Intergroepexposure in tijd en ruimte Een kwantitatieve analyse van segregatie in activiteitenruimten

Measuring urban segregation - the uneven distribution of people in cities - is both necessary and challenging. It is necessary because it allows us to track changes in the city over time, assess the impact of urban policies, and explain other phenomena that may stem from segregation itself. One such example is our attitudes toward other groups: how welcoming we are toward people with a migrant background, or how much trust we have toward other ethnicities. This has much to do with how familiar we are with other groups. This familiarity grows through contact and exposure, which is, among other factors, limited by segregation. This is why measuring segregation is necessary. But why is it difficult? Reasons range from technical limitations and lack of universal definitions, up to the fundamental question whether any urban experience can be precisely measured. Segregation, as any other urban experience, can be very individual and shaped by many hard-to-measure factors. But even if we cannot measure it perfectly, we can move closer using new tools. This thesis applies such tools, using a new type of data to improve segregation measurement. Instead of limiting the analysis to one's residential area, it includes the places visited during daily activities - reflecting the fact that we meet people not only where we live but also where we spend time. Using large-scale geolocation data from mobile applications and social media, the research examines how incorporating mobility changes our measure of, and perspective on, segregation. The findings show that daily mobility strongly alters exposure levels: people from low-diversity areas often experience more diversity in their daily movements - and this holds for both residents with a migratory background and native-born residents. Importantly, acknowledging the role of mobility opens the door to new questions: for example, how does the level of segregation change across different spaces in the city , or how does segregation fluctuate within a 24-hour rhythm? I found that certain amenities - for example, green areas and public transport hubs - act as spaces of mixing, while others reinforce separation. We also show that incorporating the time component changes our understanding of segregation levels across different areas. Lastly, we return to the motivation for measuring segregation - its potential to explain attitudes. We found that acknowledging mobility can help in this regard: in particular, areas attracting more diverse visitors are linked with more positive attitudes towards migrants, demonstrating that visitor diversity, not just resident diversity, matters for social cohesion. Overall, this research demonstrates that incorporating mobility into segregation measurement changes both the results and the questions we can ask. Mobility reveals that segregation is not fixed but shifts 6 across space and time, with certain urban spaces acting as pivotal nodes in these dynamics. This perspective moves the debate beyond static descriptions of where people live and into the realm of how cities function socially on a day-to-day basis. It connects segregation research more closely to fundamental questions about urban equality, the right to the city, and the design of spaces that foster meaningful encounters across social boundaries. By treating segregation as a dynamic process shaped by movement, accessibility, and temporal rhythms, this work offers a framework that can better inform policies aimed at social cohesion and inclusion in increasingly diverse urban societies