Game theory basics

The minimum theory needed to see the structure of a collective action problem. The point of all of it is that defection is usually rational — no villain is required for a group to end up somewhere none of its members wanted.

The games

• Prisoner's Dilemma — mutual defection as the only equilibrium
• Stag hunt — cooperation is an equilibrium, but so is caution
• Tragedy of the commons — the shared resource case
• Public goods and Free riding — the undersupply case
• Assurance game — where the problem is trust rather than incentive

The apparatus

• Payoff matrix
• Dominant strategy
• Nash equilibrium — and why an equilibrium can be stable and terrible at once

What it means

• Defection is not a deficiency
• Collective action problem and Collective action opportunity
• Moloch, Multipolar trap, Race to the bottom — the same structure under other names