Altruistic behavior often comes at a personal cost, but there are also benefits. The person you help might return the favor directly — tit-for-tat. Or, people might talk about your good deeds, and reciprocity could come via a third party. In a recent paper in Evolution and Human Behavior, SFI Graduate Fellow Victor Odouard and former Applied Complexity Fellow Michael Price explore the communication systems necessary to sustain indirect reciprocity.

The authors propose three conditions that can maintain stable, truthful communication. First, the norm is self-consistent: it rewards the behaviors it prescribes. Second, the communication system should be used for disseminating information about both the altruism of actions and the truthfulness of communication. Third, people can make mistakes — and those errors can create stability by introducing diversity.  

“As institutions, legal systems, and governments develop, the role of the third party, and therefore, communication, only increases,” the authors write. “It is therefore vital to understand how a communication system maintaining all of this social information could possibly be stable.”

Read the paper “Tit for tattling: Cooperation, communication, and how each could stabilize the other” in Evolution and Human Behavior (July 2023). doi.org/10.1016/j.evolhumbehav.2023.06.002