"Nowadays, they say, everything is moving faster and going further" (Kaufmann, â€¦, p. 41). Our world seems to shrink for those who are able to connect in the swift evolving networks: we live in a hypermobile epoch where flows are both speeding up and spreading out (Adams, 1999). As Tim Cresswell (2006, p. 1) wonderfully points out in his book 'On the Move': "Moving your hand, walking, dancing, exercising, driving to work, moving home, going on holiday, marching, running away, immigrating, travelling, exploring, attending conferences. All of these are forms of mobility but they rarely enter each other's orbit in social and cultural enquiry. The slippery and intangible nature of mobility makes it an elusive object of study. (â€¦) From the first kicks of a newborn baby to the travels of international business people, mobility is everywhere". It is clear that something what we call 'mobility' seems to affect, structures and classify every ingredient of our live.
Defining what mobility is is extremely difficult because of the broad appliance within all different kind of fields (Urry, 2007; Hubbard, 2006, p. 165-173). Mobility is also used differently in the many scientific fields: "When a geographer uses the term 'mobility', s/he wants first to evoke the idea of movement in a geographical space. This is not talking about the same thing as the traffic engineer for whom mobility refers to transport flows, or the sociologist for whom it refers to change of social position or role" (Kaufmann, â€¦, p. 41). But also the appearance in every space around the globe.
In this difficulty of defining (and promoting as Urry tends to do (Urry, 2007)) mobility, this diversity of acceptances becomes an obstacle to understand mobility. In other words, when we speak of mobility, we are not exactly sure what we are talking about-it all depends on which social science we are coming from.
As an array of geographers such as Tim Cresswell (2010), Doreen Massey (1991), and Nigel Thrift (1996) have suggested, we need to rework our definitions of place, taking account of complex spatialities and temporalities, and the ongoing mobilities of people, nonhuman things, and information into and out of places. Rather than thinking of places as fixed, rooted, frozen in time and space, and closed off to the world, we need to think of places as relational, open to the world, and 'in process'. Places are constantly performed through the 'gathering' of materials and movements. It is useful, here, not just to think of 'places' as concretized 'nouns' or 'things', but to think about the ongoing, incessant 'placing' of the world, and the processes which lead to the emergence of both highly reflexive and mundane/backgrounded attachments, associations, and significations. An understanding of different mobilities and mobile processes can therefore highlight the importance of conceptualizing place as a noun and a verb. Places are continually undergoing processes of 'placing' and the same could be said of landscapes.
0. Hypermobility, the mobility paradigm and the lack of identity of places
0.0 The mobility paradigm?
The sparkling new discovery - a noise which John Urry (2007) tediously articulate in his book 'Mobilities' - of the 'new mobilities paradigm' and the 'mobility turn' has become omnipresent in contemporary social, geographical and cultural sciences (Cresswell, 2001; 2006 & 2010; Hannam et al., 2006; Kaufmann, 2010; Hubbard, 2006, pp. 165-173; Urry, 2007; Peters et al., 2009) and is simultaneously suggesting something revolutionary and entirely new by some researchers while others firmly reject (Cresswell, 2010). John Urry (2004, cited from Hubbard, 2006, p. 171) claims that: "there is a 'mobility turn' spreading into and transforming the social sciences, transcending the dichotomy between transport research and social research, putting the social into travel and connecting different forms of transport with the complex patterns of social experience conducted through various communications at-a-distance". Indeed, the attention to issues of mobility opened up new relations and inspired many scientists in diverse disciplines (see Blunt, 2007, pp. 684-687). The new academic journal 'Mobilities' (the first edition was presented in 2006, see Hannam et al., 2006) suggests to establish this vast body of attention as the 'new paradigm' which raises deep-rooted questions about 'the appropriate subjects and objects of social inquiry' (Hannam et al, 2006, p. 10).
The wide scope of this research field not only encompasses mobility across a wide range of forms, practices, scales, locations and technologies (â€¦), but also interrogates the politics of mobility and immobility (Baeten, 2000; 2010), the material contexts within which they are embedded, and their representational and non-representational dynamics (Thrift, 1996; 2008).
As with many scientific theorisations the aim of the mobility paradigm has been seen as something "other than the norm" (Cresswell, 2010, p. 3-4; citation: Adey, 2006, p. 77). This is particularly caused throughout the humanist interpretations that gave pessimistic connotations as contradiction to fixity and boundedness of place and territory (Cresswell, 2004; Delaney, 2005; Tuan, 1977). Cresswell (2010, p. 3) labels this as 'sedentarist'. Thus, the places where we live, spend time and lay down meaning are seen as extremely immobile places. For geographers such as the humanist geographer Edward Relph (1976) the airport or the motorway, are even seen as placeless - abstract and without meaning suggesting that increasing mobility had brought, through globalization (Sassen, 1998 & 1999), the extension of placelessness in the twentieth century. Antony Giddens (1990, p. 29) contends that his strechting of social relations has produced a "global present" where world events, people and lifestyles are increasingly visible in our everyday surroundings. Appadurai (1996) likewise suggestes that the prodigious mobility of people and goods is producing new global landscapes that we now take for granted. The French anthropologist Marc Augé (1995) offers examples of common examples include spaces of mobility such as motorways, airports, and hotel lobbies, as well as other spaces of modern consumption and circulation, like restaurant franchises (such as global chains like Starbucks and McDonalds; see e.g. Ritzer, 2004), shopping centers, theme parks, and industrial estates. He call these spaces 'nonplaces'. Augé argued that 'nonplaces' were characteristic of an era of 'supermodernity', with an excess of information, increasingly mediated social relations, a shrinkage of space, and people becoming increasingly closed-off to the world (not having a local identity). Nonplaces were seen to be fairly generic ubiquitous spaces of detachment and solitariness - environments dominated by a devotion to mobility to the exclusion of any sense of fixity, place or local identity.
X Accordingly, they are governed by explicity 'extra-architectural' and non-local rules of play or economic interaction. Similar in design throughout the world, and offering a standard repertoire of services. Experiences of distraction, boredom, solitariness, and detachment are characteristics of all manner of environments and the production of many different places (Sorkin, 1992), in line with the globalization and standardization of architectural styles (Harvey, 1989) and the fact that a large proportion of travelers may not actually reflect on or remember their surroundings. People may feel isolated or bored at home, at work, or in picturesque villages (which are frequently upheld as the archetypal, meaningful social place). What is more, while spaces of mobility may appear to be asocial environments where people rarely converse with one another, and where there is little sense of community, academics such as Marc Augé operate with rather narrow and conservative definitions of both 'the social' and 'place', overlooking the ways in which different mobilities may be conceptualized and enacted as practices of connection, and the importance of all manner of material technologies in social relations. Mobile telephones, letters, e-mails, light houses, or indeed car horns, wing mirrors, and indicator lights, are integral to the social relations and communications of mobile actors, and mobilities are produced and performed through an array of more-or-less transitory, individualized and embodied social relations and associations with these and other things.
This is clearly outlined by the Swiss writer and philosopher Alain de Botton. He wrote a marvelous piece of work entitled 'A Week At The Airport: A Heatrow Diary' (De Botton, 2009) and, starting from the idea of a 'non place', noticed the differences of people passing by in the airports' lounge. For his work he spoke with everyone from airline staff and senior executives to travelers passing through, and based on these conversations he produced this extraordinary account of life at an airport and what it says about modern existence. He stress that we often miss the contact at the airport and therefore interpreted it as something as a 'non place'. Differences are, however, more present than we might expect.
X From the other side of the coin, more recent approaches show signs of a 'nomadic metaphysics' (Cresswell, 2001). In this schema, mobility is constructed as a means to transgress power structures through both material and metaphysical domains. Seen primarily in scholarship influenced by the philosophers Gilles Deleuze and Felix Guattari (1988), though not necessarily in their own work, power structures of domination are given fixed and immobile characteristics, while mobility is attributed with an emancipatory power (Cresswell, 1997). In David Harvey's (1996) treatment of the circulations of capital, although he is trying to foresee a dialectical flow of money and material processes, there must be some permanencies, some 'solid foundations' somewhere.
X Obviously, for some the new-found hyper-mobility of capital, migrants, workers and commodities unroots the city from time and space, to the extent that they find it difficult to imagine cities as bounded space-times with definite surroundings (Adams, 1999; Crang, 2002). For others, this intensification of mobility and movement merely signals a change in the role of cities as articulators of capitalism, with some cities gaining, and others losing (Sassen, 1998 & 1999).
0. New paradigm
But is it a new paradigm? [Cresswell] Bruno Latour has suggested that there are only three problems with the term Actor Network Theory - and they are the words "actor", "network" and "theory" (Latour, 2005). A similar point could be made of "new mobilities paradigm". First of all the work "paradigm" suggests the Kuhnian notion of normal science being transformed by sudden revolutions where what went previously is unceremoniously tipped into the junkheap of academic history (Kuhn, 1996). We have to be careful about such implications. Any study of mobility runs the risk of suggesting that the (allegedly) immobile - notions such as boundaries and borders, place, territory and landscape - is of the past and no longer relevant to the dynamic world of the 21st Century. This would be wrong and, to be fair, does not seem to be the point of advocates of the new mobilities paradigm where "moorings" are often as important as "mobilities". The second problem concerns the different ways the "new mobilities" bit can be read. If the emphasis is on the word "new" then this suggests an old mobilities paradigm. If the emphasis is on the word "mobilities" then this suggests that old paradigms were about the immobile or sedentary. The second of these options seems untenable because movements of one kind or another have been at the heart of all kinds of social science (and particularly geography) since their inception. In sociology notions of movement and mobility were central to the concerns of thinkers such as the Chicago School sociologists for instance (Park et al., 1974 ). If we think of geography there have been any number of sub-disciplinary concerns with things and people on the move ranging from Saurian concerns with origins and dispersals through spatial science's fixations of gravity models and spatial interaction theory (De Pater & Van der Wusten, 1996; Aitken & Valentine, 2006). Transport geography, migration theory, time geographies, geographies of tourism - the list is endless. The same could be said of anthropology. So the question that arises is, what is "new" about the new mobilities paradigm?
Despite all the caveats above there clearly is something "new" about the ways mobilities are being approached currently that distinguishes them from earlier accounts of movement, migration and transport (to name but three of the modes of mobility that have long been considered). If nothing else, the "mobilities" approach brings together a diverse array of forms of movement across scales ranging from the body (or, indeed parts of the body) to the globe. These substantive areas of research would have been formally held apart by disciplinary and sub-disciplinary boundaries that mitigated against a more holistic understanding of mobilities. In addition, the approaches listed above were rarely actually about mobility but rather took human movement as a given - an empty space that needed to be expunged or limited. In migration theory movement occurred because one place pushed people out and another place pulled people in. So despite being about movement, it was really about places. Similarly transport studies have too often thought of time in transit as 'dead time' in which nothing happens - a problem that can be solved technically (Cresswell, 2006). Mobility studies have begun to take the actual fact of movement seriously. Here I further develop such an approach by focusing on the entanglement of the fact of movement, meaning and power. In this formulation mobility exists in the same relation to movement as place does to location. I develop this notion in more detail taking forward some of the approach to mobility recently developed in On the Move (Cresswell, 2006) and suggested by Norman Bryson in his arguments for a new field of "social kinetics" (Bryson, 1997) - a field which would chart the history of socially-structured movement. While the term kinetics has a residual scientism about it and the adjective social is much abused, I build on this notion to suggest a way of thinking about mobilities that brings together more or less coherent, if fragile, constellations of physical movement, meanings and practices. I want, then, to understand mobility holistically, as part of historically specific constellations of mobility that pervade a multitude of specific instances of people on the move.
0.0 Mobility is always present, even if we do not mention it explicitly
Indeed, as Cresswell (2006) critically examine, it is not something revolutionary new. Kaufmann (..., p. 42) stress the term 'mobility' came into use in the 1920 by the publication entitled 'Social Mobility' by the Russian-American sociologist Pitirim Sorokin (1998 ). Sorokin introduced two forms of mobility within the social world: horizontal mobility and vertical mobility. "By horizontal social mobility, or shifting, I mean the transition of an individual or social object from one social group to another situated on the same level. Transitions of individuals, as from the Baptist to the Methodist religious group, from one citizenship to another, from one family (as a husband or wife) to another by divorce and remarriage, from one factory to another in the same occupational status, are all instance of social mobility. So too are transitions of social objects - the radio, automobile, fashion, communism, Darwin's theory - within the same social stratum, as from Iowa to California, or from any one place to another. In all these cases, shifting may take place without any noticeable change of the social position of an individual or social object in the vertical direction. By the vertical social mobility, I mean the relations involved in a transition of an individual (or a social object) from one social stratum to another. According to the direction of the transition, there are two types of vertical social mobility: ascending and descending, or social climbing or social sinking. According to the nature of the stratification, there are ascending and descending currents of economic, political, and occupational mobility, not to mention other, less important types. The ascending current exists in two principal forms: as an infiltration or the individuals of a lower stratum into an existing higher one; and as a creation of a new group by such individuals and the insertion of such a group into a higher stratum instead of, or side by side with, the existing groups of this stratum. Correspondingly, the descending current has also two principal forms: the first consists in a dropping of the individuals form a high social position into an existing lower one, without a degradation or disintegration of the higher group to which they belonged; the second is manifested in a degradation of a social group as a whole, in an abasement of its rank among other groups, or in its disintegration as a social unit. The first case of "sinking" reminds one of an individual falling from a ship; the second of the sinking of the ship itself with all on board, or of the ship as a wreck breaking itself to pieces" (Sorokin, 1998, pp. 174-175). Sorokin's work about mobility could be understood as a movement in geographical space, but its real implication was change at the social level.
Summary of social mobility. Source: Sorokin, 1998, p. 176.
Also the Chicago School emphasized the work on mobility (see Park et al., 1974 ), especially in geographical mobility with a focus on urban living, spatial segregation, and is further developed in the 1960s during the upsurge of the individual approach by the behavioralists and humanists. A clear ecological approach became continual in urban and social sciences, which shows similarities to earlier approaches. The enormous influence of the Chicago School with its human ecology approach (with the central terms of 'invasion' and 'succession') is omnipresent in earlier gentrification research. Concerning the human ecology approach the city developed through a competition for space. Processes of invasion and succession involved a chain reaction, with each preceding resident wave moving outwards and being succeed by a more recent type of residential class (see the ideas by Park et al., 1974 ). The final pattern of this process towards segregation (concentric circles) was the 'mosaic of social worlds' (or a residential mosaic; see Timms, 1971) and this was seen as a 'natural' equilibrium (Van Kempen, 2002).
0.0 Residential mobility and gentrification
Despite the broad applications of the ideas concerning the term mobility, in this essay I would like to work towards an idea in which mobility could indeed open up new perspectives and fields of research. In this essay, I explorer the (possible and fruitful) links between residential mobility and the field of gentrification. Let me first point out the ideas of residential mobility: move from one house to another, and pushed and pulled trough several factors and dimensions.
Residential mobility analysis, which developed in the 1960s, aimed to examine individual changes of residence within a given geographical area, focusing primarily on its causes, links, and consequences. As concerns the reasons for moving from one house to another, the observation that individuals do not necessarily move closer to their places of work or even to where their daily activities take place was undoubtedly one of the most important observations realized by the research in the 1960s. On the contrary, individuals (as well as businesses) are geographical inert, and moving mostly takes place within the region (Hospers, 2009, p. 9-11).
Work on residential histories appearing in the 1970s (again following the influential ideas of the Chicago School) addressed the links between residential mobility, career path, and life path. This research shows that in Western societies between the 1960s and 1990, a life change in fact illustrates the important connection between mobility as change and mobility as movement. Moreover, it parenthetically shows the practical interest in having a definition of mobility that incorporates change. Moving house seems largely to be the consequence of a personal event, such as a job promotion (that leads to an increase in income), the arrival of a baby, or a divorce. A change in the social status through social mobility, as suggested by Sorokin (1998), unmistakably also affects the residential mobility. The benefit of a dynamic analysis of residential mobility does not stop at the household level. Among the most significant advances in this area, of particular note is proof that residential mobility, since the 1960s in the United States, was the root cause of social segregation dynamics in cities and further polarization of the cities demographic composition (Marcuse, 1986; Van Kempen, 2002). Within this timeframe, we will see later, also gentrification pops up (Glass, 1964). This led to the fundamental observation that residential mobility shapes the city.
A widely documented observation that centres around three main phenomena: periurbanisation, relegation, and gentrification (to use Jacques Donzelot terms). According to scientific literature, the driving force behind suburbanisation is the popularity of a model of social achievement that brings property, single-family homes, and proximity to wilderness areas. Simultaneous with the suburbanisation trend was the development of another phenomenon-the return of certain populations to old, centrally located, inner-city neighbourhoods (Caulfield, 2005, who sees a rejection of the suburbs and sees the inner city as a emancipation space; however earlier contested by Smith (1996, p. 70) who sees "Gentrification is a back-to-the-city-movement all right, but a back-to-the-city movement by capital rather than people"). This second process-typically termed gentrification-began in the 1960s and heightened in the 1990s (Hackworth & Smith, 2001). It boosted real estate prices that led to the gradual transformation of neighbourhood demographic structures and the displacement of working-class and underprivileged populations (Lees, 2001; Lees et al., 2003). The third phenomenon- relegation-was partially a result of the first two. Relegation can be defined as the social transformation of neighbourhoods tendening towards pauperization. The cause was the residential mobility of certain categories of residents who generally become property holders in peri-urban areas or who shifted to other urban neighbourhoods. The polarized city occurs (Marcuse, 1986), again after the sectoral ideas within urban planning (Hoyt & Burgess, ...).
This phenomenon, often associated with the housing estate crises in the suburbs, feeds on itself, fuelled by factors such as the reputation of schools. Migration, itself a veritable field of research, has been the subject of a great number of studies since the beginning of the 20th century and was also one of the favoured themes of the Chicago School. From early on, these studies treated international migration, internal migration (within a country), and in particular the phenomenon of urban residential 'flight'. Researchers interested in migration phenomena set forth a multitude of 'laws' and models, starting with Ravenstein's 'Laws of Migration', the Stouffer models on the process of attraction and repulsion (the 'push-pull' model), and the Zipf model, which introduced the effect of distance in 'push-pull' models. These works were at first quite quantitative, but gradually became more qualitative (Aitken & Valentine, 2006).
0. The example: Mobility in the urban area: displacement and gentrification
Mobilities are commonly constructed as fundamental to capitalist development and circulation and therefore we could say that mobilities could create unevenness and injustice (Baeten, 2000; Urry, 2006, pp. 185-210; Cresswell, 2006, pp. 147-174; Hubbard, 2006, pp. 204-205). Patterns of social inequality and spatial unevenness have long been thought of as the crucial temperament of gentrification. There are enduring statements about gentrification-induced displacement, as socially weak groups are gradually forced out of neighbourhoods being recast in the mould of more affluent newcomers (LeGates & Hartman 1986; Marcuse 1986; Hulchanski, 2007; Teixeira, 2007). However, within the current debates about gentrification, the initial focus on displacement is displaced to the periphery of the gentrification research (Slater, 2006).
Gentrification, the process by which decline and disinvestments in inner-city neighbourhoods are inverted (Smith, 1996), has emerged as one of the most controversial issues in the urban research (Davidson & Lees, 2007, p. 1187). By attracting a specific group of a (potential, e.g. young graduates) wealthy middle-class residents and encourage investment (Ley, 1996), gentrification has the potential to revitalize depressed inner city neighbourhoods (Zukin, 1982; 1987), but also already gentrified neighbourhoods tends to, especially in western cities, to gentrify again (Lees, 2003). After decades middle-class exodus and subsequently the emerge of disinvestment and declining tax bases, some view this as a welcome development (and suggest nobody is displaced because wealthy people move back to city again). The threat of displacement, however, whereby current residents are forced to move because they can no longer afford to reside in the gentrifying neighbourhoods has become such a concern that some are reflexively opposed to gentrification (Smith, 1996; Slater, 2006), especially because the idea of gentrification is emerged during a period of social segregation dynamics in cities during the 1960s (Glass, 1964). Indeed, the fear of displacement has been one of the motivating forces behind community activists organizing against gentrification (see e.g. Smith, 1996; Davidson & Lees, 2007). Moreover, some critical scholars look doubtfully at the central assumptions within gentrification: especially the assumption that it harms the indigenous residents by displacing them is often contested (Hartman 1979; Smith 1996). In fact, the conservative gentrification scholars suggests that sedentarism (e.g. the group should stay) is better than the progressive idea of nomadism (e.g. groups in city move because cities are subject to change), and therefore the conservative thinkers shown a lack of recognizing the dynamics of (capitalist) societies.
When discussing gentrification - in academic circles as well as with city planners, community activists, policy makers or journalists - the question of where the former inhabitants of gentrifying neighbourhoods moved to is very often raised. This question is very much in line with Millard-Ball's (2002, pp. 834) statement that "gentrification does not merely affect the single property or neighbourhood that is gentrified; the people displaced have to move somewhere, and the consequences can ripple up the 'chain of moves' that is initiated". Millard-Ball (2002) is suggesting, slightly similar as Smith (1996), a perspective from people driven by capital, instead of capital driven by people.
However, when we look for empirical evidence of displacement, the process by which neighbourhoods putatively undergo gentrification, the evidence is much less definitive despite some notable claims that there is evidence. Measuring gentrification is extremely difficult. Especially due to the lack of good methodologies and the difficulties to individually measurement of residential movements (Aktinson, 2000; Denkers, 2010). Two examples. The Canadian Sociologist Jon Caulfield (2005) claims a return of people who were previously moved to suburbs (due to better housing, more space and less problems) and went back to the inner city, suggesting the city is an emancipatory space. On the contrary, the American Marxist anthropologist Neil Smith (1996, pp. 53-58) suggests there is no evidence that people move back from the suburbs, instead he is - famously - suggesting "a back-to-city movement by capital rather than people" (p. 70). Existing literature has generally little to say about where former inhabitants of gentrifying neighbourhoods who moved out do actually relocate. This dearth of analyses has been linked to a scarcity of research tools to trace those leaving a neighbourhood (Atkinson 2000; Denkers, 2010).
Nevertheless, some scholarly, such as Van Criekingen (2008) works have paved the way for the exploration of the socio-spatial impacts of gentrification via analyses of migration flows originating from gentrifying neighbourhoods. Evidence from these works - typically making use of longitudinal surveys conducted on population samples - indicates, first, that heterogeneity in types of households and socioeconomic profiles is recurrent among sets of out-movers from gentrifying neighbourhoods (see e.g. LeGates and Hartman 1986). Put simply, neither all those moving in such neighbourhoods are new wealthy households, nor all those moving out are low-income displacees.
As Slater (2006, p. 748) has pointed out, methodological barriers to measuring the extent of displacement (movement) in quantitative terms "(â€¦) did not steer researchers in the way of a qualitative agenda to address displacement, but rather steered them away from displacement altogether". That is why in recent research the issue of "displacement itself got displaced from the gentrification literature" (Slater, 2006, p. 748). As Newman and Wyly (2006, p. 27) points the problem of quantification: "In short, it is difficult to find people who have been displaced, particularly if those people are poor... By definition, displaced residents have disappeared from the very places where researchers and census-takers go to look for them". This selective bias in quantitative methodologies could use the 'mobility turn' to solve this neglect in gentrification research. By example, Kaufmann et al. (2010) already publish a few attempts.
A study by Kaufmann et al. (2010) and Van Criekingen (2008) aims to shed light on the process of neighbourhood change in gentrifying neighbourhoods through (residential) mobility. More specifically, it will test whether displacement is the driving force behind demographic change in gentrifying neighbourhoods. In both articles they examine the gentrification trajectories taken by different inner city neighbourhoods (in the French Ile-de-France region (Paris metropolitan area) (Kaufmann et al., 2010) and the Belgian city of Brussels (Van Criekingen, 2008)), all neighbourhoods were characterized by a sharp increase in real estate prices and changes in the socioeconomic structure of the resident population. Research concerning failed gentrification processes (Ley & Dobson, 2008; Shaw, 2005; Kaufmann et al., 2010) is still rare: the recent tendency is to focus on success stories (and those success stories were often critically examined, but, according to Slater (2006), this critical perspective is vanished out of the research).
[Van Criekingen] Empirical results in the study conducted by Van Criekingen (2008) clearly shows that residential mobility patterns of very different nature are conflated in the set of migrants whose 2001 residence was in a Brussels' gentrifying district. Surely, the majority of these out-migrants do not match the idea of low-status residents being forced out of their neighbourhoods as gentrification develops in the inner city, i.e. gentrification-induced displacement. Rather, educated young adults in non-family households, renting homes from private landlords and strongly valuing the new, "trendy" atmosphere of inner neighbourhoods compose the largest group among these migrants. These households show high levels of residential mobility in relation with changing professional and family positions, and their residential trajectories are heavily focused on the densely-built urban environment, in Brussels or in other large cities. These findings eventually point to importance of middle-class young adults opting for the inner city as temporary holding areas among the protagonists of gentrification in Brussels' inner neighbourhoods. Yet, empirical results also highlight a specific mobility pattern associated with low status individuals moving out of gentrifying neighbourhoods (i.e. less-educated persons, unemployed people and workers). This group account for a sizeable 37% of the whole set of migrants considered in this study, and their destination municipalities are primarily in economically depressed areas, in the western part of Brussels or outside the city. The precise number of those among them who have actually been displaced by the advance of gentrification is an information that is not provided by the data and methodology used in this paper-such quantitative dataset actually does not exist for the Brussels' case. However, I argue that these findings make a relevant contribution to the debate on gentrification induced displacement for they outline a believable picture of the geography of displacement. That is to say that they show where former inhabitants displaced by gentrification are most likely to relocate. These households appear most likely to move over short distances, and relocate within the city, in impoverished working-class neighbourhoods in the western inner city in particular. Nevertheless, they are also likely to move over longer distances, leave the city and relocate in smaller cities hit by disinvestment in the post-industrial period where affordable housing opportunities are less uncommon. These findings echo earlier works that have commented on the growing social-spatial polarization of the Brussels' urban landscape. In addition, they validate to some extent appraisals by local community organizations (such as tenants unions and neighbourhood associations) that stress that part of the urban poor are being "exported" from gentrifying inner neighbourhoods in Brussels towards other, generally depressed cities in the rest of the country, hence adding even more load on supportive services in destination areas. In my view, these results eventually stress the relevance of re-invigorating research work on the many meanings and impacts of current waves of reinvestment in inner city neighbourhoods, including gentrification-induced displacement. Further empirical works are needed in this respect-both qualitative and quantitative ones, and views on the destination areas of those affected by gentrification are valuable contributions to this field.
[Kaufmann] The findings in the work by Kaufmann et al. (2010) indicate that an across-the-board hike in real estate prices in all six neighbourhoods masks the plural gentrification phenomena apparent in different strategies, aspirations, and manifestations of attraction or repulsion. Fundamentally, this situation harks back to a diversification of gentrification models, or rather a diversification of residential mobilities within the middle classes and its expression in the urban environment. This raises an essential methodological question: the observation of the social upgrading of any given neighbourhood alone does not reflect the diversity of gentrification processes. Only by looking closely at the logics of action of the individuals involved and repositioning them in the historic context of the neighbourhoods were we able to account for the diversity of gentrification processes and the factors that shaped them.
The identification and analysis of the trajectories of the six neighbourhoods shows clearly that there are several distinct gentrification processes. Thus, we are not observing a "stage model" (to use the term coined by Neil Smith in 1996) but several processes. A first process-the closest to the stage model-could be described as bohemian (or culturally oriented) gentrification dynamics. This process-which is, in fact, multi-staged-begins with "pioneer" gentrifiers' attraction to a depressed neighbourhood , followed by something akin to the arrival of "bohemian" middle classes gentrifiers and finally ends with the arrival of more traditional middle classes. Among the cases we studied, Bagnolet, Montreuil and Ménilmontant typify the first process. A second process-also resulting from a deteriorating built environment, but in this case followed up by demolition and subsequent large-scale reconstruction of the neighbourhood - might be described as real estate-driven gentrification dynamics, akin to what Davidson and Lees (2005) call "New-build gentrification". We identified such dynamics in La Réunion, an area that attracts an "upwardly mobile middle class" population on the lookout for affordable property. A third process could be described as thwarted gentrification. These are cases where the dynamics of gentrification are partially or completely defeated by the nuisances encountered on a day-to-day basis by middle class residents along with the level of effective social housing.
Our results indicate that only by focusing on the long term trajectory and the daily life of and in a neighbourhood can we understand the reasons for "thwarted gentrification phenomena". Static analyses attentive only to the structure of the property market do not account for the nuisances that over time make an environment intolerable and drive residents away. Thwarted gentrification mirrors another phenomenon at the heart of this debate: "colonisation", i.e. the unfortunate effect of ongoing gentrification that drives out former residents (Bridge & Atkinson, 2005). These two opposite situations (thwarted and ongoing gentrification) may be approached symmetrically, as both refer to the ways in which one lifestyle may exclude another. The "colonisation" issue therefore invites us to pursue more extensively our study of the various expropriation mechanisms involved in urban development. For a better understanding of the diversity of these exclusion mechanisms, our studies suggest that we must consider the many ways the built environment influences choices and lifestyles, as well as the level of tolerance to social diversity among middle class gentrifiers. Thus, during residential decision-making, certain elements become particularly important (price and type of available housing, access to public transport, reputation linked to the degree of social diversity, etc.), while others crop up in the long term as a result of day-to-day problems (noise, school-related issues, unease in the public space, etc.). Each of these relationships to the built environment is likely to dynamically add to the phenomena of expropriation: exaggerated prices that make certain strategies impossible, a bad reputation that clashes with certain aspirations, or negative sensitive qualities that become increasingly intolerable.
The study of gentrification thus opens the door to a fundamental reflection on the diversity of relationships to the city and the public policies likely to foster this diversity, thus ensuring an inclusive city and allowing individuals and families with substantially different means and modes of living to find their place in the city.
This phenomenon - gentrification - is not limited to spatial mobility, also concerns social mobility. Thus, paths of upward social mobility are specific to the migrant, the type of migration, and the professional career. This observation illustrates the need for and pertinence of a global approach to mobility.
We should aware, both with the issues of mobility as well as with the issue of gentrification and many other issues within social sciences, that we should focus on clear concepts and not fall in an utterly long process of defining what mobility or gentrification is, should be or could be. It is more important to discuss the effects in specific fields and relations between subjects.
By using the research of Kaufmann et al. (2010) and Van Criekingen (â€¦) it is useful to add mobility to the field of gentrification, especially the methodological approaches of mobility could be used to cover the methodological gaps within gentrification research (Denkers, 2010).
Human geographers have held a long-standing interest in different mobilities, focusing on geographical patterns of migration, transportation, and tourism, but in the last decade or so there has been a resurgence of writings on mobility in human geography and across the social sciences. With the increasing purchase of anti-essentialist, post-structuralist thinking, participative and performative methods, and the emergence of an interdisciplinary interest in themes such as globalization, transnational migration, diasporic cultures, communication technologies, and the geographies of the car and airport, so the topic of mobility has assumed a more prominent position in a wide range of international, interdisciplinary debates and agendas. Mobilities have been celebrated for their transgressive potential, but social scientists have argued that we must not see a language of mobility, flux, and movement as a simple solution to overcome sedentarist thinking.