The Other Side of the Coin: Recipient Norms and Their Impact on Indirect Reciprocity and Cooperation

TL;DR

This paper investigates how recipient reputation updating influences cooperation in a donation game, revealing a trade-off between cooperation levels and stability, affected by social norms and gossip group dynamics.

Contribution

It introduces a time-scale parameter for updating recipient reputations and analyzes its impact on cooperation and stability under different social norms.

Findings

Forgiving norms increase cooperation but are vulnerable to defectors.

Unforgiving norms reduce cooperation but resist defector invasion.

Gossip groups influence the evolution of generous versus strict norms.

Abstract

Human cooperation depends on indirect reciprocity. In this work, we explore the concept of indirect reciprocity using a donation game in an infinitely large population. In particular, we examine how updating the reputations of recipients influences cooperation. Our work adds a time-scale parameter for updating donor and recipient reputations. We find a trade-off between the level of cooperation and evolutionary stability influenced by social norms. `Forgiving' recipient norms enhance cooperation but increase susceptibility to defectors, whereas `unforgiving' norms reduce cooperation but defend against invasion by defectors. Expanding to include gossip groups allows us to analyze the evolutionary dynamics of the time-scale parameter, identifying `generous' norms that support cooperation, and `strict' norms that discourage such generosity, ultimately showing vulnerability to defector invasions and potential cooperation collapse.