR; Schmidt K; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013)
Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
EXPERIMENTAL DESIGN FOR FIELD EXPERIMENT IN HEALTHY EATING BEHAVIOUR (2013)
Sample
Experimental conditions
Standard buffet
391CEO’s attending a
coffee break
Predicted effects
Standard eating
behaviour
Control
n = 189
Re-arranged buffet
Healthier eating
behaviour (Less
cake, more apples)
Intervention
n = 202
Participants in a national conference for
550 Danish CEO’s held in the Danish Opera
Self-selection by choosing one of two stairs
leading to floor featuring two identical brownie
and fruit buffets
Measurement brownie and apple intake
Hansen, PG; Schmidt; Jespersen AM & Skov, LR; Skov, KL (2013) ‘Apple vs. Cake! A Choice Architectural Field-Experiment in
Promoting Healthy Eating Behaviour’ (Forthcoming 2014)
Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
1 12/09/14 Average consump/on per person measured in whole of cake and apples respec/vely Cake vs. Brownies in the Opera 2013 0.9 0.8 0.7 0.6 0.5 Control 0.4 Reduced size 0.3 0.2 0.1 0 Cake consump9on Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
Cake vs. Brownies in the Opera 2013 Cake vs. Brownies in the Opera 2013 45 1800 40 1600 35 1400 30 1200 25 20 Standard 15 Interven9on 10 Kilo Jules Grams per person Apple consump9on 1000 800 600 5 400 ei
n
br
e Pr
ot
ry
ﬁ
ga
rs
et
a
200 0 Total energy intake per person (KJ) Di
e su
ed
Ad
d
fa
Ca
rb
o
ed
Fa
ar
at
tu
Sa
hy
dr
at
t t 0 Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
Skov LR; Schmidt K; Hansen PG; Skov KL; Mikkelsen BE; Pérez-Cueto FJA (2013) The smaller the piece the healthier consumption –
a choice architectural experiment in behavioral nutrition
Table over energy use for different activities
Activity
KJ/10 minutes
Watching TV
33
Kissing
34
Doing the dishes by hand
71
Vacuuming
80
Brushing teeth
80
Playing music
85
Playing volleyball
Playing Frisbee
95
100
Source: ‘Become your own food detective’ – Danish Board of Product Facts
2 12/09/14 nudge
Et nudge er en samlebetegnelse for forsøg på at påvirke
menneskers valg og adfærd i forudsigelige retninger
uafhængigt af
ADFÆRDSINDSIGTER I
1)  at begrænse deres valgmuligheder, eller
DUAL PROCESS THEORY
2)  ændre afgørende ved handlingsalternativernes
omkostninger (herunder økonomi, tid, besvær, social
sanktioner, o. lign.)
baseret på antagelsen at kognitive bias påvirker individuel
og sociale beslutninger og adfærd, og som gør brug af
disse som integrerede dele af sådanne forsøg.
1. 
2. 
3. 
4. 
Sloman S.A. (1996) The empirical case for two systems of reasoning. Psychological Bulle/n, 119, 3-‐22. Kahneman D. (2003) A perspec9ve on judgement and choice. American Psychologist. 58, 697-‐720. Evans, J. (2003). "In two minds: dual-‐process accounts of reasoning". TRENDS in Cogni/ve Sciences 7 (10). Stanovich, K E.; West, R F. (2000). "Individual diﬀerence in reasoning: implica9ons for the ra9onality debate?". Behavioural and Brain Sciences 23: 645–726. 5.  Stupple, E.; Waterhouse (2009). "Nega9ons In Syllogis9c Reasoning: Evidence for a Heuris9c -‐ analy9c Conﬂict". The Quarterly Journal of Experimental Psychology 62 (8). Hansen, PG & Jespersen, AM (2013) Nudge & The Manipulation of Choice – A Framework for the Responsible Use of the Nudge
Approach to Behaviour Change in Public Policy, The European Journal of Risk Regulation, Volume 1, 2013, 3-28 Decision-making and behavioral biases
Anchoring – the common human tendency to rely too heavily, or "anchor," on one trait or piece of
information when making decisions.
Attentional Bias – implicit cognitive bias defined as the tendency of emotionally dominant stimuli in
one's environment to preferentially draw and hold attention.
Backfire effect - Evidence disconfirming our beliefs only strengthens them.
Bandwagon effect – the tendency to do (or believe) things because many other people do (or believe)
the same. Related to groupthink and herd behavior.
Bias blind spot – the tendency to see oneself as less biased than other people.[2]
Choice-supportive bias – the tendency to remember one's choices as better than they actually were.
[3]
Kahneman, D (2002) Maps of Bounded Rationality: A Perspective on Intuitive Judgment and Choice, Prize Lecture, December 8, 2002.
Confirmation bias – the tendency to search for or interpret information in a way that confirms one's
preconceptions.[4]
Congruence bias – the tendency to test hypotheses exclusively through direct testing, in contrast to
tests of possible alternative hypotheses.
Contrast effect – the enhancement or diminishing of a weight or other measurement when compared
with a recently observed contrasting object.[5]
Denomination effect – the tendency to spend more money when it is denominated in small
amounts (e.g. coins) rather than large amounts (e.g. bills).[6]
Distinction bias – the tendency to view two options as more dissimilar when evaluating them
simultaneously than when evaluating them separately.[7]
Empathy gap - the tendency to underestimate the influence or strength of feelings, in either oneself
or others.
Endowment effect – "the fact that people often demand much more to give up an object than they
would be willing to pay to acquire it".[8]
Experimenter's or Expectation bias – the tendency for experimenters to believe, certify, and
publish data that agree with their expectations for the outcome of an experiment, and to disbelieve,
discard, or downgrade the corresponding weightings for data that appear to conflict with those
expectations.[9]
Focusing effect – the tendency to place too much importance on one aspect of an event; causes error
in accurately predicting the utility of a future outcome.[10]
Framing effect – drawing different conclusions from the same information, depending on how that
information is presented.
Hostile media effect - the tendency to see a media report as being biased due to one's own strong
partisan views.
Hyperbolic discounting – the tendency for people to have a stronger preference for more
immediate payoffs relative to later payoffs, where the tendency increases the closer to the present both
payoffs are.[11]
Illusion of control – the tendency to overestimate one's degree of influence over other external
events.[12]
Impact bias – the tendency to overestimate the length or the intensity of the impact of future feeling
states.[13]
Information bias – the tendency to seek information even when it cannot affect action.[14]
Irrational escalation – the phenomenon where people justify increased investment in a decision,
based on the cumulative prior investment, despite new evidence suggesting that the decision was
probably wrong.
Loss aversion – "the disutility of giving up an object is greater than the utility associated with
acquiring it".[15] (see also Sunk cost effects and Endowment effect).
Mere exposure effect – the tendency to express undue liking for things merely because of familiarity
with them.[16]
Money illusion – the tendency to concentrate on the nominal (face value) of money rather than its
value in terms of purchasing power.[17]
Moral credential effect – the tendency of a track record of non-prejudice to increase subsequent
prejudice.
Negativity bias – the tendency to pay more attention and give more weight to negative than positive
experiences or other kinds of information.
Neglect of probability – the tendency to completely disregard probability when making a decision
under uncertainty.[18]
Normalcy bias – the refusal to plan for, or react to, a disaster which has never happened before.
Omission bias – the tendency to judge harmful actions as worse, or less moral, than equally harmful
omissions (inactions).[19]
Outcome bias – the tendency to judge a decision by its eventual outcome instead of based on the
quality of the decision at the time it was made.
Planning fallacy – the tendency to underestimate task-completion times.[13]
Post-purchase rationalization – the tendency to persuade oneself through rational argument that
a purchase was a good value.
Pseudocertainty effect – the tendency to make risk-averse choices if the expected outcome is
positive, but make risk-seeking choices to avoid negative outcomes.[20]
Reactance – the urge to do the opposite of what someone wants you to do out of a need to resist a
perceived attempt to constrain your freedom of choice.
Restraint bias – the tendency to overestimate one's ability to show restraint in the face of
temptation.
Selective perception – the tendency for expectations to affect perception.
Semmelweis reflex – the tendency to reject new evidence that contradicts a paradigm.[21]
Social comparison bias – the tendency, when making hiring decisions, to favour potential
candidates who don't compete with one's own particular strengths.[22]
Status quo bias – the tendency to like things to stay relatively the same (see also loss aversion, endowment effect, and system justification).[23][24]
Unit bias — the tendency to want to finish a given unit of a task or an item. Strong effects on the
consumption of food in particular.[25]
Wishful thinking – the formation of beliefs and the making of decisions according to what is
pleasing to imagine instead of by appeal to evidence or rationality.[26]
Zero-risk bias – preference for reducing a small risk to zero over a greater reduction in a larger risk.
(1) "The price of these note cards is $3.”
ADFÆRDS INDSIGTER II
BIASES & HEURISTIKKER
(2) "The price of these note cards is 300
pennies… It's a bargain.”
Social biases
Most of these biases are labeled as attributional biases.
Actor–observer bias – the tendency for explanations of other individuals' behaviors to
overemphasize the influence of their personality and underemphasize the influence of their situation
(see alsoFundamental attribution error), and for explanations of one's own behaviors to do the
opposite (that is, to overemphasize the influence of our situation and underemphasize the influence of
our own personality).
3 12/09/14 DTR Technique DTR PO RO DO BYAF technique Asking for bus fare, charitable dona9ons, par9cipa9on in voluntary services… meta-‐
analysis of 42 studies involving 22.000 par9cipants shows that ending with “… but you are free to accept of refuse” doubles the likelihood of people saying “yes”. •  Presence bias •  not aﬀected by whether pro-‐social or self-‐
interested RTD 80 70 70 65 65 60 50 40 35 35 35 30 30 30 25 25 20 10 0 Study 1 Study 2 Study 3 Davis, Barbara Price & Knowles, Eris S. (1999) ‘A disrupt-‐then-‐
reframe technique of social inﬂuence’, Journal of Personality and Social Psychology, Vol. 76(2), Feb 1999, 192-‐199. Christopher J. Carpenter & Franklin J. Boster (2009) ‘A Meta-‐
Analysis of the Eﬀec9veness of the Disrupt-‐Then-‐Reframe Compliance Gaining Technique’, Communica/on Reports, Vol. 22, No. 2, July–December 2009, pp. 55–62 Carpenter, Christopher J. ‘A Meta-‐Analysis of the Eﬀec9veness of the “But You Are Free” Compliance-‐Gaining Technique’. Communica/on Studies 64, no. 1 (2013), 6-‐17 FITD technique Once someone has agreed to a small request he is more likely to comply with a larger request. 60.00% 52.80% 50.00% 40.00% 33.30% 27.80% 30.00% 22.20% 20.00% 10.00% 0.00% One-‐Contact Familiariza9on Agree-‐Only Performance 2 experiments were conducted to test the proposi9on that once someone has agreed to a small request he is more likely to comply with a larger request. The 1st study demonstrated this eﬀect when the same person made both requests. The 2nd study extended this to the situa9on in which diﬀerent people made the 2 Freedman, Jonathan L. & Frase, Scoq C. (1966) ‘Compliance requests. Several experimental groups were run in an eﬀort to explain these Without Pressure: The Foot-‐In-‐The-‐Door Technique’, Journal of results, and possible explana9ons are discussed. Personality and Social Psychology, 1966, Vol. 4, No. 2, 155-‐202 Hansen PG; Schmidt K; Rathman, A; Schuldt J
450 379 Kroner 294 1 2 3 68 % 16 % 32 % 84 % 4 12/09/14 EXPERIMENTAL DESIGN FOR FIELD EXPERIMENT IN TOWEL REUSE THROUGH DESCRIPTIVE NORMS
Sample
Experimental conditions
Predicted effects
50%
Participation in towel reuse program by percentage
N = 428
48%
46%
Environmental
message on towelrack
Standard reuse rate
44%
42%
Control
44%
40%
1,058 hotel guests over a
80 day period
38%
Descriptive norm
messages on towelrack
Increase in towel
reuse
36%
34%
Intervention
35%
32%
Part of sample was removed for various
reasonsCollected from a mid-priced chainhotel in the southwest U.S.
Rooms were randomly assigned to either
condition. Environmental messages are an
industry standard
30%
Measurement of towel reuse participation
Environmental Message Descrip9ve norms message iNudgeYou © Nudge 101 iNudgeYou © Nudge 101 N. J. GOLDSTEIN, R. B. CIALDINI, V. GRISKEVICIUS (2008); ”A Room with a Viewpoint: Using Social Norms to Mo9vate Environmental Conserva9on in Hotels” Journal of Consumer Research, October 2008. N. J. GOLDSTEIN, R. B. CIALDINI, V. GRISKEVICIUS (2008); ”A Room with a Viewpoint: Using Social Norms to Mo9vate Environmental Conserva9on in Hotels” Journal of Consumer Research, October 2008. UDBEDT STILLINGTAGEN TIL ORGAN DONATION
Johnson, Eric J. and Daniel Goldstein. 2003. "Do Defaults Save Lives?" Science 302: 1338-1339.
HANSEN, P.G. (2012). Should we be ”nudging” for cadaveric organ donations? The American Journal of Bioethics, Routledge, Vol. 12, Issue 2, p. 46-48, 2012. HANSEN, P.G., Jespersen, A.M. & Schmidt, K. (2012). Udbedt svar for organdonation: den rette løsning i en kompliceret verden. In Dråben - Tidsskrift for anæstesi-,
intensiv-, og opvågningssygeplejersker, September, 2012.
HANSEN, P.G. & Jespersen, A.M. (2013). Nudge and the Manipulation of Choice. The European Journal of Risk Regulation, Vol. 4, Issue 1, pp. 3-28, 2013. Thaler, R & Benatzi , S (2004) Save More Tomorrow: Using Behavioral Economics to Increase Employee Saving, Journal of Political Economy,
2004, vol. 112, no. 1, pt. 2
BIT (2013) Applying behavioural insights to charitable giving Behavioural 5 12/09/14 Multi-layered Intervention for Raising Compliance
Hansen PG; Schmidt K; Skov KL (2013)
ERST LeXer experiment 2013 80.0% 70.0% 60.0% 58.4% 50.0% 40.0% 30.5% 30.0% 20.0% 10.0% 0.0% 1 2 Serie1 Serie2 50% 45% 40% 35% 30% Kontrolbrev 25% Nudgede brev 20% 15% 10% 5% 0% Runde 1 Runde 2 Runde 3 Runde 4 I alt 50% 45% 40% 35% 30% 25% Optagende 20% 15% 10% 5% 0% Nudgede brev Social Norm What's in it for me Rødt brev 6 12/09/14 Behavioural Insights Team (Applying Behavioural Insights to Organ Donation: preliminary results from a randomised controlled trial Behavioural Insights Team (Applying Behavioural Insights to Organ Donation: preliminary results from a randomised controlled trial N = 1.085.322 Behavioural Insights, Team Applying Behavioural Insights to Organ Donation: preliminary results from a randomised controlled trial 7 12/09/14 Twitter:!
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