Prisoner’s Dilemma. What do you choose? Cooperate or defect?

aanya khandelwal
3 min readJan 21, 2021


You and your friend have been caught in a homicidal crime. The police has taken both of you into two separate rooms. The inspector comes in and informs you about your current state. He tells you that you have 2 options. You can put the blame of the crime on your partner or you could choose stay quiet. He then shows you this sheet:

If both of you remain silent and cooperate with one another, you both only get a year in prison sentence because they won’t be able to pin down who has done the crime. Now, if you defect, but he cooperates, you go free and he gets a life sentence. That is the best case scenario for you. But what happens when you cooperate and he defects? Well, you get a life sentence while he gets to goes Scott free. But the worst case scenario is if you both defect and end up getting 20 years in prison each because both of you seem to blame it onto one another.

Sitting in this room the officer waits for you to make a decision. What do you choose?

Here’s, the best case scenario. Both of you cooperate and get out of prison in just a single year. Or, you could defect and hope that your partner doesn’t do the same, because if he does; then 20 years in prison for both of you. The risk of both of you defecting each other for your own personal benefits is both extremely high and can be extravagantly costly.

But, what if the officer tells you that your partner has already defected on you. What do you do then? Do you still cooperate and be silent or do you choose to defect upon him too?

Known as the Prisoner’s Dilemma, this is one of the most popular theories in both psychology and game theory. Once you know the phenomenon, you will see it everywhere. From Politics, divorces, to decision making and even business and economics.

To answer to this dilemma is undefinable. Perhaps you had planned for this situation already and both agreed on staying quiet. But your partner uses your loyalty to his advantage and defects. Maybe you defect on him while he keeps his word and cooperates. There are an end number of possibilities to such a dilemma. Various police police agencies use this dilemma against criminals in real time and see very favoring results(without the sheet of possibilities of course).

In day to day life, coming across a single, individual Prisoner’s Dilemma is deviously rare. Instead, we see an iterated Prisoner’s Dilemma; a chain of events. In other words, these iterated Prisoner’s Dilemma’s flow and make our social lives.

In a competition to find answers for this iterated Prisoner’s Dilemma, there were 2 Robert Axelrod’s tournaments(aimed to solve the Prisoner’s Dilemma by calling Game Theorists to submit their strategies to be run by computers), held around 1980 with an aim to solve this. Eventually, it was only the simplest and most basic strategy that won each time. Psychologists call this human behavior, but Anatol Rapoport introduced this at the Tit for Tat strategy.

Anatol developed the Tit for Tat strategy wherein the course of action (or response) by the player was the same as the previous one by the opponent. For example, if the opponent had cooperated the last time, on this turn, the player will mimic the opponent by cooperating too. Anatol’s Tit for Tat theory was the most clear and successful winner of the Axelrod’s Tournaments.

But what can we infer from this solution? Well, you may have heard it before. The circle of life? Karma? All these things rely on the same basis . The Tit for Tat strategy.

If you do someone else good, you receive goodness back. On the other hand, if you do someone bad, you receive the same treatment. Ergo, when people tell you to not do ill for you will receive ill yourself; it is not just a moral that has fallen down from generations; instead, it is a psychological and game theory fact.

So, what would you choose? Cooperate or deflect?