Studies on ethnic residential segregation analyze how the inter-neighborhood mobility of individuals shapes their spatial distribution across cities. This literature has shown that the residential choices of households partly depend on the ethnic composition of their neighborhoods: higher in-group shares promote the presence of more in-group members, and vice versa. However, and in spite of the remarkable contributions, it remains unclear what exactly these studies refer to as "the neighborhood," and how alternative definitions could challenge previous findings. 

A large majority of studies have primarily adopted an administrative definition of the neighborhood due to limitations in the data collection process. Nevertheless, this definition has typically forced researchers to hold unrealistic assumptions about how households collect the information about the other individuals (Crowder and Krysan, 2016), and to treat the heterogeneity of social processes of large district areas as being homogeneous (Hipp, 2007). More generally, the large extensions of administrative areas have prevented an accurate description of how inter-group exposure affects the mobility dynamics of the individuals at more granular scales, and an assessment of the sociological concept of "the neighborhood" to analyze residential mobility dynamics. 

This thesis studies the inter-neighborhood mobility patterns of Westerner households for the years 1998-2017 in Sweden. In particular, it aims at analyzing in detail how close and how permanent inter-group contact and exposure must be in order to prompt native out-mobility and, consequently, ethnic residential segregation. In the first study, I examine how the spatial distance between Westerner and ethnic minorities moderates the salience of the minority presence and contributes to drive Westerner out-mobility. In the second study, together with Eduardo Tapia, I focus on examining how the previous out-mobility decisions of individuals foster further out-mobility of the in-group neighbors: the social influence effect on residential mobility. In the last study, I examine how the refugee crisis of 2015 has contributed to shaping natives' out-mobility through two modalities of local exposure on Westerners: asylum centers and refugees choosing their own accommodation. 

The Analytical Sociology approach (Hedström and Bearman, 2009) informs the research design of the thesis, which seeks to unravel the interdependent aspect of segregation processes whereby the previous mobility actions of individuals may trigger further mobility responses. By applying a counterfactual design (Woodward, 2003) and utilizing Swedish register data, I analyze native out-mobility following the exposure to ethnic growth near the residences of Westerners. This analytical strategy enables me to overcome common limitations of random sampling studies and capture the spatial interaction between individuals using a causal inference approach (Coleman, 1986). 

Results described in the above-mentioned studies provide empirical evidence showing the importance of the physical and social environment of Westerners to understanding their mobility patterns and the dynamics of segregation. Study 1 shows that growth in the minority presence in small areas centered on Westerners' home locations is capable of prompting native out-mobility. The closer the groups are to one another, the more likely it is to observe native out-mobility. These findings suggest that neighborhoods defined as administrative areas undermine the measurement of these kinds of interaction effects. 

Study 2 confirms the previous findings by showing a greater propensity to move out following Westerners moving out the closer they previously were to other Westerners' residential locations. Moreover, results also show that the higher the number of out-movers and the better the visibility of these out-movers in low population density areas, the greater the likelihood of Westerners of out-moving. By adjusting for theoretically relevant factors known to affect residential mobility, this study goes beyond out-group exposure and proposes a new alternative mechanism that partially drives the residential mobility of Westerners. 

Finally, Study 3 shows that the perceived temporal duration of ethnic change might also influence the mobility decisions of Westerners. More concretely, this study shows that temporary asylum centers do not prompt native out-mobility despite markedly increasing the visibility of out-group salience in the area where this temporary asylum center is established, not even for Westerners living in ethnically mixed areas. Conversely, the absence of this temporary restriction for refugees entering the housing market and self-selecting into Westerner-based areas positively increases native out-mobility, even despite refugees moving in produce overly lower increases in out-group salience. Moreover, native out-mobility is greater when the exposure to new refugees occurs in areas that are already inhabited by other non-Westerners.