Evolutionary games and spatial periodicity

TL;DR

This paper develops a theoretical framework for understanding the long-term behavior of spatial evolutionary games under strong selection, revealing conditions for cyclic or stable outcomes and explaining complex spatial patterns.

Contribution

It introduces a rigorous mathematical framework for analyzing spatial game dynamics under strong selection, applicable to various game types and extending to aspiration dynamics.

Findings

Strategies tend to cycle or stabilize under strong selection.

Spatial patterns persist and evolve over generations.

Framework applies to multiple game types and dynamics.

Abstract

We establish a theoretical framework to address evolutionary dynamics of spatial games under strong selection. As the selection intensity tends to infinity, strategy competition unfolds in the deterministic way of winners taking all. We rigorously prove that the evolutionary process soon or later either enters a cycle and from then on repeats the cycle periodically, or stabilizes at some state almost everywhere. This conclusion holds for any population graph and a large class of finite games. This framework suffices to reveal the underlying mathematical rationale for the kaleidoscopic cooperation of Nowak and May's pioneering work on spatial games: highly symmetric starting configuration causes a very long transient phase covering a large number of extremely beautiful spatial patterns. For all starting configurations, spatial patterns transit definitely over generations, so cooperators and defectors persist definitely. This framework can be extended to explore games including the snowdrift game, the public goods games (with or without loner, punishment), and repeated games on graphs. Aspiration dynamics can also be fully addressed when players deterministically switch strategy for unmet aspirations by virtue of our framework. Our results have potential implications for exploring the dynamics of a large variety of spatially extended systems in biology and physics.