Carlos Lemos presented his PhD thesis on the 16th of December 2016, at ISCTE-IUL, entitled “On Agent-Based Modelling of Large Scale Conflict Against a Central Authority: from Mechanisms to Complex Behaviour”. The jury was composed by Ernesto Costa, Francisco Santos, Pedro Magalhães, Luis Antunes, Jorge Louçã, Rui Lopes (supervisor), and Helder Coelho (co-supervisor).
In this work, an Agent-Based model of large scale conflict against a central authority was developed. The model proposed herein is an extension of Epstein’s Agent-Based model of civil violence, in which new mechanisms such as deprivation-dependent hardship, generalised vanishing of the risk perception (`massive fear loss’) below a critical ratio between deterrence and `group support’, legitimacy feedback, network influences and `mass enthusiasm’ (contagion) were implemented. The model was explored a set of computer experiments and the results compared with statistical analyses of events in the “Arab Spring”.
The main contributions of the present work for understanding how mechanisms of large scale conflict lead to complex behaviour were (i ) a quantitative description of the impact of the “Arab Spring” in several countries focused on complexity issues such as peaceful vs violent, spontaneous vs organized, and patterns of size, duration and recurrence of conflict events; (ii ) the explanation of the relationship between the estimated arrest probability and the size of rebellion peaks in Epstein’s model; (iii ) a new form of the estimated arrest probability with a mechanism of `massive fear loss’; (iv ) the derivation of a relationship between the legitimacy and action threshold for complex solutions to occur with both low and high values of the legitimacy; (v) a simple representation of political vs economic deprivation with a parameter which controls the `sensitivity’ to value; (vi ) the effect of legitimacy feedback; and (vii ) the effect of network influences on the stability of the solutions.