top of page

Prisoner's Dilemma

In this article I will be talking about the prisoner's dilemma game: what it is, how to play, and why it's important. To learn more about the prisoner's dilemma check out this video: The Prisoner's Dilemma

What it is! The rules are simple, let's say two people named Miss Red and Mr. Blue committed a crime but the police only have enough evidence to put them away for 1 year without any confession. So the police put Red and Blue in different rooms and try to get a confession by playing prisoner's dilemma! Both Mr. Blue and Miss Red can cooperate or defect. Defecting would mean betraying your partner and telling the police that he or she did it. Cooperating would mean staying silent. If Miss Red defects and Mr. Blue stays silent, then she does not have to go to prison, but Mr. Blue would have to go to prison for three years. It would be the same thing but switched around from Mr. Blue’s perspective. If both of them stay silent then they would each get one year in prison (top right quadrant). If they both defect then they will both get two years in prison as you can see above in the bottom right quadrant.

How to play! Prisoner's dilemma is a two person game. Let's say you and your friend are playing. You can do two things, cooperate or defect at the same time. There are a few ways you can calculate your outcome. First you can see that if you both cooperate then it ends up with the least amount of years but you still have to spend one year in prison. However, you can’t control what your friend does and if they defect then you have to spend three years in prison (top right and bottom left quadrants). One way to strategize is to calculate your outcome based on see what makes you better off given the other players decision. If the other player cooperates then you are better off defecting because 0 years in prison is better than 1. If the other player defects then you will also want to defect because 2 years is better than 3. This means that bo