EconSim

Prisoner's Dilemma

Play repeated rounds against classic strategies and watch cooperation pay off — or not.

Understand why rational players defect in a one-shot game, yet cooperation can emerge when the game is repeated.

  • Game theory
  • Nash equilibrium
  • Cooperation vs defection
  • Tit-for-Tat
  • Iterated games

Guided walkthrough

Step 1 of 3
Predict first

With Tit-for-Tat selected, play Cooperate for several rounds.

Before you act, predict what will happen. How does the opponent respond to your cooperation? Then do it — did your prediction match what happened?

Cooperates first, then copies whatever you did last round.

Payoffs shown as you / opponent.
Your moveOpp. CooperateOpp. Defect
You Cooperate3 / 30 / 5
You Defect5 / 01 / 1
Round 0 · You 0 · Opponent 0

Cumulative score

Total points each side has earned as rounds accumulate.