Research
• Updated
17 January 2025
IJN
ESC

Institutions: tools for solving the challenges of cooperation

Institutions are vital to human societies, yet they rest on a paradox: designed to foster cooperation, they themselves rely on the cooperation of their members. As the Roman poet Juvenal once asked, "Who will guard the guards themselves?" An interdisciplinary team combining evolutionary biology and social sciences has tackled this question in a recent study published in PNAS.


 

Institutions are the backbone of our societies. They encourage us to act for the common good by rewarding altruistic behavior and punishing wrongdoing. Thanks to them, strangers can come together to protect shared resources or uphold sophisticated mechanisms like the rule of law.

Yet institutions rest on a paradox: while designed to promote cooperation, they cannot function without it. If their members prioritize personal gain or succumb to corruption, institutions fail. How, then, can institutions foster cooperation when they depend on it?

Using a mathematical model, researchers from the Max Planck Institute for Evolutionary Biology, the Institute for Advanced Studies in Toulouse, and the Jean Nicod Institute at ENS-PSL show that institutions work as social levers. Much like a physical lever amplifies force to lift heavy objects, institutions amplify a universal yet modest psychological force: the desire to maintain a good reputation. This mechanism creates a powerful incentive that drives individuals to cooperate far beyond what they might otherwise do.

Consider a forest ranger tasked with protecting a shared forest. Without oversight, each user has an incentive to exploit more than their fair share, leading to resource depletion and eventual destruction—an example of the tragedy of the commons. By appointing a ranger to monitor and sanction abuses, the community can avoid this fate. However, the solution hinges on the ranger’s integrity. A corrupt ranger who accepts bribes or misuses their authority would render the institution ineffective.

This is where reputation comes in. The ranger is more visible than any individual forest user, and their task is straightforward: protect the common good. Misconduct or abuse of power could cost them their job, status, and the trust of the community. In this way, the “forest ranger” institution is an ingenious piece of social engineering: the ranger’s simple concern for their reputation creates a ripple effect, encouraging the entire community to cooperate and preserve the forest.

institution
Institutions amplify the effects of reputation to tackle challenging cooperation problems. For example, appointing a forest ranger helps regulate the use of a shared forest. Driven by concern for their reputation, the ranger acts with integrity, which, in turn, motivates the community to cooperate and protect the forest.

Image credit: Icons (magnifying glass and forest) designed by Freepik - www.freepik.com.

Reference: J. Lie-Panis, L. Fitouchi, N. Baumard, J. André (2025). The social leverage effect: Institutions transform weak reputation effects into strong incentives for cooperation, Proc. Natl. Acad. Sci. U.S.A. 121 (51) e2408802121, doi:10.1073/pnas.2408802121