Baranski, BastianBastianBaranskiBartz-Beielstein, ThomasThomasBartz-BeielsteinEhlers, RüdigerRüdigerEhlersKajendran, ThusinthanThusinthanKajendranKosslers, BjörnBjörnKosslersMehnen, JörnJörnMehnenPolaszek, TomaszTomaszPolaszekReimholz, RalfRalfReimholzSchmidt, Jens M.Jens M.SchmidtSchmitt, KarlheinzKarlheinzSchmittSeis, DannyDannySeisSlodzinski, RafaelRafaelSlodzinskiSteeg, SimonSimonSteegWiemann, NilsNilsWiemannZimmermann, MarcMarcZimmermann2020-10-212020-10-212006IEEE Congress on Evolutionary Computation (CEC 2006)http://hdl.handle.net/11420/7635This paper presents results from extensive simulation studies on the iterated prisoner's dilemma. Two models were implemented: a nongroup model in order to study fundamental principles of cooperation and a model to imitate ethnocentrism. Some extensions of Axelrod's elementary model implemented individual reputation. We furthermore introduced group reputation to provide a more realistic scenario. In an environment with group reputation the behavior of one agent will affect the reputation of the whole group and vice-versa. While kind agents (e. g. those with a cooperative behavior) lose reputation when being in a group, in which defective strategies are more common, agents with defective behavior on the other hand benefit from a group with more cooperative strategies. We demonstrate that group reputation decreases cooperation with the in-group and increases cooperation with the out-group.enConference Paper10.1109/CEC.2006.1688449Other