A Mutation Threshold for Cooperative Takeover

TL;DR

This paper uses agent-based modeling of the iterated prisoner's dilemma to identify a mutation threshold that promotes the emergence of cooperation, crucial for understanding the origin of life.

Contribution

It introduces the concept of a mutation threshold that enables cooperative takeover, highlighting the role of simple strategies like Tit-for-Tat in early life evolution.

Findings

A mutation threshold exists that favors cooperation.

Cooperative takeover persists up to the error catastrophe.

Tit-for-Tat strategy is key in the emergence of cooperation.

Abstract

One of the leading theories for the origin of life includes the hypothesis according to which life would have evolved as cooperative networks of molecules. Explaining cooperation$-$and particularly, its emergence in favoring the evolution of life-bearing molecules$-$is thus a key element in describing the transition from nonlife to life. Using agent-based modeling of the iterated prisoner's dilemma, we investigate the emergence of cooperative behavior in a stochastic and spatially extended setting and characterize the effects of inheritance and variability. We demonstrate that there is a mutation threshold above which cooperation is$-$counterintuitively$-$selected, which drives a dramatic and robust cooperative takeover of the whole system sustained consistently up to the error catastrophe, in a manner reminiscent of typical phase transition phenomena in statistical physics. Moreover, our results also imply that one of the simplest conditional cooperative strategies, "Tit-for-Tat", plays a key role in the emergence of cooperative behavior required for the origin of life.