From Passive to Active: A Multiplayer Economic Integration Process of Turkish Immigrants in Berlin

: Recently, economic integration of lower-skill immigrants in Western countries has become the most researched area in ethnic studies. Traditional studies have highlighted the inﬂuences of immigration policy and economic structure in the host society. This paradigm perceives immigrants as a passive actor in the economic integration process. Recently, more studies have paid attention to the active inﬂuence of lower-skill immigrants (e.g., informality, social and human capital accumulation, ethnic economy), presenting an academic transformation from passive to active economic integration. However, this transformation is disputed as the lower-skill immigrants’ active integration behavior does not afﬁrmatively represent successful economic integration. Moreover, inspired by the “three-way approach” model, whether lower-skill immigrants could successfully integrate may also depend on actors beyond the natives and lower-skill immigrants (e.g., visitors). In this sense, two questions remain uncertain: (1) In the process of an active economic integration, what are the roles played by the two traditionally highlighted actors? (2) Enlightened by the “three-way approach” model, is there a third or fourth actor exerting inﬂuences in the active economic integration process? To answer these questions, from a food ethnic economy perspective, we analyzed how actors play roles in the Turkish immigrants’ economic integration process in Mitte, Berlin. Through our ﬁeldwork observations and interviews, we concluded that (1) there are four actors in total (e.g., Turkish immigrants, Germans, non-Turkish immigrants, and transnational visitors) in the Turkish integration process, presenting a multiplayer model distinct from the traditional bi-player research framework; (2) Turkish immigrants launched the Turkish food ethnic economy through actively adjusting their ethnic food’s eating forms; (3) Germans promote the economic integration of Turkish immigrants by providing a larger market for Turkish ethnic food; and (4) non-Turkish immigrants and transnational visitors also promote the integration process through consumption.


Introduction
Historically, Europe has been confronted with massive and successive waves of immigration from its surroundings, inflicting potential public budget deficit and insecurity in the receiving countries. Meanwhile, the cultural contrast between natives and immigrants is also intensive, especially in religious and ethnic issues [1]. In this sense, an exclusionary and discriminatory attitude towards lower-skill immigrants has emerged in receiving societies, deepening the economic, social, and cultural conflicts between natives and immigrants [2].
To mitigate the conflicts, academics initially suggest that immigrants (in this context, "immigrant" specifically represents "lower-skill immigrant") should be encouraged to adapt their behaviors to the host society [3]. However, this notion is disputed as it arrogantly negates the positive effects of ethnic diversity [4]. In this sense, academics advocate "integration", which means that immigrants can be "incorporated by sharing their experience and history" with the receiving society [5]. Subsequently, the integration approach has become a hotspot in immigration research and an increasing number of studies on the process and mechanism of the integration of immigrants have sprung up in recent years.
Contemporarily, the integration of lower-skill immigrants can be identified as taking three key forms: economic, social, and cultural/identity, where economic integration is perceived as the most typical and influential form [5,6]. Traditionally, economic integration studies have highlighted the roles of immigration policy and economic structures, perceiving immigrants as passive actors, which presents a research mainstream from the perspective of "passive" integration [7,8]. However, recently, more studies have shown that immigrants play a much more active role, which presents a transformation from passive economic integration to active economic integration [9,10].
However, this transformation is disputed as the immigrants' active economic integrating behavior does not affirmatively represent successful economic integration [11]. Moreover, whether immigrants can successfully integrate may also presumably depend on actors beyond the natives and immigrants (e.g., visitors, local governments, original societies) [12]. In this sense, two questions need explicit analyses in further research: (1) In the process of an active economic integration through ethnic economy, what are the roles played by the two most highlighted actors (e.g., immigrants, natives)? (2) Enlightened by the "three-way approach" model, aside from the natives and immigrants, is there a third or fourth actor exerting influence on the process of active economic integration?
To answer these questions from a food ethnic economy perspective, we analyzed the successful economic integration process of Turkish immigrants in Mitte, Berlin through fieldwork observations and interviews. We collected basic data from the Turkish food sellers and consumers, and we then quantitatively analyzed what different consumer groups preferred among the different attributes of Turkish food. Finally, we put forward a multiplayer model to explain how Turkish immigrants, Germans, visitors, and immigrants from other origins play roles in the active economic integration process.

Integration Theory: Economic Integration, Social Integration, and Cultural/Identity Integration
Integration was first conceptualized by Gordon in 1964. In 1969, Park and Burgess gave one of the earliest definitions of integration, namely, "a process of interpenetration and fusion in which persons and groups acquire the memories, sentiments and attitude of other persons and groups and, by sharing their experience and history, are incorporated with them in a common cultural life" [5]. Since then, integration studies have received much attention in ethnic relation studies.
In the 1990s, Alba and Nee presumed that as time went by, immigrants would become more integrated into the host society economically, socially, and culturally [6]. This presumption identified lower-skill immigrant integration as economic, social, and cultural forms. On the basis of this identification, Wang and Fan supplemented identity integration, quoting Gordon's classical integration framework [5]. As identity integration (i.e., immigrants losing their own cultural/ethnic identity and instead accepting the cultural/ethnic identity of the dominant group) is a further discussion on immigrants' cultural integration, in this regard, we perceive economic integration, social integration, and cultural/identity integration as the three key forms of immigrant integration.
Economic integration refers to immigrants achieving a more equal or average economic standing when compared to natives in the host society through social or human capital accumulation, employment, and homeownership [5]. For instance, studies on Chinese, Indian, Slav, and Lebanese immigrants in Australia have shed light on a melting pot model where the employment rate and the income level of the third generation of the immigrants is more equal to the average in the host society than are those of the first and the second generation due to their language proficiency and better education [13]. Immigrants in Denmark steadily increased their presence in an ethnic neighborhood at the beginning of their arrival, but significantly declined after 15 years due to their move to a neighborhood with a higher presence of Danes [14].
Social integration refers to the extent to which immigrants adopt daily customs, norms, and practices indistinguishable from mainstream society, which can be measured by the extent of social adaptation, positioning, interaction, and identification [5,15]. For instance, over time, when compared to the first generation of Polish immigrants who immigrated to Australia to avoid WWII, the communication with the local natives among the second generation of Polish was more frequent due to their proficient English speaking, and the rate of their intermarriage with the natives was higher [16].
Cultural/Identity integration refers to immigrants losing their own cultural/ethnic identity and instead accepting the identity of the dominant group in the host society over time. For instance, the South Africans in New Zealand reconstituted a feeling of home and identity belonging to the host society to integrate culturally through home-making [17]. However, some multiculturalism scholars have disputed that cultural/identity integration does not necessarily mean losing one's original identity while acquiring a new one [18]. In fact, pan-ethnic identities, signifying the coexistence of the original identity and the new one, are more common [5]. For instance, as time went by, the original identity of Iraqis and Moroccans, measured by the degree to which the immigrants perceived themselves as Dutch, became weaker, but the frequency of social transnational contacts and ethnic cultural activities remained unchanged [19].
Although, based on studies on the Burmese in Norway and on Filipinos in Canada, social and cultural elements play more essential roles in the lower-skill immigrants' ethnic relations, economic aspects as the initial and substantial dynamics for immigration are still the most typical and influential ones [20,21]. Therefore, economic integration is "perhaps the most researched area of integration" [22].

Passive Economic Integration: Immigration Policy and Economic Structure
Among the various factors acting on economic integration, immigration policy has been highlighted. A large number of studies have concluded that immigration policy regimes play dominant roles in the economic integration of immigrants. For instance, the employment rate and average income of Somali immigrants in the UK are better than those of their compatriots in the Netherlands due to the mature immigration policy regimes in the UK, as the UK has a longer and more complex migration history than the Netherlands [23]. Better economic integration also took place for immigrants in Malmö, a Swedish city, and Genoa, an Italian city, both of which experienced a period of post-industrialization economic decline and implemented a series of pro-immigration policies to attract abundant immigrants for the demand for cheap labor [8]. Thus, pro-immigration policies (e.g., equal access for immigrants to social welfare and employment training) and a multinational conception of citizenship (e.g., strengthening citizenship education, providing citizenship classes to immigrants) are supposed to significantly promote the economic integration of lower-skill immigrants while unfriendly immigration policies prohibit it [24,25].
Conversely, an exclusionary attitude in immigration policies may impede the economic integration of immigrants. For instance, as the context in countries is generally quite different to the West, certain receiving countries like Sweden have refused to recognize the immigrants' skill certification obtained in their original country, which means that it is more difficult for immigrants in Sweden to find a job unless they receive compulsory employment training [26]. The overregulated employment procedures and social housing applications in Finland have also become obstacles for Asian, African, and East European immigrants trying to make a living in the host society [11].
Nevertheless, sometimes pro-immigration policies may also unexpectedly obstruct immigrants' economic integration. For instance, a large proportion of Tamils, Turks, and Pakistanis in Oslo, engaged in low-skilled works or remaining jobless, present a much lower rate and weaker passion to relocate "upwards, outwards, and westwards" to live in better neighborhoods than their compatriots in other countries. This contradictory phenomenon results from the higher welfare in Oslo, as the local government provides adequate well-equipped social houses for homeless immigrants and complete welfare for the jobless immigrants. Therefore, the immigrants' passion to work hard and to improve their living condition in Oslo is weak [27]. Similar to the previous study, Copenhagen provides immigrants with diversified desirable social houses, which has decreased the Turkish and Somali immigrants' passion to learn more skills, find higher-paid jobs, and live in a more integrated community [28]. Therefore, hospitable policies for lower-skill immigrants may instead impede their economic integration.
Furthermore, some academics have pointed out that whether the immigration policy is hospitable or hostile to immigrants depends on the local economic structures. For instance, Malmö and Genoa are experiencing a period of economic decline due to post-industrialization, so both these two cities hold a "welcoming" attitude towards immigrants for cheap labor [8]. The fluctuating process of Russian immigrants' economic integration in Israel has also resulted from the dynamically changing economic relations between Russia and Israel. Once the employment situation in Russia becomes better, Russian immigrants present a lack of passion when finding a job in Israel as most of them would prefer to seek jobs in their homeland [29]. Immigration policies in England and Wales have recently become more exclusionary towards immigrants because of the shortage of temporary accommodation and rising housing costs [7].
In this regard, academics have highlighted the impacts caused by immigration policy, the welfare institution, and economic structure on the economic integration of immigrants. However, these three factors are all activated by the host society. In other words, the above-mentioned studies perceive the immigrants' economic integration as a passive process as immigrants do not play a dominant role in economic integration.

Active Economic Integration: Informality, Social and Human Capital, and Ethnic Economy
However, over time, lower-skill immigrants do not always participate in economic integration only passively. Some recent studies have indicated that immigrants will also play an active role in economic integration through informality, social and human capital accumulation, and ethnic economy.
Informality provides lower-skill immigrants with a temporary springboard to earn for themselves. The informal economy employs immigrants in unregulated and unregistered sectors (e.g., street vendors, home-based work). In some host societies, as immigrants cannot be engaged in a formal job due to the nonrecognition of their skill qualifications or the mismatch of the employment training between the original and the host society, they divert to being employed in the informal economy [30]. Although this phenomenon initially takes place in developing countries, it becomes more common in developed countries due to continuous immigration. Moreover, studies have presented that it is the informal employment of immigrants that offers adequate manual labor for dirty, dangerous, and demeaning jobs. For instance, agricultural work in the city outskirts in Greece is toilsome. Hence, although it is necessary for Greek cities, few natives would like to be engaged in it. Consequently, local landowners begin to hire skilled immigrants for agricultural manual work like ploughing, sowing, irrigating, weeding, and harvesting, privately and seasonally. This informal employment provides jobs for immigrants on the one hand, and provides certain toilsome but necessary jobs with manual labor on the other, which is eventually encouraged by local governments [31]. Therefore, some scholars have disputed many studies that implicitly accept the opinion connecting informality to negative economic outcomes but arbitrarily overlook the positive effects on economic integration of immigrants [10].
Accumulating human and social capital is another common route for lower-skill immigrants to promote economic integration actively as both capital accumulations contribute to business start-up or participation in the formal labor market [32]. Human capital refers to observable human capital, like education level or work experience, and unobservable types, like ability and talent [33]. A study on Burundian and Burmese in Michigan, United States indicated that the proficiency of language provided access to necessary information and employment opportunities for these two ethnic groups, which significantly benefited their economic integration [34]. Social capital refers to the immigrants' relationship with other people and their ability to make use of the relationship to improve their economic well-being in the host society. Additionally, the family network and friend network are the most common social capital used by immigrants [35]. Moreover, the friend network is perceived as a more efficient route to economic integration as it can provide more valuable and diversified information related to employment while information provided by the family network is quite familiar to the individuals. This presumption has been proven by a study on day labor worker centers in the United States where immigrants, who seek employment information through a friend network built up at the worker centers, are more likely to be employed than their compatriots who stay at home and seek information through the family network [36]. However, although the friend network is more efficient, immigrants generally rely on the family network as it is difficult to truly get in with others, especially the natives [22,35]. In this regard, intermarriage with the natives becomes a compromised route to building up both the family and friend networks simultaneously, which exerts positive effects on male immigrants in Sweden [26].
Although informality and capital accumulation are two active ways for lower-skill immigrants to integrate economically, both of them rely heavily on the players in the host society. Recently, academics have pointed out that there is another relatively more independent and more active economic integration route for immigrants named the ethnic economy. The ethnic economy was first systematically conceptualized by a sociologist called Bonacich in the 1980s as "a type of certain economic activities with strong and obvious ethnic attributes while employers and most employees are ethnic immigrants". Subsequent studies on the Chinese in Los Angeles, Koreans in New York, Cubans in Miami, and Vietnamese in South California have generally focused on how the ethnic economy interacts with the formation of ethnic enclaves [37]. However, a study on Latino immigrants in Charlotte implied a potential relationship between the ethnic economy and active economic integration. In this study, most of the natives in Charlotte moved to outer-ring suburbs for a better neighborhood environment in the 1960s, leaving a dilapidated and vacant inner space. Due to the surplus stock of retail shops and low-rental housing units, Latino immigrants began to agglomerate in the inner city, starting up retail shops for handicrafts or clothing as well as ethnic food restaurants alongside Central Avenue, which was once one of the best commercial places in Charlotte in the late 1950s. In this sense, the inner space of Charlotte has been transformed into a Latino ethnic economic space, which has retarded the pace of inner city decline and regenerated the downtown area unexpectedly. At present, many newly arrived immigrants usually head to this place for jobs and rental houses where they can also build up their friend network and accumulate their social capital. In a word, this case study more or less proved the presumption that the ethnic economy positively influences the economic integration of immigrants [9].
To sum up, a transformation from passive economic integration to active economic integration has emerged in studies on lower-skill immigrants, and the ethnic economy exerts influential effects on the integration process. However, some empirical studies have disputed that a more active role played by immigrants in host societies does not mean an affirmative successful economic integration. Furthermore, inspired by the "three-way approach" model, whether immigrants can successfully integrate may also depend on actors beyond the two most highlighted actors (i.e., immigrants, natives) [12]. For instance, although African immigrants in Guangzhou (China), who are mainly engaged in the apparel trade and stimulate the local economy positively (e.g., pay tax, increase volumes of export, provide jobs for other immigrants, and even some local Chinese), they are overregulated and rooted out by the local government for the sake of social stability and security [38]. Although Estonian immigrants in Helsinki are active in making money, their motivation to engage in Finland permanently is weak due to the preferential policies on returnees implemented in their homeland, or due to their families' expectations [11].
Hence, although it has been proven that lower-skill immigrants are playing more active roles, two questions still remain uncertain or have been implicitly analyzed. (1) In the process of active economic integration through the ethnic economy, what are the roles played by the two traditionally highlighted actors (e.g., immigrants, natives)? (2) Enlightened by the "three-way approach" model, aside from the host society and immigrants, is there a third or fourth actor that exerts influence on the process of active economic integration?

Materials and Data Collection
To answer the above two questions from a food ethnic economy perspective, we focused on analyzing how the actors played roles in the economic integration process of Turkish immigrants in Berlin.

Case Study Area: Mitte, Berlin
Berlin, the capital city of Germany, is a world-class city with a long transnational migration history since the late seventeenth century [39]. After the 1939-45 War, the following economic boom led to a shortage of manual labor. Thus, the government of West Germany signed a recruitment agreement with Turkey in 1961 to attract "Gastarbeiter" (guest workers). During the Cold War, the downtown district named Mitte (meaning "middle" in English) was converted into prohibited military zones filled with desolation and horror after the construction of the Berlin Wall ( Figure 1). After reunification in 1989, the formerly desolated Mitte was massively invested in and drastically reconstructed, generating great demand for manual labor [40]. Due to the previously signed recruitment agreement, most of the Turkish immigrants, especially the less educated and low skilled, agglomerated in Mitte for construction jobs [4]. Consequently, we selected the unique but typical Mitte as our study area. traditionally highlighted actors (e.g., immigrants, natives)? (2) Enlightened by the "three-way approach" model, aside from the host society and immigrants, is there a third or fourth actor that exerts influence on the process of active economic integration?

Materials and Data Collection
To answer the above two questions from a food ethnic economy perspective, we focused on analyzing how the actors played roles in the economic integration process of Turkish immigrants in Berlin.

Case Study Area: Mitte, Berlin
Berlin, the capital city of Germany, is a world-class city with a long transnational migration history since the late seventeenth century [39]. After the 1939-45 War, the following economic boom led to a shortage of manual labor. Thus, the government of West Germany signed a recruitment agreement with Turkey in 1961 to attract "Gastarbeiter" (guest workers). During the Cold War, the downtown district named Mitte (meaning "middle" in English) was converted into prohibited military zones filled with desolation and horror after the construction of the Berlin Wall ( Figure 1). After reunification in 1989, the formerly desolated Mitte was massively invested in and drastically reconstructed, generating great demand for manual labor [40]. Due to the previously signed recruitment agreement, most of the Turkish immigrants, especially the less educated and low skilled, agglomerated in Mitte for construction jobs [4]. Consequently, we selected the unique but typical Mitte as our study area.

Data Collection
At the beginning of Turkish immigration, most of the immigrants were engaged in manual construction jobs. However, at present, the most common job type for Turkish immigrants is not as a laborer, but in the Turkish food retail shops. The Turkish food ethnic economy has become a successful economic integration route for Turkish immigrants in Germany [41]. In this regard, we intended to explore how Turkish immigrants, Germans, and other actors, if possible, acted on the whole integration process of the Turkish food ethnic economy in Berlin to respond to our research questions. Following these thoughts, we collected the basic data for further research on this presumption from the sides of both the Turkish food shops and the consumers (Table 1). We interviewed the owners of all Turkish food shops in our study to collect basic data (e.g., starting time, food products). We also marked down all locations of the shops on a map and recognized whether the shop was a formal fixed one or an informal movable one through field observations. We also interviewed consumers about their nationality, their intention to visit Berlin, and their preferences in Turkish food at two Turkish food shops, located at Alexanderplatz (Alexander Plaza) and Checkpoint Charlie separately (Figure 1). These two places are high profile as the former is a historical and renewed urban center where Rot Rathaus (the former city hall of Berlin), Fernsehturm (TV tower), and Alexander Bahnhof (the key railway interchange in Berlin) are located, while the latter, endowed with great commemorative value as a "window connecting two worlds", is one of the seven entrances for people from East Berlin to the West [41]. Every day, abundant natives, immigrants, and visitors all go there for shopping, sightseeing, leisure, or social activities. Therefore, interviews with Turkish food consumers at these two places could ensure the diversity and representativeness of the interviewees [42].

General Information on Turkish Food Shops
On the basis of our interviews with the owners or the staff of all Turkish food shops, there were in total fifty Turkish food shops in our study area, all of which could be identified as formal fixed shops or informal movable shops (Table 2). Forty-five of the fifty shops were formal shops, while the other five were informal. Among the thirty-nine formal shops accepting our interviews, the first shop was started in June 1997, and shops starting after 2010 took up the highest percentages. The two sole informal shops accepting our interviews were started in October 1998 and June 2002, respectively. Consequently, the Turkish food shops in our study area generally started after 2000, especially after 2010. The food products sold in these shops were identified as three types. The first type was the Turkish classical ethnic food, döner, and its derivative forms (e.g., vegetable döner, Turkish sandwich). The second type was some Eastern Mediterranean food (e.g., haloumi, falafel, schawarm), and the third type was local snacks (e.g., pommes, curry wurst, and fried chicken).

General Information on Turkish Food Consumers
We interviewed a total of 93 Turkish food consumers at the two selected food shops ( Table 3). All the consumers came from eighteen countries, while the ones from Germany represented the largest portion (29.0%). Among the total German consumers, 48.2% originated from Berlin, while the others came from Duesseldorf, Bremen, Dortmund, Cologne, Dresden, and Hannover. Among the 66 non-German consumers, 65.2% came from Europe (e.g., the United Kingdom, Italy, Poland, Belgium and Sweden), while the rest originated from Asia (e.g., China, Japan, Iraq) and South America (e.g., Brazil). Overall, the nationality composition of interviewed Turkish food consumers was quite diversified.  0  8  8  Italy  8  0  8  Poland  7  0  7  Turkey  2  4  6  China  0  5  5  Japan  5  0  5  Belgium  0  3  3  Sweden  0  3  3  Iraq  3  0  3  Denmark  2  0  2  Greece  2  0  2  France  1  0  1  India  1  0  1  Lithuania  1  0  1  Norway  1  0  1  Pakistan  1  0  1  Total  60  33  93 Of the 93 consumers, 29.0% were Germans, 23.7% were immigrants, and 47.3%, the most, were transnational visitors (Table 4). Among the German consumers, 55.6% were native inhabitants in Berlin, while the other 44.4% visited Berlin mainly for education and travel. Of the immigrants, 72.7% visited Berlin for jobs while the other 27.3% were there for education purposes. Unexpectedly, the job seekers originated not only from developing countries (e.g., Turkey, Iraq, Poland), but also developed ones (e.g., the United Kingdom). Meanwhile, five Japanese consumers and one Danish customer were international students, visiting Berlin for education. For transnational visitors, 81.8% visited Berlin for travel and sightseeing. Among them, 72.2% came from European countries (e.g., Italy, Poland, Sweden), suggesting that Europeans were the major group of tourist consumers. Seven transnational visitor consumers, consisting of five Chinese, one British, and one Lithuanian, visited Berlin for business. Only one French consumer visited Berlin for family reasons. Consequently, we concluded that although immigrants and Germans, the two traditionally highlighted actors in the process of economic integration, provided an adequate market niche for the Turkish food ethnic economy, transnational visitors, especially tourists, are the most predominant consumers of Turkish food. In this regard, it is rational to presume that besides natives and immigrants, transnational visitors also exert an influence on the process of active economic integration, which we will further analyze in the following. Last, but not least, we interviewed consumers about their preferences among Turkish food (Table 5). At least 44.1% of the consumers were attracted to its delicious taste and smell, while 17.2% chose Turkish food only because the shops were easy to find and were more accessible to them. Some 11.8% of consumers were attracted by the Turkish food on account of the similar taste of the Turkish food to their flavors in their homeland. Specifically, consumers attracted by this attribute all originated from Eastern Mediterranean countries (e.g., Turkey, Iraq, Greece). At the same time, as the most classical Euro-Turkish food, döner, was first created in Berlin, Berlin's Turkish food is consequently perceived as one of the most authentic throughout the whole of Europe. Thus, 11.8% of customers consumed the food due to its high reputation while 8.6% of consumers including three Polish, two Danish, one British, and even two Germans from Bremen consumed Turkish food on account of their desire for authenticity, though all of them had tasted it previously. Finally, the remaining 6.5% of consumers chose Turkish food as it was quickly prepared and portable.

The Multiplayer Model of Active Economic Integration
After generally analyzing the identity of the 93 Turkish food consumers, we concluded that Turkish food consumers in Berlin mainly consisted of Germans, immigrants, and transnational visitors. Therefore, we further shed light on how key consumers participated in the active economic integration process of Turkish immigrants through the ethnic economy.

Turkish Immigrants: Actively Self-Adjusting Their Ethnic Food
Although Berlin is the cradle of the Euro-Turkish food, döner, its creator is a Turkish immigrant. This story can dated back to the 1950s. During World War II, Berlin, the capital of the Third Reich, suffered from the most devastating attack, causing a large demand for construction workers at the beginning of the post-war era. In addition, the previously signed recruitment document made it easier for Turkish people to find jobs in Germany. Thus, abundant numbers of Turkish people immigrated to Germany as guest workers and the number of Turkish immigrants increased rapidly in the 1950s [41,43].
The immigration of Turkish guest workers and their families in Berlin inevitably resulted in the emergence of a Turkish ethnic economy [41]. Among various daily consumption, ethnic food is the most common and necessary product [43]. Traditionally, Turkish food employs beef, lamb, and chicken as basic ingredients and roasts or grills these ingredients on a vertical rotisserie. The roasted meat is usually sliced into pieces or stabbed as skewers and served on a plate with fresh vegetables and pommes. However, as guest workers in the 1950s, the Turkish preferred to have meals anywhere and anytime. Thus, a portable eating form of Turkish food would be more in accord with the requirements of Turkish guest workers at that time. Under this current condition, in 1972, a Turkish-born German restaurateur named Kadir Nurman had the initiative to roll the sliced meat, vegetables, and pommes in a toasted flatbread and named this packaged Turkish food "döner", as in the Turkish language, döner means rolling or rotating, which explicitly epitomized how the meat was roasted in a vertical rotisserie and how the portable eating form was created by rolling the ingredients in bread [44].
More precisely, as this creation was actually a process of adjusting Turkish food into a more convenient and more portable eating form, which is quite uncommon in Turkey, we prefer to conceptualize this creation as an adjustment. Since the adjustment, launched by a Turkish immigrant, initially intended to conform to the contemporary requirements of the Turkish guest workers, we perceived this adjustment as an active behavior of Turkish immigrants. Thus, we concluded that in the whole integration process of Turkish ethnic food, Turkish immigrants mainly acted in the creation stage through actively self-adjusting their ethnic food.

Germans: Promoting Ethnic Economy through Consumption
Since döner was created in the early 1970s, not only Turkish immigrants but also other social groups have become consumers attracted by Turkish ethnic food and food products with similar Mediterranean/Mesopotamia regional attributes (e.g., Germans, immigrants, transnational visitors) ( Table 4). The increasing amount of consumption directly provides Turkish food shops with an abundant market and, finally, promotes the food ethnic economy.
However, Tables 3-5 show that the nationality, identity, and preferences of the increasing consumers are diverse. In other words, although all of them promote the Turkish food ethnic economy through consumption, their motivations to consume are different. In this regard, to explicitly shed light on what kinds of food attributes attract different consumer groups, we formed a cross-contingency table and further analyzed the different consumer groups' preferences (Table 6). In Table 6, the first column presents three consumer groups (e.g., German, immigrant, transnational visitor), while the first row presents the six consuming preferences (e.g., delicious and tasty, easy to find, highly reputable, similar to motherland flavor, authenticity, and quickly prepared and portable). Each cell in Table 6 represents the frequency of different consumer groups with different consuming preferences.  Note: "Tas." represents "delicious and tasty"; "Eas." represents "easy to find"; "Rep." represents "highly reputable"; "Sim." represents "similar to motherland flavor"; "Aut." represents "authenticity"; "Por." represents "quickly prepared and portable".
To analyze whether the preference in Turkish food differs significantly among the three different consumer groups, we calculated the distance between the expected number and that observed of different consumers. Its calculation equation can be seen in Equation (1).
In Equation (1), d ij represents the distance, while f e ij and f o ij represent the expected and the observed number of consumers in group i, attracted by preference j, respectively. Meanwhile, f e ij is calculated through Equation (2).
In Equation (2), x ij represents the frequency of group i with preference j in Table 6 and N represents the total number of Turkish food consumers (i.e., N = 93). Thus, f e ij represents how many consumers in group i are expected to be attracted by preference j on the basis of the frequency distribution in Table 6.
Herein, once f o ij is larger than f e ij , it means that more consumers in group i are attracted by preference j than they probabilistically ought to be. In this sense, the higher the distance value (i.e., d ij ), the greater the consumers who are de facto attracted by a certain preference, rather than the expected number.
Following this mathematical law, a significantly higher number of German consumers were attracted by Turkish food's portability (d = 6.09). Moreover, the number of the "Living" subgroup consumers (i.e., German consumers living in Berlin) who were attracted by this advantageous aspect was significantly higher than that expected (d = 16.80). In our opinion, German consumers, especially those living in Berlin, generally perceive Turkish food as a common fast food in their daily lives. Hence, "quickly prepared" and "easy to find" became the most attractive preferences. In a word, attracted by its quick preparation and portability, German consumers play a positive role in the development of the Turkish food ethnic economy through consumption.
"I want to have something before I take a train to my school. It has meat and vegetables. It's easy to eat. I can take it away." (Respondent 41, a German female around twenty years old)

Non-Turkish Immigrants and Transnational Visitors: Actors beyond the Traditional Bi-Actor Model
In a traditional research framework, Turkish immigrants and Germans are the two predominant actors in the economic integration of lower-skill immigrants. However, in our study, through providing a niche market, non-Turkish immigrants and transnational visitors also play roles in the whole integration process.
For non-Turkish immigrant consumers, six Turkish immigrants were also included, whose motivations of migrating to Berlin were job transfer instead of making a living by being engaged in the Turkish ethnic economy. Hence, they were also broadly perceived as "non-Turkish immigrants". In this regard, the number of non-Turkish immigrants who were attracted by Turkish food's similar taste to their motherland flavor was significantly higher (d = 15.73), while the number of job seekers who were attracted by this flavor similarity strikingly exceeded the probabilistic amount (d = 26.69). As jobless immigrants are faced with stronger material and mental stress due to the lack of stable income, ethnic food with similar motherland tastes may be conducive to relieving their nostalgia. "We all come from Brazil. We are travelling here. Our guide also comes from Brazil. He says [Euro-]Turkish food is good here!" (Respondent 61, a Brazilian female tourist) Moreover, although the numbers of consumers attracted by the other preferences of Turkish food (e.g., deliciousness, accessibility, authenticity) presented were insignificantly higher than the expected ones, all of the three primary consumer groups (e.g., German, immigrant, transnational visitors) mentioned that they are more or less attracted by these preference aspects (Table 7).
"If you ask me why I choose it, I will say [that] it looks good, smells good, and tastes good!" (Respondent 2, a man of about thirty-five years old) "I've been shopping for [the] whole morning. I am tired and hungry. So, I take one." (Respondent 16, a female student around twenty) "I have tasted döner before. I want to compare [it] to my motherland's." (Respondent 33, a Danish male tourist, twenty-four years old) To sum up, consumption by both non-Turkish immigrants and transnational visitors plays a positive role the in Turkish immigrants' economic integration process. On the one hand, non-Turkish immigrants consume Turkish ethnic food mostly because it is similar in taste to their motherland flavor so can relieve their nostalgia. On the other hand, transnational visitors are mostly attracted by the high reputation of Turkish food-döner in particular-in Berlin. These findings, as supporting evidence, show that besides the typical bi-actor perspective (i.e., Turkish immigrants and Germans in this research), transnational visitors and immigrants from other countries also promote the economic integration of lower-skill immigrants by providing a niche market for ethnic food (i.e., consuming Turkish food in this research). Therefore, we humbly put forward a multiplayer model to conceptualize the whole process as well as to directly respond to the research question "what are the roles played by the two traditionally highlighted actors (e.g., immigrants, natives) as well as by third or fourth actors (e.g., transnational visitors, other immigrants) in the process of active economic integration?" * means that f o ij is larger than f e ij. In the first row, "Tas." represents "delicious and tasty"; "Eas." represents "easy to find"; "Rep." represents "highly reputable"; "Sim." represents "similar to motherland flavor"; "Aut." represents "authenticity"; "Por." represents "quickly prepared and portable".

The Multiplayer Model of Active Economic Integration
On the basis of our analyzed results, there are four key actors in the whole economic integration process of Turkish immigrants. Thus, we put forward a multiplayer model to conceptualize the specific roles played by these four actors ( Figure 2).
To begin with, Turkish immigrants actively adjusted the Turkish food eating form to make it more portable. This active adjustment satisfied the Turkish guest workers' contemporary requirement for portability, resulting in the development of the Turkish food ethnic economy. As time went by, Germans, non-Turkish immigrants, and transnational visitors were unexpectedly attracted by some other advantageous attributes of this Euro-Turkish ethnic food, resulting from its active adjustment (e.g., portability and quick preparation, similarity to Eastern Mediterranean flavor, high reputation). Naturally, the enlargement of the consumer group provided a much larger market niche for Turkish food shops, resulting in the rapid growth of the Turkish food ethnic economy. As the ethnic economy can provide jobs for newly arrived Turkish immigrants, help them earn more money, and improve their economic status, the development of the Turkish food ethnic economy, promoted by the consumption by Germans, immigrants, and transnational visitors, has significantly promoted the economic integration of Turkish immigrants. Therefore, in the economic integration process of Turkish immigrants in Berlin, (1) lower-skill immigrants (i.e., Turkish immigrants) launched the food ethnic economy by actively adjusting their food's eating form; (2) attracted by the food's portability and quick preparation, natives (i.e., Germans) promoted the economic integration process of immigrants by providing a larger market for the food ethnic economy; and (3) besides lower-skill immigrants and natives, non-Turkish immigrants and transnational visitors have also promoted the economic integration process of immigrants by consuming the ethnic food, thus presenting a distinctive multiplayer process.

Conclusions and Discussion
Recently, the economic integration of lower-skill immigrants in Western countries has become a hot topic in ethnic studies [5,6]. Traditional studies perceive immigrants as passive actors in the economic integration process [7,8]. However, recently, more studies have shown that immigrants are playing a much more active role (e.g., informality, human and social capital accumulation, ethnic economy), which presents a transformation from passive economic integration to active economic integration [9,10]. However, this transformation is disputed as immigrants' more active economically integrating behavior does not represent a positively successful economic integration [11]. Moreover, inspired by the "three-way approach" model, whether lower-skill immigrants can successfully integrate may also depend on actors beyond the natives and immigrants (e.g., visitors). In this sense, two questions still remained uncertain and needed to be explicitly analyzed: (1) In the process of an active economic integration through ethnic economy, a more active integration route, what are the roles played by the two traditionally highlighted actors (e.g., immigrants, natives)? (2) Enlightened by the "three-way approach" model, aside from the natives and immigrants, is there a third or fourth actor exerting influence on the integration process?
To answer these questions from a food ethnic economy perspective, we analyzed the economic integration process of Turkish immigrants in Mitte, Berlin. Through our fieldwork observations and interviews, there were in total four actors (e.g., Turkish immigrants, Germans, non-Turkish immigrants, and transnational visitors) in the economic integration process of Turkish immigrants, presenting a multiplayer model that is quite distinctive from a traditional bi-player research framework. In the multiplayer model, first, the Turkish immigrants promoted their own economic integration process by actively adjusting their ethnic food's eating forms. As the adjusted Turkish ethnic food was more portable and satisfied the Turkish guest workers' contemporary requirement in the 1970s, this self-adjusting behavior launched the Turkish food ethnic economies. Second, Germans promote the Turkish immigrants' economic integration by providing a larger niche market for Turkish food shops. Since the self-adjustment behavior equips Turkish ethnic food with higher portability, Germans have gradually become one of the key consumer groups and promoted the rapid growth of the Turkish ethnic food economy. Third, attracted by the Turkish ethnic food's similarity to the flavors from the motherland and high reputation, non-Turkish immigrants and transnational visitors, respectively, also promote the economic integration of Turkish immigrants through consumption. As the ethnic economy can provide jobs for newly arrived Turkish immigrants, helping them earn more money and improving their economic status, the development of the Turkish food ethnic economy, promoted by Turkish immigrants, Germans, non-Turkish immigrants, and transnational visitors directly or indirectly, has become an active route for the

Conclusions and Discussion
Recently, the economic integration of lower-skill immigrants in Western countries has become a hot topic in ethnic studies [5,6]. Traditional studies perceive immigrants as passive actors in the economic integration process [7,8]. However, recently, more studies have shown that immigrants are playing a much more active role (e.g., informality, human and social capital accumulation, ethnic economy), which presents a transformation from passive economic integration to active economic integration [9,10]. However, this transformation is disputed as immigrants' more active economically integrating behavior does not represent a positively successful economic integration [11]. Moreover, inspired by the "three-way approach" model, whether lower-skill immigrants can successfully integrate may also depend on actors beyond the natives and immigrants (e.g., visitors). In this sense, two questions still remained uncertain and needed to be explicitly analyzed: (1) In the process of an active economic integration through ethnic economy, a more active integration route, what are the roles played by the two traditionally highlighted actors (e.g., immigrants, natives)? (2) Enlightened by the "three-way approach" model, aside from the natives and immigrants, is there a third or fourth actor exerting influence on the integration process?
To answer these questions from a food ethnic economy perspective, we analyzed the economic integration process of Turkish immigrants in Mitte, Berlin. Through our fieldwork observations and interviews, there were in total four actors (e.g., Turkish immigrants, Germans, non-Turkish immigrants, and transnational visitors) in the economic integration process of Turkish immigrants, presenting a multiplayer model that is quite distinctive from a traditional bi-player research framework. In the multiplayer model, first, the Turkish immigrants promoted their own economic integration process by actively adjusting their ethnic food's eating forms. As the adjusted Turkish ethnic food was more portable and satisfied the Turkish guest workers' contemporary requirement in the 1970s, this self-adjusting behavior launched the Turkish food ethnic economies. Second, Germans promote the Turkish immigrants' economic integration by providing a larger niche market for Turkish food shops. Since the self-adjustment behavior equips Turkish ethnic food with higher portability, Germans have gradually become one of the key consumer groups and promoted the rapid growth of the Turkish ethnic food economy. Third, attracted by the Turkish ethnic food's similarity to the flavors from the motherland and high reputation, non-Turkish immigrants and transnational visitors, respectively, also promote the economic integration of Turkish immigrants through consumption. As the ethnic economy can provide jobs for newly arrived Turkish immigrants, helping them earn more money and improving their economic status, the development of the Turkish food ethnic economy, promoted by Turkish immigrants, Germans, non-Turkish immigrants, and transnational visitors directly or indirectly, has become an active route for the economic integration of Turkish immigrants. However, it should be noted that among the Turkish ethnic food consumers, the high number of transnational visitors, especially tourists, may result from the particular locations of the two Turkish food shops where this research was conducted. Thus, transnational visitors, as a third actor in the process of immigrants' economic integration, may not be always as present and influential as this study identifies in the process of lower-skill immigrants' economic integration.
All in all, this study has supplied a multiplayer model for lower-skill immigrants' active economic integration through the ethnic economy, which is distinctive from typical research views (e.g., passive economic integration, bi-player model). However, there are three glaring drawbacks that remain to be resolved and further discussed. First, our study perceived "Turkish immigrants have successfully integrated into Berlin through ethnic economy" as a precondition. Therefore, whether Turkish immigrants, being engaged in Turkish ethnic food shops, feel more integrated than their compatriots who are not, requires further discussion. In this regard, Turkish owners and staff in Turkish shops as well as unemployed Turkish immigrants should be interviewed and studied. Second, our study was limited to analyzing the economic integration process from a bottom-up route, but generally overlooked the institutional influence of local governments and original societies, which were emphasized by Kirisci in his "three-way approach" analysis framework [12,45]. Moreover, since the findings presumably implied a mutual effect where Turkish immigrants actively integrated into the German context while Germans have also adopted Turkish ethnic food as a local cultural product, how the multiplayers mutually influence and resonantly promote the economic integration process still remains implicit, which is worthy of further discussion. Third, how socio-cultural aspects (e.g., inclusive atmosphere, cultural diversity, etc.) of actors (e.g., immigrants, natives, etc.) influence lower-skill immigrants' economic integration should also be stressed in our following study [22,46]. Recently, how the cultural aspects of immigrants and native inhabitants influence their economic integration has been studied. For instance, although Uyghur immigrants in Beijing actively participated in accumulating human capital (e.g., language learning, skill training), their economic integration process was stagnant due to their strong ethnicity and religious practices [47]. Conversely, Han Chinese in Tibet are subjectively eager to integrate into local society. However, as Tibet is a relatively religious, exclusive, and ethnic place, the economic integration process of Han Chinese is also slow [48]. Moreover, to change the public perception towards Ordos as a "Ghost City", native inhabitants have constructed an inclusive civil society and good employment environment to attract population and investment. This cultural image construction has hitherto positively influenced immigrants' economic integration [49]. All in all, further research should highlight the above potential improvement aspects and discuss these research topics in more depth.
Author Contributions: D.X. conceived and designed the research; H.L. performed the research including the acquisition and analysis of the materials, interpretation of the data, and drafted the work. X.H. and J.v.W. substantially revised the work.