Under 50- och 60-talet i USA växte bilismen och städer byggde väldigt mycket motorvägar. Trots detta började då i Washington, D.C. det förlopp som skulle leda till att de fick en tunnelbana på 70-talet. Denna uppsats studerar hur denna osannolika och oväntade tunnelbana kunde uppstå med hjälp av teorin om stigberoende.Genom att använda teorin om stigberoende som ett analytiskt verktyg, identifierar denna uppsats följande: (1) vilka små händelser, även kallade formativa moment, som startade processen att ge D.C. en tunnelbana, (2) den resulterande kedja av händelser, även kallade reaktiva sekvenser, vilka ledde tunnelbanerörelsen till den punkt där den upplevde självförstärkande processer. (3) Dessa självförstärkande processer, vilka slutligen resulterade i uppkomsten av tunnelbanan i D.C.Uppsatsen identifierar tre relativt små händelser som genom olika kedjor av reaktiva sekvenser leder till att kongressen, år 1965, beviljar tunnelbanan pengar vilket, genom efterföljande självförstärkande processer, säkerställer tunnelbanans uppkomst. / During the 50's and the 60's automobile usage in the United States grew significantly and cities constructed extensive highway networks. In spite of these trends, key events in the 1950's initiated a process that would result in the construction of the Washington, D.C. Metro System – one of the first metro systems built since the 1920's. By applying the Path Dependence Theory and examining narratives of actors and events in Washington, D.C. that influenced the development of the metro during that time, this paper shows how this unlikely and unexpected process occurred.Using the Path Dependence Theory as an analytical tool, this paper identifies the following: (1) certain small events, also known as critical junctures, which started the process of giving DC a metro; (2) the resulting chain of events, also known as reactive sequences, which allowed the metro (movement) to reach the point at which it experienced self-reinforcing processes; (3) these self-reinforcing processes, which finally resulted in the genesis of the metro in DC.The paper concludes that three relatively small events, through different chains of reactive sequences, led to Congress granting the metro funds in 1965 – which then brought about self- reinforcing processes that ensured the metro's genesis. / To be translated into English (upon request).; Appendix included.

This doctoral thesis examines the history of the Iraqw’ar Da/aw area in the Mbulu Highlands of northern Tanzania. Since the late nineteenth century this area has been known for its intensive cultivation, and referred to as an “island” within a matrix of less intensive land use. The conventional explanation for its characteristics has been high population densities resulting from the prevention of expansion by hostility from surrounding pastoral groups, leading to a siegelike situation. Drawing on an intensive programme of interviews, detailed field mapping and studies of aerial photographs, early travellers’ accounts and landscape photographs, this study challenges that explanation. The study concludes that the process of agricultural intensification has largely been its own driving force, based on self-reinforcing processes of change, and not a consequence of land scarcity.