Complexity and Higher-order Rationality: an Experimental Study

Last registered on April 02, 2024


Trial Information

General Information

Complexity and Higher-order Rationality: an Experimental Study
Initial registration date
March 31, 2024

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 02, 2024, 12:49 PM EDT

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


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Primary Investigator

University of Edinburgh

Other Primary Investigator(s)

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
We study how the complexity of games influences subjects' higher-order rationality. Our approach involves employing the ring game to gauge an individual's rationality level, with the game’s complexity varied to examine the potential causal relationship between game complexity and subjects' higher-order rationality. This study is particularly focused on three main sources of complexity: the structure of the game, the number of zero payoffs within the payoff matrices, and the salience of iterative strategies and dominant strategies in the ring game. Instead of playing with other human players, participants will play with computer-controlled players, which are pre-programmed to always maximize their achievable payoffs and act as equilibrium players. This setup ensures that any reflection on the depth of subjects' thinking is primarily influenced by the game's inherent complexity, rather than their perceptions of how other players might respond to varying levels of complexity. As the study progresses, we aim to compare different methods of measuring complexity, including ex-ante approaches like the subjective rating of games, as well as ex-post methods that consider reaction times and error rates.
External Link(s)

Registration Citation

Li, Jiaying. 2024. "Complexity and Higher-order Rationality: an Experimental Study." AEA RCT Registry. April 02.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Our outcome variables are subjects' identified levels in each game, reaction times, and cognitive reflection test scores.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We vary the complexity across ring games. We will consider the following factors that affect complexity:
1. The structure of the game, including variations in the game grid (e.g., 3x3 and 5x5 designs).
2. The number of zero payoffs within the payoff matrices.
3. The salience of iteration and dominant strategy in the ring game.

During the experiment, subjects first read the instructions and must pass a comprehension test to continue. This ensures they understand how to interpret the payoff matrices of the ring games. They will then play 18 different ring games followed by 4 cognitive reflection tests. Finally, they are asked to complete an anonymized questionnaire that gathers demographic information, including age, gender, and field of study.
Experimental Design Details
Not available
Randomization Method
Subjects will be randomly assigned to different order of treatment.
Randomization Unit
We randomize at the individual level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
120 individuals (or more, as budget allows)
Sample size: planned number of observations
120 individuals (or more, as budget allows)
Sample size (or number of clusters) by treatment arms
120 individuals (or more, as budget allows)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
School of Economics Ethics Sub-Committee (Research) at University of Edinburgh
IRB Approval Date
IRB Approval Number