Fig. 3.

The normalized mean fixation time for the prisoner’s dilemma game as a function of $N$. We set $a=1$, $b=0$, $c=T$, and $d=0$. In a, we set $m=0.2$ and $w=1$. In b, we set $T=1.2$ and $m=0.1$. In c, we set $T=1.2$ and $w=1$. The dashed lines represent $400\sqrt{N}exp(\mathit{\gamma }N)$ divided by the $t_0$ value for the neutral game