One consistent finding in research on social movement organizations is that people's participation as well as their involvement in the formation of these organizations is linked to their structural location in several social dimensions. Hence, understanding the premises for social movement organizations is ultimately a question of examining the structure of people's social networks.
Drawing on these findings, the first study in this thesis argues that an individual's decision to leave a social movement organization is the result of similar influences. By using information about membership turnover in a local Swedish temperance organization, the question of whether existing members' dropout propensity is related to prior members' dropout decisions is tested. It is found that existing members' dropout propensity increases when their socially relevant others drop out of the organization. The results suggest that the decision processes concerning leaving and joining an organization are mirror images. This should have implications for any analysis of social movement organizations because only when this duality of interpersonal influences is considered can we fully understand the social dynamics of social movement organizations.
The second study in this thesis calls into question an important and usually implicit assumption in the literature, namely, that social movement organizations are units capable of growth. Organization ecology is an organization theory that has developed parallel to traditional social movement research. Ecologists have argued that organizations are inert structures that hardly ever change and that a micro process such as recruitment is only marginally important for the assessment of aggregate membership. To test whether the ecological argument is relevant for our understanding of social movements, a series of analyses are performed on three Swedish movements - the temperance, the free church, and the trade union movement. The results show considerable merit in the ecological argument and bolster the argument that we cannot fully understand social movements using micro models alone: the macro processes that influence organizational founding and disbanding also need to be included.
The third study addresses the free-rider problem from a network perspective. It is suggested that individuals' groups of relevant others are considerably smaller than is usually assumed in the work of Mancur Olson and his followers. Instead of focusing on the interest group as a whole, it is argued that a group of relevant others consists of those to whom the individual is tied through various social bonds. Since these groups tend to be small, social incentives are likely to be effective in inducing individual participation. These ideas are tested empirically by using microdata on members in a Swedish temperance movement organization. The results of the analysis support the "small group" thesis - additional movement members in the group of relevant others increase an individual's propensity to join a social movement organization. However, the results also lend support to Olson's free-rider thesis - when controlling for the composition of the group of relevant others, the more members a movement has, the less likely it is for an individual to join the movement.
Finally, the fourth study analyzes the relative importance of two networks in explaining the spatial diffusion of the Swedish Social Democratic Party. The first is a micro-network of interpersonal contacts and the second is a macro-network linking otherwise disconnected local networks. The macro-network considered here emerged out of the travel routes of political agitators affiliated with the Social Democratic Party. Party diffusion, thus, is analyzed as the combined result of two contagious processes operating at different analytical levels, and it is suggested that this multi-level approach provides a deeper understanding of the way in which the diffusion process operated. Analyses of a unique data set on the founding dates of local party organizations during the period 1894 - 1911 show that both types of networks were of considerable importance for the spatial diffusion of the Swedish Social Democratic Party.
Stockholm: Stockholm University , 1998. , 102 p.