Analyzing learning under ambiguity

Last registered on September 02, 2021


Trial Information

General Information

Analyzing learning under ambiguity
Initial registration date
September 01, 2021

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
September 02, 2021, 11:06 AM EDT

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



Primary Investigator

Paderborn University

Other Primary Investigator(s)

PI Affiliation
Oxford Brookes Business School

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project aims to better understand under which conditions people use social information to learn and imitate others. In many situations, people can either follow their own signals or follow a social signal. Depending on the quality of the signals one might be more informative than the other. We are interested in what happens if both the private and the social signals become less informative. In the real world, this can be the case in situations where information is ambiguous. This paper investigates whether people in such situations are more likely to follow the social signal. To answer this question we conduct an experimental study that observes whether people are prone to imitate in a risky or in an ambiguous environment.
External Link(s)

Registration Citation

Bopp, Fabian and Sara Le Roux. 2021. "Analyzing learning under ambiguity." AEA RCT Registry. September 02.
Experimental Details


In the study, we vary the degree of ambiguity in a binary choice. By doing this we create an ambiguous environment and a risk environment and observe the environmental effects on social learning. To create an ambiguous environment, we vary the presentation of lottery tickets, which are at the core of the experiment.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Revision after learning the majority choices in the group. (Revise/ Not revise)
Primary Outcomes (explanation)
Subjects make a binary choice between two options. We are interested in whether they revise their choice more likely depending on the environment.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Subjects have to repeatedly make a choice between two lotteries. We use the lottery design of Cooper and Rege (2011) as a graphical illustration of a lottery. In our study, the lotteries differ in the characteristic. Our intervention is the level of ambiguity. In an unambiguous environment, the characteristics of the lottery tickets are fairly easy to observe. In an ambiguous environment, the characteristics are harder to learn. After deciding on one of the tickets subjects learn what other subjects in their group have done and can revise the decision. This allows us to observe, whether subjects use this group information for social learning and revise their choice and whether this behavior is affected by the level of ambiguity in the environment,
Experimental Design Details
Randomization Method
Randomization of the treatments is done on an individual level by the computer.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
1 (not clustered)
Sample size: planned number of observations
420 subjects
Sample size (or number of clusters) by treatment arms
Half of the subjects in each treatment arm. =210 individuals
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Ethics commission (Paderborn University)
IRB Approval Date
IRB Approval Number


Post Trial Information

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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