Table 1. Pay-off matrix of two-player games if α = c/(2ρ_C) and β = θ(ρ_C)b. For 2b > c > b > 0 we have the prisoner's dilemma, and for b > c > 0 the snowdrift game.

	C	D
C	R = b−(c/2)	S = b−c
D	T = b	P = 0