REMODELING CONSUMER BRAND CHOICE BEHAVIOR: THE EFFECTS OF SOCIAL MEDIA INFLUENCES AND CELEBRITY ENDORSEMENT

Social media influences and celebrity endorsers are the dominant marketing strategies marketers follow to promote brands and businesses. The scholars also prioritized examining the diverse issues of social media influences and celebrity endorsers. On this ground, we systematically review the current trend of research to provide a state-of-the-art understanding of the factors prior researchers explored related to social media influences and celebrity endorsers to influence consumer brand purchasing behavior. We have extensively reviewed 200 peer-reviewed papers, including 86 research frameworks from recent (last five years) scientific double-blind articles that obtained at least four citations. We also deeply studied the social learning and source credibility theory used to test the proposed relationships. In the vein of the reviewed articles on social media influences and celebrity endorsers, we have summarized and listed the variables examined in different research contexts. The study reveals that interaction, customization, entertainment, word of mouth, and trendiness are the popular dimensions of social media influences, which the previous scholars explored to measure their effects on consumer brand purchasing intention in diverse contexts. Additionally, attractiveness, trustworthiness, credibility, and expertise are the widely used constructs for assessing the impact of celebrity endorsers on consumer brand purchasing behavior. To the best of our knowledge, this study is the first to provide a list of recent factors associated with social media influences and celebrity endorsers through which the scholars can get insight into the current trend of research. This study is the blueprint for future research to capture a quick view of recent trends in social media influences, celebrity endorsers, and consumer brand purchasing behavior. Finally, based on the comprehensive review of previous literature, we suggested a study to measure the associations of social media influences and celebrity endorsers with brand image, consumer attitude, and consumer brand choice behavior by the backdrop of social learning and source credibility theory in the context of any brands like Smartphone.

research found that over 50 million businesses have registered for a Facebook account, and over 88% use Twitter as part of their marketing communication platforms (Dwivedi et al., 2020). The growing acceptance and high usage rates of Smartphones in accessing social media, on the other hand, have provided long-lasting brand-consumer relationships, positive word-of-mouth, brand loyalty, influenced consumer decision-making (Kong et al., 2020), and eventually changed consumer behavior (Faizol & Nawi, 2018;Malik & Qureshi, 2016).
Apart from social media, celebrity endorser (CE) is another prominent marketing strategy used by marketers.
The statistic shows that CE allowed for 11 times higher returns on investments particularly through social media advertising (Lim et al., 2017), and there are now 25% and 61% of Chinese and South Korean firms, 65% of Indian firms, and 15% of European firms are endorsing celebrities (Misra et al., 2019;Waqas et al. 2020). Meanwhile, CE in virtual world has enhanced their influences by fostering closer ties with their fans through direct engagement. Its association with social media has significantly improved celebrities' attractiveness and potential to influence consumer behavior (Aw & Labrecque, 2020). Consequently, the celebrity endorsement creates credibility, competency, reputation, and adoration that could steer consumers' brand recognition and recall, which ultimately increased the effectiveness of advertisements and developed a favorable customer attitude (Misra et al., 2019).
However, while the social media influences (SMI) and CE' amenities are evidenced; other criticisms such as fake news and rumors in social media (Alzanin &Azmi, 2018; Visentin et al., 2019); celebrity' personal issue (Zhou &Whitla, 2013) have cast doubt on their efficacy. A brand's reputation can be affected easily, thus it's crucial to understand how social media and celebrities might impact brand choice behavior (BCB) in the long run. Keeping this in mind, this paper was attempts to systematically review the existing studies to give an up to the minute understanding regarding the factors associated with SMI and CE to influence consumer brand purchasing behavior.
The study also intends to critically review the social learning and source credibility theories to be best suited to the study perspectives. Despite the tremendous research on SMI, CE, and consumer brand purchasing intention, it has a paucity of studies that summarize the factors previous scholars examined in their studies (Wang et al., 2021a). Therefore, this study is the first which critically examine and list factor prior scholars explored on the various issues of social media influences, celebrity endorsers, and consumer brand purchasing behavior. The novel contribution of this study is to provide a guideline to identify the research gaps and initiate further research by investigating the factors related to SMI, CE, and consumer brand purchasing behavior which previous researchers explored in their studies. The study is a pathway to short view the current trend of research on the study contexts through which the scholars can understand the factors already researchers examined and identify the noble issues for further studies.
Moreover, this study is the basement for the practitioners to use SMI and CE for promoting the brands. It is the direction for marketers to understand which factors significantly influence the effectiveness of SMI and CE to leverage consumer brand purchasing behavior. Based on the previously investigated factors, this study also proposes further research on social media influences, celebrity endorsers, and consumer brand purchasing behavior.

Social learning theory (SLT)
Social learning theory (SLT) is a widely used theory in the communication and advertising areas developed by Bandura (1967) to represent influencers in the communication network as social agents capable of predicting consumption or use behavior. In the setting of social media networks (SMN), users establish a virtual community in which people can change their preferences or thoughts after learning from their peers (Lee & Son, 2019). SLT proponents assert that learning is a socially situated mental activity that is learnt by observing and imitating other people (Kabiri et al., 2020). Learning is believed to include four components: differential association, definitions, differential reinforcement, and imitation. First component -differential association defines person's belief in certain buying behavior with regards to the buying experiences from one's peer group. Second component -definition describes as the level of beliefs whether the buying behavior of the peer groups pondering the religious ground and morality. Third component -differential reinforcement relates to the encouragement of particular buying behavior influenced by the variant groups in the social community context; while the last components -imitation intends to cope-up with others social influences by primary group (i.e., family, friends) and the ancillary group In particular to SMI, it has a significant impact on a social learning process that relies on social contact since consumers can observe the actions of others on an online platform and modify their behavior as implied by SLT Further, the uses of SMN for promoting and establishing customer brand relationships are profound due to their customization and entertainment amenities in the process. For instance, customized advertisements through social media can always addressed customers' needs and influenced their purchase decision effectively and thus more successful in managing the customer BCB (Winter et al., 2021). Aside from that, one of the elements influencing the virtual networks and information sharing is entertainment (Hur et al., 2017). Peer social and entertainment interaction on social media enhances other peers' daily lives and enriches their thinking, hence significantly influencing the BCB (Yu & Oh, 2018). Social learning theory effectively examines consumer brand purchasing behavior using social media networks. The main notion of this theory is that in addition to the social media influencers and mainstream celebrities' motivation, the other users of social media networks also have incredible influences to change the consumer brand purchasing behavior. The theory illustrates that the users of social media networks act as agents in the virtual community, which have tremendous effects on consumer brand purchasing behavior by providing reliable information regarding particular brands. Furthermore, the theory also argues that the virtual community significantly influences consumer behavior because of their incredible trust in messages provided by the virtual community rather than commercial celebrity endorsers. As a result, social learning theory is crucial to examine consumer brand purchasing behavior through the influences of social media networks.

Theory of Source credibility (TSC)
The theory of source credibility (TSC), put forth by Hovland et al. in 1953, claimed that when sources are provided, people's beliefs or attitudes are altered (Chin et al., 2019). It clarifies how senders (the source) are regarded as genuine and intelligent by receivers (the recipient) in the information transmission process and shows how likely it is for individuals to believe a message and be convinced (Wong et al., 2020;Ismagilova et al., 2020). Because they feel that "credibility infers accuracy," people are more likely to believe and accept communications from highly reputable sources because they perceive them as being more authentic (Hsieh & Li, 2020). Source credibility is a multidimensional concept that generally incorporates source competencies (a source's ability to supply accurate information) and trustworthiness (an information provider's ethical qualities that ensure they provide accurate information) (Hu et al., 2020). Ohanian (1990) developed source credibility by integrating two theories: source attractiveness theory (McGuire, 1985) and old credibility theory, which had two dimensions: trustworthiness and expertise (Hovland et al., 1953). With reference to Ohanian's (1990) suggestion, the current study inferred that the effectiveness of CE in purchasing behavior. Therefore, using the source credibility theory to measure the effectiveness of celebrity endorsers in swaying consumer brand purchasing behavior is highly justifiable. Apart from the aforementioned theories and series of studies, the following researches (see table 1 and 2) were reviewed to get accounted with the previous constructs and their proposed relationships.

Method
An extensive literature search was accomplished using research keywords: "social media," "celebrity endorser," "social media influences," "brand choice behavior," "brand purchase intention", "effects of customer attitude towards SMI and CE," "perceived brand image," factors influence to brand purchase intention", "efficacy of celebrity endorser", etc. The related keywords to SMI, CE, and BCB such as "interaction," "customization," "entertainment"; "credibility," "expertise"; "customer relationship" "customer advocacy", etc. were also used to ABDC-listed journals with a minimum C category, and the search was extended since few suitable papers were found. Figure 2 below shows the scientific search process.

Findings
In light of the research goals, we have extracted the contracts associated with social media influences, celebrity endorsers, and consumer brand purchasing behavior. In addition to table 1 and Table 2, where we have referred to the previously investigated variables, we also summarized and presented other constructs along with the theories and model in Table. (Refer to Table -3, Table-4, and Table-5).  Table 3 demonstrates the listed constructs associated with social media influences, which authors examined from different perspectives and brands. The tables also mentioned the research field, study nature, and respective theories and models.  Table 4 shows already explored constructs associated with a celebrity endorser, which the celebrity researchers examined in diverse contexts and fields. It also referred to the area of research fi, study type, and particular theories and models. The influence of celebrity endorsements and social media influence on consumer brand purchasing behaviour is seen in Table 5. The mentioned constructs are examined as the consequences of consumer brand purchasing behavior or brand purchasing intention. The table also illustrated the research field, study type and the used theories and models.

Discussion
The findings showed that the key elements of social media marketing that researchers evaluated to examine customer brand purchase behaviour are entertainment, personalization, engagement, trendiness, and word of mouth  (Zhang & Hung, 2020). University students, electrical appliance stores, sports apparel stores, millennial internet users, luxury brands, cellphones, and mineral water were among the groups studied for the aforementioned outcome constructions. The meaning transfer model, the customer-based brand equity model, the theory of planned behaviour and social learning theory, the stimulus organism response, the self-congruity theory, the social influence theory, the theory of brand experience and customer equity, and the theory of reasoned action were also tested.
The studied constructs mentioned in Tables 1, 2, 3, 4, and 5 demonstrated what theories, variables, fields, and study types previously scholars examined in their research. This study is the first to make tables composed of those items to showcase the current trend of studies in social media influences, celebrity endorsers, and consumer brand purchasing behavior. The tables also showed the direct, mediating, moderating, dependent, and control variables already examined in divergent contexts. The tested theories and models were illustrated to get insight into the justifications for using those theories in their studies. The study shows room for identifying the research gaps associated with the brands, fields, theories, constructs, methodologies, etc., in social media influences, celebrity endorsers, and consumer brand purchasing behavior.

Conclusion and Implication
In this comprehensive evaluation of the literature, 200 peer-reviewed articles over the last five years were studied.
The study drew out the structures related to consumer brand purchasing behaviour, celebrity endorsements, and social media influences. The associations that had been looked at were analyzed to determine a potential area for future research using special factors connected to celebrity endorsers and social media influences on consumer brand purchasing behaviour. The study discovered that the social media factors that previous researchers examined to gauge their impact on customer brand purchasing intention are interaction, customization, entertainment, word of mouth, and trendiness. In addition, the often employed constructs for evaluating the effects of celebrity endorsers on consumer brand purchasing behaviour include attractiveness, trustworthiness, credibility, and expertise. The social learning and source credibility theory was also extensively reviewed to test the proposed relationships in future studies related to social media influences and celebrity endorsers for changing consumer brand choice behavior. To the best of our knowledge, this study would be the first, which extracted and listed the constructs from previous reputed journals, through which future scholars may be able to guess the current trend of studies nexus to social media influences, celebrity endorser, and consumer brand purchasing behavior. Besides, this study may be conducive to sharpening the idea generation for further study and supporting the proposed relationships. The brand practitioners may enable to gain insight into the mechanisms for the effectiveness of social media influences and celebrity endorsers for promoting the brands.
Moreover, we also discovered that rumors, messages distortions, celebrities' personal illegal issues, business motives, etc., dampened the relationships of social media influences and celebrity endorsers with the consumer brand purchasing intention. As a result, prior scholars revealed that establishing brand image and hiring the perfect celebrities for the perfect brand may enhance their efficacy for influencing consumer brand purchasing intention.
They also found that the efficacy of social media influences and celebrity endorsers may depend on the consumer attitude towards the messages provided by social media networks and celebrity endorsers. Therefore, based on the lens of their grounds, we propose that future studies may assess the relationships of social media influences and celebrity endorsers with the brand image, consumer attitude towards the social media influences and celebrity endorser, and consumer brand purchasing behavior considering any brands like Smartphone.