I explain collective action games and multi-player Prisoner’s Dilemmas. I relate these to public goods, the tragedy of the commons, and drop-in-the-bucket problems. There is also a discussion of stable and unstable equilibrium in multi-player games. 0:00 - Overview 0:36 - Real-World Situations 1:16 - Starting with 2x2 Prisoner's Dilemma 4:05 - Goal: Changing the Payoffs 6:07 - Public Good / Tragedy of the Commons 6:52 - Building Objective Function 7:49 - Drop-in-the-Bucket 8:57 - Functional Form 10:27 - Adding Uncertainty 11:18 - Multi-player Nash Equilibrium 17:09 - Stability of Equilibrium 18:00 - Take-Aways from Exercise 19:07 - Multi-Player Prisoner's Dilemma 19:44 - How do you Address Collective Action Problems? Solving for Nash Equilibrium: https://www.youtube.com/watch?v=6rs_EQpxTI4 The numbers in the multi-player Nash Equilibrium Example come from the following video, which is posted on an excellent game theory channel... https://www.youtube.com/watch?v=IOUG-aREruo