Source-sink cooperation dynamics constrain institutional evolution in a group-structured society

TL;DR

This paper models how cooperation and institutions co-evolve in group-structured societies, revealing that global cooperation spread can lead to institutional free-riding, which constrains institutional evolution and impacts social change.

Contribution

It introduces a model linking behavior and institutions in society, highlighting source-sink dynamics and the limits of institutional evolution due to cooperation diffusion.

Findings

Cooperation and institutions mutually reinforce each other.

Behavioral source-sink dynamics can boost non-institutional groups.

Global cooperation spread can limit the evolution of beneficial institutions.

Abstract

Societies change through time, entailing changes in behaviors and institutions. We ask how social change occurs when behaviors and institutions are interdependent. We model a group-structured society in which the transmission of individual behavior occurs in parallel with the selection of group-level institutions. We consider a cooperative behavior that generates collective benefits for groups but does not spread between individuals on its own. Groups exhibit institutions that increase the diffusion of the behavior within the group, but also incur a group cost. Groups adopt institutions in proportion to their fitness. Finally, cooperative behavior may also spread globally. As expected, we find that cooperation and institutions are mutually reinforcing. But the model also generates behavioral source-sink dynamics when cooperation generated in institutional groups spreads to non-institutional groups, boosting their fitness. Consequently, the global diffusion of cooperation creates a pattern of institutional free-riding that limits the evolution of group-beneficial institutions. Our model suggests that, in a group-structured society, large-scale change in behavior and institutions (i.e. social change) can be best achieved when the two remain correlated, such as through the spread successful pilot programs.