Effect of Experience on Ingroup-Outgroup Discrimination

Last registered on April 01, 2026
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Pre-Trial

Trial Information

General Information

Title
Effect of Experience on Ingroup-Outgroup Discrimination
RCT ID
AEARCTR-0016163
Initial registration date
March 26, 2026

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
April 01, 2026, 9:59 AM EDT

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

Locations

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Primary Investigator

Name
Wendelin Schnedler
Affiliation
Paderborn University
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Other Primary Investigator(s)

PI Name
Christian Walter
PI Affiliation
Ghent University
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Additional Trial Information

Status
In development
Start date
2026-03-27
End date
2026-11-01
Keywords
Behavior, Crime, Violence, & Conflict, Governance, Lab
Additional Keywords
discrimination, experiment, ingroup favouritism, experience
JEL code(s)
C91, D91
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This study examines whether negative experiences in a coordination task with a specific outgroup member and positive experiences with a specific ingroup member affects the trust in other ingroup and outgroup members. This is done in a setting where the experience logically does not allow for any inferences about the other member's trustworthiness.
External Link(s)

Registration Citation

Citation
Schnedler, Wendelin and Christian Walter. 2026. "Effect of Experience on Ingroup-Outgroup Discrimination." AEA RCT Registry. April 01. https://doi.org/10.1257/rct.16163-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We vary whether subjects have a postive experience with an ingroup and a negative experience with an outgroup member before they decide on how much to trust a different ingroup and a different outgroup member. In one treatment group, they have this experience before their trust decisions (With-experience) and in the other they have it after their decisions (Without-Experience).


Intervention Start Date
2026-03-27
Intervention End Date
2026-11-01

Primary Outcomes

Primary Outcomes (end points)
Trust difference between ingroup and outgroup members
Primary Outcomes (explanation)
Trust in the partner is measured with an incentivized slider. The slider position indicates how much an individual trusts an ingroup or outgroup member. The difference in the slider positions between ingroup and outgroup is the key outcome.

Secondary Outcomes

Secondary Outcomes (end points)
* Difference in self-reported identification with arbitrary ingroup or outgroup members
* Difference in non-incentivized self-assessed trust in the first encountered ingroup and an outgroup member
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We study whether experience with ingroup and outgroup members influences to what extent subjects discriminate between other ingroup and outgroup members.

All subjects go through a training phase. In this training phase, two groups are created. Subjects within each group are randomly allocated to the With-Experience and Without-Experience treatment.

In the With-Experience treatment, subjects experience a member of the ingroup and of the outgroup before deciding on how much to trust in a different ingroup and a different outgroup member.

In the Without-Experience treatment, subjects decide on how much they trust in an ingroup and outgroup measure before they experience another ingroup and outgroup member.

This allows us to measure the impact of experience with ingroup and outgroup members on trust.
Experimental Design Details
Not available
Randomization Method
Randomization is implemented by an algorithm when subjects enter the experiment. Each participant is randomly assigned to one of the two groups (BLUE or YELLOW) and independently to either the With-Experience or Without-Experience treatment and again independently to whether their first trust decison is with respect to an ingroup or outgroup member.
Randomization Unit
Individual

Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
600
Sample size: planned number of observations
600 (we will invite 800 participants but we expect only 75% of them to experience success with their ingroup and failure with their outgroup member, which is the experience that we are interested in).
Sample size (or number of clusters) by treatment arms
300 observations in the With-Experience treatment arm
300 observations in the Without-Experience treatment arm
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
For 300 observations in each treatment arm with the respective pattern, the minimal detectable effect size d for a one-sided two sample t-test with a significance level of 5% and a power of 90% is .239.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
German Association for Experimental Economic Research
IRB Approval Date
2025-09-09
IRB Approval Number
E74Evb2X
Analysis Plan

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