Prisoner's Dilemma

Definition

The prisoner's dilemma is a classic game theory scenario that demonstrates how two individuals acting in their own self-interest can ultimately produce an outcome that is less than optimal for both of them. It highlights the tension between individual and collective rationality.

5 Must Know Facts For Your Next Test

1. In the prisoner's dilemma, two suspects are arrested and interrogated separately. Each has the option to either confess or remain silent.
2. If both suspects remain silent, they will both receive a light sentence. If one confesses and the other remains silent, the confessor will be released while the silent suspect receives a harsh sentence.
3. If both suspects confess, they will both receive a moderate sentence, which is better than the harsh sentence but worse than the light sentence.
4. The dominant strategy for each suspect is to confess, even though the collectively optimal outcome is for both to remain silent.
5. The prisoner's dilemma illustrates how the pursuit of individual self-interest can lead to a suboptimal outcome for the group as a whole.

Review Questions

• Explain how the prisoner's dilemma relates to the concept of oligopoly in economics.
  • The prisoner's dilemma is relevant to the study of oligopoly because it demonstrates how the pursuit of individual self-interest can lead to a suboptimal outcome for the group. In an oligopoly, firms face a similar dilemma - they can either cooperate by maintaining high prices and profits, or they can compete by undercutting each other's prices. The collectively optimal outcome would be for all firms to cooperate, but the dominant strategy for each firm is to compete, leading to a price war and lower profits for all. This dynamic in an oligopoly is analogous to the prisoner's dilemma, where individual rationality can lead to a suboptimal collective outcome.
• Analyze how the concept of the Nash equilibrium relates to the prisoner's dilemma.
  • The Nash equilibrium is a key concept in game theory that is closely tied to the prisoner's dilemma. In the prisoner's dilemma, the Nash equilibrium occurs when both players confess, even though this leads to a suboptimal outcome for both. This is because confessing is the dominant strategy for each player - it is the best response regardless of what the other player does. The Nash equilibrium represents the point where neither player has an incentive to unilaterally deviate from their strategy, even though a different set of strategies would lead to a better outcome for both players. Understanding the Nash equilibrium is crucial to analyzing the prisoner's dilemma and its implications for decision-making in oligopolistic markets.
• Evaluate how the prisoner's dilemma can be used to explain the challenges of achieving collusion in an oligopoly.
  • The prisoner's dilemma provides valuable insights into the challenges of achieving and maintaining collusion in an oligopolistic market. In the prisoner's dilemma, the collectively optimal outcome is for both players to cooperate by remaining silent, but the dominant strategy for each player is to confess, leading to a suboptimal outcome. Similarly, in an oligopoly, the collectively optimal outcome for firms would be to cooperate by maintaining high prices and profits, but the dominant strategy for each firm is to undercut the others and gain a larger market share. This creates a strong incentive for firms to deviate from any collusive agreement, even though cooperation would lead to better outcomes for all. The prisoner's dilemma highlights the inherent tension between individual and collective rationality, which is a key obstacle to achieving and sustaining collusion in oligopolistic markets.

Related terms

Game Theory: The study of mathematical models of strategic interaction between rational decision-makers.

Nash Equilibrium: A solution concept in game theory where each player's strategy is the best response to the strategies of the other players.

Dominant Strategy: A strategy that is the best choice for a player regardless of the choices made by the other players.