The effect of memory in the spatial continuous-valued prisoner's dilemma

The standard spatial formulation of the Prisoner's Dilemma is ahistoric (memoryless, i.e. only results generated in the last round are taken into account in deciding the next choice), and binary (players are confined to fully cooperating or defecting). The spatial historic model admitting intermediate degrees of cooperation (fuzzy model) is studied in this work. Comparisons are made between the binary and fuzzy models. The effect of errors and discounting is also assessed.