Fig. 3.

Noise in gossip transmission tends to destabilize cooperation. (A) The critical gossip duration ${\tau }^{\ast }$ required to stabilize cooperation as a function of the benefit-to-cost ratio $b/c$, under the Stern Judging norm. Colors denote different amounts of unbiased noise in gossip ($\mu +\nu$). The orange curve indicates the critical gossip duration for noiseless transmission ($\mu =\nu =0$; Fig. 2E). (B and C) The equilibrium average reputation and agreement level at the DISC vertex as a function of scaled gossip duration $\tau$, evaluated with a fixed benefit-to-cost ratio ($b/c=5$). Colors are as indicated in A. Solid (dashed) segments denote parameters for which the DISC-only equilibrium is locally stable (unstable). Other parameters: $u_a=u_e=0.02$. Analogous results for the Simple Standing and Shunning norms are shown in SI Appendix, Fig. S4.