You and a partner are being interrogated. Each round, choose to stay silent (Cooperate) or betray (Defect) — without knowing what they'll do.
Play 10 rounds of the classic Prisoner's Dilemma against a simulated opponent.
Your goal is to maximize your own total score — but mutual cooperation pays off more than mutual betrayal.
First formalized in 1950 by Merrill Flood and Melvin Dresher at RAND Corporation, the Prisoner's Dilemma is the cornerstone of game theory and behavioral economics. It reveals a fundamental tension: what is individually rational (defecting) can lead to a collectively worse outcome than mutual cooperation.
The payoff matrix:
Tit-for-Tat — cooperate first, then mirror the opponent's last move — famously won Robert Axelrod's 1980 computer tournaments, beating pure defection strategies. It demonstrates that in repeated interactions, reciprocal altruism and conditional cooperation outperform pure self-interest.
The dilemma models real-world situations: arms races, climate agreements, business competition, and even everyday social cooperation. It explains why trust is hard to establish but easy to destroy.