Agent-based modelling of complex systems in political science: Social norms and tolerance in immigrant societies

Migration is a political issue that has received more attention in recent years. Many questions remain as to how Western societies can successfully absorb migrants- economic arguments have largely been in favour of migration, but the social impact of diversity in previously homogeneous societies has been subject to ongoing debates in social science. Migrant societies are complex social systems with many interacting moving parts. How do rapid migration-changes in society affect the hosts? How do norms of tolerance towards minorities hold up when intergroup con icts emerge? Can segregating behaviour of different population groups be reduced by encouraging different settlement locations for new migrants? The questions address both the physical aspect of migrants entering an already populated space, and the social dimension in which the hosts are adapting their attitudes. I develop a Schelling model using Agent-based modelling to address these questions. I introduce the concept of external migration into an existing society and test how, by varying the kind of migration, introducing diversity affects local tolerance. In the second chapter, I show that large-scale migration results in short-term shocks to the populace, but that these effects are heavily dependent on the population density and how large the native majority is. In Chapter 3 I implement a version of the `contact hypothesis' which stipulates that contact with out-group members increases tolerance and I show that the adaptability increases the importance of native majorities further. In the fourth chapter, I move on to the social norms of tolerance, introducing an ABM in which agents can deceive others by signalling false information about their true attitudes. I show that the emergent pattern of these behaviours can lead to a false consensus effect in which the perceived majority public opinion is unstable. The thesis is able to generate societies that bear many similarities with the Western countries of today and can suggest explanations for the mechanisms that lead to changes in public opinion more negative towards migration, as well as reasons for growing separation of different population groups.