Mirek Kordos
AI RESEARCH, SOFTWARE DEVELOPMENT and more

Iterated Prisoner's Dilemma

The one-time prisoner's dilemma was formulated as follows:

"Two suspects are arrested by the police. The police have insufficient evidence for a conviction, and, having separated both prisoners, visit each of them to offer the same deal. If one testifies (defects from the other) for the prosecution against the other and the other remains silent (cooperates with the other), the betrayer goes free and the silent accomplice receives the full 10-year sentence. If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must choose to betray the other or to remain silent. Each one is assured that the other would not know about the betrayal before the end of the investigation. How should the prisoners act?" (More in Wikipedia)


In the iterated prisoner's dilemma the choice is made over and over again.

Each point is worth $1.000. The purpose of the game is to make as much money as possible. As in real life, it doesn't matter how much money your partner makes, it matters only how much you make. For example, if you make $10.000 and your partner makes $30.000 your result is better than if you make $9.000 and your partner loses $30.000. C means cooperation, N stands for Non-cooperation. It's a good idea to play in several pairs (e.g. all students in the classroom) and than this student who earns the most money wins. However, in general it is not a winner-loser game but a game where you must become rich and the partner's outcome is irrelevant for you. Both players make a move at the same time and only after the move they let the other player know their choice.


Print the tables below, have a good time and learn the lesson well.




Red Blue points Red points Blue
Red Blue points Red points Blue
C C 1 1




C N -2 2




N C 2 -2




N N -1 -1






















Red Blue points Red points Blue





















































































































































































































































































Creative Commons License. You are free to copy, share and adapt all articles and software from my web page for noncommercial purposes, provided that you attribute the work to me and place a link to my home page. What you build upon my works may be distributed only under the same or similar license and you may not distort the meaning of my original texts. Mirosław Kordos