Social imitation vs strategic choice, or consensus vs cooperation in the networked Prisoner's Dilemma

TL;DR

This study investigates how social imitation and strategic decision-making influence cooperation and consensus in a networked Prisoner's Dilemma, revealing that social imitation promotes uniformity and cooperation, with implications for understanding human social behavior.

Contribution

It introduces a model combining social and strategic updates in the Prisoner's Dilemma, showing how social imitation affects consensus and cooperation across different network structures.

Findings

Voter dynamics enhances consensus and cooperation.

Social imitation acts as interface noise, similar to random noise.

Mixed dynamics may explain moody conditional cooperation.

Abstract

The interplay of social and strategic motivations in human interactions is a largely unexplored question in collective social phenomena. Whether individuals' decisions are taken in a pure strategic basis or due to social pressure without a rational background crucially influences the model outcome. Here we study a networked Prisoner's Dilemma in which decisions are made either based on the replication of the most successful neighbor's strategy (unconditional imitation) or by pure social imitation following an update rule inspired by the voter model. The main effects of the voter dynamics are an enhancement of the final consensus, i.e., asymptotic states are generally uniform, and a promotion of cooperation in certain regions of the parameter space as compared to the outcome of purely strategic updates. Thus, voter dynamics acts as an interface noise and has a similar effect to a pure random noise; furthermore, its influence is mostly independent of the network heterogeneity. When strategic decisions are made following other update rules such as the replicator or Moran processes, the dynamic mixed state found under unconditional imitation for some parameters disappears, but an increase of cooperation in certain parameter regions is still observed. Comparing our results with recent experiments on the Prisoner's Dilemma, we conclude that such a mixed dynamics may explain moody conditional cooperation among the agents.