Replication of the Demographic Prisoner’s Dilemma

Abstract

This paper documents our efforts in replicating Epstein’s (1998) demographic prisoner’s dilemma model. While, qualitatively speaking, our replicated model resembles the results of the original model reasonably well, statistical testing reveals that in quantitative terms our endeavor was only partially successful. This fact hints towards some unstated assumptions regarding the original model. Confronted with a number of ambiguous descriptions of model features we introduce a method for systematically generating a large number of model replications and testing for their equivalence to the original model. With the help of this approach we show that the original model was probably based on a number of dubious assumptions. Finally we conduct a number of statistical tests with respect to the influence of certain design choices like the method of updating, the timing of events and the randomization of the activation order. The results of these tests highlight the importance of an explicit documentation of design choices and especially of the timing of events.Demographic, Prisoner’s Dilemma, Replication, Simulation, Complex Adaptive Systems, Social Science Models