Impact of social media influencers ’ credibility on millennial consumers ’ green purchasing behavior: a concept paper on personal and social identities

Purpose – Thepurposeofthispaperistoprovidethetheoreticalinsightswithregardtothe greenpurchasing intention – behaviorgapandtheroleplayedbysocialmediainfluencesinabatingthisgap.Thispapertakesinto considerationawideraspectwithregardtotheantecedentsofbehavioralintentionthroughpersonalandsocialidentitiesinplaceoftheantecedentspresentedinthetheoryofplannedbehaviorandsocial-identitytheory.Furthermore,asthetheorieslackanexplanationofhowtoreducetheintention – behavior gap, this paper also arguesthesourcecredibilitymodel(SCM)inexplainingtheimpactthatsocialmediainfluencescanhaveonthebehavioralgap. Design/methodology/approach – Hypothetical deductive method is proposed for this concept paper under the positivism research paradigm. Findings – Not applicable as this is a concept paper. However, the paper discusses the theoretical and managerial implications. Research limitations/implications – This is a concept paper. Yes this paper discusses the theoretical, managerial, and social/ecological implications. Practical implications – This paper highlights the relevance of consumers ’ personal and social identities when consumers make purchasing decisions regarding green products. How managers can make marketing strategies, based on credibility model, involving social media influences as product endorsers and ambassadors, as well as the policy makers to design products, earmark consumer behavior and to conduct marketing campaigns in time to come. Social implications – As to how policies can be designed and adopted for bio-based economies where sustainability and circularity are given priority and to increase the attention of businesses moving toward sustainable practices. Originality/value – Original thought developed based on research, theoretical and market gaps.


Introduction
The upsurge in environmental issues has led to an interest in sustainability in consumers' practices, which, in turn, has generated an interest in green brands, environmentally friendly production and green products (Khare, 2015;Yuan et al., 2022;Duong, 2021;Sun et al., 2021).As countries are formulating policies with a focus on sustainability, businesses have also become congruent toward green strategies as part of their social responsibility (Mehdikhani and Valmohammadi, 2021), causing a growing managerial interest in understanding consumer purchasing behaviors (Sharma and Foropon, 2018).Therefore, academia has been quick to provide insights on green purchasing, where consumers' environmental knowledge and concern, the consumer decision-making process, implications of consumer attitudes and the impact of product attributes as well as previous purchase experiences have an impact on purchasing decisions (Sharma and Foropon, 2018;Costa et al., 2021;Chowdhury and Samuel, 2013;Yadav and Pathak, 2016).Furthermore, as Escalas (2012), Yang et al. (2018) and Fong et al. (2021) confirmed that the self-identity of a consumer displays a consistent relationship with their purchasing choices.Hence, consumers' purchasing behavior would depend on their personal connection to products developed through self-identity and social pressure, where the consumer needs to maintain a social identity (Escalas, 2012;White et al., 2012).In addition, with the significant upsurge in social media usage, businesses have taken to the utilization of social media as a form of modern marketing (Kumar and Gupta, 2016;Kapoor et al., 2021).Due to their high popularity and wide reach, businesses employ these social media influencers as product endorsers in order to gain access to their target customer segments (Upadhyay and Khemka, 2019;Wang and Liu, 2022).
However, the existent literature on identity-based purchasing does not address differences in identities of consumers and their impact on green purchasing behaviors (Khare, 2015).Moreover, Kautish and Khare (2022) identified that there is a lack of studies that differentiate clearly between social and self-identities as well as a dearth of studies on the influence social media can have on green purchasing behaviors among specific consumer generations such as millennials and younger generations.The majority of empirical studies available on marketing practices for green products focuses on traditional advertising methods (Mehdikhani and Valmohammadi, 2021), even though social media influencers are a widespread modern marketing method (Kumar and Gupta, 2016;Kapoor et al., 2021;Upadhyay and Khemka, 2019).
As the environmental impacts of purchasing behavior have moved toward increasingly detrimental consequences, more attention is now being paid to bio-based economies and green products.When considering global statistics identified through the Global Sustainability Study (2021), 85% of consumers practice green purchasing, whereas 63% are adapting to sustainable purchasing.However, according to a survey carried out by the National Cleaner Production Centre (2018), only 42% of Sri Lankans are ready to purchase green products; though in relation to personal identity, 99% of individuals are aware of the impact of consumption and 91% of respondents consider green purchasing to be their responsibility.In terms of social identity, a majority of these respondents are aware of environmental problems and believe that purchasing needs to move toward greener practices.
Hence the problem is, "What is the impact of personal and social identities on green purchasing intention and what impact does social media influencers have on narrowing the gap between green purchasing intention and behavior?"This paper attempts to clarify the gap between identity led purchase intentions of green consumers and their purchasing behavior, with the inclusion of personal identity and social identity as variables that lead toward purchase intention.This purpose opens up the following questions: The first question addressed in this paper is as follows: What is the impact of self-identity on green purchasing intention?Subsequently, the paper discusses the impact of green purchasing intention on green purchasing behavior.Finally, the paper discusses the impact of social media influencers on the green purchasing intention-behavior gap.
Hence, this paper contributes toward filling the gap with regard to the lack of empirical studies on the impact of identity on green purchasing as these concepts are not considered in Impact of social media the theory of planned behavior (TPB) or in the social identity theory (SIT) (Khare, 2015;Moser, 2015;Kautish and Khare, 2022).Thereafter, the effectiveness of adopting social media influencers to encourage customers to comply with green purchasing behavior is addressed through this paper.This contributes toward filling the lacuna in research regarding modern advertising methods for green products with the application of the source credibility model (SCM), as indicated by Kautish and Khare (2022) and Mehdikhani and Valmohammadi (2021).Also, the contradictory empirical findings on the significance of attractiveness, expertise and trustworthiness of social media influencers are addressed.Moreover, the paper considers the theoretical gaps identified in the TPB and SIT by drawing conclusions on the impact that personal and social identities drawn from the SIT can have on green purchasing intention, which leads toward green purchasing behavior, as explicated by the TPB.
The paper is organized in four sections as follows.The subsequent section includes a review of existing literature on green purchasing, identities and social media influencer marketing and related theories.It is followed by the formulation of hypotheses and the conceptual framework.Then, the proposed methodology for the study is discussed.Thereafter, the theoretical, managerial and societal/ecological implications are elucidated, together with avenues for future research.The paper ends with the conclusion.

Green purchasing intention and behavior
Green purchasing intention refers to the motivators that influence consumers' perceptions and provide potential encouragement to behave in a selected manner (Costa et al., 2021;Ajzen, 1991).Based on empirical studies, the personality of consumers can be said to have an impact on their green purchasing decisions (Duong, 2021), even though difficult situations would cause them to avoid such practices, unless it is considered a moral obligation (Sharma and Lal, 2020).
The intention and behavior of consumers is addressed through the TPB, and researchers have stated that the TPB has been applied in different contexts in terms of culture as well as specified age groups to study features green purchasing behaviors (Yadav and Pathak, 2016;Ivanova et al., 2019;Arora and Sahney, 2018).Apart from the theoretical facets of the TPB, variables such as gender and gender identity (Stets and Biga, 2003), the impacts of actual behavioral control and the situational context (Carrington et al., 2010), willingness to pay (Moser, 2015), environmental awareness and environmental concern (Sharma and Foropon, 2018), environmental knowledge (Emekci, 2019) and previous purchase experience (Costa et al., 2021) have been discussed in the existing literature.Hence, purchasing intention and purchasing behavior, as laid out by the TPB, provides the basis for a study of the intentionbehavior gap.However, the TPB does not explicitly consider the impact of identities (Ajzen, 1991) or the external influence of variables, including advertising methods such as social media influencers, on the green purchasing intention-behavior gap.

Green purchasing intention-behavior gap
As explained through a literature review, it is evident that many individuals are conscious of environmental issues.However, Carrington et al. (2010), Barbarossa and Pastore (2015), Yuan et al. (2022), Wang and Liu (2022) and Duong (2021) stated that consumers who consider themselves to be green consumers only rarely actually show green purchasing behaviors, and thus, Sun et al. (2021) stated that there is a lack of understanding regarding the gap between the intentions of ethical consumers and their behavior.This gap has been identified as the intention-behavior gap (Carrington et al., 2010), as well as the ethical purchasing gap and the attitude-behavior gap (Bray et al., 2010).Hence, it is evident that this is a prominent issue among many societies and has been the center of attention in empirical studies in the area.
There are several reasons for the reluctance of consumers to adopt green purchasing, which have been identified through literature.Jansson et al. (2010) stated that it is because consumers will have to change their usual behaviors and adopt green purchasing behaviors, while Gleim and Lawson (2014) and Naderi and Van Steenburg (2018) identified that price, quality perceptions, the availability of green products and brand loyalty result in the green gap.
Even though green purchasing intention has been the focus of many researchers, Khare (2015) and Kautish and Khare (2022) stated that there is a lack of research on identity-related green purchasing behavior, where green self-identity can be accommodated through the social identification theory.

Personal and social identity of consumers
The behavior of consumers has been explained through such features as their global identity (Yang et al., 2018), value and belief systems (Ha and Jang, 2013), ethnocentrism (Pekkanen and Penttila, 2020) and generational differences (Nguyen and Nguyen, 2020).
The attitude, subjective norms and perceived behavioral control proposed in the TPB are extractions from the identity perspective (Ajzen, 1991), and, therefore, the identity of an individual is capable of determining the motivation to perform an action (Reed, 2004;McGowan et al., 2022;Trafimow et al., 2002;Lei et al., 2020).
This paper intends to study green purchasing intention determined through personal and social identities as presented through the SIT.The SIT identifies that there are two levels of identities, namely, personal and social, which lead toward creating in-group stereotyped consumer behaviors (Hogg et al., 1995).Consumers create goals related to their self-identity, and these determine whether they would be willing to associate or disassociate themselves with a product (Escalas, 2012), and these behaviors are adopted to build self-esteem (Stets and Burke, 2000).Furthermore, Escalas (2012) stated that consumers are likely to be motivated to purchase identity-consistent products.Stets and Biga (2003) revealed that the prominence and the level of salience of environmental identity determines the commitment of consumers toward environmental behavior.
Therefore, the aforementioned empirical findings validate the fact that the identity of an individual has an impact on their purchasing decisions.The TPB outlines the impact of identity to a certain extent; however, there is a lack of studies explicitly combining identities and the purchasing behavior of consumers (Khare, 2015).This relationship is explained to a certain level through group behaviors which are created by individuals' identities in the SIT (Stets and Burke, 2000).Hence, the personal and social identities taken from the SIT are applied to study consumer intention and behavior within the framework of the current study.
Due to prevailing environmental issues, concerned consumers prefer to express their identity as a consumer contributing toward green practices through the products purchased (Nguyen and Nguyen, 2020).Furthermore, Khare and Pandey (2017)'s study points out that if consumers express a high level of ecological commitment, then they will demonstrate signs of eco-friendly behavior.As research progresses on the study of social identity, identity is increasingly becoming recognized as a vital factor that drives the attitudes, norms and behaviors which affect the decision-making process for purchases of consumers as they attempt to be part of groups such as cultural consortiums that validate their identities (Yang et al., 2018;Zhang et al., 2022).
The prevalence of green identity also differs among various generations.As Kautish and Khare (2022) have stated, there is a lack of empirical research on generational differences in consumer segments with green purchasing behaviors.Contributing to this statement, Ivanova et al. (2019) mentioned that eco-friendly identities are more prevalent among millennials than among generation X because generation Y grew up in a time when environmental consciousness was highly prioritized.Moreover, millennials have been identified as a group of consumers who are more prone toward having a green attitude, than actually practicing green behaviors, as they are more concerned with convenience, affordability and performance quality (Naderi and Van Steenburg, 2018).
Whether a consumer has related a product with his/her identity or not would depend on the level of independence they demonstrate with regard to their self-worth.However, consumers value the ability to connect their identities with the products (White et al., 2012).With differences in consumer identities, their reactions to various marketing stimuli will differ (Reed, 2004).Therefore, how consumers evaluate various brands depends on their salience to their identity (Reed, 2004).This highlights the importance of the role played by identities in shaping consumer behavior and implies that different identities can affect the motivations of consumers to adopt green purchasing behaviors.
Moreover, social identification with online sources such as social media influencers create group conformance by leading to a vast array of perceptions and knowledge sharing through social media platforms (Kautish and Khare, 2022).According to Kautish and Khare (2022), this affects purchasing intentions toward green products due to the enhancement of product knowledge.

Social media influencers
As consumers presumably connect well with products that suit their identities, they also prefer advertisements which are less prototypical and more suitable to their identities (McGowan et al., 2022;Till and Busler, 2013;Nguyen and Nguyen, 2020).Hence, the messages shared through advertisements would be more effective if they can connect with the relevant customer segments and their social identities.Hence, with the upsurge in social media usage, businesses have taken to the utilization of social media platforms as a form of modern marketing (Kumar and Gupta, 2016;Kapoor et al., 2021).
Moreover, social media users include a vast community of individuals with varying interests and preferences, which make traditional advertising approaches such as mass advertising campaigns through social media not always fruitful (Upadhyay and Khemka, 2019).Hence, popular social media personalities, who are employed by companies, have been developed as social media influencers who share their perceptions, ideas, experience and views among the large number of followers in their social media communities (Wang and Liu, 2022).Therefore, to connect better with customers and advertise the products in line with customer identities, businesses are using social media and categorical social media influencers rather than traditional promotional actors (Upadhyay and Khemka, 2019;Taillon et al., 2020;Quan et al., 2020;Kapoor et al., 2021).
According to Sun and Wang (2019), using social media as a source of marketing has proved to be effective as it has a positive impact on consumers' subjective norms, knowledge that consumers have regarding the products, as well as consumers' belief that they can actually have an impact on reducing environmental issues through adopting green purchasing behaviors.On the contrary, Johnson and Chattaraman (2020) have pointed out that the inclusion of face-to-face contact with the target audience while employing social media is a more prudent method of communicating socially responsible behaviors.Furthermore, Schouten et al. (2019) have posited that influencers are more capable of connecting with customers as they are considered by customers to be more similar to themselves.
Nonetheless, similar to the use of product endorsers utilized for advertising, social media influencers have to be selected carefully to suit the products promoted and the targeted audience.Hence, variables such as the follower base and the expertise of social media influencers as well as their attractiveness and trustworthiness impact these influencers' ability to encourage purchases (Bauer et al., 2022;Schouten et al., 2019).The effectiveness of a product endorser can be measured through attractiveness, expertise and trustworthiness, which are included in the source-credibility model developed by Ohanian (2013).Wiedmann and Mettenheim (2020), in the research study done on identifying the requirements of influencers in order to be successful, stated that attractiveness and trustworthiness have a significant importance, while expertise is required, but not given priority by consumers.However, there is contradictory evidence regarding the importance of expertise, as Till and Busler (2013), Santos et al. (2019) and Ramirez and Merunka (2021) identified expertise to be an important factor that affects the effectiveness of a product endorser.Hence, this paper intends to use all three factors of Ohanian's (2013) SCM, namely, attractiveness, trustworthiness and expertise, to identify the ability of social media influencers to mediate the green purchasing intention-behavior gap.

Theorization of the research problem
A theory expresses a relationship between two or more variables and this relationship between cause and effect may not always be tested and confirmed, and these different theories are categorized as grand, middle-range and substantive theories (Saunders et al., 2009, p. 36).In quantitative studies, theory is studied deductively as the research studies aim to test and verify theories rather than to develop theories (Creswell, 2014, p. 93).Hence, in quantitative research studies, the theories are applied in order to explain the scenario that is studied while providing the rationale and argument behind the proposed study (Creswell, 2014, p. 86).
This paper is focused on developing an understanding of the impact the identity of a consumer can have on their purchase intention, which is assumed to determine their green purchasing behavior under the impact of social media influencers.Toward this end, the paper employs three theories, namely, the TPB, SIT and the SCM.These theoretical models, which formulate the relationships which are advanced in this paper, are discussed below.

Theory of planned behavior
The theory of reasoned action developed by Ajzen (1991) explains that the intention to behave that is influenced by the attitudes and subjective norms of the individual can be used to determine behavior.The modified theory of reasoned action, named the TPB, includes the variable "intention" as the central factor that affects behavior, while perceived behavioral control is also included with intention as it was identified as a determinant of the decision to behave in a particular manner (Ajzen, 1991).Therefore, the variables attitude toward the behavior, subjective norms and perceived behavior are selected as the factors that would determine the intention to behave, while the achievement of the stated behavior is said to be impacted by intention as well as by perceived behavioral control (Ajzen, 1991;Yadav and Pathak, 2016;Emekci, 2019;Arachchi and Mendis, 2021;Costa et al., 2021).The relationship between the aforementioned variables in explaining human behavior is therefore demonstrated through the model shown in Figure 1.
The TPB has been adjusted and readjusted throughout the years by researchers to suit various fields of study through either including variables to explain the relevant phenomenon, which improves the theory's comprehensiveness or by removing variables so as to suit the context of the study (Zhang et al., 2022;Costa et al., 2021;Trafimow et al., 2002;Ivanova et al., 2019).
Further studies have confirmed this relationship as Emekci (2019) stated that the attitude toward a behavior has a strong and positive influence on behavioral intentions.Subjective norms refer to the influence that society has on the intention to perform or not to perform a behavior (Yadav and Pathak, 2016).Such forces can persuade and influence the intention to perform the selected behavior (Cheah and Phau, 2011).Moreover, Johnson et al. (2012) stated that certain theories have inherent limitations, which impose boundaries on the generalizability of the theory and its applicability to various situations.By considering this aspect of the theory, Ajzen (1991) identified that there is a limitation in the TPB due to the distinction between behavioral, normative and control beliefs as well as the distinctions made between the relationships linking the three antecedents of attitudes, subjective norms and perceived behavioral control, as these distinctions can be subject to arguments regarding the exclusion of relevant aspects.However, the TPB is open to the addition of predecessors, considering that the original variables are not sufficient to explain a significant influence on intention and behavior in selected situations (Ajzen, 1991).For instance, as suggested in this paper, the adjunction of social and personal identity to the TPB extends its scope in analyzing behavioral intentions.
Furthermore, the attitude, subjective norms and perceived behavioral control affecting an individual's behavioral intentions vary under different circumstances and situations, since different circumstances and unique personal factors are capable of inducing different behaviors among individuals (Ajzen, 1991).However, the theoretical model of the TPB is widely applied in studies on green purchasing behavior of consumers as the theory allows for the opportunity to include additional predictors to its model (Emekci, 2019;Yadav and Pathak, 2016;Costa et al., 2021).
Even so, the theory does not address the issue whether personal and social identities of individuals would lead toward green purchasing behaviors through green purchasing intention as the theory only considers three selected facets extracted from identity as antecedents of purchasing intention (Ajzen, 1991).Furthermore, the TPB does not provide insights on closing the intention-behavior gap, such as the inclusion of the impact of adopting marketing techniques.

Social-identity theory
The SIT developed by Tajfel and Turner (1979) is a theory that explains intergroup relations among individuals, group processes as well as the social self (Hogg et al., 1995).Furthermore, the SIT identifies that the phenomenon of social categorization is affiliated with the social identity of an individual (Hogg et al., 1995).Hence, it is explained through the theory that social categorization and social comparison result in the accentuation of self with perceived similarities to the selected social group and through designed styles of attitude, beliefs, styles of speech as well as other behavioral aspects (Stets and Burke, 2000).Moreover, the SIT states that individuals tend to categorize their identities in line with various groups of behavior and beliefs because it allows them to reduce social uncertainty and improve their self-esteem (Johnson et al., 2012;McGowan et al., 2022).For instance, individuals who believe themselves to belong to the category of individuals who are concerned for the environment are likely to develop green self-identities based on their self-perception of being a consumer who is concerned for the environment (Khare and Pandey, 2017).
As per the SIT, based on the two levels of identities, namely, personal and social identities, individuals display in-group or out-group behaviors (Hogg et al., 1995).Personal identity, which is the unique categorization of self that is distinct from others in the group, is considered to be the lowest level of self-categorization, which determines the personal goals of an individual (Stets and Burke, 2000;White et al., 2012).Stets and Burke (2000) and Chan et al. (2007) recognized that personal and social identities can generate unique methods of expressing in-group behaviors, while personal identities are capable of penetrating group stereotypes and therefore resulting in out-group behaviors.For instance, consumers use various products to express their membership in social groups and therefore favor products that align with their social identities, while rejecting products that do not suit their social categorization (Fong et al., 2021).
Moreover, the SIT combines the sociocognitive processes of categorization and self enhancement together with the subjective belief structures of individuals (Hogg et al., 1995).In the process of enhancement, individuals tend to associate themselves closely with the social group of their choice through shaping their behaviors, ideas and interests to align with those of the group (McGowan et al., 2022;Lei et al., 2020).However, the alignment of behavior with a social category is said to be decided based on identity salience, which refers to the possibility of an identity being activated during a certain situation (Hogg et al., 1995).
Throughout the years, there have been arguments on the concept of identity salience in SIT because the reasoning behind the activation of identities in different situations is subject to the individual's psychological significance regarding the social category which he/she chooses (Hogg et al., 1995).Following the relationship between social and personal identities and aligned behaviors, businesses have taken to customizing products and services as well as marketing communications to suit various identities of consumers as it provides better symbolic value and a stronger connection for the consumers between themselves and their identities (Lei et al., 2020).Hence, the levels of identity are contextual, and their applicability is therefore situational.Stets and Burke (2000) and Khare (2015) have successfully applied the contextual characteristics of identity in environmental sociology and concluded that the prominence of the environment or green identity as well as its salience in certain situations determines the commitment an individual is willing to make toward environmentally friendly behaviors.
The SIT formulates an understanding of the identity-based group behaviors of individuals in terms of their personal identity which focuses on individual goals and desires as well as the social identity, which determines the role an individual is motivated to maintain within a social group (Stets and Burke, 2000).However, the theory is not concerned with addressing contextual differences such as identity-driven luxury value purchases (Yang et al., 2018), identity-driven green purchases (Khare and Pandey, 2017) and identity-driven purchases of cultural heritage products (Zhang et al., 2022).

The source credibility model
In the marketing context, as well as in other scenarios where communicators are involved, their ability to persuade the audience is believed to be connected to the character of the communicator (Ohanian, 2013).Hence, to identify the credibility of a source, various characteristics have been identified throughout empirical studies.These dimensions include safety, the qualifications of communicators, dynamism, authoritativeness of the communicators, their objectivity, likability and character (Ohanian, 2013).However, with the identification of too many dimensions, the comprehensiveness and parsimony of source credibility was lost in the literature (Ohanian, 2013).Therefore, the SCM was developed as a core model that identifies the dimensions of credibility that determine the persuasiveness of a communicator (Wiedmann and Mettenheim, 2020).
Attractiveness, trustworthiness and expertise are identified as the primary dimensions of source credibility (Schouten et al., 2019;Ohanian, 2013;Wiedmann and Mettenheim, 2020;Till and Busler, 2013).Hence, the SCM demonstrates a comprehensive explanation of source credibility, as shown in Figure 2.
Ohanian ( 2013) considered various scales of source credibility that were empirically available when developing the SCM, where 182 adjectives were used to explain the credibility of a communicator.With the adoption of rigorous methodologies of analysis, Ohanian (2013) developed the SCM, which ensures the reliability and validity of the scales selected.
Similar to the concept of ethos, the trustworthiness of a communicator is generated through the perception that a communicator has integrity and honesty while also being believable (Schouten et al., 2019).Furthermore, if a communicator is believed to be objective and not influenced by a third party, then the listeners are more likely to trust the message being shared (Wiedmann and Mettenheim, 2020).Furthermore, consumers are more likely to trust product endorsers whom they can identify as other consumers similar to themselves as they consider such endorsers to be in many ways similar to ordinary people (Taillon et al., 2020;Jin et al., 2021;Jin and Ryu, 2020;Schouten et al., 2019).Hence, consumers develop trust toward product endorsers in several aspects and thereby judge the products being promoted.
Moreover, the dimension of attractiveness is defined as the physical attractiveness of a communicator in terms of the appeal of their facial features (Ozanne et al., 2019;Patzer, 1983).The physical attractiveness of a communicator has a halo effect, where the personal traits of the communicator are affiliated with the messages being shared in a positive stance (Ozanne et al., 2019).This is confirmed through empirical studies which revealed similar results regarding the physical attractiveness of product endorsers being able to exert more persuasive power (Till and Busler, 2013;Kumar and Gupta, 2016;Patzer, 1983).Hence, as identified by the SCM, trustworthiness drives a change in the attitude of the listener as they have confidence in the reliability of the communicator.Their expertise provides credibility to the advice shared in order to change the attitudes of the listeners (Jin and Ryu, 2020;Jin et al., 2021).The communicators' attractiveness induces a positive attitude change in the listener as a dimension that affects the initial judgment itself (Ohanian, 2013;Wiedmann and Mettenheim, 2020;Ozanne et al., 2019).
In empirical studies, there have been contradictory findings related to this model as some studies have suggested that either one or two dimensions do not have a significant influence on audiences when tested.For instance, Wiedmann and Mettenheim (2020) stated that the trustworthiness and attractiveness of social media influencers had a significant impact on their ability to persuade consumers regarding brands, while the impact of expertise was nil, though Schouten et al. (2019) found that expertise plays a major role.Till and Busler (2013) mentioned that expertise is more important than attractiveness when considering the product endorser's ability to fit with the brand and persuade consumers.
However, Ohanian (2013), who developed the SCM, warns of these possibilities as she states that the scales can be expanded and modified as done by Schouten et al. (2019), Taillon et al. (2020), Arora et al. (2021) and Nguyen and Nguyen (2020).Furthermore, Ohanian (2013) stated that the findings can vary when applied to different types of communicators and different types of products, as was confirmed by Till and Busler (2013), Jin et al. (2021) and Wiedmann and Mettenheim (2020).Finally, Ohanian (2013) identified that certain aspects of the audience, such as their knowledge and confidence, can also mediate the impact of the dimensions identified in the SCM.
Hence, this paper suggests that the SCM be used to study the impact that SMI can have on persuading consumers to engage in green purchasing behavior through employing attractiveness, trustworthiness and expertise to address the contradictory empirical understanding of the model.

Formulation of hypotheses
The relationship between self-identity and green purchasing intention.The SIT as developed by Tajfel and Turner in 1996 mentions that there are two levels to identity, namely, personal identity and social identity (White et al., 2012).According to Khare and Pandey (2017), the behavior of a consumer forms a requited relationship between the personal self and society.Yang et al. (2018) stated that people use identities to categorize themselves based on social categories.According to the SIT, this is known as self-categorization (Stets and Burke, 2000).For example, consumers can categorize themselves according to culture, status and social structures or in this case, they can categorize themselves as environmental enthusiasts, naturalists, or ecologists (Escalas, 2012).
A consumer expects to identify themselves with a product as they consider the products to be a representation of who they are, so that they can communicate their personal identity through these products (Lei et al., 2020).Due to the assimilative nature of customers, they try to communicate the inclusiveness of their identities in a group through purchasing products that are seen within the group, while their need to differentiate themselves encourages customers to purchase products that can set them apart from the common group (Chan et al., 2007).Hence, this study proposes that: H1.The personal identity of millennials has an impact on their purchase intention.
Based on the SIT, social identity creates a sense of self within a person as they play a certain role within society (McGowan et al., 2022).For instance, a person's political affiliations or sports affiliations would have an impact on their behavior (Zhang et al., 2022).Therefore, if a person feels that they belong to a social group of athletes, then that person would purchase clothing, arrange food patterns and activities to suit the role of an athlete (Hogg et al., 1995).Therefore, the personal judgments of individuals based on their perceived social identities determines how they act in society (Chan et al., 2007).When a product is able to appear attractive to a customer through being an instrument of self-expression, the configurations of that product appeal to the identity of a customer as a representative of a certain social group (Lei et al., 2020).Therefore, it is proposed that: H2.The social identity of millennials has an impact on their purchase intention.
The relationship between green purchasing intention and green purchasing behavior.As one of the main behavioral theories, the TPB identifies that a considerable part of a person's behavior is owing to the intentions generated within that person (Ajzen, 1991).Even though individuals' intention to behave in a certain manner is associated with their identities, there are certain instances where people do not behave as they intend to because they prefer to create certain uniqueness for themselves while staying within social groups (Lei et al., 2020).Therefore, consumers with concerns regarding the impact of consumption on the environment do not necessarily involve themselves in green purchasing behaviors (Khare, 2015).Carrington et al. (2010) identified the availability of accurate information to be a factor that determines purchasing behavior among other situational factors such as availability and convenience and behavioral control of consumers determined by self-efficacy.As consumers have to change their usual behaviors and adopt green purchasing behaviors in order to become more sustainable, there can be a lack of follow through in the behavior related to purchasing intentions (Jansson et al., 2010;Sun et al., 2021;Yuan et al., 2022).If consumers have strong beliefs with respect to the environmental impacts of their purchasing behavior, then they follow their judgments on purchases to be in line with their personal beliefs (Bray et al., 2010).Hence, the current study proposes that: H3.Personal and social identity-based purchase intention has a weak impact on green purchasing behavior.
The moderating role of social media influencers' (SMI) attractiveness.In the marketing technique of using social media influencers for advertising campaigns, the effectiveness of these influencers depends on their ability to persuade consumers by creating an attachment to the promoted products through the connections built by influential social media users (Jin et al., 2021).According to the SCM presented by Ohanian (2013), a factor that determines the effectiveness of these SMI is their attractiveness.Ohanian (2013) defined attractiveness as the physical attractiveness of the SMI.The attractiveness of the endorser is capable of creating an appeal or likability toward the products through the association of such endorsers, as explained through the SCM (Kumar and Gupta, 2016).Due to the characteristic of imitation, consumers are willing to develop their ideal identities by following and imitating social media influencers, and, therefore, social media influencers who are environmentally concerned are likely to have an ability to persuade their followers to adopt green purchasing behaviors (Dinh and Lee, 2021).Hence, the current study proposes that: H4. Social media influencers' attractiveness moderates the impact of green purchasing intention on green purchasing behavior.
The moderating role of social media influencers' (SMI) expertise.As per the SCM (Ohanian, 2013), the expertise of a product endorser determines their ability to persuade recipients; as such, expertise will allow them to create a favorable reputation as individuals who have personally experienced the use of the products and therefore are able to connect better with target consumers.Kumar and Gupta (2016) specify that the credibility of information shared with consumers affects their decisions on whether to purchase green products or otherwise.Interpersonal influence is a factor that impacts the attitudes customers have toward ecofriendly products, which in turn creates a willingness within consumers to purchase these green products (Cheah and Phau, 2011).SMI provides information to followers and subscribers through sharing their life choices, personal ideas, beliefs and viewpoints as well as experiences through a form of storytelling (Kapoor et al., 2021).
Hence, the expertise of SMI in terms of their knowledge and skills on the subject, as well as the experiences they share, has the ability to make consumers perceive them as experts who would know a great deal about the products (Schouten et al., 2019).Therefore, when SMI, who are the source of information, are perceived to be experts in the field of information which they are sharing, these SMI are considered to be more effective in persuading or appealing to customers to make the purchases (Kapoor et al., 2021).Hence, the current study proposes that: H5.Social media influencers' expertise moderates the impact of green purchasing intention on green purchasing behavior.
The moderating role of social media influencers' (SMI) trustworthiness.The SCM has identified the trustworthiness of the product endorser to be a factor that determines the effectiveness in persuading consumers because consumers are more likely to accept the recommendations of product endorsers that they consider to be reliable (Ohanian, 2013).
The influence that product endorsers such as social media influencers would have on consumers' purchasing behavior depends on their fittingness to the products as consumers are likely to associate these influencers with the brands they are endorsing (Till and Busler, 2013).Furthermore, social media influencers are capable of connecting with the identities of consumers as they can customize the advertising campaigns to suit the expectations and characteristics of various social groups and their different identities (Kumar and Gupta, 2016).Wang (2005) has pointed out that consumers are more likely to trust the products that are recommended by other consumers who they can relate with.When consumers evaluate the brands they are planning to purchase, they consider the trustworthiness of the source of information (Bailey et al., 2016).Hence, the current study proposes that: H6.Social media influencers' trustworthiness moderates the impact of green purchasing intention on green purchasing behavior.

Conceptual framework
The TPB provides insights on how attitude, social norms and perceived behavioral control create a behavioral intention that leads to actual behavior (Ajzen, 1991).A person's identity goes beyond the above three factors.Here, identity includes accentuation between self and other members, which then determines attitudes, beliefs and values, behavioral norms and other properties directed toward the behavior of a certain group (Stets and Burke, 2000).Hence, the TPB does outline the impact of identity to a certain degree; however, this relationship is explicitly considered only through group behaviors which are created by individuals' identities and described in the SIT (Stets and Burke, 2000).Attitude, social norms and perceived behavioral control are not included in the framework as it was developed from the perspective that the aforementioned concepts lead toward developing an identity contingent on empirical arguments (Marta et al., 2014;Rise et al., 2010;Sparks and Guthrie, 1998).
Hence, personal and social identities drawn from the SIT are applied to study consumer purchasing intention and behavior in the framework.
However, both theories do not examine the methods by which customers' purchase intentions are influenced to create a greater impact on their behavior.Hence, the framework is designed to illustrate the mediating effects of the attractiveness, expertise and trustworthiness factors drawn from the SCM) of social media influencers (SMI) in persuading customers with green purchasing intentions to adopt green purchasing behaviors.
However, it should be noted that the SMI are capable of influencing both the purchasing intentions and purchasing behaviors through sharing knowledge and ensuring transparency (Woodroof et al., 2020).Through studying this relationship between purchasing intention and SMI credibility, empirical findings provide evidence of SMI attractiveness and expertise having an impact on purchasing intention, while trustworthiness was identified as a component that does not have an impact on purchasing intention (AlFarraj et al., 2021).On the other hand, some researches have focused on source credibility itself and its impact on purchasing intention (Han and Chen, 2021).A majority of empirical studies have focused on the impact that SMI can have on purchasing intentions (Woodroof et al., 2020;AlFarraj et al., 2021;Han and Chen, 2021;Dinh and Lee, 2021;Lee and Watkins, 2016;Abhishek and Srivastava, 2021;Sun and Wang, 2019).Hence, this research considers the impact of SMI credibility on the relationship between purchasing intention and purchasing behavior, rather than concentrating purely on the purchasing intention of consumers.
The aforementioned relationships are depicted in Figure 3.

Methodology
A quantitative research design is recommended to be adopted under a positivist paradigm for this research.A self-administered structured questionnaire can be distributed based on the mall intercept method.The unit of analysis is an individual consumer in a selected geographical area.The questionnaire is to be designed with seven sections, one section per variable, based on prior studies.As such, personal identity can be operationalized with four items adopted from Lei et al. (2020) and social identity can be measured with a three-item scale developed by Fong et al. (2021).Green purchasing intention can be measured utilizing a threeitem scale developed by Persaud and Schillo (2017).Green purchasing behavior is to be measured with a four-item scale developed by Duong (2021).SMI attractiveness, expertise and trustworthiness are to be measured through a scale developed by Wiedmann and Mettenheim (2020), consisting of five items each.

Theoretical implications
Despite the substantial empirical evidence that points to a gap between green purchasing intention and behaviors, there is a lacuna in the literature regarding the involvement of identities in explaining this gap.The TPB addresses the impact of identity by dealing with certain components of identity, namely: attitude, subjective norms and perceived behavioral control.These three facets have been empirically tested in the context of green purchasing.However, there is a lacuna in the empirical literature as identity has not been addressed in depth through the separation of social and self-identities.The behavior of an individual is fed through their PI and SI.Hence, this study has incorporated these two identity facets with behavioral intention as brought forward by the TPB, as an extension which expands the antecedents of behavioral intention to include the overall impact of a consumer's personal and social identities.Furthermore, this paper utilizes a modern marketing technique in order to curtail the intention-behavior gap.Hence, the paper studies whether social media influencers are able to push through green purchasing intentions toward becoming actual green purchasing behaviors.Through incorporating the SCM and clarifying the conflicting empirical arguments, this paper addresses the lack of insight in the literature regarding the manner of use of modern advertising and promotional techniques for green products.

Managerial implications
This paper highlights the relevance of consumers' personal and social identities when they make purchasing decisions regarding green products.Hence, the explanations in this paper would provide a basis for managers and marketers to decide whether they should consider consumer identities when designing products and when considering the market placement of products in the event that identities do have an impact on consumers' purchasing behavior.
The insights on the credibility of SMI in motivating customers to adopt green purchasing behaviors would assist managers in designing marketing strategies involving SMI as product endorsers and ambassadors.
Since the world is moving toward eco-friendly businesses, the outcome of this study will pave the way for decision makers and policy makers to design products, earmark consumer behavior and also to conduct marketing campaigns in the time to come.

Societal/ecological implications
With the continuous and growing uproar on the impact of industrialization on the environment, a majority of developed countries have designed policies to adopt bio-based economies where sustainability and circularity are given priority.
This has increased the attention of businesses to move toward sustainable practices, which need to be congruent with economic policies.Thus, businesses have adopted strategies to provide green products which follow bio-economic goals, and many governments award sustainability grants and green business loans to encourage these businesses.
Even though Sri Lanka is currently facing an economic crisis, previously there were provisions for bio-economic and green projects sponsored by the UN Framework Convention on Climate Change.Therefore, consumers need to be persuaded to purchase more green products; as such, an increased demand for products would induce businesses to supply these products.Hence, this study plays a significant role in understanding the impact of consumer identities in generating green purchasing behaviors.
Current purchasing behaviors have resulted in a detrimental impact on the environment, creating a need for a change in purchasing and consumption patterns toward more green practices.Hence, this paper contributes toward providing an understanding on the manner in which citizens can be encouraged to adopt green purchasing behaviors.

Avenues for future research
The green purchasing behavior of consumers has been a concern in recent years as the penetration of green purchases needs to be increased.As this paper focused on the impact of identities, further research can be carried out focusing on identity differences present among generations, which would result in different perspectives regarding green purchasing.Hence, based on this paper, researchers can conduct future research and create discussions as to how the presented model contributes to academia and practice.
Furthermore, it is likely that varied economic conditions that prevail in countries can also lead toward differences in green purchasing behavior, and these can be accounted for in future research relating to the intention-behavior gap.As this paper considered personal and social identities in a broad aspect, future research can explore the different types of identities differentiated through cultures and their impact on the green purchasing intention-behavior gap.In considering the role of social media influencers, this paper used the SCM, and in future research, other factors that are unique to social media influencers such as content creation, follower base and engagement rate, can be accommodated in the conceptual model.Moreover, the connection between social mediabased identity creation and the green purchasing intention-behavior gap can also be pursued in future research.

Conclusion
This paper elaborates the ability of personal and social identity to generate green purchasing intentions which can precipitate green purchasing behaviors, while assessing the role of social media influencers in addressing the behavioral gap related to green purchasing, thereby contributing to filling the lack of empirical studies in the area.As individuals tend to communicate their personal identities through the products they consume, they are more likely to associate themselves with products that complement their personalities.Similarly, individuals tend to adopt behaviors that conform to the social groups they like to represent in order to maintain their social identities.Hence, the paper suggests that personal and social identities lead toward creating green purchasing intentions, which are then actualized to green purchasing behaviors.However, as it was identified that there was a gap between green purchasing intention and behavior, the paper advocates the involvement of social media influencers in order to encourage green purchasing behaviors through strengthening consumers' green purchasing intentions.Hence, it is suggested that attractive influencers who have expert knowledge regarding green products, and who are also considered to be trustworthy, are likely to be able to persuade consumers to adopt green purchasing behaviors.Accordingly, the TPB, the SIT and the SCM have been combined to conceptualize the relationship between identity driven green purchases as well as the role played by social media influencers in narrowing the green purchasing intention-behavior gap.
Figure 1.Theory of planned behavior Figure 2. Source credibility model Figure 3. Conceptual framework