Governments are increasingly concerned with the pattern of the income distribution that is emerging in most advanced societies. Present social and technological changes seem to generate growth paths whose benefits tend to fall on a fraction of society only. As a result, the income distributions of some relevant countries are becoming bi-modal showing a diminishing weight of the "middle class". Among the OECD countries two patterns seem to be emerging. On the one hand, the USA and UK display a distribution of income that is becoming increasing polarized. On the other hand, continental Europe and Canada continue to exhibit distributions with a low degree of polarization.The polarization in the distribution of income is the monetary counterpart of the formation of social clusters. The tendency towards a more "polarized" society is taking a central place in the political debate. There are fears that the splitting of the society into "two nations" could drive social conflict to levels that have been unknown in Europe since 1945. The combination of this polarization with other individual factors such as race or religion is an additional factor of concern.The enlargement of the social group left aside by the new technologies substantially increases the necessary size of the social transfers, adding strain to the financial viability of the Welfare State. At the same time, and possibly not independently, we are witnessing a change in social values towards favouring more conservative redistributive policies, limiting the funds devoted to the alleviation of the poorer.In sum, there are growing signs of social clustering and polarization and these phenomena seem to favour the raise of social unrest. Indeed, we live in a world in which conflict is all present in our everyday life. Civil wars, strikes, riots and all kinds of social tensions or open conflicts are daily reported in the press. Social conflict has always been a fundamental area in Sociology and Political Science. The main focus however has been on case study rather than on the building of a formal theory of conflict. On its side, Economics is now starting to address this issue. All in all, the different areas of the Social Sciences have analysed conflict from nearly independent points of view. There is much to be gained by combining the different disciplinary approaches, as well as by putting together theorists and applied researchers. Furthermore, we are persuaded that by coordinating our research we might be able to have a greater impact on the thematic research priorities of our disciplines.The purpose of this multi-disciplinary research project is to promote and coordinate research on the conceptualization, modelling and measurement of polarization and conflict and the links between the two. We find especially fruitful to bring closer together towards a common, analytical framework the intellectual traditions that have developed quite independently in the different disciplines in the Social Sciences. Furthermore, we attempt at bringing together scientists specialised in data collection and case analysis with the researchers more specialised in modelling and in using quantitative methods.Main tasks for a research programA first essential task is to integrate the theoretical work that is being developed in the different areas of the social sciences. This might be decisive in establishing the study of polarization and conflict as a major area in the social sciences.A second task is to promote a stronger interaction between empirical and theoretical work. Empirical evidence is now quite rich and hopefully permits the drawing of the fundamental regularities in conflicts. On the other hand, we are equipped with tractable models that can be empirically tested. We can expect major advances by combining the two approaches. This will require bridging the present gap between the more analytically minded scientists and the various research centres devoted to data collection and to the study of specific cases of conflict.There is a third, long-run task. This involves a more conceptual type of work. This is to push for a different view of social interaction. On the one hand, we do observe that conflict and fight are a rule rather than an exception. Opposing interests are often settled in the courts. At the societal level, we also observe frequent open conflicts between groups and countries. But, on the other hand, and even most important, social agreements are quite often conditioned by the power of the parties. We thus need to understand the outcome of conflict if we wish to explain the terms of an agreement.Summary of potential thematic lines of research1. Understanding conflict (Itzhak Gilboa)1.1. Modelling conflict1.2. Group formation1.3. Social and economic structure and conflict1.4. Conflict and groups in a multidimensional world1.5. Social and economic consequences of conflict2. Measurement (Conchita d¿Ambrosio)2.1. Inequality and polarization2.2. Social exclusion and discrimination2.3. Social and economic mobility3. Agreements in the shadow of conflict (Jean-Paul Azam)3.1. Right and might in agreements3.2. Institutional arrangements to lessen conflict3.3. Political systems and conflict of interests4. Governance and conflict (David Stasavage)4.1. Stability of democracies and economic development4.2. Political parties and conflict of interests4.3. The working of democratic institutions4.4. Crime and violence in a polarized society
