Endogenous Horizon Information Choices in Repeated Prisoner's Dilemma

Last registered on August 22, 2025
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Pre-Trial

Trial Information

General Information

Title
Endogenous Horizon Information Choices in Repeated Prisoner's Dilemma
RCT ID
AEARCTR-0016185
Initial registration date
August 20, 2025

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
August 22, 2025, 5:59 AM EDT

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

Last updated
August 22, 2025, 9:59 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.

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Primary Investigator

Name
Wenbo Zou
Affiliation
Nankai University, Tianjin, China
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Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2025-09-01
End date
2026-06-30
Keywords
Behavior, Lab
Additional Keywords
JEL code(s)
C72, C73, C92.
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We investigate whether individuals choose to forego horizon information when its availability is endogenously determined in repeated prisoner’s dilemma games. Theoretically, avoiding horizon information preserves the structure of an indefinitely repeated game—rather than a finitely repeated one—thereby potentially supporting cooperative equilibrium. We test this prediction in a laboratory experiment that also includes exogenous finite and indefinite treatments for comparisons.
External Link(s)

Registration Citation

Citation
Zou, Wenbo. 2025. "Endogenous Horizon Information Choices in Repeated Prisoner's Dilemma." AEA RCT Registry. August 22. https://doi.org/10.1257/rct.16185-1.1
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
The intervention concerns the availability of horizon information in repeated prisoner's dilemma.
Intervention Start Date
2025-09-01
Intervention End Date
2026-06-30

Primary Outcomes

Primary Outcomes (end points)
Information acquisition choices, and cooperation in repeated game.
Primary Outcomes (explanation)
We examine four measures of information choices in the two endogenous treatments:

V1. Dummy variables of whether to avoid horizon information at the individual-supergame level;
V2. Percentage of supergames in which a player choose to avoid horizon information at the individual-level;
V3. Percentage of players choosing to avoid horizon information at the supergame level.
V4. Dummy variables of whether a player ever chooses to avoid information in any of the supergames at the individual level.

For V2 and V4, we also ask participant to recall their own choices and provide answers in the exit survey. We denote these two self-reported measures as SV2 and SV4.

We examine choices to cooperate or defect by each player in the following four forms:
C1. Dummy variable of cooperation in the first round at the individual-supergame level;
C2. Cooperation rates at the individual-supergame level: Percentage of rounds a player cooperates within a supergame;
C3. Cooperation rates at the individual level: Averaging C2 over all the supergames;
C4. Cooperation rates at the supergame level: Averaging C2 over all players within a treatment.

Regarding the mean value of C1 at the individual level, we also ask participant to provide an answer by recalling in the exit survey. We denote this self-reported measures as SC1.

Secondary Outcomes

Secondary Outcomes (end points)
Beliefs that the other player chooses to cooperate in the first round.
Secondary Outcomes (explanation)
The belief data will only be available for the last eight supergames.

In the two endogenous treatments, we collect three sets of four belief variables regarding whether the other player cooperates in the first round in each supergame:
B1. Belief conditional on no horizon information;
B2.1. Belief conditional on no horizon information and the other player choosing to acquire horizon information in the two endogenous treatments;
B2.2. Belief conditional on no horizon information and the other player choosing to avoid horizon information in the two endogenous treatments.
B3. Belief conditional on revealed horizon information.

In the two exogenous treatments, we collect the unconditional belief.

Experimental Design

Experimental Design
We adopt a between-subject design of four treatments that differ in the availability of horizon information: the (exogenously) Finite treatment, the (exogenously) Indefinite treatment, and two endogenous treatments.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer
Randomization Unit
Experimental sessions.
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
16 experimental sessions.
Sample size: planned number of observations
272 laboratory participants.
Sample size (or number of clusters) by treatment arms
68 laboratory participants in each treatment.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB

Institutional Review Boards (IRBs)

IRB Name
Nankai University, Institutional Review Board (IRB)
IRB Approval Date
2025-07-02
IRB Approval Number
NKUIRB2025132
Analysis Plan