Why?
Explore one of the most fascinating puzzles in game theory: when should you trust, and when should you betray?
What?
The Dilemma
Two players independently choose: cooperate or defect. Cooperation benefits both, but defection offers a higher personal payoff—at your partner's expense. The catch? If both defect, both lose.
The Payoffs
Mutual cooperation earns +3 each. Mutual defection earns only +1 each. But if you defect while they cooperate, you get +5 and they get nothing. The temptation to betray is strong—but risky.
Why It Matters
This simple dynamic appears everywhere: climate agreements, business partnerships, international relations, and everyday social interactions. It's the fundamental tension between individual gain and collective good.
Repeated Interactions
When the game repeats, everything changes. Strategies emerge: some always cooperate, others always defect, some retaliate when betrayed, others forgive. Reputation matters. History matters.
Competing Strategies
Meet different AI opponents: the eternal optimist who always trusts, the cynic who never does, the reciprocator who mirrors your moves, and the grudge-holder who never forgives. Each has strengths and weaknesses.
Experiment & Discover
Test your strategies against different AI opponents in the game, then experiment in the sandbox to see how different payoff structures and parameters affect which strategies succeed or fail.
Payoff Matrix
| Opponent Cooperates | Opponent Defects | |
|---|---|---|
| You Cooperate | +3 / +3 | 0 / +5 |
| You Defect | +5 / 0 | +1 / +1 |
You are playing against..
Opponent
Let's play against different strategies...
You
Opponent
History
Sandbox Mode
Experiment with different parameters to see how they shape the evolution of cooperation. Each setting creates a different environment where strategies must adapt and compete.
Configure Payoff Matrix
Adjust the rewards for each outcome. The classic prisoner's dilemma requires: Temptation > Reward > Punishment > Sucker (T > R > P > S).
Current Matrix
| Opponent Cooperates | Opponent Defects | |
|---|---|---|
| You Cooperate | +3 / +3 | 0 / +5 |
| You Defect | +5 / 0 | +1 / +1 |