What is a non-zero sum game?

A non-zero sum game is a concept from game theory where the fortunes of participants are interdependent, meaning that it is possible for all players to either win or lose together, rather than one party's gain being equivalent to another's loss (as in zero-sum games).

For example, when players are on the same side in tennis doubles, their successes or failures are shared, which is a non-zero sum relationship 1 2. This contrasts with sports like singles tennis, where one player's win is another's loss 1.

In the broader context of society and evolution, non-zero sum games are crucial because they foster cooperation and innovation, benefiting all parties involved. Historically, societies have become more integrated and interdependent through the discovery and facilitation of non-zero sum games, enhancing overall progress and complexity 3 4.