CONTAGIOUS COLLECTIVITIES - ON THE SPATIAL DIFFUSION OF SWEDISH TRADE-UNIONS, 1890-1940

This article analyzes how distances and relations between actors are l ikely to influence the growth and spread of social movements. A formal theoretical model is developed that extends previous work on threshol d models of collective behavior. Spatial distribution of a population influences the networks that are likely to emerge within the populatio n; these networks, in turn, will influence the likely outcome of a mob ilization effort. Key theoretical predictions are tested using data on the.founding of local union organizations in Sweden, 1890-1940. The e mpirical analyses show that contagious spatial processes were of consi derable importance for the growth of the Swedish union movement, thus supporting the theoretical argument. The analyses presented in the art icle provide an alternative interpretation of density-dependent foundi ng rates to the one offered by organizational ecologists.