Payoff Matrix
| Cooperate | Defect | |
|---|---|---|
| Cooperate | 3, 3 | 0, 5 |
| Defect | 5, 0 | 1, 1 |
Robert Axelrod's famous tournament where different strategies compete in iterated Prisoner's Dilemma games. Surprisingly, the simple "Tit-for-Tat" strategy often wins by being nice, retaliatory, and forgiving.
| Cooperate | Defect | |
|---|---|---|
| Cooperate | 3, 3 | 0, 5 |
| Defect | 5, 0 | 1, 1 |
Two criminals are arrested and interrogated separately. Each can either cooperate (stay silent) or defect (betray the other).
Strategies in this tournament:
• Tit-for-Tat: Cooperate first, then copy opponent's last move
• Always Cooperate: Never defect, always cooperate
• Always Defect: Never cooperate, always betray
• Grudger: Cooperate until opponent defects once, then always defect
• Random: Randomly choose to cooperate or defect (50/50)
• Tit-for-Two-Tats: Only retaliate after two consecutive defections
• Pavlov: Repeat move if rewarded (3+ points), switch if punished