What is the Prisoner’s Dilemma, and Why Do Gangs Have a Code of Silence?

The prisoner’s dilemma is probably the most famous paradox studied in game theory. This paradox occurs when two parties act in their self-interest but do not produce the optimal outcome.

Assume there are two gang members, Alex and Ben. They are caught and being interrogated by police. Alex and Ben are separated and cannot communicate with each other. The police are confident that Alex and Ben committed a serious crime. However, there is not enough evidence to punish them to the full extent. The police ask Alex and Ben to confess in exchange for freedom.

What should Alex and Ben do?

On the one hand, remaining silent is the right solution for Alex and Ben — both will stay in prison for one year only. On the other hand, confessing may help Alex or Ben avoid prison at all. Here is the dilemma: if Alex thinks that Ben confesses, then Alex’s best strategy is to confess too — otherwise, he would be imprisoned for 20 years. If Alex thinks that Ben remains silent, Alex’s best strategy is to confess as well — this way, he will avoid being imprisoned at all. The same applies to Ben. As a result, the best individual strategy for both gang members is to confess, which leads to 5 years in prison.

The prisoner’s dilemma is observed in different fields, such as economics, criminal justice, politics, and sports. Besides, the discovery of the prisoner’s dilemma in 1950 led to the investigation of other social dilemmas such as the dinner’s dilemma and volunteer’s dilemma.

One example of the prisoner’s dilemma in economics is related to the instability of collusive agreements, which I discuss in my article The Math Behind Cartels and Collusive Agreements. While collusive agreements may help companies gain more profits, such agreements do not last long as each member has a strong incentive to “cheat.”

How to avoid the prisoner’s dilemma?

To do this, parties must find a way to cooperate. In every-day life, the prisoner’s dilemma can be avoided through formal and informal codes of conduct and social norms. The prisoner’s dilemma is also easier to avoid when parties cooperate repeatedly.

One interesting example is the organizational structure of street gangs. In the article “Common Characteristics of Gangs: Examining the Cultures of the New Urban Tribes,” Dr. Gregg Etter analyzes the most common characteristics of street gangs. He finds that the central element of any gang organization is the code of conduct, which includes a code of silence. According to the principle of silence, gang members are not allowed to cooperate with authorities in any way. As a result, gangs with a strong code of conduct avoid the prisoner’s dilemma when caught by police.



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