What are the causes of civil conflict? On the basis of recent theoretical and empirical research, professors Joan Esteban and Laura Mayoral (IAE and BSE) and Debraj Ray (NYU) show that preexisting ethnic divisions do influence social conflict. Their analysis provides evidence that ethnic conflicts are likely to be instrumental, i.e, driven by political or economic reasons, rather than by ancestral hatreds across groups. Funding for this project was provided by AXA Research Fund and Recercaixa.