Complexity and Preferences

Last registered on September 21, 2026
View Trial History

Pre-Trial

Trial Information

General Information

Title
Complexity and Preferences
RCT ID
AEARCTR-0019085
Initial registration date
September 16, 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
September 21, 2026, 10:18 AM EDT

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

Locations

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information

Primary Investigator

Name
Simon Weidenholzer
Affiliation
University of Essex
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Andrea Albertazzi
PI Affiliation
IMT Lucca
Contact Investigator
PI Name
Paolo Pin
PI Affiliation
University of Siena
Contact Investigator
PI Name
Dennie Van Dolder
PI Affiliation
University of Essex
Contact Investigator

Additional Trial Information

Status
In development
Start date
2026-09-16
End date
2026-12-31
Keywords
Behavior
Additional Keywords
Preferences, Complexity
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This within-subject Prolific experiment investigates how cognitive complexity drives choices over lotteries and so-called deterministic mirrors. The experiment comprises two blocks. In the first, replicating Oprea (2024), subjects choose between certain rewards, lotteries, and deterministic mirrors using multiple price lists. In the second, subjects encounter the same objects but are instead asked to provide the expected value of the lottery or the absolute value of the deterministic mirror and are paid based on accuracy. Within this block, we elicit five complexity measures—number of mistakes, deviations from the correct answer, confidence, decision times, and willingness-to-accept complexity costs to avoid doing the task—across three conditions: lotteries, deterministic mirrors, and a simple benchmark. We examine how complexity differs across these tasks, assess individual consistency across measures, and use these metrics to understand choices as a result of complexity and preferences. Finally, we test whether block order produces learning effects.
External Link(s)

Registration Citation

Citation
Pin, Paolo et al. 2026. "Complexity and Preferences." AEA RCT Registry. September 21. https://doi.org/10.1257/rct.19085-1.0
Sponsors & Partners

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information
Experimental Details

Interventions

Intervention(s)
Subjects participate in an incentivized online decision-making study on Prolific. In a within-subject design, we elicit subject preferences over probabilistic lotteries and corresponding deterministic mirrors. We also assess subjects’ abilities to solve such tasks by asking them to correctly compute the expected value (for lotteries) or absolute value (for deterministic mirrors) and elicit several measures of task-specific complexity and individuals’ ability to deal with complexity. Our design aims at understanding the role of complexity and preferences in choice.
Intervention Start Date
2026-09-16
Intervention End Date
2026-12-31

Primary Outcomes

Primary Outcomes (end points)
Absolute Deviations from Expected Value in Choosing Block and in Comparison Block, Number of Mistakes in Choosing Block, Confidence Levels, Decision Times, and Complexity Costs
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment is conducted on the online platform Prolific using a within-subjects design. Subjects receive a participation fee and a chance of receiving a bonus payment depending on their choices in the experiment.
The experiment encompasses two main blocks (the order of which will be randomized):
• Choosing Block: Replicates the experimental framework of Oprea (2024). Subjects use Multiple Price Lists (MPLs) to make choices involving lotteries and deterministic mirrors across varying parameters. Subjects are paid according to their choices in these tasks.
• Comparison Block: Consists of two parts and provides several individual measures of subjects’ ability to deal with complexity across different complexity conditions (including a cognitively low-demanding simple anchor condition). In Part 1, subjects make comparisons, and payment depends on making correct choices. In Part 2, subjects participate in a Becker, DeGroot, & Marschak (BDM) slider task to elicit complexity costs.
At the end of the experiment, we administer a a 3-question Cognitive Reflection Test and a questionnaire that collects age, gender, and student status.

Experimental Design Details
Not available
Randomization Method
On the fly by the software.
Randomization Unit
Order in which individuals encounter tasks will be randomized at the individual level.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
400 subjects
Sample size: planned number of observations
400 subjects
Sample size (or number of clusters) by treatment arms
200 subjects encounter Choosing Block first
200 subjects encounter Comparison Block first
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
University of Essex Ethics Review Application and Management System (ERAMS)
IRB Approval Date
2026-07-21
IRB Approval Number
ETH2526-1451
Analysis Plan