An algorithmic approach to communicating reciprocal altruism in interstellar messages: Drawing analogies between social and astrophysical phenomena

Altruism has previously been proposed as a topic for interstellar communication, because it begins to describe one important class of human and non-human behaviors, and because it can be modeled in mathematical and physical terms. Prior research has focused on altruism toward close relatives. The current paper explains how we could communicate basic principles of reciprocal altruism, in which one entity undergoes short-term self-sacrifice for the benefit of another, as well as for long-term self-interest. After providing an algorithmic description of the loss of mass involved in the evolution of stars—a phenomenon that should be familiar to extraterrestrial astronomers—an analogous process is described at a human scale, where the maintenance or loss of mass represents the maintenance or loss of health, and ultimately life. An adaptation of the Prisoner's Dilemma game is communicated, showing limitations of both cooperation and defection as strategies for interacting with other agents. For the overall stability of a population, there are significant advantages for entities not always either cooperating or defecting in their responses; we end by modeling a more flexible strategy discussed by game theorists, known as Tit For Tat.