Norms, Frames and Prosocial Behavior in Games - ETH Z · Norms, Frames and Prosocial Behavior in...

Norms, Framesand ProsocialBehavior in

Erik O.Kimbrough,

Joshua Miller,Alexander

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Norms, Frames and Prosocial Behavior inGames

Erik O. Kimbrough Joshua Miller Alexander Vostroknutov

Simon Fraser University

Bocconi University

Trento University

May 14, 2015

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Norm-Dependent UtilityQuestion: How do we account for cooperative and altruisticbehavior (in the lab)?

Usual Answer: “Social preferences”

Our Answer: Norm-dependent preferences

Individuals care about own payoffs and (heterogeneously) aboutwhether their actions correspond to social norms.

They bring norms with them to the lab and their behavior reflects atradeoff between norm-following and selfishness.

We can account for prosociality (without relying on explicitdistributional preferences) and well-known context effects (for whichpure distributional preferences cannot account).

We attempt to manipulate norms and test the predictions of themodel in variants of two well-known games.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Model of Norm-DependentPreferences

� We model social norms in extensive games

� N = {1, ..., n} - set of players

� 〈N,H〉 - extensive form with observable actions

� H - finite set of histories

� h = (a1, a2, ..., a`) - history of length `

� Actions at = (at1, ..., atn) at time t

� Ai (h) - set of actions of player i after h

� A = ∪i∈N ∪h∈H\Z Ai (h)

� π : Z → Rn - payoffs

� S - set of pure strategies

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

� g : A→ [−1, 1] is a norm: assigns a “social appropriateness”index to each action

� The norm defines behavior in all contingencies in the game (so,includes things like reciprocity)

� In each node, each player knows what is the “most sociallyappropriate” thing to do

� Players should choose a trade-off between desire to increasepersonal payoff and following the norm

� Redefined payoffs:

Ui (z) = πi (z) + φi

∑t=1

g(ati (z))

Implication 1: individuals with higher φ will more nearly adhere tosocial norms.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

∑t=1

g(ati (z))

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

∑t=1

g(ati (z))

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Frames

The definition of a norm suggests a natural definition of a “frame” ofa game:

A frame is a payoff-irrelevant description of a choice setting thatevokes a particular norm.

Implication 2: changes in behavior due to ‘framing effects’ operateby changing the norm individuals bring to bear.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Frames

The definition of a norm suggests a natural definition of a “frame” ofa game:

A frame is a payoff-irrelevant description of a choice setting thatevokes a particular norm.

Implication 2: changes in behavior due to ‘framing effects’ operateby changing the norm individuals bring to bear.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Preliminary Evidence for (1)In settings where we think we know the norm, individuals who caremore about norms should be more cooperative.

“The rule is to wait at each stop light until it turns green”

We measure how long individuals spend waiting at the light.

This allows us to measure the underlying heterogeneity, else whywould people vary in willingness to incur the cost?

In a previous paper, we found evidence consistent with thishypothesis in Dictator, Ultimatum, Trust and Public Goods games(Kimbrough and Vostroknutov 2014)

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Rule-Following

Waiting Time

Density

0 10 20 30 40 50+

No Rule

Waiting Time

Density

0 10 20 30 40 50+

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

The Data

0 2 4 6 8 10

(a) PG - Percent Contributed

Period

Percent

Rule-Breaking GroupsRule-Following Groups

0 20 40 60 80

(b) TG - Amount Sent

Tokens (out of 80)

1-20 21-60 61-80

(c) TG - Proportion Returned

Bins of Amount Sent by First Movers (out of 80 Tokens)

Returned/Received

29 42 40 39 48 43

(d) DG - Amount Sent

Percentiles of the RF Task Distribution (Wilcoxon tests, * < 0.1, ** < 0.05)

* * ** * ** *

35th 30th 25th 20th 15th 10th

(e) UG - Amount Sent

(f) UG - Acceptance Threshold

8 ** **

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

The Elicitation TaskOne concern with the stop light task is that it is too noisy becauseindividuals might follow the rule out of concern that their “littleman” will be hit by a car, e.g.

We want a “culture-free” norm task, so we designed a new one:

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Dictator Game

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Preliminary DataRF - Percent Rule-Following

Balls Allocated to Blue (out of 100)

Frequency

0 20 40 60 80 1000

DG - Amount Given

Balls Allocated to Other (out of 100)

Frequency

0 20 40 60 80 100

Spearman’s test of rank correlation, ρ = 0.41, p-value < 0.01, N=44.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Preliminary DataRF - Percent Rule-Following

Balls Allocated to Blue (out of 100)

Frequency

0 20 40 60 80 1000

DG - Amount Given

Balls Allocated to Other (out of 100)

Frequency

0 20 40 60 80 100

Spearman’s test of rank correlation, ρ = 0.41, p-value < 0.01, N=44.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Measuring Norms

We can directly elicit beliefs about the norm with the Krupka &Weber (2013) task

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Testing Implication (2)

We construct framed variants of the dictator and ultimatum gamesmeant to manipulate norms.

We measure norms and behavior in a between-subject design.

We test whether induced changes in norms can explain observedchanges in behavior across frames.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Give and Take Dictator Games

Give TakeWe also have a “give-take” treatment in which half the balls areinitially allocated to each bucket.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Can We Alter Norms?

Dictator's Payoff/Dictatee's Payoff

$15/$0 $12/$3 $9/$6 $6/$9 $3/$12 $0/$15

teInappropriate

Appropriate

GiveDG

TakeDG

Give_TakeDG

Unfortunately, these manipulations did not substantially alter thenormative profile, although there are minor differences at the veryselfish actions.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

A Replication

Our treatment fails the manipulation check, but:

(a) RF Task

% Rule-Following

Frequency

0 20 40 60 80 100

0 5 10 150.0

(b) Dictator Game

$ Sent

Rule-FollowersRule-Breakers

We replicate the relationship between RF and DG giving(Spearman’s ρ = 0.36, p-value < 0.01., N=186)

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Omission vs. Commission

We introduce two frames of the UG, using a graphical manipulation:1 2

Omission: Do I fill the tank?

Commission: Do I drain the tank?

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Elicited NormsHere our norms data pass the manipulation check:

(a) Proposers

Proposer's Share/Responder's Share

100/0 80/20 60/40 40/60 20/80 0/100

teInappropriate

Appropriate

teOmissionCommission

(b) Responders

Proposer's Share/Responder's Share

100/0 80/20 60/40 40/60 20/80 0/100

Omission (Don't Fill)Commission (Drain)

The model implies that players 1 in the Omission treatment(divide-the-not-yet-created-pie) should make offers in the 50/50 rangemore frequently to avoid the relatively greater likelihood of rejection.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Preliminary Results

There is more clustering at the normative 50/50 split in thedivide-the-pie version (permutation test, p-value = 0.02, N=71).

(a) 0-Frame

Amount Kept

25 50 75 100

(b) x-Frame

Amount Kept

Density

25 50 75 100

Regression analysis indicates that players’ response to a questionabout the rejection threshold of player 2 is a significant predictor ofamount sent, only for the empty tank case (p-value = 0.049,two-sided test).

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

The norm (rule) followingframework

What does it buy us to think about individuals in terms of a model ofdisutility from norm violation?

� This can explain many “context effects” in games that aren’taccounted for by simple models of (social) preferences (e.g.Dictator, Ultimatum games)

� Different contexts activate different normative benchmarks(fairness/equity, reciprocity, winner-take-all)

� Thus it is not an “error” or “irrationality” if people exhibitprosocial behavior in some contexts and not in others.

� Ex: Forsythe et al. (1994); Hoffman et al. (1994); Hoffman etal. (1996); Cherry et al. (2002); List (2007)

� But not everyone cares about norms to the same degree, sothere’s still heterogeneity.

� It could also explain cross-cultural differences. The normassociated with a particular context may vary across cultures.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

� Social preference models can be thought of as a special case ofnorm-following, where the norm is pro-social.

� Note that social preference models also rely on norms. They aresimply implicit in the form of preferences specified. Our modelmakes this connection explicit.

Erik O.Kimbrough,

Vostroknutov

Introduction

PreviousEvidence

A New Design

RF Task

Norm Elicitation

Dictator Games

UltimatumGames

Discussion

� Social preference models can be thought of as a special case ofnorm-following, where the norm is pro-social.

� Note that social preference models also rely on norms. They aresimply implicit in the form of preferences specified. Our modelmakes this connection explicit.

Norms, Frames and Prosocial Behavior in Games - ETH Z · Norms, Frames and Prosocial Behavior in...

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