Co-action provides rational basis for the evolutionary success of Pavlovian strategies

TL;DR

This paper demonstrates that considering symmetry through a co-action perspective provides a rational foundation for Pavlovian strategies, promoting cooperation in the Iterated Prisoner's Dilemma and Public Goods games.

Contribution

It introduces a co-action framework that explains the emergence of Pavlovian strategies as rational outcomes in symmetric repeated interactions.

Findings

Co-action solutions correspond to Pavlov strategies in 2-player IPD.

In multi-player Public Goods games, cooperators outnumber defectors at equilibrium.

Co-action strategies enable robust cooperation through symmetry awareness.

Abstract

Strategies incorporating direct reciprocity, e.g., Tit-for-Tat and Pavlov, have been shown to be successful for playing the Iterated Prisoners Dilemma (IPD), a paradigmatic problem for studying the evolution of cooperation among non-kin individuals. However it is an open question whether such reciprocal strategies can emerge as the rational outcome of repeated interactions between selfish agents. Here we show that adopting a co-action perspective, which takes into account the symmetry between agents - a relevant consideration in biological and social contexts - naturally leads to such a strategy. For a 2-player IPD, we show that the co-action solution corresponds to the Pavlov strategy, thereby providing a rational basis for it. For an IPD involving many players, an instance of the Public Goods game where cooperation is generally considered to be harder to achieve, we show that the cooperators always outnumber defectors in the co-action equilibrium. This can be seen as a generalization of Pavlov to contests involving many players. In general, repeated interactions allow rational agents to become aware of the inherent symmetry of their situation, enabling them to achieve robust cooperation through co-action strategies - which, in the case of IPD, is a reciprocal Pavlovian one.