5 n O. B 0.005 0 -0.005 -001 o. 0.2 OA x Fig. 6. Picas of k for the models in Fig. 4. that is for two diferent Prisoner's Dilemmas at n = I. Panel A: a = 0.97,8 = 0.94.4 = 0.99. = 0.95 and ao = do = 0.9. Panel It a = 0.9733.6 = 0.94, c = 0.99. d = 0.9567 and ao = do = 0.9. In both panels. the t