Reviving, Reproducing, and Revisiting Axelrod's Second Tournament

This repository contains the code and manuscript source files for the project Reviving, Reproducing, and Revisiting Axelrod's Second Tournament.

The project reproduces Robert Axelrod’s second Iterated Prisoner’s Dilemma tournament, originally run in the early 1980s, using the original Fortran implementations of the submitted strategies. It uses Axelrod-Python and TourExec to run the computer tournament simulations.

A preprint of this work is available at: https://arxiv.org/abs/2510.15438.

Requirements

• Install TourExec (see installation instructions in that repository).
• You will also need Python.

Setting up the Environment

To install all necessary Python dependencies, we recommend creating a conda environment using the provided configuration file src/environment.yml. From the root of this repository run:

conda env create -f src/environment.yml
conda activate axelrod_tournament

Source Code

• The code for generating and reproducing the original tournaments is located in the src/ directory.

• It includes:

  • Tournament execution scripts to reproduce Axelrod’s results.
  • Analysis scripts and Jupyter notebooks for generating all figures used in the manuscript.

To rerun the original tournaments, refer to the documentation in src/.

Data

Running the simulations will generate the tournament data.

If you prefer not to rerun the entire simulation, you can download the archived data from Zenodo:

1. Download the dataset archive from https://doi.org/10.5281/zenodo.20811704.
2. Unzip it into the data/ folder.

This will allow you to reproduce the analysis and figures directly.

Analysis and Figures

All data analysis and manuscript figures were generated using Python and Jupyter notebooks, available under src/.

If you have downloaded the archived data, you can simply open and run the notebooks to reproduce all figures without rerunning the full simulations.