*This paper develops a dynamic model of addiction on networks, where individuals' consumption is shaped by peer influence. We analyze the long-run effects of social interactions by characterizing steady-state consumption as a function of both network position and forward-looking behavior. We also examine the welfare implications of network structure and evaluate the effectiveness of various public policies aimed at reducing the demand for addictive goods. In particular, we study a key-player policy—modeled as a targeted rehabilitation program—that leverages the network’s interpersonal influences to maximize impact.

**Cultural integration has become a mainstay of policy discourse. Recent works point to two factors that play determinant roles in the cultural integration of a minority group : the number of cross-group linkages and the majority group’s response to the integration efforts of the minority. Motivated by these facts, I study a two-stage model of integration. Individuals belong to either the majority or the minority group and derive utility from their engagement with both cultures during the second stage. In the first stage, individuals can choose to ‘specialise’ in their own culture, increasing the utility they derive from interactions with their own culture, whilst decreasing that derived from the other. I show that individuals with a greater number of out-group relations are less likely to ‘specialise’ and that the relative strength of the majority culture is crucial in determining whether an equilibrium is ‘segregating’ or not.