"Prosocial behavior: a tale of two images"

Last registered on May 16, 2022


Trial Information

General Information

"Prosocial behavior: a tale of two images"
Initial registration date
May 16, 2022

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
May 16, 2022, 5:22 PM EDT

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



Primary Investigator

Sciences Po

Other Primary Investigator(s)

PI Affiliation
Sciences Po
PI Affiliation

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The aim of this paper is to study the linkages between self and social image. Our framework introduces two new elements. First, players can either (i) strategically choose the criterion based on which they will judge their own actions or (ii) decide to ignore all moral dimensions and pay for blindness. Second, and most importantly, we link self-image to social-image by imposing a coherence principle between the way self-image is calculated and the way other people’s actions are judged: individuals use the same criterion to judge themselves and others. The benefit of this coherence motive can be microfounded by the cost documented in the literature in social psychology of being perceived as a hypocrite, as well as the willingness of people to avoid cognitive dissonance induced by behaving inconsistently. We test the predictions of our model in the context of a dictator game experiment with passive observers. The main treatment is a game in which observers are themselves active and need to take the action they judge before sending their evaluation of the behaviour of the dictators. The change in observers’ evaluations allows to test the coherence principle, while the change in dictator’s behavior provides empirical evidence on whether such a change in social image is internalized.
External Link(s)

Registration Citation

Galbiati, Roberto, EMERIC HENRY and Nicolas Jacquemet. 2022. ""Prosocial behavior: a tale of two images"." AEA RCT Registry. May 16. https://doi.org/10.1257/rct.9449
Sponsors & Partners

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Experimental Details


We have 5 treatments
T1 donation without observers
T2 donation with passive observers
T3 donation with active observers
O1 passive observers
O2 active observers
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The main outcome of interest is the level of donation by treatment
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes are the excuses used by those who don't donate and the evaluations of the actions of the others
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Recruitment and Pool of participants
The experiment will be run online. We will use the services of Foule Factory, a firm that gives us access to a pool of participants. Subjects first respond to a survey on socio-demographic characteristics. After the survey, subjects will be divided into two groups, the “observers” and the “observed”. The observed will be asked to decide whether they want to transfer a large sum (100 euro) to an NGO (whose identity will be revealed at the end of the experiment) or to keep a smaller amount for themselves (the actual choices will be implemented with some probability). The choice will be implemented with a 5% probability.
Donation decision
Before making the decision, the participants will be allocated to one of three experimental conditions:
T1 in which their actions are observed by no-one
T2 in which the observed are told their actions will be observed by individuals (the observers), who will evaluate their moral conduct and whose rating will subsequently be transmitted to them
T3 same setting as in T2 except that the observed are told that the observers will play exactly the same game as them before evaluating their moral conduct
In both T2 and T3, the observed will have to see the rating they received from the observers before being able to obtain their payment.

The observers are accordingly allocated to either of the two treatments (there are no observers in T1):
- in T2 they simply have to rate the behavior of the observed on a morality scale (Passive observers).
- while in T3 they play the same game as the observed before rating the behavior of the observed (Active observers)
Experimental Design Details
Randomization Method
random allocation to treatments (rotation done by the computer)
Randomization Unit
individual level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
1500 individuals
Sample size: planned number of observations
1500 individuals
Sample size (or number of clusters) by treatment arms
300 by treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials