How to Cause War and Why we May be Moving Away From it: Grouping by encounter probability in an FSS society

Abstract

The question of how to obtain high levels of cooperation in a Prisoner’s Dilemma-like situation has been the subject of many models and simulations. Few have, however, tackled the problem from as realistic a viewpoint as Nakai and Muto have, with their artificial society in which Friend Selection Strategies are evolved. They try to mimic how human societies show not only periods of ‘peace’ (high cooperation), but also periods of ‘war’ (less cooperation). Although results are promising, their model only shows plausible results with regard to human societies when the society is of a certain size; for large societies, the model only shows peaceful behaviour, without periods of war. In order to improve the plausibility of the model – and thereby also that of its behaviour – for larger societies, we will divide the society into groups with high intra-group encounter probabilities and low inter-group encounter probabilities. Results show that by this addition a war-like state is reintroduced into the model’s behavioural repertoire, thus improving the model’s behaviour in terms of plausibility.