Week IV · 13 plates
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The Prisoner's Dilemma

Nash, and the logic of defection

The big idea

Nash showed that rational players in tension settle at a point where no one can improve by moving alone. In the Prisoner's Dilemma that point is mutual defection — worse for both than cooperation. Understanding why is how you learn to change it.

By the end of this week you can
  • Read a payoff matrix and find the equilibrium.
  • Explain why mutual defection is rational and still bad.
  • Name the three levers that turn defection into cooperation.
Lecture hall · Week IV

The Prisoner's Dilemma

Plate 01 · leading message · use ← → keys

Plate 01
1951

Nash defined the point no player can improve alone.

An equilibrium is a set of strategies where each player, taking the others as given, has no better move. It does not have to be good. It only has to be stable.

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Slides
Reading notes · Week IV

What you took from the pages

Write your own notes once you have finished Non-Cooperative Games and Equilibrium Points, then revisit them before class. Notes are private to your account and never seen by anyone else.