 Since tit-for-tat is a very simple strategy, computationally, one can begin to explore a notion of rationality that emerges in a group of boundedly rational agents and even see evidence of those bounds contributing to the emergence of pro-social norms. Rubinstein (Rubinstein 1986) studied finite automata which play repeated prisoner’s dilemmas and whose aims are to maximize average payoff while minimizing the number of states of a machine. Finite automata capture regular languages, the lowest-level of the Chomsky-hierarchy, thus model a type of boundedly rational agents. Solutions are a pair of machines in which the choice of the machine is optimal for each player at every stage of the game. In an evolutionary interpretation of repeated games, each iteration of Rubinstein’s can be seen as successive generations of agents. This approach is in contrast to Neyman’s study of players of repeated games who can only play mixtures of pure strategies that can be programmed on finite automata, where the number of states that are available is an exogenous variable whose value is fixed by the modeler. In Neyman’s model, each generation plays the entire game and thus traits connected to reputation can arise (Neyman 1985). More generally, although cooperation is impossible for infinitely repeated prisoner’s dilemmas, for finitely repeated prisoner’s dilemmas, a cooperative equilibrium exists for finite automata players whose number of states is less than exponential in the number of rounds of the game (Papadimitriou &amp; Yannakakis 1994; Ho 1996). The demands on memory may exceed the psychological capacities of people, however, even for simple strategies like tit-for-tat played by a moderately sized group of players (Stevens, Volstorf, et al. 2011). These theoretical models showing a number of simple paths to pro-social behavior may not, on their own, be simple enough to offer plausible process models for cooperation.