The Prisoner's Dilemma

The Prisoner’s Dilemma is a scenario where the benefits from cooperating are larger than the benefits of pursuing self-interest.

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Game Theory

The Prisoner’s Dilemma is a type of game theory.
This is a branch of mathematics where one analyses situations in which players must make decisions and then either benefit or lose out from the decisions of other players.

The Prisoner’s Dilemma

This is the scenario:
- Two criminals are arrested. When they are taken to the police station, they refuse to say anything and are put in separate interrogation rooms.

Prisoner A

Eventually, a police officer enters the room where Prisoner A is being held and says: “You know what? Your partner in the other room is confessing. Your partner is going to get a light prison sentence of just one year, and because you’re remaining silent, the judge is going to stick you with eight years in prison. If you confess, too, we’ll cut your jail time down to five years, and your partner will get five years, also.”

Prisoner B

Over in the next room, another police officer is giving exactly the same speech to Prisoner B.
What the police officers do not say is that if both prisoners remain silent, the evidence against them is not especially strong, and the prisoners will end up with only two years in jail each.

Why is this a dilemma?

If the two prisoners had both stayed silent, they would serve a total of four years in jail time between them.
- The prisoners would be better off if they cooperate with each other and neither confesses.
- If they pursue their own self-interest, they could receive longer jail terms.

Diagram of the prisoner's dilemma

Oligopolies and the Prisoner's Dilemma

We can use the prisoner’s dilemma to understand the behaviour of oligopolies.

The Oligopoly version of the prisoner’s dilemma

If oligopolists cooperate in reducing output, then everyone can maintain high profits.
If an oligopolist is pursuing its own self interest, however, then they would increase its output and then earn even more profits.

Diagram of an Oligopoly version of the prisoner’s dilemma

Firm A being cheated by Firm B

If A thinks B will cheat and increase their output, then A will also increase their output.
- This means that both firms receive £400 in profits.
- This is better than the profit of £200, which will happen if A doesn’t change their output levels.
- But this is lower than the £1,000 which A would have if B stuck to their agreement.

Firm A cheating Firm B

On the other hand, A could believe that B will stick to their agreement.
If so, they will want to take advantage of this and raise their own output.
- This means that they will receive £1,500 in profits.
- Their competitor, B, will only have £200 in profits.

Evaluation

Overall, it is in the best interest of Firm A and Firm B to both cooperate.
Ultimately, however, they need to trust each other.

1Introduction to Markets

2Market Failure

2.1Market Failure

2.1.1Types of Market Failure

2.1.2Externalities

2.1.3The Deadweight Welfare Loss of Externalities

2.1.4A-A* (AO3/4) - The Externalities of Education

2.1.5Public Goods

2.1.6Information Gaps

2.1.7End of Topic Test - Market Failure

2.1.8Application Questions - Market Failure

2.2Government Intervention

2.2.1Government Intervention in Markets

2.2.2Subsidies & Price Controls

2.2.3Pollution Permits & Regulation

2.2.4A-A* (AO3/4) - European Emissions Trading

2.2.5State Provision & Information Provision

2.2.6Government Failure

2.2.7End of Topic Test - Government Intervention

2.2.8A-A* (AO3/4) - Government Intervention

3The UK Macroeconomy

3.1Measures of Economic Performance

3.1.1Measuring Economic Growth

3.1.2National Income Data

3.1.3Inflation

3.1.4Causes of Inflation

3.1.5Consequences of Inflation

3.1.6Employment & Unemployment

3.1.7Causes & Impact of Unemployment

3.1.8A-A* (AO3/4) - Hysteresis

3.1.9Balance of Payments

3.1.10Current Account Deficit & Imbalances

3.1.11End of Topic Test - Economic Performance

3.1.12Application Questions Macroeconomy

3.2Aggregate Demand

3.2.1Aggregate Demand

3.2.2Consumption

3.2.3Investment

3.2.4Government Expenditure

3.2.5Net Trade

3.2.6End of Topic Test - Aggregated Demand

3.2.7Application Questions - AD

3.3Aggregate Supply

3.3.1Aggregate Supply

3.3.2End of Topic Test - Aggregated Supply

3.3.3A-A* (AO3/4) -Aggregate Supply

3.4National Income

3.4.1National Income

3.4.2Injections & Withdrawals

3.4.3Equilibrium Level of Real National Output

3.4.4Multiplier Effect

3.4.5End of Topic Test - National Income

3.4.6Application Questions - National Income

3.5Economic Growth

3.5.1Causes of Economic Growth

3.5.2Output Gaps

3.5.3Business Cycle

3.5.4Impact of Economic Growth

3.5.5End of Topic Test - Economic Growth

3.5.6A-A* (AO3/4) - Growth

4The UK Economy - Policies

4.1Macroeconomic Objectives & Policies

4.1.1Possible Objectives

4.1.2Demand-Side Policies - Monetary

4.1.3Demand-Side Policies - Monetary 2

4.1.4A-A* (AO3/4) - The Future of Interest Rates

4.1.5Demand-Side Policies - Fiscal

4.1.6Demand-Side Policies in 2007-08

4.1.7Strengths & Weaknesses of Demand Side

4.1.8Supply-Side Policies

4.1.9Supply-Side Policies 2

4.1.10Conflicts Between Objectives

4.1.11A-A* (AO3/4) - Conflicting Incentives

4.1.12Phillips Curve

4.1.13End of Topic Topic - Policies & Objectives

4.1.14Application Questions - UK Policies

5Business Behaviour

5.1Business Growth

5.1.1Size & Types of Firms

5.1.2Business Growth

5.1.3Pros & Cons of External Expansion

5.1.4Demergers

5.1.5End of Topic Test - Business Growth

5.1.6A-A* (AO3/4) - Business Growth

5.2Business Objectives

5.2.1Business Objectives

5.2.2End of Topic Test - Business Objectives

5.2.3Application Questions - Business Objectives

5.3Revenues, Costs & Profits

5.3.1Revenue

5.3.2Costs

5.3.3Economies & Diseconomies of Scale

5.3.4Profits

5.3.5Profits 2

5.3.6End of Topic Test - Revenue, Costs & Profits

5.3.7A-A* (AO3/4) - Revenue, Costs & Profit

6Market Structures

6.1Market Structures

6.1.1Efficiency

6.1.2Perfect Competition

6.1.3Perfect Competition 2

6.1.4Monopolistic Competition

6.1.5Oligopolies

6.1.6The Prisoner's Dilemma

6.1.7Collusion in Oligopolistic Markets

6.1.8A-A* (AO3/4) - Which Factors Affect Collusion?

6.1.9Monopolies

6.1.10Price Discrimination

6.1.11Monopsony

6.1.12A-A* (AO3/4) - Models in Economics

6.1.13Contestability

6.1.14Benefits of Contestability

6.1.15End of Topic Test - Market Structures

6.1.16Application Questions - Market Structures

6.1.17A-A* (AO3/4) - Cereal Collusion

6.2Labour Market

6.2.1Demand for Labour

6.2.2Supply of Labour

6.2.3Labour Market Imperfections

6.2.4A-A* (AO3/4) - Labour Productivity & Unemployment

6.2.5A-A* (AO3/4) - What Level of Unionisation is Good?

6.2.6Wage Determination

6.2.7Elasticity of Labour Supply & Demand

6.2.8Intervention in Setting Wages

6.2.9End of Topic Test - Labour Market

6.2.10A-A* (AO3/4) - Labour Markets

6.3Government Intervention

6.3.1Reasons for Government Intervention

6.3.2Government Promotion of Competition

6.3.3Usefulness of Competition Policy & Examples

6.3.4A-A* (AO3/4) - Modern Competition Policy

6.3.5Privatisation

6.3.6Government Regulation

6.3.7A-A* (AO3/4) - Nationalisation vs Privatisation

6.3.8Government Protection of Suppliers and Employees

6.3.9Impact of Government Intervention

6.3.10End of Topic Test - Government Intervention

6.3.11Application Questions - Government Intervention

7A Global Perspective

8Finance & Inequality

8.1Poverty & Inequality

8.1.1Absolute & Relative Poverty

8.1.2Inequality

8.1.3Inequality 2

8.1.4Lorenz Curve

8.1.5Government Policy on Poverty

8.1.6End of Topic Test - Poverty & Inequality

8.1.7A-A* (AO3/4) - Inequality & Poverty

8.2Emerging & Developing Economies

8.2.1Measures of Development

8.2.2Factors Influencing Growth & Development

8.2.3Barriers to Development

8.2.4Barriers to Development 2

8.2.5A-A* (AO3/4) - The Bottom Billion

8.2.6Development Strategies

8.2.7Interventionist Strategies

8.2.8Aid

8.2.9International Institutions

8.2.10International Institutions 2

8.2.11End of Topic Test - Emerging & Developing

8.2.12Application Questions - Developing Countries

8.3The Financial Sector

8.3.1Role of Financial Markets

8.3.2Market Failure in the Financial Sector

8.3.3Role of Central Banks

8.3.4End of Topic Test - The Financial Sector

8.3.5A-A* (AO3/4) - Financial Sector

8.4Role of the State in the Macroeconomy

8.4.1Public Expenditure

8.4.2Taxation

8.4.3Public Sector Finances

8.4.4End of Topic Test - Role of the State

8.4.5Application Questions - Role of the State

9Examples of Global Policy

9.1International Policies

9.1.1Global Debt & Deficit Policies

9.1.2Poverty & Inequality Policies

9.1.3Changes in Interest Rates

9.1.4Competitiveness Policies

9.1.5End of Topic Test - International Policies

9.1.6A-A* (AO3/4) - International Policies

9.2Policy Responses to Shocks

9.2.1International Tax Policies

9.2.2Problems for Policymakers

9.2.3End of Topic Test - Policy Responses

9.2.4Application Questions - Policy Responses

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