Influencer Marketing and Applicable Theories

Outline of the Topic

Simply defined, influencer marketing means the engagement of people who have gathered a substantial following through their online social media accounts and who are willing to work with brands to promote new products. As Kapitan and Silvera (2016) state, influencer marketing is a continuation of celebrity endorsements that were popular in the past — brands continue sending their products to celebrities, but in a digital space. One theory explaining how influencers impact the decision-making process of consumers is the Similarity-Attraction Model (SAM). SAM explains why influencers have become so important in the context of digital advertising — they affect their followers and their purchasing decisions (Kapitan and Silvera, 2016; Lin, Spence and Lachlan, 2016; Zhou, Lu and Wang, 2016). SAM implies a high level of trustworthiness and relatability, which is why influencer marketing has developed into being an integral part of modern-day advertising. However, SAM is one theory out of many developed and explored by researchers in an attempt to determine the best conceptual and theoretical framework for this marketing tactic. This report will examine the basics of influencer marketing, how it emerged and developed and highlight the recent research on this topic.

Influencer marketing affects consumers and their desire to purchase something in a different manner than traditional marketing. Another proof that influencer marketing is an important topic to study is the fact that many regulators in the United States, Europe, and other parts of the world created policies of ethical marketing that guide the work of the influencers (Association of National Advertisers, 2018). This means that the authorities recognise the impact that influencers have on the population. Influencers have a unique bond with their followers — something that no other advertising platform can offer. People follow influencers willingly and look through the content, unlike traditional advertising, where individuals see banners or ads on TV or websites. Hence, the engagement of such advertisements is higher, and the trust in the recommendation provided by an influencer is bigger.

Influencer marketing generates more profits when compared traditional advertising (Childers, Lemon and Hoy, 2019). According to Childers, Lemon and Hoy (2019), 89% of marketers who used social media influencers reported that this advertisement channel generated a better return on investment than others. Different research provides varied explanations of why influencer marketing has become so popular — some argue that influencers are opinion leaders, while others point out the idea that they are tastemakers (Childers, Lemon and Hoy, 2019). Either way, influencers have become an effective tool for promoting a brand.

The focus of the influencer marketing campaign is on the collaboration between an influencer and a marketing specialist of a brand, which differs from other advertising methods. Collaboration with influencers is a distinct process, and a brand manager should be aware of how to manage it, assess results, and plan for better results. This paper will help address these questions with peer-reviewed sources.

Therefore, this topic is worthy of a review because influencer marketing has become a part of a brand’s marketing strategy, the impact that influencers have on the consumer’s decision making is significant, and brand managers or advertisers should be aware of the theories and studies on influencer marketing. Influencer marketing can contribute to the growth and development of any brand. Moreover, influencers can impact the consumer’s decision to either purchase or avoid buying a product, which is why this narrative literature review aims to summarise peer-reviewed articles on influencer marketing. The aim and goal of this research are to investigate the phenomenon of influencer marketing and the theories applicable to it by investigating peer-reviewed literature. Some of the specific topics that were uncovered as part of this review include the various theories that help explain why people engage with the content that these social media personalities post and why the recommendations of the latter matter, such as the word of mouth theory, social exchange theory, similarity attraction model, the theory of visual congruence. The topics that were investigated include the issue of why this type of marketing is integral for inbound marketing, what is the definition of influencer marketing and how brands can use it to affect consumer behaviour.

Critical Reflection on the Methods

In this report, the approach of the narrative literature review is applied, which allows the author to cross-check the findings from different studies. Mainly, this report uses quantitative studies, which examine the impact of influencers on advertising efforts because it is a more reliable source of information. Literature reviews are a collection of articles on a single topic that allows systemising the evidence one can gain a better comprehension of the topic (Xiao and Watson, 2019). In this case, the relationship between influencer marketing and consumer decision-making.

As noted by Xiao and Watson (2019), a literature review is an essential part of any academic research, and this literature search was conducted using Google Scholar and library resources. The main keywords were ‘influencer marketing,’ ‘quantitative research on influencer marketing,’ ‘consumer decision making, and influencer marketing.’ The inclusion criteria were the time of publication – articles that were older than five years were excluded. As a result, forty articles were found that suited the topic of this research and were published in peer-reviewed journals. According to Charles Sturt University Guide, narrative reviews are ‘an essential part of the research process and help to establish a theoretical framework and focus or context’ of the research (Literature review: traditional or narrative literature reviews, no date; Wilson, 2019). The main strength of this method is that through it, the author of this report can identify the key themes in the literature on this marketing domain, as well as gaps that can be still addressed through further research. However, there are limitations to the method that the author has chosen. For example, there is no framework or method to ensure that all relevant literature on this topic was considered. Moreover, as the theme of influencer marketing has been gaining more attention from practitioners and academics, there are many published articles and books that disclose this topic. Hence, it is possible that some bias exists in the way the articles were selected since the author may have subconsciously chosen the articles of interest since the number of sources one can review for this type of paper is limited.

Literature Review

The main themes in the literature on influencer marketing are the history of how this phenomenon emerged. This includes a brief overview of marketing tactics that preceded influencer marketing, such as word-of-mouth (WOM) and celebrity endorsements. Next, key findings on why influencer marketing has become popular among marketing specialists will be presented. Finally, at the end of this review, there is a summary of theories that explain the engagement of customers from the perspective of influencer marketing.

What is Influencer Marketing

Firstly, this report will define the notion of ‘influencer’ and the type of relationship they develop with their followers. Argyris et al. (2020, p. 106443) state that ‘influencers are non-celebrity individuals who gain popularity on social media by posting visually attractive content (e.g., photos and videos) and by interacting with other users (i.e., Followers) to create a sense of authenticity and friendship.’ Influencers are online personalities with profiles on social media who typically do not have any other associated work, unlike celebrities, who can engage in acting, singing or other things.

Other authors offer different explanations for influencer marketing. Childers, Lemon and Hoy (2019, p. 258) define an influencer as someone who has ‘the potential to create engagement, drive conversation and/or sell products/services with the intended target audience.’ Alternatively, in their report, the Association of National Advertisers (2018, p. 3) uses the following definition of influencer marketing: ‘marketing that identifies and activates individuals who can sway the brand preferences, buying decisions, and loyalty of the broader population using their own opinions, beliefs, and/or marketing channels.’ The Association of National Advertisers (2018) also notes that this term can be viewed as the process of brands selecting and working with individuals on social media, the management of such advertisement campaigns, reimbursement for them and other relevant elements. Hence, influencer marketing encompasses not only the impact that online personalities have on people who follow them but also the process of cooperation with such individuals.

Some studies, for instance, by Johansen and Guldvik (2017), take a different approach to defining the term influencer marketing, which may impact the way the evaluation of these phenomena is conducted. Johansen and Guldvik (2017) argue that influencer marketing is a tool that brands use to drive their message to a larger market. In essence, influencers can be categorised as a source of information for individuals, somewhere between opinion leaders and celebrities. Typically, they are not as well known as celebrities. However, they have a larger impact and audience when compared to opinion leaders.

Influencers use different social media platforms and can have different sizes of followers. Association of National Advertisers (2018) provides the following categorisation of influencers, based on the number of people who follow them: micro, or those with up to 25,000 followers; macro with up to 100,000 followers, mega with up to 500,000 followers and celebrity influencers with more than 500,00 followers. Opresnik, Kotler and Hollensen (2017) promote the concept that the size of the company should define the type of influencer selected for promotion. For instance, small and medium businesses should use micro-influencers. Although these individuals have a relatively small following, the trust and engagement with their content are usually higher when compared to mega influencers. Haenlein and Libai (2017) argue that micro-influencers generate more conversions, and 80% of consumers are willing to follow their recommendations. Al-Emadi and Yahia (2020) report that 54% of customers use social media peer communication as a decision making source. Therefore, there is a difference in terms of the benefits that micro and mega influencers bring to the brand.

How Influencer Marketing Emerged and Developed

This section will focus on exploring the emergence and evolution of influencer marketing based on the existing studies. The literature on this topic mainly relies on other articles of authors’ own reflections regarding the development of influencer marketing. Historically, people have always tended to the opinions’ of others, especially notable people, such as church leaders or wealthy individuals, due to a belief that they possess more knowledge (Johansen and Guldvik, 2017). Moreover, people in the past had less access to information that would allow them to make a certain choice.

This lack of access to information encouraged individuals to use the opinions of others, people they could view as a source of information for a purchasing decision. However, the development of technology transformed the way information is consumed and perceived, and it allowed individuals to access a variety of brands and products. Blogs created by people to share information have rapidly become a credible marketing tool (Mohit, 2011). Word of mouth (WOM) marketing developed simultaneously with the increasing popularity of social media since people aimed to share their reviews and opinions about the things they bought, and others were willing to read these messages (Johansen and Guldvik, 2017). Influencer marketing, as a result, is a cohesive continuation of people’s intrinsic desire to share information about items and to look for reviews and opinions of others.

Initially, influencers used primarily text content posted in blogs. The Association of National Advertisers (2018) reports that in 2013 86% of all influencer content was generated in the form of blog posts. Although blogs still are a valid influencer platform for content creation, currently, images and video content have gained a lot more popularity. The visual element has become an integral part of this marketing strategy. Mohit (2011) presents a framework for explaining how the association between the visual elements of an influencer’s page are associated with better brand perceptions. Further development of technology and the increasing popularity of social networks aided the influencer marketing niche since ordinary people, and consumers gained an opportunity to affect the decisions of millions (Johansen and Guldvik, 2017). Despite its popularity, there is limited evidence for the theory of influencer marketing.

Why Brands Use Influencer Marketing

Many companies now choose influencer marketing as one of the key instruments in their advertisement strategies. According to Childers, Lemon and Hoy (2019), the financial investment in digital marketing campaigns suppressed those made to advertise in traditional media in 2008. Since then, companies have dedicated more attention to the unexplored opportunities for online marketing. In 2017, the spending on influencer marketing campaigns in the United States was estimated at $2 billion (Childers, Lemon and Hoy, 2019). According to Hughes, Swaminathan and Brooks (2019), nearly 75% of advertisers use influencer marketing as part of their current strategy, and 65% of brands plan on increasing their budget to incorporate more influencer-sponsored content. The popularity of influencer marketing is expected to increase in the following years. Another aspect of the place that influencer marketing has is in inbound marketing in general, and the associated spending is discussed by The Association of National Advertisers (2018). The report by this organisation cites that its members have spent $81 billion on influencers in 2016 and plan on spending $101 billion collectively in 2020. These studies and reports use company records and insights. Hence, their methods of evaluating influencer marketing are valid.

Influencer marketing has become exceptionally popular among brands in different industries, and it is essential to determine what are the benefits of it. According to Argyris et al. (2020, p. 106443), advertisers use influencers ‘to garner engagement from their target consumers in a new marketing strategy known as “Influencer marketing.’ Despite the increasing popularity of influencer marketing, there are both successful and unsuccessful examples of these types of campaigns. Examples of success include Nokia’s campaign in Finland, while unsuccessful influencer marketing is Dr Pepper ‘Raging Cow’ campaigns (Hughes, Swaminathan and Brooks, 2019). However, most of the examined studies conclude that in the majority of cases, influencer marketing is more beneficial and prominent when compared to traditional advertising methods.

Influencer marketing is a relatively unexplored niche, despite it having the potential to make a multi-billion pound impact on brands. According to Johansen and Guldvik (2017), 14% of the respondents cannot recall the last advertisement they saw, which is consistent with the idea of consumer blindness to ads. Simply defined, this concept means that because individuals are exposed to a large number of advertisements on a daily basis, they no longer respond to them, memorise them, or use them as prompts for purchasing decisions. This is another reason why advertisers are looking for new ways of engaging with consumers. Contemporary marketers are focusing on ads that have ‘higher ROI, more credible and believable, less interrupting than regular ads, arbitrage opportunities, new technology, changing markets, and predictions’ (Johansen and Guldvik, 2017, p. 3). As a result, the studies that use surveys and responses from advertisement management conclude that influencer marketing is highly effective. Table 1 presents the key themes and facts that explain why many brands use influencer marketing as a part of their strategies.

Table 1. Main themes in the articles discussing how influencers use social media

Theories and Concepts

The focus of this narrative review is in particular on consumer behaviour because this is the main factor that companies and advertisers use when evaluating the potential benefit of collaborating with an influencer — whether the consumer decided to purchase an item after they saw a promotional post or not. Chetioui, Benlafqih and Lebdaoui (2020) define purchasing intention as a likelihood of a consumer buying a specific product. Table 2 summarises the main theories that were presented in the explained studies, and the following paragraphs will explain each concept in detail.

When a person makes a decision to purchase something, they usually seek a recommendation from someone they know. According to Childers, Lemon and Hoy (2019), approximately 82% of adult Americans ask for a recommendation from their friends or family when making a purchasing decision. People who have amassed a significant following on their social media platforms are sometimes referred to as ‘instafamous’ (Djafarova and Trofimenko, 2019, p. 1432; Jin, Muqaddam and Ryu, 2019). These instafamous influencers have such an impact on their followers because they are perceived as someone familiar. Hence, people take their recommendations seriously. Moreover, consumers perceive the messages they receive from trusted sources more positively when compared to advertisements (Childers, Lemon and Hoy, 2019). Hence, research reports that advertisers face the need to create a sense of ‘word of mouth’ recommendations since those are more valuable to consumers.

Some researchers focused on the way that consumers reason their purchasing decisions. According to Johansen and Guldvik (2017), the Theory of Reasoned Action (TRA) is a framework for understanding purchasing decisions induced by influencers. The authors argue that influencer marketing posts have no direct impact on the consumer’s decision to purchase something. Instead, consumers base their decisions on the outcomes they think they will be able to achieve with a certain action, such as a purchase using a recommendation from an influencer. Johansen and Guldvik (2017) found that TRA explains the majority of consumer decisions, and therefore, the impact of influencers is not as prominent as other studies assume.

Another idea explored in multiple narrative studies and empirical researchers is word of mouth (WOM) marketing and opinion leadership. Opinion leaders are individuals who have certain expertise and can affect the decision of others, which links this theory with WOM since opinion leaders can serve as valuable sources of information for consumers. However, Johansen and Guldvik (2017) note that there is a major difference between opinion leadership and influencer marketing since the latter targets a multimillion audience, while opinion leaders usually communicate with a few people. Here, it is important to make a distinction between WOM and influencer marketing since the latter is a process — an influencer is continuously investing their time into creating content and collaborating with brands, while WOM is typically a single-action event.

SAM is a common theory in social sciences, explored both empirically and theoretically. Based on SAM, people tend to prefer to be around those who are similar to them (Argyris et al., 2020). Moreover, they are influenced by people with whom they have a large number of perceived similarities. Mainly, the similarities are assessed based on similar attitudes that individuals have. These attitudes can be further divided into important and less important, and the former category will help predict the attraction better. Argyris et al. (2020) provide an example of people with similar views on family and views and those who share a taste in coffee, stating that the latter category will have less attraction. In the context of influencers, SAM and the theory of decision making where individuals seek advice from others when deciding to make a purchase. In conclusion, followers are attracted to influencers who they perceive as similar to themselves.

The relationship between an influencer and their audience is based on trust. Hu, Zhang and Wang (2019) introduce the concept of trust transfer, which is a cognitive theory. According to this theory, if a person trusts in one entity, this perception can be trusted by another one as well. Using the example of social media influencers, one can state that if a person trusts an influencer and their opinion, they will transfer this feeling onto the products and brands that these influencers advertise. Hu, Zhang and Wang (2019) cite different examples of how this phenomenon impacts consumers and their decision. For example, if a website familiar to consumers has a link to an unknown page, the customer is more likely to trust the latter resource. A similar relationship exists between associated known and unknown brands. Hu, Zhang and Wang (2019) found that social media influencers as ‘power users’ who can prompt potential customers to make purchasing decisions through their networking power. Notably, the transfer of trust depends on an individual’s perception, mainly belonging, similarity and proximity.

Table 2. Synthesis of influencer marketing theories found in the literature

Notably, Ki and Kim (2019) also explain the theory of power dynamic, where the different stages of how influencers impact their followers are explained. In the first stage, an influencer attempts to make an influence, at the second, the target audience responds. Next, the target desires to comply with the recommendation, which leads to the final stage — the completion of an action (Ki and Kim, 2019). The consumer doppelganger effect is the theory of consumers mimicking the behaviour of influencers. The reasoning behind such behaviour is a desire to look or be perceived similarly to the other person that is being mimicked (Ki and Kim, 2019). These mimicking relationships can be either unidirectional or omnidirectional, with family members being the example of the first category and celebrities of the second. Berger suggests that the mimicker engages in this behaviour unconsciously (cited in Ki and Kim, 2019). Similar behaviour was reported when examining people’s everyday behaviour — for instance, how one person mimics the posture, gestures and facial expressions of the other during a conversation. However, mimicry can also be deliberate, with an intent to be more like the person that is being mimicked. As explained by Ki and Kim (2019), in the context of consumption, this means that an individual changes their purchasing patterns for clothing and other items to the ones of their favourite influencers.

Chetioui, Benlafqih and Lebdaoui (2020) explore the industry of fashion and how consumers’ perceptions are shaped by the influencers in this industry. The key theme explored by the authors is the Theory of Planned Behavior (TPB), which suggests that the attitudes towards an influencer affect the perception of a brand. Chetioui, Benlafqih and Lebdaoui (2020) state that among the factors that correlate with purchasing intention and brand perception, there are — credibility, trust, behavioural control, expertise, perceived norms and congruence.

The relevance of the TPB model is in the notion that thoughts and perceptions affect people’s emotions and subsequent actions. As noted by Chetioui, Benlafqih and Lebdaoui (2020), TPB is an extension of TPA, which was discussed earlier. TPB suggest that there are three key factors that determine the likelihood of a purchase — ‘attitude, subjective norms and behavioural control’ (Chetioui, Benlafqih and Lebdaoui, 2020, p. 3). Subjective norms are the buyers’ perception of social pressure. For example, if the potential customer perceives that others will approve of his or her actions, they are more inclined to make a purchase and vice versa. Behavioural control theory suggests that if a person has a positive attitude towards some behaviour, they are more likely to execute it. Finally, behavioural control is the perception of factors that can impact a certain behaviour.

Next, the specifics of what attracts followers and prompts them to follow influencers should be discussed. Visual congruence is a sense of harmony, and in the case of modern-day influencers, the congruence mainly applies to photos, for example, posted on Instagram (Argyris et al., 2020). Moreover, some evidence suggests that visual congruence actually impacts the effect that the influencer’s content has on their followers. Argyris et al. (2020) point out that visual congruence correlates with better engagement when reviewing influencers’ posts. Based on this, one can hypothesise that influencers who create better visual content can provide brands with better advertisements.

The theory of Visual-Congruence-induced Social Influence (VCSI) should be discussed as the basis for understanding how an influencer’s content affects the followers’ decision-making. Hughes, Swaminathan and Brooks (2019) focus their research on the consumer funnel on determining what drives brand success in the context of influencer marketing. The researchers found that the following factors: platform, content, and sponsored content affect brand engagement. The SAM implies that shared interests and opinions result in affiliations between individuals (Argyris et al., 2020). The concept of social proof is the basic theory of how trust between people affects decision making.

Consumer Behavior

This section will focus on examining the impact that influencer marketing has on consumer behaviour. Shahid and Farooqi (2019) used structural equation modelling to examine the brand attachment of consumers, more specifically Indian citizens, who purchase luxury goods. Brand attitude correlates with an intention to purchase and actual sale, as Shahid and Farooqi (2019) conclude, which means that people who have a good perception of a brand are more likely to purchase its products.

Florenthal (2019) focused on an important matter — why consumers actually choose to engage with influences and how this interaction impacts their decision making and applied two theories — uses and gratification (U&G) and the technology acceptance model (TAM). The combination of these two models allowed determining the motivating and demotivating factors that impact young consumers’ decisions. Notably, Florenthal (2019) argues that customer-brand relationships go beyond a transaction, where the former purchases something from the latter. Social media websites allow consumers to have more ways of connecting with their favourite brands.

One of the findings suggests that a significant difference in the visual elements of the brand’s website and its social media account will demotivate consumers from purchasing. Moreover, promotional posts can be irritating to users, serving as a demotivation factor rather than encouraging them to buy something. Huges, Swaminathan and Brooks (2019) state that influencer posts are effective in improving the WOM of the brand. However, consumer engagement with posts remains low. For example, on Facebook, the average engagement level is 35%, while on Twitter, it is only 0.5%. Notably, Lin, Spence and Lachlan (2016) focus primarily on the attachment mechanism that guides the influencer-follower relationship.

Recently, regulators in many states developed policies that oblige influencers to reveal sponsored content, although, before this, they could integrate it into their content in whatever way they deemed suitable. In the United States, for instance, the Federal Trade Commission (FTC) is a governmental institution enforcing these regulations (Association of National Advertisers, 2018). FTC requires any association between an influencer and a brand to be clearly disclosed in a post. The commission has already begun to enforce these regulations and reach out to influencers who violate the rules.

Moreover, some social media platforms, for example, YouTube, included the necessity to disclose sponsorship as part of their user agreement. As a result, ‘sponsorship compensation justification generates more positive consumer attitudes toward influencers receiving sponsorship compensation, and increases source and message credibility, compared to a simple sponsorship disclosure'(Stubb, Nyström and Colliander, 2019, p. 109). This study helps answer the question of whether consumers are affected by the idea that certain content was paid for by an advertiser, and the results suggest that there are ways of mitigating the adverse effects of such perceptions.

Singh and Banerjee (2019), celebrity worship is explained as a result of communication channels and publicity. Since celebrities are comparable in their effect on the consumers to influencers, the approach to viewing the follower-influencer relationship through the perspective of celebrity attachment is helpful. In the previous section, the different types of influencers based on the number of followers were discussed. The Association of National Advertisers (2018) cites that the majority of its marketers work with macro or micro-influencers as their main tool for advertisement, with a few citing mega influencers as their main choice for campaigns. Another factor that determines the choice of an influencer is the brand fit, quality of content and authenticity.

Although, as suggested by research, a distinction should be made between influencers and celebrities, there is some correlation between the two notions. To clarify, influencers are typically not viewed as celebrities, as they rarely have any other platform or job, unlike movie actors, singers, or other well-known individuals. However, nowadays, many celebrities are joining social media and gaining a massive following, which means that they can also be categorised as influencers since they have a following on social media platforms where they post content, including that created in partnerships with brands. In both cases, these are influencers, but the engagement with the followers that the two categories have differs. Al-Emadi and Yahia (2020) examine the issue of becoming an influencer and influential marketing development. The authors distinguish between ordinary celebrities and well-known celebrities, both can also be influencers on social media, but their engagement with consumers differs. Although typically, one perceives that well-known individuals are a better choice for endorsement deals, studies by Djafarova and Trofimenko (2019) prove that it is not the case. So-called ‘ordinary celebrities’ or people who have gained their following through social media platforms can extort more influence on their followers. Celebrity endorsements have been a popular marketing tactic for brands for years (Bergkvist and Zhou, 2016; Knoll and Matthes, 2017). The assumption is that they have to continuously put effort into creating content and showing the details of their everyday life, which improves their credibility. As a result, these ordinary celebrities appear to be more credible when compared to traditional celebrities as their relationship with their followers is closer.

In a broader context, the online interactions, their popularity and the rise of influencer advertisement can be explained through a lens of social science theory. Miltgen, Cases and Russel (2019) studied the response of consumers to advertisements on Facebook. The basis of this study is the social exchange theory (SET), which implies that social relationships arise to maximise the benefits for individuals and minimise the costs. In the environment of social media websites, SET helps explain the nature of transactions between the network of ‘friends’ since these communication means provide multiple benefits.

Opposing Views

Not all studies provide support to the generally accepted concept that social media influencers affect the potential consumers purchasing decisions and, therefore, should be used by advertisers of brands. Nurhandayani, Syarief and Najib (2019) report the findings of their purchasing intention study based in Jakarta, which focused on female millennials who use social media. The researchers found no correlation between sales numbers and influencer advertisement. However, Nurhandayani, Syarief and Najib (2019) found an improvement in brand image recognition and overall perception. The results of this research suggest that the impact of social media influencers on consumers’ purchasing intentions is not direct. Rather, they improve the brand’s image, which goes against the theories that were explored earlier in this literature review.

However, evidence from other researchers who use trials and valid studies proves the opposite. Coates et al. (2019) held a randomised trial to investigate the impact of influencer marketing on children’s food intake and found providing strong evidence for the impact of influencers. According to Berryman and Kavka (2017, p. 307), influencers and their followers develop a special intimate relationship, which some people perceive as friendship or even as having ‘a sister.’ This idea was developed based on the input from beauty bloggers — a popular category of influencers on platforms such as Instagram and YouTube, who think that people viewing their content see these influencers as close friends or family members. De Veirman, Cauberghe, and Hudders (2017) prove that the number of followers affects the brand’s perception. A heuristic-systematic model can explain how influencer marketing is perceived by consumers (Xiao, Wang and Chan-Olmsted, 2018). As a result, the studies provide multiple theories of influencer-follower interactions and the impact they have on one another.

Analysis and Critical Discussion

In total, forty articles on influencer marketing were analysed in this research using a systematic literature analysis process. The implication of this research for practitioners is the need to incorporate influencer marketing into their brand’s inbound marketing strategy. The majority of advertisers already use this tool, and its popularity will continue to grow. However, the recently developpe regulations, for example, by FTC, may suggest that this marketing domain is becoming overused. As was seen with traditional marketing, the consumers develop a certain ‘blindness’ to advertisements they see, which decreases the marketing ROI. While this may become a problem in the future, currently, influencer marketing remains to be extremely efficient.

The analysis and critical discussions of the findings provide multiple implications for practitioners since the current research into influencer marketing has developed and tested several theories explaining the motivation of consumers and the interactions with the followers. Most importantly, advertisers should keep in mind the unique relationship that an influencer has with their followers, which the Similarity-Attraction Model explains as a connection based on a shared interest. Trust, therefore, is the key motivational factor that drives consumer behaviour when an influencer posts a brand advertisement. For practising managers, this report and literature review on influencer marketing suggest that attention should be dedicated to engaging influencers in advertising and brand management practices. The literature review reveals that a large number of marketing specialists already uses influencers in their marketing campaign. Moreover, they generate a better return on investment, suggesting that modern brands have to include influencer marketing in their advertisement strategies (Pick, 2020; Zhang, Moe and Schweidel, 2017).

Practitioners can also benefit from understanding what factors have a negative impact on brand engagement and demotivate consumers from buying. For example, advertisements may be irritating to a consumer and mitigate the willingness to purchase (Quelhas-Brito et al., 2020). In terms of influence marketing, in particular, the ‘fit’ of an influencer with an overall perception of the brand appears to be the central matter for consideration with practising managers. TPB and TRA theories help practitioners understand how customers make decisions. For example, social norms and perceived correctness of behaviour are important predictors of the potential purchase. In the context of these theories, important factors that managers should consider when evaluating an influencer’s potential are their fit with the social norms and the perception of their behaviour by others.

Notably, the research that opposes the idea that influencers impact purchasing decisions should be considered for practitioners as well. Mohit (2011) used empirical research to prove that although there is an effect on the brand’s perception and image after Instagram influencers are engaged in the marketing campaigns. Notably, other researchers, such as Mohit (2011), Lou and Yuan (2019) and Chatterjee (2011), outline the theories rather than provide empirical support to their hypothesis. Hence, the only source of information suggesting that influencer marketing is indeed effective in promoting potential customers into making decisions are various social theories. These theories outline the basis of relationships between humans, interactions and purchasing decisions. Hence, a suggestion for practitioners is to approach influencer marketing with caution and use sales figures and other metrics to ensure that the campaign is reaching the expected results. In the case of using influencer marketing as a way of increasing brand awareness, multiple researchers prove the effectiveness of this approach, both theoretical and empirically. Moreover, the recommendation from an influencer can increase brand trust because it comes from a follower’s trusted source.

In terms of academic implications, influencer marketing has a plethora of potential for research. The majority of the examined studies claim that they are the only research on a specific element of influencer marketing. Hence, although there are some theories developed to explain the specifics of influencer marketing, they can be further supported and tested with empirical evidence. For example, the research on TPB and TRA is based on a literature review and does not have empirical results to support the findings. Many factors have an effect on how the sponsored post will be perceived by the followers. In this regard, the literature does not provide a single framework or strategy for developing influencer marketing strategies, although theories outline some of the underlying assumptions about influencer marketing. Researchers should focus on developing a theoretical framework that cohesively explains how advertising campaigns can engage in influencer marketing for better results.

Social exchange theory, the theory of reasoned action, the theory of planned behaviour, visual congruence model examine the relationship between an influencer and their followers. These theories are based on the notion that in social interactions, people look for recommendations from a source they trust and by developing a relationship with an ‘instafamous’ person, they tend to mimic the behaviour of the influencer. The mimicking is typically conscious because an individual wants to adopt a certain type of behaviour — look in a particular way or have similar habits, or for other reasons. As a result, the evidence suggests that influencers indeed have an immense impact on their followers and can help brands in their advertising campaigns. Hence, the popularity and the positive impact that influencer marketing has on brand recognition can be explained by social theories of how people engage with each other and seek advice from one another.

In terms of managerial education, one implication of this narrative literature review is the urgent need to emphasise the impact that influencer marketing has on brands and on consumers in particular. Apart from better ROI, influencers leverage the psychological aspects of human communication — the need to ask for advice, evidence or a recommendation from a trustworthy source (Trivedi and Sama, 2020; Onwuegbuzie and Frels, 2016; Magno and Cassia, 2018). One example of the impact of influencers and advertisements is the consumption of junk food, which is associated with advertisement since the consumers perceive ads as a cue (Boyland et al., 2016). Moreover, some consumers willingly and consciously choose to mimic influencers in order to look a certain way.

For policymakers, influencer marketing has already become a concern. The FTC in the United States recognised the impact that influencers have on people and the issue of deception — advertising something without disclosing that the post is sponsored. Notably, this has been the basis of influencer marketing for many years, as prior to these regulations, any influencer could post product recommendations as personal advice without stating that this is an endorsement.

Considering the impact of influencers and the established practice of failing to disclose partnerships, it is essential for policymakers outside the United States to create policies and guidelines for fair advertisements. Notably, since digital advertisement is a relatively new development as opposed to traditional media advertisement, this issue has been ignored for many years. In terms of research, it would be interesting to investigate if posts with hashtags ‘ad’ and ‘advertisement’ generate less engagement from viewers as opposed to regular posts.

The understanding of distinct strategies for managing influencer advertising is also supported by the idea that influencers are not celebrities. Hence they usually do not have management and other personnel or familiarity with traditional advertising methods. This can complicate the work of the influencer and a brand. As was mentioned in the report, the majority of practitioners and brands already use Instagram advertisement as the main method of promoting their products. Hence, another suggestion for marketing managers is to develop new concepts and guidelines that can be used to further improve influencer marketing. This is important considering the variety of different niches since influenced followers interested in fashion and electronics may have different expectations and different engagement with the content. To sum up, although practitioners already apply influencer marketing, some further improvements can be made to help others apply this tool by developing guides and frameworks for influencer marketing.

In terms of management education, this research highlights the importance of dedicating attention to digital marketing tools and the changing trends in consumer behaviour and advertisement tactics. Hence, it is vital to include influencer marketing in the process of teaching students the basics of inbound marketing to ensure that their skills are relevant to the demands of the contemporary marketing environment. The examined theories provide a framework for such education since students should understand not only how to interact with influencers but how the followers perceive this relationship. Hence, educators should include the different theories of influencer marketing into the curriculum to help students learn relevant marketing strategies.

In terms of academic research, there are many factors in the influencer-follower model that require further clarification. Some of the findings of this research imply that influencer marketing does not always have a direct impact on a consumer purchasing decision. Although most researchers agree that, in any case, a good influencer marketing campaign will contribute to a brand’s image, the exact relation to the purchases remains unknown. Hence, academics should focus on further examining the discussed field and empirically providing that by using influencer marketing, firms can generate more profits from sales or the opposite. This will also help policymakers design effective guidelines for influencer advertisements that will protect consumers from unfair practices and the potentially harmful effect of these ad campaigns.

Conclusion

Overall, this paper is a narrative review of the literature on the topic of influencer marketing and consumer decision making. The findings suggest that influencer marketing can contribute to a brand’s success because of the unique relationship between an influencer and their followers. Several theories help understand the relationship between brands and influencers, including some studies that focus on the effect that celebrities have on their worshipers, which can be used as a basic framework for the influencer-follower relationship. There are a large number of theories that aim to explain the relationship and communications between influencers and their audience. The research examined in this narrative review is both qualitative and quantitative, with sufficient validity to rely on the author’s conclusions.

Learning Statement

Over the course of this project, I deepened my understanding of digital marketing strategies and developed a cohesive comprehension of what influencer marketing is, how it is used, and the actual impact it has on brands and sales. When conducting a literature review, I tried to find empirical evidence and theories that would clearly explain why people trust influencers more than other advertisement means and how this can be used by brands. Despite influencer marketing being a relatively new subject, there is a plethora of research and evidence on how to select an influencer for partnership, what to expect, and how this advertisement will impact consumer decisions.

The aspect of consumer decision-making is especially interesting since according to the Similarity-Attraction Model suggests that people are attracted to others who are similar to them. Hence, influencers, which create an image of a regular person rather than a famous and rich celebrity, are relatable and more trustworthy. As a result, they can increase brand awareness and encourage consumers to purchase more.

This report was a challenge for me since influencer marketing is a new domain of marketing. Another challenge was to escape the potential bias since I myself often make decisions based on an influencer’s recommendations, and this could affect the selection of literature and implications. However, I tried to focus only on the findings of the articles and empirical evidence as a main source of judgment.

Through the process of preparing this report, I learned that influencer marketing is present in a variety of niches, not only in beauty and related industries. Moreover, the empirical evidence collected shows the significant advantage that influencer marketing has before traditional marketing. Hence, I will be able to use the gained knowledge in practice when managing the campaigns of my company and collaborating with influencers.

In general, this report contains many implications for practitioners and researchers that are interested in influencer marketing that has taught me how to use influencer marketing appropriately. It suggests that marketers should be concerned with how to present their brands through influencers on different social media platforms, and researchers should continue developing and testing theoretical frameworks for this advertisement means since it is apparent that influencer marketing will continue to be an essential aspect of advertisement in the nearest future.

One learning point that will help me in the future is the need to plan a project similar to this and adhere to the plan. Since the literature review contains approximately forty peer-reviewed articles, I had to use some time management techniques to be able to read the material, make notes, systemise it and write this report. I received some help from my supervisor, who helped me plan the process of selecting articles for the review and advised me on how to approach the reading. As a result, I gained valuable experience in collecting and synthesising data from a large number of sources. In addition, I comprehend the value of reliable data since some of the insights from peer-reviewed articles in this narrative literature review contain information that contradicts claims from popular online-based advertising magazines.

Over the course of writing this report, I encountered some difficulties connected to not being able to strictly adhere to the schedule because I overestimated my capabilities. I realised that I had to take a step back, have a break and return to the project as soon as possible. As a result, I have collected digital notes on all the reviewed articles with my reflections on how scientific information can be used by me as a marketing practitioner. I think that this is very helpful since it allows rethinking the information from peer-reviewed sources from a perspective of how I would use it. I have improved my understanding of theories, especially those relating to consumer behaviour and motivation for purchasing.

This narrative literature review implied summarising the information from multiple articles on the topic of influencer marketing without providing an interpretation of the results. As a result, the focus is on theories and findings and not on the potential outcomes of the research. However, I think that this report will contribute greatly to my future career since influencer marketing will continue to be an essential advertising channel for brands, while traditional advertising will continue losing its relevance. According to Laurie, Mortimer and Beard (2018, p. 765), ‘the advertising landscape has changed considerably during the past two decades as e-mail, search engines, smartphone apps, advergames, social media networks, mobile, and other forms of digital media and marketing have become increasingly important.’ Notably, the understanding of the underlying theory that guides the influencer-follower relationship and what prompts followers to trust the suggestions of influencers is an essential component of planning effective influencer marketing campaigns.

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