Evolutionary Snowdrift Game

Cooperators (blue) and defectors (red) on a spatial grid. Coexistence via spatial structure.
Also known as hawk-dove or chicken game.

Parameters

Cost-benefit ratio r: 0.50 Grid size: 80 Init cooperator frac: 0.50 Noise (mutation): 0.01 Speed: 3 gen/frame

Generation: 0

Cooperators: —

Mean payoff: —

Payoff matrix (r = c/b):
C vs C: 1−r/2
C vs D: 1−r
D vs C: 1
D vs D: 0

Mean-field equil: ρ_C = 1−r
Spatial: higher C than MF.
Spatial clustering helps C.