Promoting synergies for sustainability through peer-to-peer sharing: an analysis of drivers and barriers

ABSTRACT Peer-to-peer (P2P) sharing may foster sustainability synergistically by saving resources, reducing costs and promoting satisfaction of consumer needs and social connectivity. A survey of Swiss and Swedish consumers (N = 1522) was conducted to analyze drivers and barriers for P2P sharing of household products as taker and/or provider in a complementary way referring to social exchange theory. More than two-thirds (69.1%) of the participants took or provided shared household products during the previous 12 months. The traditional mode of sharing was more prevalent (53.5%) than sharing on online platforms (14.5%). Nearly half of the participants (44.5%) both took and provided shared products, 18.1% exclusively took and 6.5% exclusively provided them, and 30.1% were non-sharers. The traditional mode of sharing involved more reciprocal sharers (66.7%), who both took and provided products, compared to online sharing. Reciprocal sharers were on average younger and had higher income and education levels than non-sharers. Furthermore, their ecological, social, and economic value orientations were stronger, and they rated the benefits of sharing higher than non-sharers. Knowledge about sharing and experience of positive emotions when sharing were consistently positively related to both the number of products taken and provided. To promote the sharing economy, online sharing platforms should enhance consumer’s knowledge and trust through information campaigns and review or insurance systems. Marketing activities should communicate easy access and application of platforms, and the ecological, socio-emotional and economic benefits. A meaningful social interaction between takers and providers should be promoted to promote social connectivity and emotionally positive experiences.


Introduction
The growing production and consumption of goods that accompany postindustrial technological development and population growth on the global level aggravates current environmental problems and contributes to climate change as well as the depletion of natural resources. The sharing economy has strong potential to contribute to achieving the Sustainable Development Goals (UN 2015) by facilitating the collaborative usage of products to reduce the consumption of goods and, thus, save natural resources without significantly limiting people's access to and use of important products (Mi and Coffman 2019;Dabbous and Tarhini 2021;Karobliene and Pilinkiene 2021;Zhang et al. 2023). In addition, sharing processes could trigger social interaction and contribute to the development of social relations and networks, as well as improve the access of economically disadvantaged consumers to products usually inaccessible to them. Therefore, the sharing economy could strengthen the social, economic, and ecological aspects of sustainability in a synergistic way (Teles et al. 2018;Mi and Coffman 2019; Labbate et al. 2021). Striving for such positive couplings and synergies between the ecological, social, and economic dimensions of sustainability has been acknowledged as a key path to sustainable development (Hansmann et al. 2012).
However, to live up to this potential and make a real difference, the sharing economy must play a quantitatively much more substantial role in future economies than presently, which means that more consumers must engage in sharing practices (Martin 2016;Mi and Coffman 2019). This requires policy interventions and social marketing approaches to trigger cultural change, as well as the further development, spread, and elaboration of sharing platforms to turn sharing into a prevalent form of social and economic exchange (Geissinger et al. 2019). In-depth knowledge of the motives, drivers, and barriers that determine whether consumers adopt sharing practices and use sharing platforms is crucial to the design and development of interventions promoting the sharing of products between consumers to facilitate sustainable development (Böcker and Meelen 2017;Toni et al. 2018). Different sectors of the sharing economy can be distinguished. Though drivers and barriers for sharing accommodation, cars, food, labor, and household products may overlap to some extent, specific studies are required in each domain to gain detailed insights of the specific processes that play a role there.
The accommodation and mobility sectors attracted most attention in previous research (Khalek and Chakraborty 2023). The present study investigates the drivers of and barriers to sharing of household products, leisure and gardening equipment on a peer-topeer (P2P) basis, a topical area which received only limited attention in previous studies (e.g. Laurenti and Acuña 2020;Hunka and Habibi 2023). The study thus aims to generate valuable insights for the further development of the sharing of these tangible products by addressing three distinct but interrelated levels of inquiry: (1) The drivers of and barriers to P2P sharing that motivate and facilitate or prevent participation in P2P sharing.
(2) The socio-demographic characteristics of sharers, such as gender, age, country of residence (Switzerland and Sweden), education level, and income. (3) The different roles of providers and takers of shared products, who may have distinct characteristics and drivers and may face different barriers. (4) The different modes of sharing, which may occur either i) conventionally in communities between family, friends, and acquaintances (i.e. traditional sharing) or via the internet on ii) online sharing platforms and iii) social media.
The characteristics of sharers and the drivers of and barriers to the distinguishable processes of taking and providing products in P2P sharing will thus be investigated separately to fill a gap in the previous research, which focused mostly on the borrowers and rarely examined the motives for providing products (e.g. Huang and Kuo 2020;Ertz et al. 2021;Vicente and Gilde-Gómez 2021). Furthermore, whereas previous studies of the dual, partly complementary roles and motivations of obtainers and providers focused exclusively on users of digital platforms (e.g. Torrent-Sellens et al. 2022), this study also addresses traditional forms of sharing between family, acquaintances and friends. Current research on the sharing economy often focuses on digital platforms, as they have a large and partially still unfulfilled economic, ecological and social potential (Khalek and Chakraborty 2023). However, in terms of synergies for sustainability, traditional sharing may be equally important as corresponding exchange processes could be connected to more meaningful social interactions and networks that can generate emotional, economic and ecological benefits. In addition to this, the further development and promotion of digital platforms may also learn from insights into traditional sharing practices.
The different processes, drivers and barriers influencing participation in different modes of sharing (i.e. traditional sharing and sharing via online platforms or social media) will therefore be partially investigated separately in this study, and based on considerations of social exchange theories (Cropanzano and Mitchell 2005;Wang et al. 2019;Lai et al. 2020), the reciprocity of sharing will be analyzed.
The analyses of drivers and barriers will particularly focus on the social, ecological, and economic value orientations and sharing motives that may lay a foundation for synergies between the three pillars of sustainability. Further drivers and barriers that are not straightforwardly assignable to one of these dimensions are also addressed to determine their role in participation in P2P sharing and implications for sustainability.
A summary of the previous findings regarding the four abovementioned levels of analysis is provided in the next subsections, together with an explanation of the research gaps that this study aims to fill.

Drivers of and barriers to P2P sharing
A considerable amount of previous research investigated the sharing economy from the perspective of drivers, motives and facilitating factors, which move people to share products, on the one hand, and barriers, obstacles and inhibiting factors preventing people from sharing, on the other hand. Table 1 shows an overview of some recent studies from 2020 to 2023 which took this approach. These studies are listed with the main drivers and barriers for sharing, which they have identified, and the measures suggested to facilitate and promote the sharing economy. Previous research accordingly identified various facilitating contextual and psychological aspects, such as expected benefits, values and motives, which may increase participation in sharing activities as well as inhibiting factors such as riskperception and ownership orientation, and availability concerns (e.g. Chou et al. 2023;Hunka and Habibi 2023;Khalek and Chakraborty 2023).
Ecological, social, and economic values, and corresponding benefits and motivations have been identified as drivers for the participation in sharing activities (e.g. Luri et al. 2021;Daškevič and Burinskienė 2022;Lynch 2023; see Table 1). Accordingly, there could be positive synergetic effects of the sharing economy regarding the three corresponding dimensions of sustainability. The ecological motivation to participate in sharing to protect the environment and reduce CO2 emissions by limiting the purchasing and, hence, production of consumer goods has been identified as a crucial factor in many studies (e.g. Piscicelli et al. 2018;Laurenti and Acuña 2020;Luri et al. 2021;Chou et al. 2023;Merino-Saum et al. in prep).
Social motives can also play a role because sharing activities can generate new and strengthen established social contacts as they involve opportunities for meeting new people and gathering with friends and acquaintances to exchange products (Böcker and Meelen 2017;Frenken and Schor 2017;Khan et al. 2021;Nguyen 2023).
Economic motives are also relevant as people may save money by borrowing a product instead of buying it, and people who have bought a product may receive financial or other compensation for lending it to someone (Hawlitschek et al. 2018;Park and Joyner Armstrong 2019;Luri et al. 2021;Torrent-Sellens et al. 2022).
In addition to ecological, social, and economic values and motives, a hedonistic and emotional component plays a crucial role in promoting sharing activities. Previous research has shown that sharers often experience engagement in sharing as pleasant and enjoyable and that the expectation of such positive emotions represents an important motivating factor for sharing (Barnes and Mattsson 2017;Trenz et al. 2018;Li and Wen 2019;Chou et al. 2023;Khalek and Chakraborty 2023).
Some additional motivating factors identified in previous research are the expectation of saving time and effort as sharing processes may be a convenient means of accessing products (Jo et al. 2018;Park and Joyner Armstrong 2019;Huang and Kuo 2020;Lee and Chow 2020;Daškevič and Burinskienė 2022). Sharing may be particularly beneficial in the case of products that individuals need or use very rarely because buying a product for single or rare usage could be disadvantageous from an effort, cost, and ecological perspective compared to borrowing it. Sharing-related knowledge is a further facilitating factor identified in previous research (Ertz et al. 2021;Labbate et al. 2021). Corresponding skills seem particularly important with regard to formally organized processes on online sharing platforms, where specific knowledge of the options, procedures, and rules is needed for participation. Sharing-related knowledge may be an antecedent factor facilitating sharing activities as well as a consequence of sharing since this knowledge can increase through participation in sharing activities. Such a bidirectional influence could constitute a circular positive coupling. Thus, a positive correlation between sharing-related knowledge and the frequency of sharing activities may be expected.
Furthermore, the following three psychological barriers, which may prevent people from sharing, have been identified in previous research: i) concerns about independence and autonomy, ii) a lack of trust in the persons involved in the sharing process, and ii) a lack of trust in the shared products.
Previous studies have shown that uncertainties about the availability of products and constraints on individual freedom to use a product whenever and however one likes as well as related concerns about dependence on providers (or takers) are a potential barrier to engagement in sharing activities (Dall Pizzol et al. 2017;Billows and McNeill 2018;Hawlitschek et al. 2018;Hunka and Habibi 2023).
Trust develops in social interactions between persons and is crucial for the initiation and course of social and economic exchange in sharing activities (Ter Huurne et al. 2017Köbis et al. 2021). Previous research has shown that a lack of trust in prospective providers or takers of products may prevent persons from engaging in sharing (Birinci et al. 2018;So et al. 2018;Cho et al. 2019;Torrent-Sellens et al. 2022). Distrust of sharers' integrity may, for example, generate concerns about not receiving a product (or not getting it back) timely or receiving invalid information and being taken advantage of (Welter and Smallbone 2006;Johnson et al. 2016;Barbu et al. 2018).
Trust in the sharing partners (providers or takers) can be distinguished to some extent from trust in the shared products. According to previous research, the lack of trust in the quality or performance of shared products or services can also discourage people from sharing (Birinci et al. 2018;Cherry and Pidgeon 2018;Jo et al. 2018;Chen et al. 2019;Ye et al. 2019).
A main goal of this study is accordingly to gain specific insights into the processes that can promote or hinder P2P sharing. For this purpose, the study takes a dual approach differentiating between the drivers of and barriers to taking and providing products as separate complementary activities and it additionally distinguishes between traditional face-to-face and online sharing. The implications of the identified drivers of and barriers to sharing for the development of possible measures to overcome the latter and promote sustainability through enhancing the sharing economy are connected foci.

Characteristics of sharers
Previous research has consistently found that younger and more educated persons are more inclined to participate in the sharing economy than older and less educated people (Smith 2016;Andreotti et al. 2017;Prieto et al. 2017;Khalek and Chakraborty 2023). Income and socio-economic status are also positively related to participation in sharing activities (Eurobarometer 2016;Smith 2016). In particular, the use of online sharing platforms is more common among younger, higher-educated, and higher-income individuals, and a gender effect was also observed, with higher participation rates among men (Eurobarometer 2016; Andreotti et al. 2017). However, the relationship between gender and sharing activities may be more complex and partly depends on the type of products or commodities. For example, Prieto et al. (2017) found greater participation of men than women on car-sharing platforms, whereas Schor et al. (2016) reported stronger participation of women on foodswap platforms for trading and sharing homegrown and homemade food on a P2P basis. Consequently, another aim of this study is to investigate possible gender differences in household-product and leisureequipment sharing.
Previous studies on cultural differences connected to nationalities found that people from Asian countries with more collectivist values, such as for example China, are more inclined to participate in sharing activities than people from individualistic Western Societies (e.g. Gupta et al. 2019;Kozlenkova et al. 2021). The present study investigates sharing in two European countries, Sweden and Switzerland, which seem culturally similar in terms of individualism and collectivism. Still, including two countries broadens the basis and generalizability of the research and opens up the possibility of investigating potential national differences in P2P sharing.
Accordingly, the second goal of this study is to investigate the relationship between sociodemographic variables (i.e. country of residence, gender, age, education, and income level) and sharing behavior. Obtaining more knowledge about the characteristics of persons who are currently more or less inclined to participate in sharing activities is useful for defining target groups for possible interventions aiming to promote the sharing economy.

Sharing as a social and economic exchange between providers and takers
Sharing already occurred in ancient times and is thus a well-established form of social and economic exchange with a long tradition and historic roots (Belk 2014;Arcidiacono et al. 2018). Social and economic exchange theories aim to understand the behavior of humans as social beings from a sociological and socialpsychological viewpoint (Cropanzano and Mitchell 2005;Cook et al. 2013;Wang et al. 2019). Accordingly, to these theories, reciprocity and equity are major principles of human interaction and socioeconomic exchange, including the buying and selling as well as the sharing of goods (Liu et al. 2016;Arcidiacono and Podda 2017;Davlembayeva et al. 2020Davlembayeva et al. , 2021. A considerable number of previous studies thus used social exchange theory as framework to investigate and better understand sharing processes by taking a complementary perspective on obtainers and providers and their interpersonal transactions Lai et al. 2020;Kozlenkova et al. 2021;Khalek and Chakraborty 2023). Socio-economic exchange can involve transactions of various kinds of goods, such as material goods, money, services, information, or immaterial psychological 'goods' like trust, sympathy, status, and reputation (Brinberg and Wood 1983). The Resource Theory of Social Exchange proposed by Foa and Foa (1980) orders these commodities from abstract to concrete and from universal to particular. While the most universal commodity, money, is usually exchanged for more particular goods, particular goods are quite often exchanged for goods of the same type (e.g. services for other services, goods for other goods), according to previous research (Mikula 1985).
Social and economic exchange processes of sharing may involve sequential transactions between individuals, notably the mutual giving and taking of products, where the same person may act as the provider of one product and the taker of another. An equilibrium between the provision or supply of and demand for goods is a prerequisite for the expansion and flourishing of the sharing economy because a shortage on either side creates a bottleneck limiting economic exchanges. The shortage of products or providers was identified as a major limiting factor of P2P online sharing platforms; consequently, efforts to promote the provision of products seem important (Davlembayeva et al. 2021;Ertz et al. 2021).
Various factors such as wealth and ownership structures and psychological factors like risk perception, motivations, knowledge, and skills influence the sharing behavior of individuals. This may lead to an imbalance if few provide and many aim to take shared products. Therefore, the third goal of this study is to analyze the overall prevalence of takers and providers of shared products among Swiss and Swedish consumers as well as the difference between providers and takers in terms of drivers of and barriers to sharing. For this purpose, the study distinguishes between the four categories of i) non-sharers, ii) unilateral takers, iii) unilateral providers, and iv) reciprocal sharers, who both took and provided products in P2P sharing during the previous 12 months. Characteristics, drivers, and barriers can thus be compared between these four groups.

Traditional P2P sharing and online sharing
In recent years, sharing on online sharing platforms and between persons who established contact via social media has supplemented the traditional modes of P2P sharing occurring between family members, friends, and acquaintances in conventional social networks (Piscicelli et al. 2018;Wang and Yu 2021).
According to a recent Eurobarometer (2016) survey, a majority of Europeans are aware of sharing platforms, but only approximately 17% have used them personally. Although sharing platforms are still relatively new, some sharing services, such as Uber in the mobility sector or Airbnb in housing and tourism, are already relevant industry players generating considerable revenues. Ride-and accommodation-sharing services are among the most frequently used sharing platforms. Platforms for sharing household and leisure products may likewise have the potential to grow substantially and increase the overall volume and, hence, social, economic, and ecological relevance of sharing. Typically, online sharing platforms can be accessed free of charge by practically everyone. They open up a space for sharing a broad variety of products with large numbers of individuals who do not yet know each other (Belk 2014). Still, traditional sharing has its advantages as it takes place between people known from previous social interactions.
Correspondingly, the fourth aim of this study is to investigate the prevalence of different modes of P2P sharing of household products and leisure equipment and analyze differences in the characteristics of consumers participating in each mode and the drivers and barriers they perceive. Three modes of sharing are distinguished and compared: 1) traditional sharing between family, friends, and acquaintances, 2) sharing via dedicated online platforms, and 3) sharing via social media. The relationships between the three sharing modes are also analyzed to determine whether they function synergistically, complement, or tend to substitute each other.

Research questions
A survey was conducted among Swiss and Swedish consumers to gain valuable insights for the further development of a sharing economy in line with the Sustainable Development Goals. The following four research questions were examined: (1) Which drivers promote or facilitate and which barriers hinder or prevent persons from taking and providing products on a P2P basis? (2) Which background characteristics (gender, age, education level, income, country) distinguish reciprocal sharers from unilateral providers, unilateral takers, and non-sharers? (3) How many people provide and take certain types of shared products and how does the mode of sharing influence the reciprocity of sharing and the ratio of takers and providers? (4) How many people take part in the P2P sharing economy in Switzerland and Sweden and what are the prevalence of and relationship between different modes of sharing, namely, a) traditional sharing, b) sharing via dedicated online platforms, and c) sharing via social media?
Addressing these four research questions will serve the study's goal to find out how P2P sharing can facilitate sustainable development in a synergistic way and which aspect must be considered to promote it.

Implementation of the survey
The survey was conducted from April 8 to 28 April 2021, in Switzerland and Sweden using the online survey tool Qualtrics. Altogether, 2,065 persons in a Swiss and a Swedish consumer panel visited the survey webpage and gave their informed consent to participate in the survey on the motivations behind and barriers to sharing practices. Participants who did not fully complete the survey were excluded from the analysis. The sample analyzed in this study thus consists of the responses of 1,522 persons.

Participants
The majority of the 1,522 participants resided in Switzerland (62.2%) and the remainder in Sweden (37.8%). The distribution of the participants in terms of gender, age, education level, and income is shown in Table 2. The gender distribution of the participants was approximately 50% men and 50% women. The age of the participants ranged from 18 to 89 years, with an average of 43.6 years (SD = 15.94) and a median of 43 years.
Only 14.5% of the participants held a master's or doctoral degree. To arrive at a common income-level variable, the five income-range categories of the Swiss and Swedish surveys, which used different currencies (CHF, SKR), were assigned to the three levels below median, median income category, and above median separately for each country. On this basis a common income variable for both countries distinguishing these three levels was formed.

Questionnaire and scales
The questionnaire was structured into four sections: • Socio-demographic items (gender, country, age, education level, and income). • Modes of sharing in which the respondents participated during the previous 12 months as either taker or provider. We distinguished between 1) sharing with family, friends, and colleagues, 2) sharing via dedicated online platforms, and 3) sharing via social media. • Specific products that the respondents shared among 15 predefined household goods. These goods were selected based on their prevalence in exchanges taking place on various sharing platforms such as Pumpipumpe (see http://pumpi pumpe.ch) and Sharely (https://sharely.ch) (see Ribera et al. in prep). The participants indicated whether they took or provided each of these products in P2P sharing processes during the previous 12 months. The participants could also mention additional products that they took or provided as part of P2P processes during the 12month period. • Drivers and barriers that may motivate and facilitate or prevent and impair the P2P sharing of products. These items addressed the following aspects: a. Basic i) ecological, ii) social, and iii) economic value orientations. b. Additional drivers and facilitators of sharing: i) ecological, ii) social, and iii) economic benefits, iv) saving time and effort, v) positive emotions experienced when sharing, vi) advantages of sharing for rarely used products, and vii) knowledge of sharing processes. c. Sharing barriers: i) concern about depending on others, ii) distrust of the persons who share products, and iii) distrust of the products that are shared.
These drivers and barriers were measured on scales consisting of three items each, except for concerns about dependence (sharing barrier i)), which was measured on a five-item scale. The items for these scales were selected based on a review of the previous literature employing the constructs (c.f. Ribera et al. in prep). All items measured agreement with a statement on a seven-point Likert scale (1 = strongly disagree, 2 = disagree, 3 = somewhat disagree, 4 = neither agree nor disagree, 5 = somewhat agree, 6 = agree, and 7 = strongly agree). With one exception, the Cronbach's alpha values of all scales were satisfying and ranged from 0.75 to 0.88. The exception was the item measuring the economic value orientation of the participants, which obtained the low value of 0.58. However, eliminating one of the three items increased the value to 0.62; consequently, only two items were used for this construct. For all constructs, the average rating a person gave on the items was calculated as a scale value. The items forming the scales and the Cronbach's alpha values and means of the items and scales are presented in Table 3.

Shared products taken and provided
The frequency with which the 15 products in this survey were taken and provided varied substantially. Figure 1 presents the percentage of persons who took or provided each product at least once during the previous 12 months. The products are ordered according to the size of the difference between the percentages for taking and providing. It can be seen that for some products (e.g. a car trailer or ski gear), very few providers shared their products with many borrowers, whereas for other products (e.g. a suitcase or a photo or video camera), the numbers of takers and providers were roughly equal.
McNemar's test for paired dichotomous variables was performed to determine for which products the number of takers differed significantly from the number of providers. There were significantly more takers than providers for 11 products (p < .01), but the number of providers was not significantly higher for any of the products.
In addition to the 15 predefined products shown in Figure 1, participants could mention a maximum of three additional products that they provided or took in P2P sharing processes during the previous 12 months. Only 6.8% of the participants mentioned one or more additional products that they took, and 6.9% mentioned additional products that they provided. These products included a broad range of objects, from kitchen and household equipment to diverse tools, media formats such as DVDs, games, or books, and vehicles like bicycles or cars.

Takers and providers of P2P shared products
A majority of the participants (62.6%) obtained products from other persons during the previous 12 months, and approximately half of the participants (51%) provided sharing products to others. A crosstable (Table 4) and Chi-square test on the four fields defined by taking (yes/no) and providing (yes/no) revealed that the two actions are not independent of each other (χ2 = 410.20; df = 1, p < .001). As the large values in the diagonals of Table 4 indicate, people who take products are much more likely to also provide products, and vice versa. Thus, only 18.1% of the participants exclusively took products, and only 6.5% solely provided products, whereas considerably more persons (44.5%) both took and provided products. A corresponding one-sample Chisquare test on equal distribution comparing (99 + 276 =) 375 persons who either only took or only provided products to 677 persons who both took and provided household products showed a clearly significant deviation (χ2 = 86.70; df = 1, p < .001). Accordingly, a clear majority of P2P sharers had both taken and provided shared household products during the previous twelve months, whereas unilateral takers and providers were in the minority.
Furthermore, Table 4 shows that the P2P sharing of household products was very common among the study participants as only slightly less than one-third (30.9%) neither obtained nor provided shared products.

Differences in socio-demographic characteristics
Four categories of persons, namely, (a) non-sharers, (b) unilateral takers, (c) unilateral providers, and (d) reciprocal sharers, were compared on possible influential background variables, their basic value orientations, and potential drivers of and barriers to sharing. Table 5 shows the percentage distributions, means, and outcomes of the significance tests comparing these four groups.
The distribution of the participants in the four categories differed significantly between Switzerland and Sweden (Chi-square test, p < .001). A higher percentage of non-sharers and reciprocal sharers was observed in Switzerland, and more people (31.4%) only took products in Sweden than in Switzerland (11.4%). This points to structural differences in P2P sharing customs in the two countries.
No gender differences were found between the four groups. In contrast, age varied significantly between the groups (one-way ANOVA, p < .001). Mutual post hoc comparisons showed that non-sharers (M = 52.4 years) and unilateral providers (M = 48.8 years) were significantly (p < .001) older than unilateral takers (M = 36.5 years) and reciprocal sharers (M = 39.7 years) ( Table 5).
The education level was also significantly related to sharing activities (Kruskal-Wallis test, p < .001). Mutual Man-Whitney U-test comparisons between the four groups revealed that unilateral providers and reciprocal sharers were significantly more educated than nonsharers and unilateral takers.
Additionally, the income of the participants was significantly correlated with their sharing activities (Kruskal-Wallis test, p < .001). Reciprocal sharers had significantly higher incomes than non-sharers and unilateral takers. In summary, reciprocal sharers were younger and more educated and had a higher income than non-sharers.

Differences in value orientations
The basic ecological, social, and economic value orientations that were investigated proved to be significantly linked to the sharing activities of the participants (p < .001, for all three one-way ANOVAs).
Mutual post hoc comparisons showed that reciprocal sharers and unilateral providers had a stronger environmental and social value orientation than non-sharers and unilateral takers (Table 5). Furthermore, reciprocal sharers and unilateral takers exhibited significantly stronger economic value orientations than non-sharers and unilateral providers. Thus, reciprocal sharers had stronger ecological, social, and economic value orientations than nonsharers.

Differences in drivers of sharing
The seven drivers investigated, namely, a) social, b) ecological, and c) economic benefits, d) saving time and effort, e) positive emotions associated with sharing, f) the need for rarely used products, and g) knowledge of sharing processes, were strongly related to the  sharing activities of the participants (p < .001 in all seven one-way ANOVAs). The sustainability-oriented sharing motives, a) protecting the environment, b) creating social contact with others through sharing, and c) achieving economic gains and savings, were significantly higher among reciprocal sharers than non-sharers. The additional drivers, d) saving time and effort, e) positive emotions, the f) need for rarely used products, and g) knowledge of sharing processes, were all rated highest by reciprocal sharers and significantly different from non-sharers.

Differences between sharers and non-sharers in barriers to sharing
The barriers a) concern about lacking independence from others and b) distrust of shared products were rated significantly higher by non-sharers than the other three groups of unilateral takers, unilateral providers, and reciprocal sharers ( Table 5).
The barrier c) distrust of sharers was highest among those who unilaterally take shared products (M = 3.4). This level was significantly higher than for the three other groups. No significant difference was observed between non-sharers (M = 2.9) and reciprocal sharers (M = 3.0) in this regard.

Models explaining the number of shared products taken and provided
Two separate analogous GLM models using background variables (gender, age, income, education level), value orientations (ecological, social, economic), drivers (seven variables) of and barriers to sharing (three variables) as predictors were calculated to explain the number of different products taken and provided by the participants during the 12 months preceding the survey ( Table 6). The explanatory power of the model for predicting the number of products taken was with R 2 = .25, approximately two times higher than for predicting the number of products provided (R 2 = .12).
Five predictor variables showed significant relationships with the numbers of different shared products both taken and provided. Age was negatively related to both taking and providing products, which means that younger persons shared more products in both roles (i.e. as takers and as providers). Furthermore, positive emotions experienced due to sharing and knowledge of sharing processes were positively correlated with both taking and providing many different types of products. Additionally, two somewhat counterintuitive findings consistently emerged in both models. First, the Table 5. Percentage distributions, means, and significance of differences between non-sharers, unilateral takers, unilateral providers, and reciprocal sharers in background variables, basic value orientations, drivers, and barriers. * p < .05, ** p < 0.1, *** p < .001 of Chi-square tests (χ 2 ) for country and gender, Kruskal-Wallis tests (H) for education and income, and one-way ANOVAs main effects (F-ratios) for the remaining variables. a Equal superscripts denote significant differences (p < .05) between two groups according to Scheffé post hoc comparisons within the one-way ANOVA and significant differences according to bilateral Man-Whitney U-tests for Kruskal-Wallis tests. b Mean values on a scale where 1 = obligatory primary school, 2 = intermediate level, 3 = master's degree, and 4 = doctoral degree. Mean ranks in brackets.
Equal superscripts denote significant differences according to mutual Mann-Whitney U-tests. c Mean values on a scale where 1= below-median category, 2 = median-income category, and 3 = above-median category. Mean ranks in brackets. Equal superscripts denote.
number of products taken and provided significantly decreased with the motive of creating social contact through sharing. Second, the barrier of distrust of sharers turned out to be significantly positively related to the numbers of shared products both taken and provided.
In addition to the five common significant findings of the two GLM models, some specific results emerged ( Table 6).
The number of products taken increased significantly with male gender and high environmental and economic values and significantly decreased with the barrier of dependence concerns. The number of products provided was lower in Sweden than in Switzerland and increased with education level and social value orientation but decreased with the motive to obtain monetary gains and savings and the barrier of distrust of shared products.

Prevalence of different modes of sharing
A majority of the participants (53.5%) shared objects in the traditional mode. Sharing with people via social media was reported by 29.8% and sharing via online platforms by 14.5% of the participants. The results of mutual McNemar tests comparing the frequencies of these sharing modes turned out to be highly significant (for all three comparisons, p < .001), confirming that the traditional sharing of household goods was the most prevalent mode.
Contingency coefficients were calculated to analyze the relationship between the different modes of sharing. No significant statistical relationship between traditional sharing and sharing via online platforms was found (c = .00, p = .862). However, small but significant positive contingencies were observed between sharing via online platforms and sharing via social media (c = .08, p = .002) as well as between traditional sharing and sharing via social media (c = .16, p < .001).

Sharer characteristics and drivers of and barriers to different modes of sharing
To investigate the characteristics of sharers and the factors determining which modes of sharing they engage in, binary logistic regressions were calculated for each mode of sharing (Table 7). Only the participants who took or provided at least one shared product during the previous 12 months (N = 1052) were considered in these analyses. The predictor variables were identical to those used in the previous multiple regression models (see section 4.4). Three separate binary logistic regressions were calculated for a) traditional sharing, b) sharing via dedicated online sharing platforms, and c) sharing via social media, with engagement in the type of sharing as the dependent variable (yes = 1, no = 0).
Sharing with family, friends, neighbors, and other acquaintances. Traditional P2P sharing was significantly positively related to the experience of positive emotions in sharing (b = 0.21, p < .05) and the advantages of sharing for rarely used products (b = 0.25, p Table 6. GLM regression for the prediction of the number of products taken and provided by the participants in P2P sharing (N = 1522). < .05) and negatively associated with the barrier of distrust of sharers (b = −0.18, p < .01). The corresponding logistic model revealed rather weak explanatory power (Nagelkerke R 2 = 0.08).
Online sharing platforms. The logistic regression model for online sharing platforms revealed that male (b = 0.57, p < .01), younger (b = −0.27, p < .001), and higher-income sharers (b = 0.26, p < .05) were particularly inclined to use this sharing mode. Furthermore, the self-evaluated knowledge of sharing processes was positively correlated with the use of sharing platforms (b = 0.40, p < .001), whereas the experience of positive emotions through sharing (b = −0.29) and the advantages of sharing for rarely used products (b = −0.30) were negatively associated with it (both predictors: p < .05).
Regarding barriers, users of sharing platforms were less concerned about losing their independence than those engaged in other modes of sharing (b = −0,25, p < .05), but they displayed comparably high levels of distrust of other sharers (b = 0,41, p < .001). The overall prediction model for the use of sharing platforms achieved substantial explanatory power (Nagelkerke R 2 = 0.25).
Sharing via social media. The logistic regression model predicting sharing via social media had rather weak explanatory power (Nagelkerke R 2 = 0.06). Here, only two predictors turned out to be significant. The motive of creating social contact through sharing was significantly positively related to sharing with social media contacts (b = 0.29, p < .001), whereas expected economic gains or savings were less important (b = −0.21, p < .05) to these sharing activities.

Reciprocity in different modes of sharing
We investigated separately the ratio of takers, providers, and reciprocal sharers among participants who a) only participated in traditional sharing, b) only used sharing platforms, and c) only shared with persons via social media. This revealed a highly significant relationship between the mode of sharing and the prevalence of takers and providers (Chi-square test, p < .001). As Table 8 shows, among those exclusively engaged in sharing via an online platform, very few participants (1.2%) were unilateral providers, more than half (53.2%) only took products, and 45.9% were reciprocal sharers. On the contrary, among those exclusively engaged in traditional sharing, the percentage of reciprocal sharers was clearly the highest (66.7%).

Discussion
Enhancing the sharing economy represents an opportunity to increase the sustainability of society on local and global scales. Against this background, a survey on the P2P sharing of household products was conducted in two European countries to investigate the motives for sharing and the barriers preventing people from engaging in this practice. The discussion of our findings begins with a general analysis of the prevalence of different modes of P2P sharing of household products and the relationships between taking and providing Table 7. Binary logistic regression for the prediction of participation of sharers in three different types of sharing activities (no = 0, yes = 1). goods. Thereafter, findings pertaining to the drivers, barriers, and characteristics of sharers are addressed and connected to ongoing discussions about the dimensionality of the sustainability concepts and corresponding synergies. A further subsection focuses on practical implications for management and marketing of sharing activities and platforms. This is followed by a brief summary of main theoretical contributions of this study, and finally limitations and future research needs are outlined.

Traditional face-to-face sharing is still prevalent
More than two-thirds (69%) of the participants took part in P2P sharing transactions for household products as takers and/or providers during the 12 months preceding the survey. This indicates that P2P sharing is very common in Switzerland (65.3%) and Sweden (76.6%) and that the sharing economy is considerably relevant. Traditional face-to-face sharing (54%) was over three times more prevalent than sharing via online platforms (15%). This suggests that there is still a large potential to further increase the volume of online sharing. Interestingly, we also found considerable overlap between different modes of sharing as some respondents were involved in all three modes of sharing distinguished in this study. This implies that synergistic effects between the different modes of sharing could be a good avenue for further developing sharing activities. For example, people contacting each other on social media may decide to share face to face or 'meet' on an online sharing platform, taking advantage of the features of each mode of sharing (e.g. insurance offers on sharing platforms).

There are more takers than providers
For most household products addressed in this study, the number of providers was much smaller than the number of takers. This finding is consistent with the results of previous research in various domains of the sharing economy (Davlembayeva et al. 2021;Ertz et al. 2021). This can be connected to two facts. First, there are products that a small number of owners can provide to a large number of takers (e.g. camping tents, beamers, ski gear, car trailers; see Figure 1). This makes sense for products that borrowers use rarely or occasionally. Second, people with lower incomes may not be able to provide the products demanded by others. This is substantiated by our finding that unilateral takers have lower incomes than reciprocal sharers and unilateral providers of products. This suggests that sharing allows people with lower incomes to access goods they would not be able to afford otherwise.
The results furthermore show that taking and providing shared products are interrelated, as reflected in the high percentage of reciprocal sharers (44.5%), who both take and provide products, compared to unilateral takers (18.1%) and unilateral providers (6.5%). Together with the consideration of reciprocity as an influential regulatory principle of social and economic exchanges, these numbers imply thatat least for affluent persons or product ownerstaking a shared product may serve as an entry point for becoming a provider and sharing one's products with others.

Traditional P2P sharing involves greater reciprocity
A clear majority (64.4%) of those engaged in P2P sharing of household goods are reciprocal sharers, who both take and provide sharing products. This suggests that there is already considerable reciprocity in giving and taking. This is consistent with previous research findings that social exchange often takes place on the basis of a common exchange currency, which, in P2P sharing, can be constituted by the taking and providing of goods (Mikula 1985).
Our study specifically investigated the reciprocity involved in different modes of sharing by focusing on the participants who were engaged in only one of the investigated modes. The percentage of reciprocal sharers is considerably higher among those engaged only in traditional P2P sharing (66.7%) than among those exclusively using an online platform (45.9%) or social media (48.1%). This suggests that online sharing does not encourage reciprocal sharing as much as sharing between friends or family members, where closer personal bonds exist. Note: Includes only persons engaged in exclusively one mode of sharing; significant relationship between sharing mode and reciprocity according to Chi-square test (df = 4, p < .001).

Reciprocal sharers are more sustainability-oriented and experience stronger drivers and lower barriers than non-sharers
The ecological, social, and economic value orientations are stronger among reciprocal sharers than among non-sharers. In addition, reciprocal sharers are on the same high level as unilateral providers regarding ecological and social values and on the same level as unilateral takers in terms of economic values. This suggests that reciprocal sharers combine the ecological and social orientations of unilateral providers with the economic value orientation of unilateral takers in P2P sharing processes. Reciprocal sharers valued the ecological, social, and economic benefits of sharing -namely, environmental protection, creating social contact, and achieving economic gains or savings -higher than non-sharers. Additional expected benefits, such as saving time and effort, the advantages of sharing for rarely used products, and the experience of positive emotions when sharing, were also rated higher by reciprocal sharers than by non-sharers. Reciprocal sharers also have a significantly higher knowledge of the processes, options, and customs of sharing than non-sharers. The drivers of sharing identified in previous research thus consistently distinguished non-sharers from reciprocal sharers in this study. In sum, reciprocal sharers ascribe more benefits to sharing and have significantly higher sharing knowledge than non-sharers.
The processes of taking and providing household products were investigated separately in two linear regression models. In line with the comparison between reciprocal sharers and non-sharers and with previous research (e.g. Eurobarometer2016; Smith 2016; Andreotti et al. 2017;Barnes and Mattsson 2017;Prieto et al. 2017;Trenz et al. 2018; Wen 2019), a younger age, positive emotions associated with sharing, and knowledge of sharing processes were significantly positively related to the number of products taken and provided.
When considering differences in drivers between the three investigated modes of sharing, knowledge of sharing processes appeared to be particularly strongly related to sharing via online platforms, which may be due to the technological complexity and novelty of corresponding transactions compared to traditional face to face interaction and even to use of social media.
Reciprocal sharers reported on average less concern about dependence and less distrust of shared products than non-sharers. Thus, strategies for reducing these two sharing barriers may be effective in promoting the sharing of household goods. A substantial body of previous research investigated the development of trust and possibilities for increasing mutual trust between borrowers and providers of products on online sharing platforms. One fruitful approach is the implementation of reputation systems, which allow the users of sharing platforms to mutually rate their trustworthiness and/or provide textual feedback on the quality of their transaction with a sharing partner (Pavlou and Dimoka 2006;Malinen and Ojala 2013;Thierer et al. 2015;Liu et al. 2016;Zloteanu et al. 2018). Facilitating online face-to-face contact between sharing partners through video chats on a platform is another approach that has been shown to increase mutual trust (Ter Huurne et al. 2017). Another possibility could be to reduce the risks associated with sharing through the implementation of insurance, guarantees, conflict resolution, compensation mechanisms, or escrow services on online platforms (Pavlou and Gefen 2004).
The analysis of the drivers and barriers influencing the chosen modes of sharing revealed that high levels of distrust of other sharers promoted the use of online platforms but hindered traditional sharing. This may indicate that trust-building and risk-reducing mechanisms are already in place on many online sharing platforms (Thierer et al. 2015;Sutherland and Jarrahi 2018). For example, on the Swiss sharing platform Sharely (https://www.sharely.ch/de), all lent items are insured.
The third investigated barrier, distrust of other sharers, was rated significantly higher by unilateral takers than by reciprocal sharers, unilateral providers, and non-sharers. Distrust of others hence seems to be a major barrier preventing unilateral takers from providing their products to others on a P2P basis. Consequently, measures aiming to strengthen confidence in other sharers could be developed and implemented on sharing platforms to turn those who so far only took products into reciprocal sharers.

Drivers and modes of sharing can moderate sustainability gains
With regard to the expected benefits of P2P sharing for the environment, it should be noted that negative environmental rebound effects limit the positive ecological effects of sharing substantially (e.g. Makov and Font Vivanco 2018;Ribera et al. in prep). Direct rebound effects are possible because the reduced cost of accessing a product may result in more frequent and intensive use of the product, and the traveling and transportation associated with the exchange of sharing goods have environmental implications. P2P sharing between persons living physically close to each other may circumvent negative environmental rebound effects resulting from the transport of shared products between households located farther from each other.
Traditional face-to-face sharing sometimes -but not always -involves physical proximity. Sustainability-oriented values may motivate persons to substitute longer-distance sharing practices with shorter-distance alternatives if options exist.
The motive of creating social contact with other people through sharing activities was particularly emphasized by participants who shared via social media. This fits well with the social contact and networking functions that are generally associated with participation in such online social networks and suggests that sharing activities may be a pleasant way to switch from pure online connectivity to real face-toface interaction. Like online sharing platforms, social media platforms may also emphasize physical proximity between their members and, hence, promote the development of neighborhood sharing networks.
Rebound effects of sharing may also occur because the money consumers save by borrowing a product instead of purchasing it can be spent on other activities and products that have a negative environmental impact (Plepys and Singh 2019;Warmington-Lundström and Laurenti 2020). Moral licensing processes may add to such negative ecological rebound effects since borrowing a product for some time instead of purchasing it is broadly acknowledged as an ecologically positive behavior. Therefore, persons who have borrowed a product may feel morally justified to put in compensation a burden on the environment when spending the saved money (Hansmann and Binder 2021). According to previous research, negative rebound effects tend to be smaller among sharers who participate in the sharing economy due to ecological motivations than among persons sharing for other reasons (Böcker and Meelen 2017;Ribera et al. in prep). Promoting ecological values and related sharing motivations may thus be helpful to counteract the negative environmental rebound effects of sharing (Luri Minami et al. 2021;Wang and Yu 2021).

Sharing fosters knowledge and quality of life
Positive emotions and knowledge are important drivers of both taking and providing shared products. However, they cannot be assigned straightforwardly to the ecological, social, or economic dimensions of sustainability. Humans naturally strive for positive affect and, more broadly speaking, pursue happiness, and aim for the fulfillment and satisfaction of their needs (Maslow 1954;Neher 1991;Clarke et al. 2006).
According to the Brundtland Report (WCED 1987), sustainable development is defined in relation to human needs as it will ensure that humanity 'meets the needs of the present without compromising the ability of future generations to meet their own needs' (p. 15). It is therefore crucial to complement the ecological, social, and economic dimensions of sustainability through an individual-centered dimension of happiness, well-being, and quality of life and develop corresponding measures (Hodge 1997;Massé et al. 1998;Hansmann 2010;Bastianoni et al. 2019) to consider in future analyses of the impact of the sharing economy on sustainability. From this perspective, an important question regarding the effects of the sharing economy on sustainable development is whether it increases people's quality of life and makes them happier.
A crucial aspect of quality of life is how fully different human needs are satisfied. In this regard, the hierarchy of needs proposed by Maslow (1954) differentiates between i) physiological needs, ii) needs for safety, iii) social needs, iv) esteem needs, and v) self-actualization, and vi) epistemological needs for skills, learning, knowledge, and information. Thus, knowledge is not only a driver of the sharing economy but also a basic human need. The satisfaction of human needs and quality of life as well as corresponding positive emotions and information and knowledge should be considered and promoted alongside ecological, social, and economic aspects when aiming at a synergistic enhancement of sustainable development through the sharing economy ( Figure 2).
Accordingly, not only ecological benefits but also the perspective of need satisfaction through better access to products -in particular for economically disadvantaged persons -and emotional and qualityof-life benefits resulting from increased social connectivity should be included in the analysis of the impact of the sharing economy on sustainability.

Managerial and marketing implications
According to our findings, traditional modes of sharing, social media and online-sharing platforms can complement each other since engaging in one mode of sharing may facilitate and serve as an entry point for sharing via the other modes. The design of online platforms and marketing strategies promoting sharing could consider how such synergies can be exploited by linking different modes of sharing more closely to each other.
The results further indicate that the number of providers may be a more crucial limiting factor of P2P sharing than the number of takers, and that taking and providing products are related to each other through reciprocity norms. Accordingly, encouraging product owners to act as providers in P2P sharing seems particularly relevant for expanding the corresponding offer of products, and to firstly motivate persons to obtain shared products can be a first step in this regard. Creating special incentives (e.g. bonuses, gift vouchers) encouraging a first experience as an obtainer, and additional ones for acting the first time as a provider, could encourage corresponding first experiences to eventually facilitate the development of long-term habits of reciprocal sharing (Torrent-Sellens et al. 2022).
Marketing activities and improvements of sharing platforms should obviously focus on the most important drivers for taking and providing shared products, which may, however vary to some extent between different persons and target groups.
To encourage sustainability-oriented people to engage in P2P sharing, it seems crucial to emphasize, communicate, and increase its ecological and social benefits. Sustainability values should generally be promoted in the population through environmental campaigns and sustainability-oriented environmental education, and such basic educational activities could be combined with information on sustainability benefits of sharing (Gazzola et al. 2019).
To increase the ecological benefits of sharing, online sharing platforms can be organized to specifically consider and promote sharing between persons in physical proximity to minimize transportation emissions. This is, for example, a clear focus of the Swiss sharing community platform PumpiPumpe (https:// pumpipumpe.ch), which provides a scalable map of available items to its users and aims at developing local sharing networks. This approach could be described as online-supported traditional sharing or also as a geographically decentralized P2P Library of things with a strong community and sustainability focus.
Designing sharing platforms with a focus on physical proximity seems to be a promising strategy to prevent negative environmental rebounds due to travel and transportation. A focus on spatially close sharing transaction processes could at the same time synergistically increase possibilities for developing closer, more meaningful social contacts and networks among sharers and enhance the advantages of sharing rarely used products by reducing economic expenses, efforts, and time for traveling and transportation.
Furthermore, offers to spend the saved or gained money in ecologically reasonable ways could be presented (e.g. investing in photovoltaic energy production, buying organic food products) on sharing platforms to avoid or reduce environmentally negative rebound effects.
The emotional and practical benefits of sharing for both takers and providers should likewise be communicated and further enhanced to increase the volume of household-good sharing, and relevant knowledge should be made available. In fact sharing knowledge and positive emotional aspects were found to be particularly strong drivers for both taking and providing of shared products. Consequently, informing people about options, offers, and processes of participating and joining online sharing platforms seems crucial. Advertising and educational media campaigns promoting knowledge of the existence of sharing platforms, their advantages and benefits, and how to use them are thus important. Furthermore, online sharing platforms should be designed to be functional but playful (e.g. by involving positive feedback mechanisms) to make their use a positive experience. The explanations and information required for the use of platforms should be presented clearly in advertising campaigns and on the platform itself.
Finally removing the barriers of lacking trust, perceived loss of independence and perceived risks of sharing seems crucial. Perceived risks could be reduced by insuring shared products optionally or per default. Trust in platforms could for example be furthered by certificates (Khalek and Chakraborty 2023), and by ensuring the secure treatment, storage, and use of personal data (Nguyen 2023). Mutual trust among sharers and in the quality of shared products could be enhanced via the implementation of review or evaluation systems in online-sharing platforms (Davlembayeva et al. 2020;Daškevič and Burinskienė 2022). In this regard, a recent study showed that providing response possibilities for persons who are reviewed (or whose products are reviewed) may improve the information value of such feedback by including the dual perspectives of provider and consumer, and may also help to prevent or reduce unpleasant feelings of having been evaluated wrongly (Rifkin et al. 2023). This could accordingly make the social exchange connected to such evaluations more meaningful and emotionally positive.
Fostering trustful and reliable sharing processes and marketing them in combination with supportive sustainability arguments could be a way to encourage more affluent people to provide products. Boosting the number of providers can increase the availability of products, which, in turn, strengthens the independence of the takers from specific providers. Therefore, increasing the number of providers could also be a possible key to overcoming the concerns among obtainers of dependence on specific providers regarding the access to products.
Male gender was significantly positively related to the use of online sharing platforms, and sharingplatform users were also younger and had higher income than sharers, who did not use them. This is in line with previous studies linking the use of sharing platforms to these factors (Eurobarometer 2016; Andreotti et al. 2017). Accordingly, advertising for online sharing platforms could specifically target women and older persons and incentivize them, and these platforms should be designed in ways that are attractive to these target groups to increase their participation.
In relation to target group specific or even individualized marketing it could be taken into account that consumers are motivated more strongly by unsatisfied needs than by satisfied needs (Maslow 1954;Neher 1991;Kozlenkova et al. 2021). Accordingly, people lacking positive social contacts may be more motivated by possibilities for meaningful social exchange and getting acquainted to other persons through sharing than those who are socially already well connected (Mellor et al. 2008), and less wealthy persons may be more strongly motivated by economic gains and savings then those who are well-off.

Theoretical contribution
Many previous studies on drivers and barriers of the sharing economy took a unilateral perspective aiming to explain either the provision or taking of shared products using individual centered social psychological theories such as for example the theory of planned behavior (Ajzen 1991;Huang and Kuo 2020;Laurenti and Acuña 2020). This study aimed to combine and supplement the personal focus on providers and obtainers with reference to social exchange theories to arrive at a more interpersonal perspective, which takes reciprocity of social interaction into account. Such an interpersonal perspective seems crucial for investigating the potential of the sharing economy for achieving meaningful social interaction and interpersonal relations between obtainers and providers. The theoretical perspective of this study was furthermore enhanced by focusing on synergies between the ecological, social and economic dimension of sustainability that may be achieved by the sharing economy, and through broadening the scope of these dimensions by considering the fulfillment of human needs with reference to the need theory of Maslow (1954). In addition to the practical and empirical insights which this study gained, this proceeding and theoretical orientation may serve to stimulate future research following similar avenues.

Limitations and future research needs
The present study gives insights into the motives of sharers (both takers and providers) and the barriers preventing people from sharing household products. Social exchange in P2P household-good sharing can take place as an exchange of goods for other goods, monetary returns, or various other material or immaterial returns. Sharing can thus increase the resilience of economic activities and freedom of choice regarding economic exchange as it could help to reduce people's dependence on monetary transactions (Arcidiacono et al. 2018). The concrete arrangement and prevalence of these different forms of socioeconomic exchange were not investigated by this research and should be addressed in future studies.
Analyzing, enhancing, and fostering the diversity of possibilities for reciprocity could be a strategy to flexibly promote online-based and traditional sharing. Further research should thus also investigate different modes of sharing -from conventional face-to-face sharing to online sharing -in more detail with an orientation towards the benefits that providers expect and receive in return for the provision of their goods.
Two further research directions following from this study are 1) to investigate paths to improve onlineplatform services in more detail and 2) to support the development of campaigns promoting online sharing. Such studies could rely on a sample consisting exclusively of online-platform users and a more participatory research design.
Additional research should also examine the linkages and possibilities for the further development of synergies between traditional sharing, sharing via social media, and the use of online sharing platforms. This could help to interrelate traditional sharing, social media activities, and online-sharing platforms and make better use of their respective advantages.
A limitation of the present study is that causalities are difficult to discern based on a cross-sectional one-time survey. Experiments and longitudinal studies are more suitable for the detection and validation of causalities and are therefore needed to enhance our understanding of the sharing economy and how to develop it further. The possibility of circular or reversed causalities, where an assumed predictor variable not only influences but may also be influenced by the dependent variable, became apparent in the two multiple linear regression models using drivers and barriers as explanatory variables to predict the number of different products taken and provided. In both regression models, two relationships displayed surprising directions. The number of products taken and provided significantly decreased with the motive of creating social contact through sharing, and the barrier of distrust of sharers was significantly positively related to both variables. The interpretation of these two counterintuitive results requires acknowledging that the nature of the GLM analysis is correlational, making the directions of causality difficult to discern, and that effects of third variables that were not covered in the survey may have influenced the findings.
In this case, it seems possible that persons with few social contacts are more strongly motivated to create social contact via sharing activities than people with a large circle of friends and acquaintances because their needs for social contact are not yet fulfilled. It is known that people are motivated more strongly by unsatisfied needs than by satisfied needs (Maslow 1954;Neher 1991;Kozlenkova et al. 2021). At the same time, persons with few social contacts may actually provide and take fewer products in sharing activities because they lack the social contacts with whom to engage in sharing.
A similar reversal of the direction of causality may also explain the surprising positive sign of the barrier of distrust of other sharers in both regression models. Trust is the result of an accumulation of experiences (ter Huurne 2017), and without actual experiences, people tend to display overconfidence in the trustworthiness of others (Welter and Smallbone 2006). People who engage frequently in sharing activities may sometimes experience disappointment with other sharers, which could then trigger distrust in the sense that sharing experiences may lead to a more careful consideration of whom to trust. Experimental studies or in-depth interviews with sharers and nonsharers regarding social motivations and trust could help to investigate and follow up on these issues.

Conclusion
P2P sharing has great potential for the integrative promotion of the ecological, social, and economic aspects of sustainable development as it improves the accessibility of goods for economically disadvantaged persons while saving natural resources, can strengthen private social networks, and facilitates the satisfaction of peoples' needs. Meeting human needs is an important aspect of the sharing economy that should be specifically valued when evaluating the sustainability of sharing processes. Indeed, the needs of individuals are in danger of being overlooked when the focus is solely on social, ecological, and economic indicators per se.
Sharing takes place in an economic exchange process where takers and providers have different roles and experience distinct but partially overlapping drivers and barriers. The positive emotions connected to the P2P sharing of household products and knowledge about sharing processes are important drivers of both taking and providing shared household products. Encouraging the provision and borrowing of shared goods through advertising and educational campaigns could focus on the multiple benefits of sharing for the environment and social aspects as well as for satisfying the needs of the participating individuals. A functional design and implementation of online sharing platforms can facilitate the development of trust among sharers, reduce the risks, and promote spatially proximal, effortless sharing. This may remove the barriers that currently prevent nonsharers from taking part in the sharing economy, such as mutual distrust among sharers, concerns about becoming dependent on others, and distrust of the quality of the shared products.
Synergies between different modes of sharing (i.e. traditional and internet based) should be promoted to use and combine their respective social and technological advantages and, thus, increase the volume and ecological benefits of P2P sharing.