Game Theory Notes

Game Theory

1.1 What Is Game Theory?

  • Definition of Game Theory: Study of interactions between rational agents; applies to various scenarios including negotiations, bidding, and strategic decisions.
  • Examples of Games:
    • Romeo and Juliet (teen romance)
    • Hitler and Stalin (historical conflict)
    • Cuban Missile Crisis (political tension)
    • Drivers in traffic (everyday decision-making)
    • Auction bidders (competitive behavior)
    • Labor negotiations (bargaining)
  • Goal: Understand rational behavior and decision-making in strategic interaction.
  • Limitations: Does not predict irrational behaviors (e.g., love-sick teenagers).

1.2 Toy Games

  • Purpose of Toy Games: Simplify complex human situations to focus on strategic decision-making.
  • Emotion and Rationality: Emotional ties can cloud judgment; toy games allow for dispassionate analysis.
  • Learning Through Simplification: Solving simpler models helps tackle more complex issues later.

1.3 The Prisoners’ Dilemma

1.3.1 Chicago Times
  • Scenario: Two criminals are arrested; they can either confess or remain silent.
  • Strategies:
    • Hawk: Confess (betray partner)
    • Dove: Remain silent (trust partner)
  • Payoff structure is crucial; matrix demonstrates outcomes based on strategic choices.
1.3.2 Paradox of Rationality
  • Common Criticism:Actors would be better off cooperating but often don’t.
  • Rational Analysis: Game theory shows that self-interest leads to suboptimal outcomes in Prisoners’ Dilemma, both get harsh penalties if both betray each other.
1.3.3 The Twins Fallacy
  • Misconception: Belief that rational agents (like twins) will automatically choose the same strategies.
  • Reality: Each player acts independently, and mutual assurances may not hold.
General Concepts of the Prisoners’ Dilemma
  • Nash Equilibrium: Both players default to strategy yielding least payoff unless cooperation occurs.
  • Free Rider Problem: Analogy in public goods where individuals prefer to benefit without contributing.
  • Effect of Incentives: Game outcomes affected by potential rewards and penalties, trust within relationships plays a huge role.

1.4 Private Provision of Public Goods

  • Definition: Goods that are available to everyone without selective restrictions.
  • Example: Charity donations; potential for under-provision if free riding occurs.
  • Game Model: Players' choices affect the availability of goods, illustrating rational, individualistic lag in cooperation.

1.5 Imperfect Competition

  • Monopoly vs. Duopoly: Monopolies have control over prices; duopolies involve competition that can lead to both cooperation and conflict scenarios.

1.6 Nash Equilibrium

  • Definition: A situation where no player benefits from unilaterally changing their strategy given the other's choice.
  • Importance: Crucial for predicting behaviors in various scenarios, reflects stable outcomes in interactive settings.

1.7 Collective Rationality

  • Cooperative Game Theory: Emphasizes binding agreements; however, untrustworthiness can arise without systems to enforce rules.

1.8 Repeated Prisoners’ Dilemma

  • Dynamics: Players face the same situation repeatedly, potentially fostering cooperation through learned behaviors and strategies, such as 'grim' strategy.

1.9 Equilibrium Selection Problem

  • Challenge: Multiple equilibria exist; choosing the right equilibrium based on context and cooperative or competitive conditions.

1.10 Social Dilemmas

  • Explanation: Situations where individual rationality leads to collective irrationality.
  • Examples: Environmental degradation, public health issues, etc., where individual actions can lead to collective disaster despite better options existing.

1.11 Roundup

  • Key Concepts:
    • The essence of games like the Prisoners’ Dilemma isn't paradoxical; they're examples of how rational players behave in tightly defined conditions.
    • Rational agents operate based on strategic incentives and constraints, showcasing human behavior across various contexts.