  This study investigates the effect of behavioral mistakes on the evolutionary
stability of the cooperative equilibrium in a repeated public goods game. Many
studies show that behavioral mistakes have detrimental effects on cooperation
because they reduce the expected length of mutual cooperation by triggering the
conditional retaliation of the cooperators. However, this study shows that
behavioral mistakes could have positive effects. Conditional cooperative
strategies are either neutrally stable or are unstable in a mistake-free
environment, but we show that behavioral mistakes can make \textit{all} of the
conditional cooperative strategies evolutionarily stable. We show that
behavioral mistakes stabilize the cooperative equilibrium based on the most
intolerant cooperative strategy by eliminating the behavioral
indistinguishability between conditional cooperators in the cooperative
equilibrium. We also show that mistakes make the tolerant conditional
cooperative strategies evolutionarily stable by preventing the defectors from
accumulating the free-rider's advantages. Lastly, we show that the behavioral
mistakes could serve as a criterion for the equilibrium selection among
cooperative equilibria.
