1
Introduction

When you walk the streets of major cities of the world, such as Cairo, London, Mexico City, New York, São Paulo, Sydney, Tokyo, and Toronto, you will quickly notice different groups of people living in different parts of the city. In some neighborhoods, most residents are of the same racial or ethnic group. They tend to know each other well as many of them have grown up in the same neighborhood. In middle-class neighborhoods, you may see rows of well-maintained houses with manicured lawns. In other parts of the city, you may also see areas with high concentration of poor families, dotted with dilapidated houses, unkempt yards, and graffiti on walls. Some other neighborhoods are home to clusters of immigrants where you may see shops and restaurants with foreign words on storefront signs. The distinctiveness and spatial arrangement of these neighborhoods contribute to the pattern of residential segregation in a city, which is the subject this book will explore.

Residential segregation creates and maintains the separation of population groups into distinct neighborhoods and shapes the living environment at the neighborhood level (Kawachi and Berkman 2003). This separation may be voluntary or involuntary. Residential segregation has most commonly been applied to the study of racial segregation, but it can be used to study the sorting of a variety of different groups into neighborhoods and other social environments (e.g. on the basis of race/ethnicity, income, age, household type, sexual orientation, religion, etc.). Most of this book will focus on residential segregation by racial/ethnic status because it has received by far the greatest amount of attention due to its role in social stratification, inequality, and conflict within society. Because racial/ethnic status is correlated with income and wealth, any investigation of segregation involves examining patterns that represent the effects of both racial/ethnic identity and economic status of people and their residential communities.

How does residential segregation relate to patterns of segregation more generally? Table 1.1 provides a simple conceptual guide that relates segregation to the social and physical distance of groups. The most common way of studying residential segregation is to examine situations where there is both physical and social distance between distinct groups. The word "residential" in residential segregation usually implies groups living in completely different neighborhoods, which are most often approximated by census tracts in empirical research. The physical distance of being in another neighborhood implies that there is also social distance, so residential segregation most commonly means both physical and social distance. In the table, we label this "complete" segregation. Research examining this kind of segregation represents the bulk of research on residential segregation and will take up most of our attention in this book. For example, in many large cities in the United States, a situation of high segregation, sometimes called "hypersegregation"1 (the concept will be elaborated in Chapter 4), persists between blacks and whites, whereby the sharing of neighborhoods and social environments is uncommon (Massey and Denton 1989).

Table 1.1 How residential segregation relates to physical and social distance

  Social distance Social closeness Physical distance Complete segregation:
Lack of social interaction and not living in the same neighborhood Community without propinquity: Maintaining social interaction but not living in the same neighborhood (e.g. complete lockdown during pandemic, soccer fanatics, Chinese diasporas, online gaming groups, antifa) Physical closeness Partial segregation:
Lack of social interaction despite living in the same neighborhood Complete integration:
Maintaining social interaction and living in the same neighborhood

Increasingly, in contemporary multicultural cities, we see a more nuanced form of segregation, whereby different groups share spatial territory (physical closeness) but have substantial social distance from one another. We term these situations "partial" segregation. Studying this kind of segregation presents both conceptual and methodological challenges for researchers. This is because despite sharing a neighborhood, a variety of physical, social, and symbolic boundaries may stifle meaningful social closeness between groups. These within-neighborhood boundaries may include the built environment (e.g. high-rise vs. low-rise residence), language, interests, affiliation, consumption practices, patterns of use, and many others. For example, in Toronto, despite sharing the same neighborhood as measured in conventional analyses, new immigrant families living in low-rent apartment buildings along major avenues are often socially distant from the long-standing residents who own single-family homes on quiet residential streets within the neighborhood. Another example is the case of social connections during a pandemic when we practice "social distancing" by keeping some degree of physical distance from our neighbors. One of the challenges in the study of segregation is to understand how and why some groups remain segregated once there is physical closeness, even after a long time. We will spend some time discussing this more complex form of residential segregation and describe how new measures and methods are needed for understanding it.

The existence of both physical and social closeness between groups, which we label "complete" integration, is an uncommon and idealized situation that is useful as a reference point. Social theorists for generations have sought to define social integration, which usually entails normative, functional, and communicative integration between group members (Durkheim 2002 [1897]; Habermas 1984; Parsons 1951). There are debates about whether such integration can be achieved in multicultural societies in a way that meaningfully and fairly incorporates diverse ethnic identities, people, and backgrounds. In Chapter 2 and beyond, we will expand upon these ideas as they relate to residential segregation.

Finally, it is worthwhile to note that in our ever-connected globalized world, it is possible to achieve social closeness with others despite physical distance. We term this combination "community without propinquity" in the table, in homage to Webber's (1970) description that the basis for social closeness between some in urbanized societies is not proximity of a local neighborhood, but common interests, be they political, religious, or leisure. This perspective is also in line with a social network view of community, in particular a community-liberated perspective, which stresses that contemporary communities are based on social networks of a diverse range of people in a diverse range of locations and are liberated from spatial arrangements (Wellman 1979). Members of these groups sometimes come together episodically for meetups, but most group communication is online. As the online world allows for more connections and richer forms of communication, people are increasingly creating and maintaining social closeness forged by common identities, interests, and associations. The glue that binds these individuals can be a variety of things, including shared affinity for particular interests in mass culture, a particular subculture, ethno-religious identity, and cultural connections of diasporas. Resonating with Claude Fischer's subcultural theory (1975), online communication technology today is a tool that gives individuals increasingly rich access to all the heterogeneous identity groups of contemporary society. What does segregation based on physical distance mean in a world of ever-richer forms of online connection possibilities? We will revisit situations of "community without propinquity" later in the book.

Residential Segregation: Bird's-Eye, Drive-By, and On-Foot Views

The common prevalent and consequential forms of residential segregation are visually apparent as we move across most major cities in North America. The most encompassing view of residential segregation - the "bird's-eye" view - sees what proportions of people belonging to different groups live in different neighborhoods across an entire city. These proportions can be color-coded onto a map of the city to reveal broad patterns, or these proportions can be summarized into an "index of dissimilarity," an index ranging from 0 to 1, with higher values indicating higher levels of segregation, or other measures that seek to capture essential qualities of segregation in a single number. (These indices will be discussed in Chapter 3.) Despite its utility for broad observation, the bird's-eye view misses a lot of details about segregation that may be important.

If we shift to what we observe driving a car along the roads, we see a bit more detail. For example, driving on Lakeshore Drive in Chicago from the north side to the south side of the city, you can see stark transitions in the racial and economic composition of residents and their neighborhoods. The combined effect of changes in both racial and economic composition of various urban communities can make it easier to visually identify changes during this drive. In the north, you see more middle-class...