How a norm-nudge affects group decisions in a social dilemma experiment

Last registered on March 09, 2020

View Trial History

Pre-Trial

Trial Information

General Information

Title

How a norm-nudge affects group decisions in a social dilemma experiment

RCT ID

AEARCTR-0005542

Initial registration date

March 08, 2020

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published

March 09, 2020, 7:47 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

Country

Tanzania, United Republic of

Region

Lake Victoria

Primary Investigator

Name

Florian Diekert

Affiliation

Heidelberg University

Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status

In development

Start date

2020-03-09

End date

2020-12-31

Keywords

Environment & Energy

Additional Keywords

Lab-in-the-field, Collective action, Natural resources

JEL code(s)

C72, C92, D7, Q22

Secondary IDs

Abstract

Research that leverages social norms to induce desirable behaviour has generally studied norm-based interventions when decisions are made by individuals. However, in reality decisions are often made by groups. This is particular true for natural resource use in developing countries.
With our experiment, we aim to build a bridge between the lab and the field to inform policy makers whether a norm-nudge could improve resource management at Lake Victoria, Tanzania.
We study the effect of norm-nudges by varying whether participants are given social information about past behavior of other groups.
Groups in our experiment are recruited from fishing crews.
At Lake Victoria, there are two relevant forms of decision making on board.
Decisions are either made by all crew members together (majority) or by a captain (representative).
Thus, we study the effect of a norm-nudge both when group action is determined by majority, or by a randomly selected representative.

External Link(s)

Registration Citation

Citation

Diekert, Florian. 2020. "How a norm-nudge affects group decisions in a social dilemma experiment." AEA RCT Registry. March 09. https://doi.org/10.1257/rct.5542-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2020-03-09

Intervention End Date

2020-04-06

Primary Outcomes

Primary Outcomes (end points)

Average cooperation by teams in a repeated two-team prisoner's dilemma experiment. Binary choice set.

Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

The experiment is a repeated two-team prisoner's dilemma game with disapproval. The prisoner's dilemma is played with a binary choice set, framed as a decision to take points from a collective account or to leave points in a collective account. Three participants play together in a team. Two teams form a collective and share an account with eight points. Both teams can either take four points from the collective account (defect) or leave the points in the collective account (cooperate). Moves are made simultaneously. The remaining points increase and are then distributed equally. For four points left in the collective account, both teams receive three points, i.e. a marginal per agent return of 0.75.
Our treatment variation crosses an empirical norm nudge with two forms of group decision making processes. We first vary whether participants are given social information about past behaviour of other groups. Second, we impose that group decisions are either determined by a majority or by a randomly chosen representative.

Experimental Design Details

Randomization Method

By design

Randomization Unit

Experimental sessions

Was the treatment clustered?

Yes

Experiment Characteristics

Sample size: planned number of clusters

36 experimental sessions

Sample size: planned number of observations

336 groups decisions

Sample size (or number of clusters) by treatment arms

13 sessions in majority treatment with social information
13 sessions in majority treatment without social information
5 sessions in representative treatment with social information
5 sessions in representative treatment without social information

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Supporting Documents and Materials

IRB