unit 7 review
Game theory analyzes strategic interactions between rational decision-makers. It explores concepts like players, strategies, payoffs, and types of games. Understanding these elements helps predict outcomes in various scenarios, from poker to business competition.
Nash equilibrium is a key concept where no player benefits from changing strategy. Game theory applications include market competition, voting behavior, and international relations. Decision trees and extensive form games visually represent sequential decision-making processes in strategic interactions.
Key Concepts in Game Theory
- Game theory analyzes strategic interactions between rational decision-makers
- Players are the individuals or groups making decisions in a game
- Strategies are the complete plans of action that players can choose
- Payoffs are the outcomes or rewards that players receive based on the strategies chosen
- Zero-sum games have a fixed total payoff that is divided among the players (Poker)
- Non-zero-sum games allow for outcomes where all players can gain or lose (Prisoner's Dilemma)
- Simultaneous games involve players making decisions at the same time without knowledge of others' choices
- Sequential games involve players making decisions in a specific order, aware of previous choices
Types of Games and Strategies
- Static games are played simultaneously, where players choose their strategies without knowing the choices of other players
- Dynamic games are played sequentially, where players take turns making decisions based on the moves of other players
- Cooperative games allow players to communicate and form binding agreements to coordinate their strategies
- Non-cooperative games do not allow for enforceable agreements, and players make independent decisions
- Pure strategies are specific actions that a player chooses to take in a game (Always confess in Prisoner's Dilemma)
- Mixed strategies involve randomly selecting among available pure strategies based on a probability distribution
- Dominant strategies are the best choice for a player regardless of the strategies chosen by other players
- Dominated strategies are those that always lead to worse payoffs compared to other available strategies
Nash Equilibrium and Its Applications
- Nash equilibrium is a state where each player's strategy is the best response to the strategies of other players
- In Nash equilibrium, no player has an incentive to unilaterally change their strategy
- Nash equilibrium can be pure (players choose specific strategies) or mixed (players randomize their strategies)
- Existence of Nash equilibrium depends on the type of game and the number of players
- Nash equilibrium helps predict the outcomes of strategic interactions in various fields (Economics, political science, psychology)
- Applications of Nash equilibrium include market competition, voting behavior, and international relations
- Nash equilibrium may not always be the most efficient or socially optimal outcome (Prisoner's Dilemma)
- Refinements of Nash equilibrium, such as subgame perfect equilibrium, address dynamic games and credible threats
- Decision trees visually represent the sequential structure of a game
- Nodes in a decision tree represent decision points for players or chance events
- Branches in a decision tree represent the available choices or outcomes at each node
- Payoffs are listed at the terminal nodes of the decision tree
- Extensive form games are represented using decision trees, capturing the order of moves and information available to players
- Backward induction is used to solve extensive form games by starting at the terminal nodes and working backwards
- Subgame perfect equilibrium is determined by finding the Nash equilibrium at each subgame (portion of the game tree)
- Extensive form games can model situations with imperfect information, where players are unaware of some previous moves
Dominant and Mixed Strategies
- Dominant strategy equilibrium occurs when each player has a dominant strategy, resulting in a Nash equilibrium
- Iterated elimination of dominated strategies can be used to simplify games and find dominant strategy equilibria
- Mixed strategy equilibrium involves players randomizing their strategies based on specific probabilities
- In a mixed strategy equilibrium, players are indifferent between their available pure strategies
- Mixed strategies can be used to exploit opponents' tendencies and avoid being predictable
- Calculating mixed strategy equilibria involves finding probabilities that make players indifferent between strategies
- Mixed strategies are common in competitive settings (Sports, poker, business competition)
- Mixed strategy equilibria may not always exist, depending on the structure of the game
Cooperative vs. Non-Cooperative Games
- Cooperative games allow players to communicate, form coalitions, and make binding agreements
- In cooperative games, players can negotiate and distribute payoffs among themselves
- Shapley value is a solution concept for cooperative games that assigns fair payoffs to players based on their marginal contributions
- Core is another solution concept that ensures no group of players has an incentive to break away from the grand coalition
- Non-cooperative games do not allow for enforceable agreements, and players make independent decisions
- In non-cooperative games, players cannot credibly commit to strategies that are not in their individual best interests
- Nash equilibrium is the primary solution concept for non-cooperative games
- Many real-world situations involve a combination of cooperative and non-cooperative elements (International treaties, business partnerships)
Game Theory in Business Contexts
- Game theory helps businesses make strategic decisions in competitive markets
- Oligopoly models, such as Cournot and Bertrand competition, analyze firm behavior in concentrated industries
- Price wars can be modeled as a Prisoner's Dilemma, where firms have incentives to undercut each other
- Product differentiation and market segmentation can be analyzed using game-theoretic frameworks
- Entry deterrence strategies, such as limit pricing and capacity expansion, can be studied using extensive form games
- Bargaining and negotiation situations, such as labor-management disputes, can be modeled using cooperative game theory
- Auctions and bidding behavior can be analyzed using game-theoretic concepts (First-price sealed-bid auction, Vickrey auction)
- Game theory helps businesses anticipate competitor moves and make strategic investments
Advanced Topics and Real-World Applications
- Repeated games involve players interacting over multiple rounds, allowing for cooperation and punishment strategies
- Evolutionary game theory studies the dynamics of strategy adoption in populations over time
- Signaling games model situations where players have private information and can send costly signals to convey their types
- Mechanism design involves creating game rules and incentives to achieve desired outcomes (Auctions, voting systems)
- Behavioral game theory incorporates insights from psychology and relaxes assumptions of perfect rationality
- Experimental game theory tests theoretical predictions using controlled laboratory experiments
- Game theory has applications in various fields beyond economics (Biology, computer science, political science)
- Real-world applications include spectrum auctions, kidney exchange programs, and climate change negotiations