Evolution of repeated prisoner's dilemma play under logit dynamics

In an evolutionary set-up, we append an ecology of iterated prisoner's dilemma (IPD) game strategies, consisting of unconditional cooperators (AllC), unconditional defectors (AllD) and reactive players (TFT) with two repeated strategies that have received less attention in the evolutionary IPD game literature: the error-proof, “generous” tit-for-tat (GTFT) which, with a certain probability, re-establishes cooperation after a (possibly by mistake) defection of the opponent and the penitent, “stimulus–response” (WSLS) strategy that resets cooperation after the opponent punished for defection. An abundance of rock–paper–scissors like patterns is discovered in the 3×3 ecologies comprising Pavlovian and “generous” players. Interestingly, the evolutionary success of Pavlov seems to depend on the absence of unconditional cooperators in the ecologies investigated.