2026-07-01
Another new preprint (it has been a productive year!): "The Cooperation Ceiling: Extrinsic Population Dynamics and the Intrinsic Escape".
In evolutionary game theory, one of the main tools used for understanding the spread of behaviour is something called a population dynamic. This is a model of how individuals change over time. Some of these work in an extrinsic way: individuals look around and see how well others are doing and change their behaviour to match. Some of these work in an intrinsic way: individuals think about what would work for them.
In this paper, we show that for Social dilemmas (think Prisoners' Dilemma, Public Goods Game etc) extrinsic population dynamics have a ceiling of the amount of cooperation that can emerge. Importantly, this is not a ceiling for intrinsic processes.
There is a nice theorem with a rigorous proof showing this but other important contributions of this paper include a formal definition of an extrinsic population dynamic as well we a bunch of nice diagrams and plots.
@misc{foster2026cooperationceilingextrinsicpopulation,
title={The Cooperation Ceiling: Extrinsic Population Dynamics and the Intrinsic Escape},
author={Harry Foster and Vince Knight and Sebastian Krapohl},
year={2026},
eprint={2606.31740},
archivePrefix={arXiv},
primaryClass={cs.GT},
url={https://arxiv.org/abs/2606.31740},
}