When we make a decision about whether or not to cooperate with someone, we usually base our decision on past experiences—how has this person behaved in the past?—and on future reciprocity—will they return the favor?—and weigh these against the possible benefits of defecting. However, when analyzing strategies for repeated dilemmas, modeling long-term memory in cooperative strategies quickly becomes computationally intractable, and in the past, researchers have either restricted the possible strategy types, or only allowed players to make their decisions based on the previous round (“memory-1”).