Migration, Diversity, Integration and Social Cohesion.

Migration changes the social composition of cities, and societies increasingly ask whether diversity weakens or strengthens the bonds that hold communities together. This paper reviews the literature on four linked concepts, namely migration, diversity, integration and social cohesion, and asks under what conditions diversity is associated with trust and cooperation. Drawing on work from Europe, North America and Africa, it argues that diversity has no uniform effect on cohesion. Associations reported in aggregate data are sensitive to what is controlled, particularly neighbourhood deprivation, and to how groups are spatially distributed; evidence from Africa suggests that segregation, rather than diversity as such, is linked to ethnocentric trust. The paper develops a three-layer framework (structural, relational and symbolic) and applies it to urban Ghana, where migration is predominantly internal and regional and where informal economies and customary institutions mediate incorporation. It derives four testable hypotheses and proposes a convergent mixed-methods design for Kumasi. The paper is a conceptual review and reports no new field data.