# Evolutionary branching and consistency in human cooperation: the interplay of incentives and volunteerism in addressing collective action dilemmas

**Authors:** Alina Glaubitz, Feng Fu  
**arXiv:** [2303.01622](https://arxiv.org/abs/2303.01622)  
**Date:** 2023-03-02  
**Summary page:** https://www.summarizepaper.com/en/paper/2303.01622v1/

## Key points

- Understanding the origins of volunteerism and free-riding is crucial in collective action situations
- Theoretical mechanisms behind successful collective action have remained largely elusive
- Study by Alina Glaubitz and Feng Fu investigates evolutionary dynamics of individual cooperativity levels in multi-round threshold public goods games
- Rewarding consistent cooperators leads to emergence of two distinct populations: volunteers and free-riders
- Punishing consistent defectors does not result in similar evolutionary branching
- Insights from the study can be used to design effective interventions for promoting collective action and addressing collective risk dilemmas
- Incentives and rewards play a key role in encouraging cooperation among individuals and mitigating free-riding tendencies

## Summary

In collective action situations where a sufficient number of cooperators is necessary to achieve shared benefits, understanding the origins of volunteerism and free-riding is crucial. This applies to various scenarios, including vaccination campaigns and social change movements. However, the theoretical mechanisms behind attaining behavior consistency for successful collective action have remained largely elusive. In this study, conducted by Alina Glaubitz and Feng Fu, the authors address this issue by investigating the evolutionary dynamics of individual cooperativity levels in multi-round threshold public goods games. Using adaptive dynamics, the researchers explore how individual behavior responses are shaped by incentives, both with and without rewards or punishment. The findings reveal that rewarding consistent cooperators can lead to the emergence of two distinct populations: volunteers who consistently cooperate and free-riders who consistently defect. On the other hand, punishing consistent defectors does not result in similar evolutionary branching. These results provide valuable insights into designing effective interventions that promote collective action and address collective risk dilemmas such as climate mitigation and pandemic control. By understanding the interplay between incentives and volunteerism in addressing these dilemmas, policymakers and organizations can develop strategies to encourage cooperation among individuals and mitigate free-riding tendencies. Overall, this research contributes to our understanding of human cooperation dynamics in collective action situations. It highlights the importance of considering incentives and rewards when designing interventions aimed at promoting cooperative behavior.