Hawk-dove game
Hawk-Dove (also called Chicken or Swerve) is a game with no dominant strategy but two Nash equilibria. It contrasts with the prisoner’s dilemma in that defection is not always the best move — the worst outcome is when both players refuse to back down.
Payoff Matrix
| P2: Swerve | P2: Straight | |
|---|---|---|
| P1: Swerve | II | III |
| P1: Straight | I | IV ← worst outcome |
- P1 prefers: I > II > III > IV
- P2 prefers: III > II > I > IV
There are two Nash equilibrium strategies:
- If the other player goes straight, the NE strategy is to swerve.
- If the other player swerves, the NE strategy is to go straight.
Neither player wants to be the one who swerves when the other goes straight (box I for P2, box III for P1), but both players most want to avoid the mutual collision/worst possible outcome of box IV.
Going straight (the “tough” move) is only rational if the other player swerves; if both go straight, both suffer the worst possible outcome.