Stephanie Nguyen
email: stephanie.nguyen@iae-aix.com

Mohamed Didi Alaoui
email: mohamed.didi-alaoui@univ-cotedazur.fr

Sylvie Llosa
email: sylvie.llosa@iae-aix.com

When interchangeability between providers and users makes a difference: The mediating role of social proximity in collaborative services

Keywords: Interchangeability, collaborative services, sharing economy, social distance, trust, construal level theory

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Introduction

Many of us have already experienced the new exchange practices often referred to as the sharing economy or collaborative consumption, for example when renting someone else's car or their home, or ride-sharing with a stranger. In fact, several reports on the sharing economy carried out by consulting companies as well as government agencies offer impressive statistics and predict exponential growth in the coming years. For example, PricewaterhouseCoopers estimates that the global revenue generated by the sharing economy will grow from $15 billion in 2015 to as much as $335 billion by 2025 [START_REF] Pricewaterhousecoopers | The sharing economy[END_REF]. Hence the sharing economy stands out and appears to be expanding rapidly, bringing forth new opportunities, but also new challenges [START_REF] Lamberton | When is Ours Better than Mine? A Framework for Understanding and Altering Participation in Commercial Sharing Systems[END_REF]. As such, it seems crucial to analyze and question this new phenomenon, in which ownership is replaced by a new paradigm based on access [START_REF] Belk | You are what you can access: Sharing and collaborative consumption online[END_REF][START_REF] Hartl | Do we need rules for "what's mine is yours"? Governance in collaborative consumption communities[END_REF][START_REF] Lawson | Freedom from ownership: An exploration of access-based consumption[END_REF], and develop a better understanding of its underlying mechanisms [START_REF] Schor | Debating the Sharing Economy[END_REF].

The research community only recently started to investigate this new trend more closely and, aside from a few visionary articles written before 2011 [START_REF] Belk | Sharing[END_REF][START_REF] Benkler | Sharing nicely: On shareable goods and the emergence of sharing as a modality of economic production[END_REF][START_REF] Lessig | Remix: Making art and commerce thrive in the hybrid economy[END_REF], most of the academic literature was published after 2013. While research on the topic is still nascent [START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF], the interest of researchers in this phenomenon is growing rapidly, as evidenced by the sudden rise of academic articles dedicated to this subject in recent literature [START_REF] Cheng | Sharing economy: A review and agenda for future research[END_REF][START_REF] Kumar | A strategic framework for a profitable business model in the sharing economy[END_REF]. To date, there is still no consensus on shared definitions [START_REF] Eckhardt | Marketing in the Sharing Economy[END_REF][START_REF] Hawlitschek | Understanding the Sharing Economy-Drivers and Impediments for Participation in Peer-to-Peer Rental[END_REF]; both the sharing economy and collaborative consumption are considered as umbrella concepts that encompass a range of activities [START_REF] Hamari | The sharing economy: Why people participate in collaborative consumption[END_REF][START_REF] Schor | Debating the Sharing Economy[END_REF]. This study focuses on a new form of resource circulation that did not exist until recently: The exchange of services between individuals (peers) intermediated by an online platform. As such, to delineate our topic clearly and avoid any confusion with other types of practices, we refer to them as collaborative services and define them as "the exchange of services between peers, intermediated by an online platform, in which individual service providers offer individual service users temporary access to their under-utilized resources (such as a home or a car)."

In line with recent literature investigating motives for participation in these new forms of exchanges [START_REF] Aspara | Sharing-Dominant Logic? Quantifying the Association Between Consumer Intelligence and Choice of Social Access Modes[END_REF][START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF][START_REF] Hamari | The sharing economy: Why people participate in collaborative consumption[END_REF][START_REF] Lawson | Freedom from ownership: An exploration of access-based consumption[END_REF], this paper focuses on a distinctive characteristic of collaborative services associated with the interpersonal nature of the exchange relationship among peers, namely the interchangeability between service providers and service users, who may one day participate as service providers, but the next day may participate as service users and vice versa. As such our research question is as follows: Does it make a difference to collaborative services participants' attitude and behavior whether they play both roles or just one?

Based on the literature on trust [START_REF] Gefen | E-commerce: The role of familiarity and trust[END_REF][START_REF] Ter Huurne | Antecedents of trust in the sharing economy: A systematic review[END_REF], as well as the construal level theory (Liberman & Trope, 2008;Trope & Liberman, 2010), we posit the influence of interchangeability on customers' intention to participate through an increase of social proximity, which in turn influences trust. The contributions of this research are as follows: First, interchangeability has been mentioned in several articles [START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF][START_REF] Eckhardt | Marketing in the Sharing Economy[END_REF][START_REF] Ertz | A conceptual perspective on collaborative consumption[END_REF][START_REF] Scaraboto | Selling, Sharing, and Everything In Between: The Hybrid Economies of Collaborative Networks[END_REF] but, to the best of our knowledge, it has never been used in any study, despite the fact that it represents a very special and unique feature of collaborative services. Second, while previous research is predominantly focused on service users [START_REF] Lawson | Freedom from ownership: An exploration of access-based consumption[END_REF][START_REF] Möhlmann | Collaborative consumption: Determinants of satisfaction and the likelihood of using a sharing economy option again[END_REF], this paper includes both service users and service providers, taking into consideration both actors' roles. By doing so, it provides a global stance, accounting for both supply and demand, which are equally important to sustaining these emerging marketplaces [START_REF] Kumar | A strategic framework for a profitable business model in the sharing economy[END_REF]. Lastly, by relying on the construal level theory, we propose a psychological approach based on a particular dimension -social distance -and as such contribute to literature on psychological distance.

After presenting the theoretical framework, we explain our methodology and the results of our study, conducted on 222 accommodation rental participants. We then discuss the results that confirm our hypothesis and conclude by outlining our theoretical contributions, as well as suggesting managerial implications and future research avenues.

Literature review

Collaborative services characteristics

Collaborative services deal with the exchange of services between peers, intermediated by an online platform. They differ from non-ownership services [START_REF] Wittkowski | Firms' Intentions to Use Nonownership Services[END_REF], when companies acquire access to an asset through non-ownership, for example when a firm rents a machine for a defined period of time in exchange for a fee. In these instances, the service exchange takes place between two businesses. They also differ from access-based services [START_REF] Bardhi | Access-Based Consumption: The Case of Car Sharing[END_REF][START_REF] Lawson | Freedom from ownership: An exploration of access-based consumption[END_REF][START_REF] Schaefers | Contagious effects of customer misbehavior in access-based services[END_REF] when, instead of buying and owning, consumers temporarily gain access to goods in exchange for payment. In those cases, exchanges happen between customers and businesses.

Finally, within the customer-to-customer (C2C) e-commerce stream of literature, collaborative services represent a distinct area of research as studies have mainly focused on the exchange of products between peers, for example on platforms such as eBay [START_REF] Standifird | Reputation and e-commerce: EBay auctions and the asymmetrical impact of positive and negative ratings[END_REF]. In these earlier forms of exchange, individuals buy or sell products to one another. In contrast, collaborative services are based on the exchange of services, hence on access rather than ownership [START_REF] Aspara | Sharing-Dominant Logic? Quantifying the Association Between Consumer Intelligence and Choice of Social Access Modes[END_REF][START_REF] Belk | You are what you can access: Sharing and collaborative consumption online[END_REF][START_REF] Lawson | Freedom from ownership: An exploration of access-based consumption[END_REF].

Collaborative services possess distinctive characteristics. First, compared to other forms of dyadic exchange already well investigated by the literature, such as buyer-seller or customerbrand, collaborative services take place within a triadic framework composed of three actors: the platform, the individual service providers, and the individual service users [START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF].

In this framework, participants (also called peers) can operate in various roles, acting either as a service provider or as a service user, interacting and influencing each other.

Second, as service providers are not employees, they do not represent a company or a brand, but rather act alone, as individuals. As such, the interpersonal relationship between the service provider and the service user during the service encounter is likely to be different from traditional forms of service encounter. The interpersonal nature of relationships between customers in the context of service experiences has already been explored by scholars [START_REF] Grove | The impact of other customers on service experiences: A critical incident examination of "getting along[END_REF][START_REF] Martin | Consumer-to-consumer relationships: Satisfaction with other consumers' public behavior[END_REF]. For example, [START_REF] Wu | The impact of customer-to-customer interaction and customer homogeneity on customer satisfaction in tourism service-The service encounter prospective[END_REF] investigates the impact of C2C interactions and customer homogeneity in a tourism service context. Other articles study different contexts for C2C interaction, such as on a cruise [START_REF] Huang | The impact of customer-to-customer interaction on cruise experience and vacation satisfaction[END_REF], a train ride, or at the gym [START_REF] Camelis | The roles of co-clients and their influence on overall satisfaction during the service experience[END_REF]. They also examine the impact of interactions between customers in the case of service failure [START_REF] Kim | The influence of other customers in service failure and recovery[END_REF][START_REF] Yi | The role of other customers during self-service technology failure[END_REF] or the contagiousness of customer misbehavior in access-based practices [START_REF] Schaefers | Contagious effects of customer misbehavior in access-based services[END_REF]. However, interpersonal service encounters between individual service users and individual service providers, also called "stranger sharing" by [START_REF] Schor | Debating the Sharing Economy[END_REF]p.7), did not exist before the emergence of collaborative services. As such, it still requires further investigation [START_REF] Milanova | Sharing intangibles: Uncovering individual motives for engagement in a sharing service setting[END_REF].

Third, collaborative services exchanges are based on temporary access to the service providers' goods, such as their home or car. Other studies have described this service as making use of underused or underutilized goods [START_REF] Breidbach | Engagement platforms in the sharing economy: Conceptual foundations and research directions[END_REF][START_REF] Piscicelli | The role of values in collaborative consumption: Insights from a product-service system for lending and borrowing in the UK[END_REF], idle capacity [START_REF] Frenken | Putting the sharing economy into perspective[END_REF][START_REF] Kumar | A strategic framework for a profitable business model in the sharing economy[END_REF][START_REF] Schor | Collaborating and connecting: The emergence of the sharing economy[END_REF], or slack (or even excess) resource capacity [START_REF] Benkler | Sharing nicely: On shareable goods and the emergence of sharing as a modality of economic production[END_REF][START_REF] Roos | Does shared consumption affect consumers' values, attitudes, and norms? A panel study[END_REF]. Because service providers are the owners of those goods, in some instances they may have a specific relationship to them, sometimes even a form of personal attachment [START_REF] Belk | Sharing[END_REF].

Finally, the ability of service providers and service users to exchange roles is an important and distinctive characteristic of collaborative services: A service provider one day can be a service user the next day. These agents endorsing dual roles have also sometimes been called prosumers [START_REF] Eckhardt | Marketing in the Sharing Economy[END_REF][START_REF] Ritzer | Production, Consumption, Prosumption: The nature of capitalism in the age of the digital 'prosumer[END_REF], and in this paper we use the term interchangeability to refer to participants acting in both roles.

Interchangeability

To date, only a handful of articles found in the literature mention interchangeability: Scaraboto (2015, p. 153) refers to "interdependent participants who switch between the roles of consumer and producer," Ertz et al. (2018, p. 27) point out the "centrality of a two-sided instead of one-sided consumer role," Kumar et al. (2018, p. 149) describe "service providers [who] can switch roles and become customers." Finally Eckhardt et al. (2019, p. 7) refer to prosumers taking on "enhanced roles as both providers and users of resources."

In order to explore and delineate the concept, we now propose to discuss several aspects related to interchangeability. First, when acting interchangeably, agents participate as both a service user and a service provider for the same type of service, but each role corresponds to a separate exchange transaction, and for each transaction the resource that is being shared is different. For example, in the case of accommodation rental, a host (service provider) shares their own home with a guest (service user), and as a guest, stays in someone else's property.

Hence, even if the type of service is the same, the object or the resource that is being shared when in each role is in fact different (their resource versus someone else's resource).

Second, a variety of different types of exchanges exist, such as sharing accommodations, cars, boats, etc. In some instances, it is possible for a participant to act in one role for a particular type of exchange and act in the other role for another type of exchange. For example, when renting someone else's power drill, as a service user, but participating in ride-sharing as a driver, as the service provider. These cases of asymmetry could have a significant impact on participants' attitudes and/or behaviors, but we do not take them into consideration in this study, as we focus on the same type of exchange.

Third, to act as a service provider, the prerequisite is to own a specific resource in order to be able to share (or rent) it with other users. Hence individuals who do not own these resources do not have the ability to act as service providers: They can only participate as service users. For example, individuals who do not own accommodation are not able to participate as a host and they can only rent someone else's place as a guest.

As collaborative services possess distinct traits that differentiate them from other forms of service -in particular the interchangeability between service providers and service users -there is real value in studying them further, in order to understand their specificities. In fact, Benoit et al. (2017, p. 226) suggest that one fruitful avenue for future research would be to investigate how acting in both roles shapes participants' expectations. Finally, in this study, our scope is limited to individuals participating in collaborative services and experiencing one role (as a guest or as a host) or both roles (as a guest and as a host), for the same type of exchange (accommodation rental).

Theoretical framework

Interchangeability and trust

The concept of trust in the marketing literature -and more specifically within relationship marketing studies -is recognized as being central to various forms of relational exchanges [START_REF] Sirdeshmukh | Consumer Trust, Value, and Loyalty in Relational Exchanges[END_REF]. In particular trust, defined by Rousseau et al. (1998, p. 395) as "a psychological state comprising the intention to accept vulnerability based on positive expectations of the intentions or behaviors of another," is crucial wherever uncertainty and dependence exist. It has been demonstrated to have a positive impact on cooperation [START_REF] Morgan | The Commitment-Trust Theory of Relationship Marketing[END_REF]. Trust has also been found to be critical in the online environment, where to gain customers' loyalty means to first gain their trust (Reichheld & Schefter, 2000, p. 107). The importance of trust online appears intensified by the absence of physical contact between customers and online firms, and by the lack of touch inherent to online exchanges.

More recently, trust has been considered in literature on the sharing economy and collaborative consumption: Several authors investigating why people engage in the sharing economy propose trust in their model as an antecedent to participation intention [START_REF] Kim | Why People Participate in the Sharing Economy: A Social Exchange Perspective[END_REF][START_REF] Möhlmann | Collaborative consumption: Determinants of satisfaction and the likelihood of using a sharing economy option again[END_REF][START_REF] Yang | Trust Breakthrough in the Sharing Economy: An Empirical Study of Airbnb1[END_REF]. Illustrating the central role of trust in collaborative exchanges, ter Huurne et al. ( 2017) offer a systematic review of the literature on trust in the sharing economy, highlighting the need to investigate sellers' (service providers') trust mechanisms, as well as those of the buyers (service users). Hence, within collaborative services, trust has been identified as playing a significant role and being essential to facilitating exchanges between participants.

Our first proposition is that interchangeability may influence participants' trust because when they assume both roles, they experience being a service provider, as well as being a service user. Through these dual and complementary experiences, they are able to learn and familiarize themselves with some of the issues specific to each role, such as the questions and challenges that participants in each position face. Furthermore, playing both roles allows them to identify more easily with their counterparts on a personal level. This identification process can reduce interpersonal barriers and raise comfort levels, and thus contribute to establishing a sense of trust [START_REF] Turner | Rediscovering the social group: A self-categorization theory[END_REF]. On the other hand, users who participate solely as a service user or as a service provider may have more difficulty understanding their counterparts' motivations or problems. Consequently, they may have fewer concrete expectations, for example regarding their counterparts' behavior. So, interchangeability is a way for participants to produce knowledge based on previous interactions, allowing them to reduce uncertainty. Because one's understanding of another's behavior based on previous interactions and/or experiences is a widely recognized predictor of trust in the literature [START_REF] Bhattacherjee | Individual trust in online firms: Scale development and initial test[END_REF][START_REF] Gefen | E-commerce: The role of familiarity and trust[END_REF], we posit the following hypothesis: H1: Interchangeability positively influences trust in peers for collaborative services participants.

Next, using the construal level theory and the concept of social distance, we intend to shed some new light on collaborative services exchanges and propose an explanation for the underlying mechanisms behind the influence of interchangeability on trust.

The construal level theory and social distance

Previous articles on the sharing economy and collaborative consumption rely on different theories for their conceptual framework. In particular, several articles take a market-based approach and adopt the social exchange theory [START_REF] Kumar | A strategic framework for a profitable business model in the sharing economy[END_REF][START_REF] Priporas | Unraveling the diverse nature of service quality in a sharing economy: A social exchange theory perspective of Airbnb accommodation[END_REF][START_REF] Tussyadiah | Factors of satisfaction and intention to use peer-to-peer accommodation[END_REF][START_REF] Wang | Unraveling customer sustainable consumption behaviors in sharing economy: A socio-economic approach based on social exchange theory[END_REF]), but only a few studies have examined the social pattern of collaborative consumption participation [START_REF] Albinsson | Alternative marketplaces in the 21st century: Building community through sharing events[END_REF][START_REF] Perren | Lateral Exchange Markets: How Social Platforms Operate in a Networked Economy[END_REF]. As early as 2004, [START_REF] Benkler | Sharing nicely: On shareable goods and the emergence of sharing as a modality of economic production[END_REF] describes a cluster of social practices that form an economic phenomenon and identifies the duality of a phenomenon that combines a pro-social behavior, based on sharing and collaborating, with an economic and market-oriented dimension. In other studies, social benefits are discussed as possible motivators: Perren and Kozinets (2018, p. 23) explore how lateral exchange market platforms create new forms of social connection and experience. Herbert and Collin-Lachaud (2017, p. 48) find that collaborative consumption participants are interested in various degrees of socialization, such as commitment or creating social links. Looking into the literature, it appears that sociality in collaborative exchanges has been explored more conceptually and using qualitative methods, than empirically, hence there is a need for additional empirical studies.

Moreover, most of the research is oriented toward service users. We did not find any empirical studies investigating the social dimension and taking into consideration the service providers' perspective. This study aims to appreciate both the users' and providers' perspectives.

Our theoretical framework relies on the construal level theory by [START_REF] Liberman | The psychology of transcending the here and now[END_REF] and, more specifically, it is based on one dimension of psychological distance (i.e., social distance). The construal level theory introduces the concept of psychological distance, defining it as "a subjective experience that something is close or far away from the self, here and now" and from reality (Trope & Liberman, 2010, p. 440). Psychological distance is an umbrella concept composed of four dimensions: Temporal, spatial, hypothetical, and social (Bar-Anan, Liberman, Trope, & Algom, 2007, p. 610). In particular, social distance is defined by [START_REF] Liberman | Construal Level Theory and Consumer Behavior[END_REF] as how close or distinct the target is from oneself. As such, two different modalities of social distance can be distinguished: Social proximity (when the target is socially close to the self) and social remoteness (when the target is further away from the self). Various types of social distance have been studied, such as self versus others (Trope & Liberman, 2010), similar versus dissimilar [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF], and in-group versus out-group [START_REF] Liberman | Construal Level Theory and Consumer Behavior[END_REF]. Power [START_REF] Smith | You focus on the forest when you're in charge of the trees: Power priming and abstract information processing[END_REF], politeness [START_REF] Stephan | The effects of time perspective and level of construal on social distance[END_REF], and culture [START_REF] Spassova | Looking into the Future: A Match between Self-View and Temporal Distance[END_REF] are also forms of social distance investigated in the literature. Social distance is arguably the most important of the four dimensions as it relates to the self, and we are immersed in our own feelings, sensations and consciousness all the time [START_REF] Pronin | How We See Ourselves and How We See Others[END_REF].

We believe that social distance is particularly relevant in the context of collaborative services. Here, because service providers and service users are individuals (peers) and not employees of a company, the social distance experienced by participants -how participants relate to each other and perceive themselves with regards to one another -could be crucial. To date, only one other study leverages the construal level theory in the context of collaborative consumption: [START_REF] Sordi | Construal level and collaborative consumption: An exploratory approach[END_REF] published a conceptual and exploratory article discussing some of the dimensions of psychological distance and their relevance in the context of collaborative exchanges. Their conceptualization of social distance is related to social identity and the reputation of an individual. Our understanding of social distance differs from [START_REF] Sordi | Construal level and collaborative consumption: An exploratory approach[END_REF] and is based on the definition by [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF]: the perceived similarity between the self and other social agents.

According to the construal level theory, the same stimulus -object, event, or person -can be mentally construed at different levels of abstraction [START_REF] Soderberg | The effects of psychological distance on abstraction: Two meta-analyses[END_REF]. Hence, one stimulus can be construed at a high level or at a low level. High-level construals are abstract representations, extracting the central feature of one stimulus. In contrast, low-level construals are concrete representations of a stimulus and highlight detailed and context-specific features [START_REF] Soderberg | The effects of psychological distance on abstraction: Two meta-analyses[END_REF]Trope & Liberman, 2010). Several studies developed using the construal level theory framework show that highlevel (low-level) construals lead to greater (lesser) perceived psychological distance with the stimulus [START_REF] Liberman | The psychology of transcending the here and now[END_REF].

Participants experiencing both roles as a service provider and a service user (which we call interchangeability) will tend to construe other participants at a concrete level (i.e., low-level construal) because their past experiences give them concrete and detailed information about their counterpart peers. In contrast, participants who never act as a service provider (or service user) will tend to construe service users (or service providers) at a more abstract level (i.e., high-level construal) because their lack of experience gives them little information about their counterpart peers. As participants' attitudes and behaviors regarding more socially close (distant) peers are likely to be based on lower-level (higher-level) construals, we suggest that interchangeability can impact people's responses by changing the way they mentally represent their exchange partners.

Moreover, it has been demonstrated that the level of construal influences perceived social distance [START_REF] Stephan | The effects of time perspective and level of construal on social distance[END_REF], where low-level (high-level) construal increases (reduces) perceived social proximity. Social proximity is induced by low-level construal, whereas social remoteness is induced by high-level construal, hence based on the construal level theory we suggest the following hypothesis: H2: Interchangeability positively influences perceived social proximity for collaborative services participants.

As participants experience higher (lower) levels of social proximity, they feel closer to (remoter from) their counterparts, hence they are more (less) likely to associate and identify with them. In fact, identification processes have already been studied and demonstrated to be an important component in the establishment of trust. For example, identification trust is recognized as one of three different types of trust by [START_REF] Lewicki | Trust in relationships[END_REF], along with calculus-based and knowledge-based trust. Moreover, it is acknowledged that individuals tend to have a higher level of attraction toward people with attitudes similar to their own, and similarity has been identified as an antecedent of trust, in both management literature [START_REF] Johnson | Cognitive and affective trust in service relationships[END_REF] and marketing literature [START_REF] Coulter | Determinants of trust in a service provider: The moderating role of length of relationship[END_REF]. Hence, with similarity and identification as two forms of perceived social proximity [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF], we suggest the following hypothesis:

H3: Perceived social proximity positively influences trust in peers for collaborative services participants.

In this research we propose that the relationship between interchangeability and trust is not only direct but it may be indirect, and explained by the concept of social distance [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF][START_REF] Stephan | The effects of time perspective and level of construal on social distance[END_REF], which was developed in the framework of the construal level theory (Liberman & Trope, 2008;Trope & Liberman, 2010). More precisely, as interchangeability could positively influence perceived social proximity (see H2), which in turn would positively influence trust (see H3), we suggest that interchangeability will influence trust positively, through the mediating effect of perceived social distance. It is also well recognized that a mediation occurs when the indirect effect, shaped by two consecutive relationships, is established [START_REF] Pieters | Meaningful Mediation Analysis: Plausible Causal Inference and Informative Communication[END_REF][START_REF] Zhao | Reconsidering Baron and Kenny: Myths and Truths about Mediation Analysis[END_REF]). Hence we propose the following hypothesis:

H4: Perceived social proximity mediates the positive effect of interchangeability on trust for collaborative services participants.

Finally, trust has also been conceptualized as a key mediator variable influencing satisfaction and long-term orientation [START_REF] Geyskens | Generalizations about trust in marketing channel relationships using meta-analysis[END_REF]. According to [START_REF] Pavlou | Building Effective Online Marketplaces with Institution-Based Trust[END_REF], trust can be seen as a confident expectation that produces a positive attitude toward transaction intention. For example, several studies demonstrate that trust in a specific online provider positively influences purchase intentions with the same provider [START_REF] Gefen | E-commerce: The role of familiarity and trust[END_REF][START_REF] Mcknight | Developing and validating trust measures for e-commerce: An integrative typology[END_REF][START_REF] Pavlou | Consumer acceptance of electronic commerce: Integrating trust and risk with the technology acceptance model[END_REF]. Moreover, previous research on collaborative consumption suggests that trust is an antecedent to peers' participation intentions [START_REF] Hawlitschek | Understanding the Sharing Economy-Drivers and Impediments for Participation in Peer-to-Peer Rental[END_REF][START_REF] Yang | Why are customers loyal in sharing-economy services? A relational benefits perspective[END_REF]. Consequently, in line with the literature, we posit the following hypothesis:

H5: Trust in peers positively influences participation intention for collaborative services participants.

The conceptual model guiding our theoretical development is presented in Figure 1. It suggests five hypotheses with four direct paths and one mediation, which is our underlying mechanism to explain the effect of interchangeability on trust, in turn influencing participation intention.

- ------------------------------Include Figure 1 about here -------------------------------

Methodology and results

In order to test our hypotheses, we decided to investigate the home rental context, where hosts and travelers participate in accommodation sharing. This collaborative service was chosen because hospitality is among the most popular forms of collaborative consumption and as such it provides a relevant representation of collaborative services behaviors.

Measurement

The measurement scales used to evaluate our model come from the literature (see Table 1). Specifically, we used the scale on perceived social proximity [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF]p. 1259), using 7-point Likert scales. The language of the constructs was adjusted to be suitable to the home-rental context, as we replaced the target with either hosts or travelers. Interchangeability was coded as a binary grouping variable, depending on whether respondents experienced one role (Did you participate as the host or the traveler?) or both roles (Did you participate as both?).

We did not choose a continuous variable to measure interchangeability because our study does not focus on the number of experiences, but rather investigates whether experiencing both roles makes a difference. The questionnaire was administered in French. To assure linguistic equivalence for the French version, we used back translation. We also added three demographic questions (gender, age, and employment).

- ------------------------------Include Table 1 about here -------------------------------We considered only participants who play both roles for the same type of exchange, in our case hosting guests as a service provider and staying at someone's place as a service user. While we acknowledge that instances of asymmetrical interchangeability exist, when participants experience both roles but for different types of exchanges, in this study we focus on cases of symmetrical interchangeability, for the same type of service, in order to mitigate potential measurement errors caused by aggregating different types of experiences.

Survey administration

For this study, data was collected using an online survey to take advantage of multiple benefits, such as flexibility, low administration cost, control of answer order and completion, and ease of data entry and analysis [START_REF] Evans | The value of online surveys[END_REF], 2018). We sought people who had participated at least once in accommodation rental activity, either as the host and/or the traveler.

The questionnaire started with a brief introduction to outline the general purpose of the study, the average time of completion, and general rules to follow in order to participate well. Next, we asked a filter question in order to keep only people who have participated in home rental activities via an online web platform, such as Airbnb or HomeAway. Respondents who had participated in one role (host or traveler) or two roles (host and traveler) were retained. The subjects then completed the questionnaire by answering questions about perceived social proximity, trust in peers, participation intention, and socio-demographic questions. Before the main survey, a pre-test was conducted on eight participants in order to refine the questions and obtain feedback on the structure.

For the main survey, participants were recruited through various means, such as personal networks, postings on social media, and snowball recruiting. A total of 286 individuals started the main survey. Respondents were automatically eliminated when they did not fully complete the survey because this reflects a lack of commitment and study interest. This procedure resulted in a final sample of 222 participants (male = 63; female = 159; Mage = 36.5) (see Table 2).

Regarding the gender ratio in our sample, several practitioner studies in the travel industry reveal an imbalance skewed toward the female population for both travelers and hosts1 . Furthermore, other empirical articles in the collaborative consumption sector are based on gender-imbalanced samples [START_REF] Hartl | Do we need rules for "what's mine is yours"? Governance in collaborative consumption communities[END_REF](Hartl et al., , p. 2759;;Lamberton & Rose, 2012, p. 117). Finally, note that further analysis showed no significant differences in terms of gender. The online survey was available for three weeks.

- ------------------------------Include Table 2 about here -------------------------------

Results

In order to test the hypotheses and assess the conceptual model, we used structured equation modeling with the software AMOS 21. The presentation of the results is organized as follows. First, we examine the common method variance (CMV). Second, we consider the measurement model in order to assess indicator reliability, construct reliability, convergent and discriminant validity, and the quality of the measurement model's fit. Thirdly, we assess the structural model in order to test our hypotheses and to check the fit between our conceptual model and the data.

Common method variance

CMV refers to covariance problems attributable to the measurement method rather than to the construct of interest [START_REF] Demiray | Exploring the impact of brand community identification on Facebook: Firm-directed and self-directed drivers[END_REF][START_REF] Spector | A New Perspective on Method Variance: A Measure-Centric Approach[END_REF]. As self-reported questionnaires are susceptible to CMV, we performed the most common technique, namely the Harman's one-factor test [START_REF] Fuller | Common methods variance detection in business research[END_REF], in order to manage potential CMV problems and rule out their effects.

The results of exploratory factor analysis with all variables show that the first factor accounted for 47.02% of the variance, which is less than the 50% threshold [START_REF] Fuller | Common methods variance detection in business research[END_REF][START_REF] Podsakoff | Common method biases in behavioral research: A critical review of the literature and recommended remedies[END_REF][START_REF] Podsakoff | Self-reports in organizational research: Problems and prospects[END_REF]. Moreover, all independent and dependent variables were separated in the survey [START_REF] Akbar | When do materialistic consumers join commercial sharing systems[END_REF]. We can thus conclude that CMV is not problematic in this study.

Measurement model

All of the items except one2 have a loading greater than 0.7 [START_REF] Kline | Principles and practice of structural equation modeling[END_REF], hence indicator reliability is achieved. For both constructs trust and participation intention, composite reliability is greater than 0.7. For perceived social proximity, composite reliability is lower (0.687), but as it is very close to the minimum value, we consider it acceptable. For each construct, the average variance extracted (AVE) is greater than 0.5 [START_REF] Kline | Principles and practice of structural equation modeling[END_REF], consequently we can confirm the convergent validity (see Table 1).

Concerning the discriminant validity, we use two criteria to assess it [START_REF] Voorhees | Discriminant validity testing in marketing: An analysis, causes for concern, and proposed remedies[END_REF]. The first one, the Fornell-Larcker criterion, suggests that the root square of each construct's AVE should be higher than the correlation with any other construct [START_REF] Fornell | Structural equation models with unobservable variables and measurement error: Algebra and statistics[END_REF]. Table 3 shows that the discriminant validity is achieved. The second criterion, the heterotrait-monotrait ratio of correlation (HTMT) by [START_REF] Henseler | A new criterion for assessing discriminant validity in variance-based structural equation modeling[END_REF], suggests that HTMT should be lower than the threshold of 0.85. Table 4 shows that this is the case. Finally, our results show that the fit index for our measurement model is totally satisfactory (χ2 = 37.063 (df =30), p = 0.175; χ2 adjusted = 1.235; GFI = 0.969; AGFI = 0.942; TLI = 0.992; CFI = 0.995; RMSEA = 0.033; SRMR = 0.032).

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Structural model

First, note that the model explains 4.6% of perceived social proximity's variation, 18% of the trust in peers' variation, and 17% of participation intention's variation (see Figure 2).

Regarding the model fit, our conceptual model matches the data completely (χ2 = 40.696 (df 21 =32), p = 0.139; χ2 adjusted = 1.272; GFI = 0.966; AGFI = 0.941; TLI = 0.991; CFI = 0.994; RMSEA = 0.035; SRMR = 0.039). Our results show that interchangeability does not have a direct effect on trust (β = -0.096; p = 0.17). Consequently H1, which predicts a positive effect of interchangeability on trust in peers, is rejected. The other results show a significant positive effect of interchangeability (β = 0.215 and p < 0.01) on perceived social distance, which in turn has a significant effect (β = 0.437 and p < 0.001) on trust, confirming H2 and H3 respectively.

All the results are in Table 5.

The bootstrap test with a minimum of 5,000 resamples offers clear evidence of significant mediation if the 95% confidence intervals do not include the value 0 [START_REF] Zhao | Reconsidering Baron and Kenny: Myths and Truths about Mediation Analysis[END_REF], indicating that interchangeability has a significant positive indirect effect on trust (β = 0.094; p < 0.01; 95% IC: 0.029, 0.18; excluding 0). These results suggest that perceived social proximity totally mediates the effect of interchangeability on trust and consequently, we can validate H4. Finally, our data shows that trust has a significant positive effect on participation intention (β = 0.413; p < 0.001), and H5 is validated.

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General discussion

Companies based on the new sharing economy and collaborative consumption business models are quite recent: For example, Airbnb and BlaBlaCar were both founded in 2008. However, their growth has been phenomenal: In just over a decade, the most successful companies already have millions of users across the globe and are valued at several billions of dollars [START_REF] Pricewaterhousecoopers | The sharing economy[END_REF]. Similarly, reports from governmental agencies expect the overall revenue generated by the sharing economy and collaborative consumption to continue to grow at a very significant pace in the coming years [START_REF] Rahim | Research on the Sharing Economy[END_REF]. Despite considerable media coverage, research on the sharing economy and collaborative consumption is only just starting [START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF][START_REF] Kumar | A strategic framework for a profitable business model in the sharing economy[END_REF] and our findings contribute to this emergent field.

One of the novelties of collaborative services is that the service experience is provided by an individual, not by a professional. This difference means that the individual service provider and the individual service user can exchange roles: Someone may be a service provider when they share their apartment via Airbnb and switch roles later to become a service user when they rent someone else's home for their next vacation. Our study leverages this distinctive characteristic of collaborative services (the interchangeability between service providers and service users), and aims to include all participants' attitudes and behaviors, service users as well as service suppliers; as such it differs from existing literature. Relying on the construal level theory, we propose a psychological approach based on perceived social proximity between participants.

Results from our study provide empirical evidence for the significant role of interchangeability within collaborative services and its influence on participants' attitude and behavior. Interestingly, the relationship between interchangeability and trust is not partially mediated by social proximity: Rather, it appears to be fully mediated. Contrary to what we posited initially in our hypothesis, interchangeability does not directly impact trust, but rather it increases social proximity, which in turn positively influences trust. Thus, we are able to propose social proximity as the underlying mechanism that explains the effect of interchangeability on participants' trust and introduce the concept of social distance (proximity) as one of the factors influencing collaborative services participants' attitudes (trust in peers) and behaviors (participation intention). As our results show no direct impact of interchangeability on trust, they suggest that the mere fact of playing both roles and actually knowing from experience what the other participants are going through does not influence the trust we have in them.

Lastly, this research is anchored in the stream of literature on trust and our results confirm its important role within social and economic exchanges [START_REF] Morgan | The Commitment-Trust Theory of Relationship Marketing[END_REF]. The positive link between attitude and behavior -in our case between trust and participation intention -is also confirmed and in line with the literature [START_REF] Hamari | The sharing economy: Why people participate in collaborative consumption[END_REF].

Contributions to the literature on the sharing economy and collaborative consumption

While prior research is focused on rational decision-making mechanisms, taking a costbenefit approach and based on theories such as the social exchange theory, our study relies on the construal level theory and as such it proposes a psychological approach to investigate collaborative services participants' attitudes and behaviors.

By focusing on interchangeability, this study contributes to a better understanding of collaborative services participants' motives and decision-making mechanisms. In particular, this article brings a new perspective to this field of research and provides empirical support for the role of interchangeability on trust in peers. While previous qualitative studies found the desire for social connection to be an important motivation [START_REF] Herbert | Collaborative practices and consumerist habitus: An analysis of the transformative mechanisms of collaborative consumption[END_REF][START_REF] Perren | Lateral Exchange Markets: How Social Platforms Operate in a Networked Economy[END_REF], some empirical studies mitigate those results [START_REF] Möhlmann | Collaborative consumption: Determinants of satisfaction and the likelihood of using a sharing economy option again[END_REF][START_REF] Tussyadiah | An exploratory study on drivers and deterrents of collaborative consumption in travel[END_REF]. Our results corroborate what was uncovered by previous qualitative investigations: the significant influence of social proximity on attitudinal (trust in peers), as well as behavioral (participation intention) outcomes.

Furthermore, this study extends the literature on trust in the context of collaborative services exchanges. While in previous research [START_REF] Möhlmann | Collaborative consumption: Determinants of satisfaction and the likelihood of using a sharing economy option again[END_REF] found that trust has a significant impact on users' satisfaction regarding both accommodation rental and car sharing, one of her hypotheses stating that trust has a positive impact on the likelihood of future participation was rejected. Our results differ from Möhlmann's and confirm previous findings on the role of trust between peers and its positive impact on participation intention [START_REF] Hawlitschek | Understanding the Sharing Economy-Drivers and Impediments for Participation in Peer-to-Peer Rental[END_REF][START_REF] Kamal | Trust in Sharing Economy[END_REF]. Hence additional research is needed in order to confirm the role of trust in peer-to-peer exchanges, perhaps by using a more granular conceptualization of trust.

Lastly, collaborative services are described by [START_REF] Benoit | A triadic framework for collaborative consumption (CC): Motives, activities and resources & capabilities of actors[END_REF] using a triadic framework composed of the online platform (1), intermediating individual service providers (2), and individual service users (3). The majority of existing studies on consumer behavior focus on service users [START_REF] Hamari | The sharing economy: Why people participate in collaborative consumption[END_REF][START_REF] Möhlmann | Collaborative consumption: Determinants of satisfaction and the likelihood of using a sharing economy option again[END_REF], without taking into consideration service providers. This is most likely due to the fact that service users correspond to the consumers in previous classical models. Our approach differs, as it considers both groups (service providers and service users) as a whole, which makes sense because they are both customers of the platform. It also considers the permeability between groups, which we call interchangeability. By including service users and service providers alike, our approach is more global and takes into account both sides of the marketplace.

Contributions to the construal level theory

The present work contributes to the construal level theory and to the concept of social distance in several ways. First, our model, built on one of the most successful and influential theories in consumer research [START_REF] Williams | The Distinct Affective Consequences of Psychological Distance and Construal Level[END_REF], reveals that the construal level theory is a relevant framework to predict consumers' responses in a collaborative services context. Indeed, based on the theory and using our empirical data, we are able to unveil the underlying mechanism (social distance) explaining the effect of interchangeability on trust.

Second, our research enriches the concept of social distance developed within the framework of the construal level theory [START_REF] Liviatan | Interpersonal similarity as a social distance dimension: Implications for perception of others' actions[END_REF][START_REF] Stephan | The effects of time perspective and level of construal on social distance[END_REF]Trope & Liberman, 2010). Most of the sources of social distance suggested by the construal level theory are related to the variation of different factors and, in particular, the distinction between the ingroup versus the out-group, which is dependent on a specific situation. For example, a co-worker may belong to the in-group (the company) or the out-group (the family). The same person could have power over one element (e.g., information), but at the same time have less power over another element (e.g., money). The concept of interchangeability appears to be more stable and robust because it is an objective situation where the consumer plays either one role or two roles and, as such, it is not situation-specific. Thus, interchangeability could be a valid cue of social distance.

Third, this work also contributes to the small but growing literature investigating social distance and trust. Past research has looked into the effect of social distance on interpersonal relations as choices for others [START_REF] Laran | Goal Management in Sequential Choices: Consumer Choices for Others Are More Indulgent than Personal Choices[END_REF][START_REF] Lu | Hedonic products for you, utilitarian products for me[END_REF][START_REF] Tu | The Friendly Taking Effect: How Interpersonal Closeness Leads to Seemingly Selfish Yet Jointly Maximizing Choice[END_REF], for example with gift-giving [START_REF] Baskin | Why Feasibility Matters More to Gift Receivers than to Givers: A Construal-Level Approach to Gift Giving[END_REF] or sharing experiences [START_REF] Bhargave | The Social Context of Temporal Sequences: Why First Impressions Shape Shared Experiences[END_REF]. However, we did not find any articles exploring the role of social distance on trust within the construal level theory framework. Hence this research contributes to the social distance and construal level theory literature by showing that in the context of collaborative services, where interpersonal relations are important, perceived social proximity can have a positive influence on trust in peers.

Finally, we collected participants' perceived social proximity for the empirical analysis using the Liviatan et al. scale (2008). While most empirical studies based on social distance rely on experiments for their methodology, they compare two instances of social distance, close (self or close other) versus far (distant other) (Kim et al., 2008;Zhao & Xie, 2011). Our study provides a finer-grained assessment of perceived social distance through a measurement scale.

Practical implications

Despite the fact that the sharing economy and collaborative consumption are projected to experience exponential growth in the coming years [START_REF] Pricewaterhousecoopers | The sharing economy[END_REF], platforms such as Airbnb and BlaBlaCar still face many challenges if they want to keep attracting new users and retain their current customers. After the early positive trends surrounding the fast emergence of these new business models, collaborative services platforms now have to deal with several challenges, such as tough competition, more careful scrutiny from their users, or even new regulations [START_REF] Arcidiacono | Sharing what? The 'sharing economy' in the sociological debate[END_REF], if they want to live up to the potential indicated by their early growth.

Our research sheds light on a possible innovative segmentation and personalization strategy that platforms could implement, which does not exist in traditional forms of exchange.

More specifically, based on interchangeability, it is possible to take into consideration that attitudes and behaviors, trust and participation intention, can vary depending on whether users have experienced both roles or just one. As such, as part of a targeted communication strategy, platforms could consider setting in place different messages and different incentives for both segments: interchangeable and non-interchangeable participants. Furthermore, implementing specific campaigns to promote permeability between both types of participants (service providers and service users) could have several fruitful and interesting benefits. Not only would it increase the overall number of exchanges and transactions for the same number of participants, but these interchangeable customers also appear to have more favorable attitudes and behaviors. In particular, they are more trusting, as well as more likely to participate in future collaborative services exchanges than their counterparts who act as only service providers or service users.

Hence platforms should encourage their customers to experience both roles whenever possible by identifying those who have only participated in one role and offering them incentives (such as a free trial transaction, for example) to experience the other role.

Moreover, because our study demonstrates that social proximity has a positive influence on both trust and participation intention, platforms could consider mechanisms other than interchangeability to increase social proximity. For example, [START_REF] Stephan | Politeness and psychological distance: A construal level perspective[END_REF] show that greater politeness can increase social distance. By promoting a more direct and less formal type of communication between members, it may be possible to reduce the social distance perceived by participants.

Limitations and future research

This study has several limitations. First, despite good fit indices and no significant differences in terms of gender, it is based on the analysis of a convenience sample that suffers from an imbalance skewed toward female respondents, as well as a possible overrepresentation of the student population. Furthermore the data was collected using only French-speaking respondents; while some exchanges are at a local scale (e.g., in the case of ride-sharing), other types of exchanges happen on a global and international level, such as accommodation rental.

Social constructs, in our case social distance, are likely to be affected by cultural differences [START_REF] Lutz | Consumer segmentation within the sharing economy: The case of Airbnb[END_REF]. Thus, further research could consider the influence of differences in culture and use a larger and more balanced sample of respondents.

Second, with the data collected we were able to compare two groups: one group of 167 respondents who had only assumed one role -either as a service provider (host) or as a service user (traveler) -and another group of 55 respondents who had assumed both roles, being both a service provider and a service user (see Table A.1 in the Appendix). Despite good fit indices, this asymmetry could be limiting because the two groups are not balanced. A different methodological approach, such as fuzzy-set qualitative comparative analysis [START_REF] Beynon | Country-based comparison analysis using fsQCA investigating entrepreneurial attitudes and activity[END_REF][START_REF] Dul | Identifying single necessary conditions with NCA and fsQCA[END_REF], could possibly provide complementary insights.

Third, we conducted our analysis on one single type of exchange (accommodation rental).

Replicating this experiment with other types of exchanges, such as car rental for example, or taking into consideration asymmetrical transactions -when participants assume both roles but for different types of services -would allow us to account for other dimensions, such as product characteristics (their price, the provider's attachment, their intimacy, etc.). The assessment of interchangeability could also be considered as limiting for two reasons: because participants' (in)ability to play both roles is not accounted for, and because we consider interchangeability as a binary variable. Either the participant has experienced both roles and interchangeability is set to 1, or the participant has only experienced one role and interchangeability is set to 0. It is also 29 possible to consider that, depending on the ratio of experiences in one role versus in the other role, the interchangeability variable could be on a continuum rather than merely binary. Fourth, we do not consider trust as a multidimensional construct (we conceptualize it as a unidimensional construct). However, trust could be multidimensional, for example with cognitive and affective facets [START_REF] Johnson | Cognitive and affective trust in service relationships[END_REF]. Consequently, it would be interesting to investigate how interchangeability impacts those sub-dimensions. Furthermore, including control variables, such as trust propensity, participants' experience, or the presence of trust mechanisms implemented by the platforms, would allow us to ensure that such variables have no effect.

Lastly, there is a type of collaborative services exchange that is based on swapping. On those platforms, participants can exchange in a symmetrical manner, for example when a family living in Paris swaps their apartment with another family who lives in a house in Los Angeles during a two-week vacation. GuesttoGuest is an example of such a platform [START_REF] Forno | Sharing economy in travel and tourism: The case of homeswapping in Italy[END_REF].Within those marketplaces, all participants experience both roles and not just one role. It could be interesting to run a comparative analysis of trust and participation intention levels among participants on those platforms with participants on exchange platforms such as Airbnb.

For more information on the gender split showing an imbalance toward female participants, see: https://www.hitwise.com/en/2016/10/31/vacation-rental-traffic-skews-female-reflects-growing-desire-for-travelexperiences/ for travelers, and https://www.airbnbcitizen.com/wp-content/uploads/2017/03/Women-Hosts-and-Airbnb_Building-a-Global-Community.pdf for hosts.

This one item is PSP2, with a loading of 0.639: "In general, to what extent do you perceive hosts/travelers to be close to you (for example, to be socially close)?" We decided to keep this item for two main reasons. First, the loading is not far from the 0.7 threshold. Second, removing one item from the scale of perceived social proximity would have led to a mono-item scale.

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Tables and Figures

Appendix