Reputation

In the prisoner’s dilemma, the rational choice is to always defect. By doing so, regardless of your partner’s decision, you end up with the better of two outcomes.

There is a very subtle caveat here, which has changed the way I approach relationships. Defecting is only optimal if there is a single trial. That is, if you only play the prisoner’s dilemma once and never again (at least with the same person), you should always defect.

The game changes entirely if there are multiple trials. If you enter the dilemma repeatedly with the same person, the optimal strategy is now to always cooperate. This is true regardless of your partner’s decision. Even more, if you stick to cooperating, even if your partner initially defects, they too will realize their ideal choice is to cooperate in the next round.

This is all based on a hypothetical situation. This dilemma does, however, shed light on how your actions do not always exist in a vacuum. I like to think of this as reputation in the abstract sense. Being the defector in the prisoner’s dilemma suggests a “single trial” mentality, whereas by consistently cooperating across multiple rounds you will build a positive reputation, after which even your partner will realize there is no better choice but to cooperate as well.