Influencing 2.0: The Credible Source
A study into the effects of Social Media Influencers’ source credibility on consumers’ brand attitudes through sponsored Instagram posts and the moderating role of disclosures.Kimberly van Stokrom 11110996
Master’s Thesis
Graduate School of Communication
Master’s programme Communication Science University of Amsterdam
dr. Marjolein Moorman
Abstract
Instagram has rapidly grown into one of the most favoured forms of social media currently used. Brands have jumped on the Instagram bandwagon, but since brands are often
considered intrusive on social media, they employ the help of brand endorsers – or the so-called Social Media Influencers (SMI). In choosing an influencer to endorse your brand, source credibility is one of the most important source attributes to keep in mind. A highly credible source has been proven to lead to more favourable brand attitudes among consumers than a source low in credibility. Also, since 2009 rules are being formed compelling SMI to disclose “material connections” with the brands they endorse, while the effects of such disclosures on consumers are still largely unknown. The purpose of this study was to examine the effects of both source credibility and disclosures through sponsored Instagram posts by SMI on consumers’ brand attitude and shed light on how both concepts interact to influence brand attitudes. The results were not significant, so future researchers must further examine the exact roles source credibility and disclosures play regarding SMI. This study has laid the groundwork for such future research, which should be conducted in a timely fashion.
Introduction
Since social media platform Instagram launched in October of 2010 (Instagram, 2016), the app has grown into one of the most favoured forms of social media currently used. The ubiquitous app has 400 million monthly active users and counting, more than 40 billion shared photos and an average of over 80 million photos posted each day (Instagram, 2016). Not only consumers are Instagram-aficionados, over 85% of top brands use Instagram as part of their marketing strategy (LePage, 2015). One of the reasons Instagram is widely used among brands is that the platform is more engaging than Facebook and Twitter, with a per-follower engagement rate 58 times higher than on Facebook and 120 times higher than on
Twitter (Beese, 2015; LePage, 2015). Most brands adopt Instagram by having brand endorsers, or influencers as they are called in the industry, post sponsored content since brands on social media often seem inauthentic and therefore their presence online can seem out of place to consumers or even negatively affect consumers’ perceptions of the brand (Fournier and Avery, 2011). As it has been said, “brands are uninvited crashers to the Web 2.0 party” (Fournier and Avery, 2011, p. 193). The presence of influencers, as they are just ‘regular’ people, does not seem disingenuous. The adoption of influencers has proven to be a successful strategy, as ad recall from sponsored posts on Instagram is 2.9 times higher than for other forms of online advertising (LePage, 2015). Many brands currently employ this strategy, with companies across industries spending between 1 and 1.5 billion dollars per year on sponsored content on Instagram (Ma, 2015).
The popularity of influencer marketing is also proven by the fact that companies now offer the service of connecting a brand to an influencer that is best suited for the brand and it’s products. The Dutch start-up Cirqle is such a company as they have created a database of brands and influencers and an automatic system that matches both for specific campaigns the brand is launching (Betlem, 2015). This service seems practical, although it is not clear if Cirqle keeps the three basic source attributes by Herbert Kelman (Belch and Belch, 2015) in mind, which are important for a brand when choosing an influencer to endorse them. All source attributes – credibility, attractiveness and power – can influence consumers’ attitudes, but especially source credibility is important as studies have found source credibility to be very prominent in persuasion (Colliander and Dahlén, 2011). Using a credible source has been proven to positively influence consumers’ brand attitudes (Lafferty and Goldsmith, 1999; Buda and Zhang, 2000; Colliander and Dahlén, 2011), so a brand will probably benefit most from a source high in credibility to endorse them online.
The sponsored nature of the content influencers post for brands often goes unnoticed by consumers. Since December 2009 the US Federal Trade Commission has regulated that social media influencers are compelled to disclaim “material connections” with the brands they endorse (Arango, 2009). This is the first step in making disclosures mandatory for endorsements on social media. Such rules and regulations have been in place for traditional media for years, but not for social media (Boerman, van Reijmersdal and Neijens, 2012). Studies on disclosures provided through traditional media have proven that more often than not providing disclosures leads to negative effects on consumers’ overall brand attitude and to consumers attributing negative feelings to the source providing the message and the
disclosure (Boerman et al., 2012). Academic literature on disclosures specifically calls for further research on disclosures on social media (Campbell, Mohr and Verlegh, 2012;
Colliander and Erlandsson, 2015). The US Federal Trade Commission has started obligating brand endorsers to disclose their sponsored content while the effect of disclosures through social media on consumer attitudes has not yet been investigated (Colliander and Erlandsson, 2015). Therefore, Colliander and Erlandsson (2015) argue future research is needed to examine these effects and add it is needed with some urgency.
This study will examine the effects of both source credibility and disclosures through sponsored Instagram posts by influencers on consumers’ brand attitude and shed light on how both concepts interact to influence brand attitudes. A comprehensive review of the academic literature on these topics will follow in the Theoretical Background.
Theoretical Background
In the following section the theories regarding source credibility as well as disclosures on brand attitude will be discussed and central concepts will be explained. Brand attitude is the dependent variable in this study because marketing communications, which include a
sponsored Instagram post by an SMI, are mostly focused on increasing consumers’ brand attitudes (Campbell et al., 2013). Studying brand attitudes would provide practical
implications for brands, as attitudes are what lead to (purchase) intentions according to the Cognitive Response Approach (Belch and Belch, 2015) and the Theory of Reasoned Action (Pai, Siddarth and Divakar, 2008). This is relevant for brands as purchases are often the main goal regarding their consumers. Regarding theory on brand attitudes, the effects of source credibility on brand attitude are well known and often studied (Gotlieb and Sarel, 1991, Grewal, Gotlieb and Marmorstein, 1994; Lafferty and Goldsmith, 1999; Buda and Zhang, 2000), but not often regarding endorsers or influencers. Since the purpose of endorsers is to ‘shape attitudes’ (Freberg, Graham, McGaughey and Freberg, 2011), it is interesting to examine if the effect of source credibility on brand attitude holds for SMI. Regarding disclosures the effects on brand attitude have not often been thoroughly studied (Colliander and Erlandsson, 2015), which leaves room for theoretic contributions from the current study.
Previous research regarding brand endorsers as well as disclosures has thus far focused mostly on other media types than social media (Gotlieb and Sarel, 1991; Cronley, Kardes, Goddard and Houghton, 1999; Lafferty and Goldsmith, 1999; Boerman et al., 2012;
Colliander and Erlandsson, 2015). However, since the use of social media has grown over the years, brands now often employ endorsers on social media as well and this marketing strategy is gaining popularity (Vogels, 2016). In the field these brand endorsers are known as
‘influencers’ and research on such endorsers has also provided us with the term Social Media Influencer (Freberg et al., 2011). A Social Media Influencer (SMI) is a third party brand endorser who influences audiences through his or her social media channels (Freberg et al., 2011). Influencers promote the brand’s products (Belch and Belch, 2015) and in the case of SMI, they do so specifically through social media. Brands employ influencers since it is said to lead to more engagement compared to a post by the brands themselves. This is due to the
feeling of friendship consumers feel with influencers, as they feel closer to them than to a brand and are therefore more willing to engage with influencers (Colliander and Erlandsson, 2015).
Source credibility. Previous research has shown that source credibility is important with regards to consumers’ responses towards the brand (Gotlieb and Sarel, 1991, Grewal, Gotlieb and Marmorstein, 1994; Lafferty and Goldsmith, 1999; Buda and Zhang, 2000). Source credibility can be defined as the extent to which the receiver of a message regards the source as having relevant knowledge or experience and therefore trusts the source to give unbiased information (Belch and Belch, 2015). In line with this definition, Gotlieb and Sarel (1991) argue that source credibility is comprised of two underlying dimensions: perceived expertise and trustworthiness. Perceived expertise refers to whether the receiver perceives the source as knowledgeable and trustworthiness reflects the receiver’s belief that the source’s information is unbiased. Previous research on source credibility has indicated that expertise is more persuasive than trustworthiness and is more strongly aligned with attitudes (O’Hara, Netemeyer and Burton, 1991) making expertise the most relevant dimension of source credibility.
Source credibility is said to lead to favourable brand attitudes among consumers when credibility is high (Lafferty and Goldsmith, 1999; Buda and Zhang, 2000; Colliander and Dahlén, 2011). According to Kelley’s (1967) attribution theory, when consumers are presented with a message they will start by assessing the source credibility and whether the message is an accurate representation of the truth (Buda and Zhang, 2000). The consumer’s assessment or attributions on why a source takes a certain position or opinion in a message greatly influences the persuasiveness of the message and thus whether the consumer accepts the message from the source or rejects it (Eagly, Wood and Chaiken, 1978; Gotlieb and Sarel,
1991). Through attribution theory consumers ask themselves if the claims made in the message they received are authentic and whether the source of the message lacks credibility (Grewal et al., 1994). When the source is identified as credible, consumers go through the process of internalization. During this process the receiver takes over the opinion of the credible source because the receiver believes this information (Belch and Belch, 2015). Therefore, if a credible source endorses a brand and is perceived as an expert, consumers are more likely to develop a favourable attitude towards that brand (Lafferty and Goldsmith, 1999).
Thus, according to attribution theory and the body of literature on source credibility, when source credibility is high, consumers are more likely to respond positively to the message and accept the message. When source credibility is low, consumers will most likely respond less positively and perhaps even disregardthe message. Based on this, the following first hypothesis can be formed:
H1: SMI with high source credibility posting sponsored advertisements on Instagram lead to more positive brand attitudes, compared to SMI with low source credibility.
Disclosures. Disclosures can be defined as a way to explicitly inform consumers when commercial content is integrated into editorial content (Boerman et al., 2012), in this case an Instagram post from a SMI. Disclosing that a post is endorsed will reveal to consumers that the post is not unbiased. These disclosures can activate persuasion knowledge, which means that people are aware that they are being persuaded, something consumers do not like
(Boerman et al., 2012). The Persuasion Knowledge Model (Friestad and Wright, 1994) gives insight into the effect of disclosures. The model describes how people develop persuasion knowledge and how they use this to respond to attempts of persuasion. The Persuasion
persuade them, before their persuasion knowledge can be activated. A disclosure would, for instance, make consumers aware of this and activate persuasion knowledge.
There is a gap in the literature on persuasion knowledge as there have been only few studies to examine persuasion knowledge with regards to its advertising effects on audiences (Tutaj and Van Reijmersdal, 2012). In addition, most studies on persuasion knowledge have focused on traditional media, while with the rapid rise of the Internet and social media it is interesting to examine the effects of persuasion knowledge on audiences within the online domain (Tutaj and Van Reijmersdal, 2012). The few studies that have focused on online persuasion knowledge have found that sponsored content leads to an activation of persuasion knowledge, which in turn leads to more scepticism and irritation among consumers (Tutaj and Van Reijmersdal, 2012; Campbell, Mohr and Verlegh, 2013). A study by Campbell et al. (2013) on sponsored content disclosures on blogs confirms this by finding that when
consumers view disclosures, they are able to activate their persuasion knowledge and thereby reflect back over the advertisement and recognize the persuasion attempt. The authors
conducted three experiments which all prove that this process ultimately leads to less favourable or lower brand attitudes (Campbell et al., 2013). Based on this, the following hypothesis was formed:
H2: Sponsored advertisement on Instagram with disclosures lead to less favourable brand attitudes, compared to sponsored advertisements on Instagram without disclosures.
Interaction effect. Colliander and Dahlén (2011) found that there is an important need for transparency on blogs and other social media and that consumers find it essential that the information is unbiased. Since promoted posts are never completely unbiased because SMI are compensated (in the form of money or materials) for their posts, disclosing that a post is endorsed will reveal to consumers that the post is not unbiased. According to attribution
theory consumers then ask themselves if the claims made in the message they received are the truth, or a result of situational factors (e.g. the source being paid). If indeed the message is a result of such situational factors, attribution theory suggests the message loses effectiveness (Gotlieb and Sarel, 1991). Grewal et al. (1994) explain that in such a case consumers attribute knowledge bias or reporting bias to the source of the message. Knowledge bias is the idea that the source’s knowledge about reality is not comparable to theirs and reporting bias refers to the idea that a source’s version of reality has been compromised (for example, by receiving a compensation). A disclosure could therefore be regarded as proof of situational factors (SMIs being compensated by brands for their endorsed posts) and lead to consumers attributing knowledge bias or reporting bias to the SMI. This would in turn lead to the activation of persuasion knowledge, which as we know leads to less favourable brand attitudes among consumers (Tutaj and Van Reijmersdal, 2012; Campbell et al., 2012). This negative effect of disclosures will weaken the positive effect of a highly credible source on brand attitudes. Boerman et al. (2012) confirm this by stating that in the case of disclosures, when persuasion knowledge is activated it negatively affects the positive effect of source credibility on brand attitude, which results in less favourable brand attitudes. Consequently, the following hypothesis is formed:
H3: Sponsored advertisements on Instagram with disclosures negatively influence the positive effect of source credibility on brand attitudes, compared to sponsored advertisements on Instagram without disclosures.
Figure 1. The conceptual model.
Methodology
Research method. To study the aforementioned hypotheses, an online experiment will be conducted. An experiment lends itself for the testing of causal relationships, as is expected between source credibility and brand attitude as well as disclosures and brand attitude and ensures that the researcher can use manipulations to create multiple conditions. Additionally, an online experiment offers to opportunity to recreate the experience of using Instagram. The online experiment will be conducted by using survey program Qualtrics.
Design. The experimental design is a 2 x 2 factorial design with source credibility (two levels, namely: expert vs. not an expert) and disclosures (two levels, namely: present vs. absent) as factors (Table 1). It is a between-subjects design since the goal is to test the effects of source credibility and disclosures on brand attitudes and not to measure change in attitudes during a certain amount of time, as would be the case for within-subjects designs.
Source credibility Disclosures (Yes vs. No) Brand attitude High (expert)
Table 1 – The experimental schema.
Source credibility Disclosures
Expert (high credibility) Present
Absent No expert (low credibility) Present Absent
Sample. Since this research focuses on Instagram, the participants will be Instagram users. These users are mostly female and between 18 and 29 years old. Instagram is used mostly by college and university students in urban and suburban areas (Patterson, 2015). The sample will consist of 100 Instagram users and due to the characteristics of Instagram users, I have chosen female college students (or recent graduates) between the ages of 18 and 29 that live in suburban and urban areas. The sampling method that will be used to reach these
participants is convenience sampling. This entails selecting individuals who are easily
accessible and in the proximity of the researcher. Such as personal friends and family who fit the aforementioned characteristics as well as Instagram ‘friends’ or followers by posting a link to the experiment on my personal Instagram account. The latter will ensure all
participants gathered this way are in fact Instagram users.
Manipulations. Fashion is chosen as the topic for the Instagram posts because it is a common topic in the so-called blogosphere (Colliander and Dahlén, 2011), since 96% of fashion brands use Instagram (LePage, 2015) and because fashion is one of the largest, most popular topics people post about on Instagram (Jassies, 2015). Additionally, fashion bloggers are especially active on Instagram and often post sponsored advertisements, which makes it a plausible choice for this experiment. Therefore, both the sources in the experiment as well as
the brand used in the Instagram posts will be part of the fashion world. The specific brand portrayed in the pictures will be a relatively new brand, namely SEGOLDA. SEGOLDA is a Dutch jewellery webshop that launched in September 2015. Although very new, the brand has been mentioned by a few (small) fashion bloggers; so it is plausible to assume that bloggers would post about the brand. In addition, it fits within the selected fashion category, being an accessories/jewellery brand. Jewellery has extended into the domain of fashion and when fashion is studied, jewellery is often included as a fashion product (Fionda and Moore, 2008; Yoo and Lee, 2009). Using an unfamiliar brand has been done previously to ensure most participants will not know the brand beforehand and thus have no existing judgements and attitudes towards it, which is important when brand attitude is the dependent variable.
The picture in the Instagram post will be the same across all conditions to ensure consistency and that there will be no differences in results due to the picture used. The picture will contain the brand’s product(s) and show the brand name, since this is very common in sponsored posts on Instagram. The text underneath the picture (apart from the disclosure hashtag) will be a short, simple line that will be kept constant throughout conditions. Lastly, the likes visible under each Instagram post are left out of the manipulated posts. Research has shown these likes and in particular how many likes a post had, can influence consumers (Schroth, 2015). Therefore, likes are not included in the stimuli, to exclude the possible influence it may have. This will not seem unrealistic to the participants, as likes are also not shown on Instagram when a picture has just been uploaded, since followers have not had the time to view the post and like it.
Source credibility. In previous experiments expertise has been used to manipulate the variable of source credibility (Gotlieb and Sarel, 1991; Grewal et al., 1994; Buda and Zhang, 2000). These previous studies have manipulated expertise by providing the experiment’s participants
with texts about the source beforehand. In the studies by Gotlieb and Sarel (1991) and Grewal et al. (1994) sources have for instance been described as electrical engineers versus car
salesmen, with engineers proving high in credibility because of their expertise and car salesmen as low in credibility. This is a tried and tested way of manipulating source credibility. Therefore, the participants in this experiment will be presented with a text
beforehand stating that the source in the Instagram post they will view is either a well-known fashion blogger with a fashion-relevant academic degree (expert on fashion and blogging, highly credible) or a fashion blogger who has just started and does not have a fashion related academic degree (no expert on fashion or blogging, so low credibility).
Specifically, the highly credible source is fashion blogger Lizzy van der Ligt. She has been a blogger for over 4,5 years, has more than 159.000 Instagram followers (as of May 2016) and can be stated to be an expert in the field of fashion as she has her Bachelor degree in all-round styling from the leading Dutch fashion academy, Academie Artemis, in Amsterdam. The source low in credibility is fashion blogger Milou Knierim with her blog Amsterdam Style Hunter. She has been a blogger for a significantly shorter amount of time than Lizzy, i.e. since the summer of 2015. She has little over 7.700 Instagram followers (as of May 2016), which is also much less than Lizzy van der Ligt, proving the difference in
popularity and how long their blogs (and therefore Instagram accounts) have been active. Lastly, Milou has no expertise regarding fashion, as she is studying for her Bachelor in Law at the Vrije Universiteit (VU) in Amsterdam.
A pretest among 22 female participants, of which 19 remained due to some not completing the survey, was conducted to check if source credibility was correctly manipulated. Participants’ scores on source credibility were assessed using five items (Harmon and Coney, 1982; Gotlieb and Sarel, 1991; Grewal et al., 1994; Lafferty and Goldsmith, 1999; Buda and Zhang, 2000). Participants answered the question “Do you find
the blogger who posted the Instagram picture” with the items trustworthy/not trustworthy, good/bad, an expert/not an expert, experienced/not experienced and trained/untrained. The 5-item scale proved reliable as indicated by a Cronbach’s Alpha of .92 (M = 3.52, SD = 1.06). An exploratory factor analysis indicated that the scale was unidimensional (EV = 3.78), explaining 75.58% of the variance.
An independent samples t-test indicated that the difference in whether the participant recognized the source as high in credibility in the high source credibility condition (M = 3.31, SD = .93) was not significantly different from whether the participant recognized the source as low in credibility in the low source credibility condition (M = 3.86, SD = 1.08), t (17) = -1.17, p = .256. To ensure recognition of the source as high in credibility in the high source credibility condition and low in credibility in the low source credibility condition, the introductory text on both sources is extended to state even clearer if the source is considered an expert or not and why or why not. Specifically, in the high credibility condition sentences were added to the introductory text stating the source ‘is an expert in the field of both fashion and blogging’ and that ‘she has made a career out of her blog and is very successful’. These additions underline the expertise of this source. In the low credibility condition an opposite addition was made, in the form of stating the source ‘is not considered an expert in fashion and/or blogging since she has just started blogging and because she studies something
completely different at university’ and that ‘her blog is just a hobby’. In all cases, participants will be asked to ‘read the following text carefully’ to make sure participants pay attention to the full text. All introductory texts can be found in the Appendix.
Disclosures. Disclosures in the Instagram posts for this experiment will be manipulated by having the disclosure condition have ‘#advertisement’ in the text underneath the picture, while the non-disclosure condition will not have this hashtag. This way of disclosing
sponsored content is a common practice worldwide. Initially the #ad was used, but the pretest indicated that in the disclosure condition all participants indicated the post was (to some degree, ranging in their answers from ‘agree’ to ‘strongly agree’) a sponsored advertisement, however, not all participants in this condition specifically mentioned the #ad as a reason for the post being a sponsored advertisement. Therefore, to be even more clear, the hashtag was changed to #advertisement for the experiment. The pretest further found that at times the participants in the non-disclosure condition thought the post was an advertisement, although it was not. They explained that they considered the post an advertisement due to the brand name (and tagging this brand name). Therefore, in the experiment the brand name will not be tagged in the non-disclosure conditions. Overall, participants clearly indicated that the hashtag as well as tagging the brand SEGOLDA indicates a post is sponsored. Therefore, the sponsored post will feature the SEGOLDA tag and the #advertisement while the
non-sponsored post (the non-disclosure condition) will not include either. This should eliminate any confusion on whether or not the post is a sponsored advertisement.
Brand attitude. Brand attitude was measured by adapting the widely used scale by Spears and Singh (2004) (Mackay, Ewing, Newton and Windisch, 2009; Kayhani Kermanshabi, 2014; Schroth, 2015). It consists of five items on a seven point Likert-scale. The participants were asked to “describe your overall feelings about the brand (SEGOLDA) described in the
Instagram post you just viewed” and answered on the items unappealing/appealing, bad/good, unpleasant/pleasant, unfavourable/favourable and unlikable/likable. The 5-item scale proved reliable as indicated by a Cronbach’s Alpha of .95 (M = 3.21, SD = 1.14). An exploratory factor analysis indicated that the scale was unidimensional (EV = 4.14), explaining 82.87% of the variance. Therefore, the five items were computed to one overall variable.
Results
Experiment. The experiment consisted of a survey through Qualtrics. The sample for this experiment consisted of 102 participants. Three men (accidentally) filled in the survey, so they were excluded from the dataset. Additionally, one participant was far older than the target group (43 years old) and so was also excluded. Lastly, 22 participants did not complete the survey, due to the survey being ended when participants indicated not to use Instagram. There were no outliers found when analysing brand attitude, so the final sample consisted of the 77 remaining participants. Equal distribution of participants over the conditions was still ensured with 21 participants in the high source credibility/disclosure condition, 18
participants in the high source credibility/no disclosure condition, 18 participants in the low source credibility/disclosure condition and 20 participants in the low source credibility/no disclosure condition. Ages ranged from 18 to 30 years old (M = 23.87, SD = 2.51). The majority of the sample (72%) indicated their highest completed education was university education, followed by higher vocational education (15%) and secondary education (9%). Additionally, 97% of participants were familiar with Instagram and almost half (45%) use Instagram multiple times a day. Of all participants 79% indicated to follow brands on Instagram and 75% indicated to follow bloggers.
Manipulation check. Manipulation checks were conducted to examine if the manipulations were successful. First of all, it was assessed if participants correctly recognized the post as an advertisement or not in the corresponding conditions. It was intended that when a disclosure was provided, the post was a sponsored advertisement and when no disclosure was provided the post would not be considered a sponsored advertisement. An independent sample t-test was conducted to examine if the answers participants gave to whether or not they considered the post they viewed a sponsored advertisement, corresponded with the condition they were
appointed to, specifically to whether or not there was a disclosure. Participants in the disclosure conditions (M = 2.51, SD = 1.52) indeed indicated the post was a sponsored
advertisement significantly more than participants in the non-disclosure conditions (M = 4.21, SD = 1.85), t (75) = -4.41, p = .000.
Furthermore, to test if source credibility was correctly manipulated, the answers to all questions regarding source credibility were measured. Participants’ scores on source
credibility were assessed using five items, as it was in the pretest (Harmon and Coney, 1982; Gotlieb and Sarel, 1991; Grewal et al., 1994; Lafferty and Goldsmith, 1999; Buda and Zhang, 2000). The 5-item scale proved reliable as indicated by a Cronbach’s Alpha of .92 (M = 3.50, SD = 1.20). An exploratory factor analysis indicated that the scale was unidimensional (EV = 3.79), explaining 75.69% of the variance. An independent samples t-test indicated that participants in the high credibility conditions (M = 2.99, SD = 1.19) regarded the source as significantly more credible than participants in the low credibility conditions (M = 4.02, SD = .98), t (75) = -4.09, p = .000. Therefore, it can be concluded that the manipulations
successfully came across as intended.
Control variables. To ensure no other variables, apart from the independent variable, may affect the dependent variable, possible control variables were examined. First of all, 87% of participants indicated they were not familiar with the brand, SEGOLDA, beforehand. This result seems to verify that the brand was unknown to most participants, as was intended. However, since in some cases previous brand knowledge existed, it must be examined if this variable influenced any results. To the question “Were you already familiar with the brand SEGOLDA in the post?” participants could answer yes or no. An independent sample t-test was conducted to examine if different levels of brand knowledge existed for the source credibility conditions or disclosure conditions. The first independent sample t-test indicated
that the level of brand knowledge among participants in the high source credibility condition (M = 1.95, SD = .22) did not significantly differ from the participants in the low sources credibility conditions (M = 1.82, SD = .39), t (58.36) = 1.82, p = .074. A second independent sample t-test indicated that the level of brand knowledge among participants in the disclosure conditions (M = 1.87, SD = .34) also did not significantly differ from the participants in the non-disclosure conditions (M = 1.89, SD = .31), t (75) = -.31, p = .758. Therefore, it can be stated no significant relationship occurred between brand knowledge and the conditions, so the variable does not have to be controlled for.
The same was done for the variable age. An independent sample t-test indicated that the age of the participants in the high source credibility conditions (M = 23.67, SD = 2.61) did not significantly differ from that of the participants in the low credibility conditions (M = 24.08, SD = 2.42), t (75) = -.72, p = .475. Additionally, the second independent sample t-test indicated that the age of the participants in the disclosure conditions (M = 24.05, SD = 2.59) also did not differ significantly from the age of the participants in the non-disclosure
conditions (M = 23.68, SD = 2.45), t (75) = .64, p = .525. Therefore, the variable of age also does not have to be controlled for.
Hypotheses testing. An independent sample t-test was conducted to assess if H1 can be assumed: if high source credibility results in more positive brand attitudes than low source credibility. It must be noted that in this experiment lower scores of brand attitude indicate a more positive brand attitude and higher scores indicate a more negative brand attitude. The independent sample t-test indicated that the difference in mean brand attitude displayed in the high source credibility conditions (M = 3.16, SD = 1.19) was not significantly different from participants in the low source credibility conditions (M = 3.26, SD = 1.09), t (75) = -.36, p = .721. It must be concluded that high credibility Social Media Influencers posting (sponsored)
content on Instagram seems not to lead to significantly more positive brand attitudes among consumers and therefore H1 must be rejected.
Next, H2 was tested and thus if providing disclosures has a negative effect on brand attitude. An independent sample t-test was conducted and indicated that the mean brand attitude in the disclosure conditions (M = 2.98, SD = 1.17) was not significantly different from the mean brand attitude in the non-disclosure conditions (M = 3.45, SD = 1.07), t (75) = -1.83, p = .072. Therefore, H2 must also be rejected since it seems providing a disclosure in a sponsored Instagram post by a Social Media Influencer does not lead to significantly less favourable brand attitudes among consumers.
A two-way ANOVA with the source credibility and disclosure conditions on brand attitude was conducted. This was done to uncover if perhaps an interaction effect between source credibility, disclosures and brand attitude occurred even though no significant main effects were found, thereby testing H3. No significant interaction effect between the
conditions and brand attitude was found, F (3, 73) = 1.21, p = .314, thereby also rejecting H3.
Conclusion and discussion
This study examined the effects of both SMI source credibility and disclosures through sponsored Instagram posts on consumers’ brand attitude and how both concepts interact to influence brand attitudes. Although a theoretical analysis suggests a positive effect between high source credibility and brand attitude (more so than for low source credibility) as well as a negative effect of disclosures on brand attitude and on the positive effect of source credibility on brand attitude, neither claims are supported by the current research.
The first hypothesis was as follows: SMI with high source credibility posting sponsored advertisements on Instagram lead to more positive brand attitudes, compared to SMI with low source credibility. This hypothesis was rejected. The mean brand attitude among participants
in the high source credibility did not differ significantly from the mean brand attitude in the low source credibility condition. It can consequently be concluded that high credibility Social Media Influencers posting (sponsored) content on Instagram seems not to lead to significantly more positive brand attitudes among consumers. It seems that the internalization process that theoretically leads consumers to take over the opinion of the credible source, did not occur in the current study. Therefore, the message could have lost effectiveness, which could have weakened the positive effect of a highly credible source on brand attitude.
The second hypothesis concerned disclosures and stated that sponsored advertisements on Instagram with disclosures negatively affect brand attitudes, compared to sponsored
advertisements on Instagram without disclosures. This hypothesis also had to be rejected. In this case, the mean brand attitude among participants in the disclosure condition did not differ significantly from the mean brand attitude in the non-disclosure condition. Next, the third hypothesis was tested and there was no interaction effect found between source credibility and disclosures on brand attitude. This leads to the conclusion that providing a disclosure in a sponsored Instagram post by a Social Media Influencer does not lead to less favourable brand attitudes among consumers or negatively affect the relationship between source credibility and brand attitude. According to the Persuasion Knowledge Model (Friestad and Wright, 1994), participants in the disclosure conditions should have experienced an activation of their persuasion knowledge, which would lead to less favourable brand attitudes. It is difficult to conclude, based on this study, if persuasion knowledge was not activated among these participants, or if it perhaps was active among all participants and they were all aware of persuasion attempts taking place because persuasion knowledge was not measured. Further research should examine this by adding persuasion knowledge as a dependent variable and by measuring the levels of persuasion knowledge among participants.
The current study has indicated that the participants’ age or their existing level of brand knowledge did not have an effect on the outcomes. It is possible that publication bias has affected this study. Publication bias entails that a number of studies are not published because they do not fit certain criteria, such as having significant results (Dickersin, 1990). Perhaps similar studies have been done before and have reported non-significant results as in the current study, but were never published. In this case it would have been helpful to have access to such studies, if indeed they exist. This still leaves us to wonder how future research could further improve this experiment.
First, research on product types in advertisements suggests that different products lead to different effects among consumers. According to the FCB grid by Vaughn (1980) the level of involvement of the consumer with the product as well as whether they rely on thinking or feeling when making a product choice, are important in determining what sort of advertising strategy suits the product best. In this study a jewellery brand was used and according to the FCB grid, jewellery and fashion are high involvement/feeling products. In such a case, consumers seek ego gratification, which entails the need to express one’s personality (Van den Putte, 2008). For such products an effective advertising strategy must be used, which aims at relating the brand to the personality of the consumer. However, in this experiment the Instagram post did not focus on the consumer’s personality, but rather on the source or Social Media Influencer since a sponsored Instagram post concerns the source, not the consumer. Perhaps in similar research conducted in the future, one should opt for products in the FCB grid’s low involvement/feeling quadrant. These products, e.g. chocolate, are based on sensory gratification, which calls for a satisfaction strategy that stresses how the brand stimulates personal satisfaction (Van den Putte, 2008). This might be more in line with a Social Media Influencer posting about a brand or product, because it often shows them using the product or explaining that they like the product and why. This positive brand image might then spill over
to consumers, as has been proven by the halo effect for various types of products (Chernev and Blair, 2015). Previous research on source credibility is not consistent in products choices when relating the products to the FCB grid. Low involvement products such as nutritional bars have been used (Priester and Petty, 2003), as well as high involvement products such as videocassette recorders (Gotlieb and Sarel, 1991; Grewal et al., 1994). Due to this
inconsistency, it might be wise to follow the FCB grid and opt for low involvement/feeling products.
Second, different dependent variables might result in different findings. As mentioned, adding persuasion knowledge as a variable would be a valid improvement for future research. Additionally, research on advertisements suggests that brand recall might be a legitimate dependent variable as well. Brand recall is a widely used outcome variable in studies regarding advertising (Schmidt and Eisend, 2015). Based on Learning Theory, Schmidt and Eisend (2015) suggest that when consumers process information, they establish associations to link new information they are given to information and experiences they have already stored in their memory. Learning Theory expects consumers to recall information, in this case a brand mentioned in an advertisement, more easily the more often the information is
provided to them. Repeated exposures to an advertisement would therefore be likely to lead to positive brand recall. In the current study a single exposure was used, but perhaps future research should employ brand recall as a dependent variable and add more exposures of the Instagram post.
It can be concluded that the current study has laid the groundwork for future research on source credibility of Social Media Influencers posting on Instagram, the effect on
consumers’ brand attitudes and the role disclosures play in this effect. Further research is required to provide more insight into these effects and perhaps it would be wise to employ the abovementioned improvements. The findings from future studies could add to the literature
that already exists on the topic as well as determine the position brands and Social Media Influencers should take regarding disclosures and if these disclosures are indeed unfavourable for both parties, as it possibly discredits the Social Media Influencers and leads to less
favourable brand attitudes among consumers. Since rules and regulations regarding
disclosures on social media are being formulated but not yet completely in place as of today, it might be prudent to conduct such studies in a timely fashion.
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Appendix A
Pretest questionnaire
Dear participant,
Thank you for filling in this short survey, which serves as the pre-test for my Master thesis. The information you provide through this survey is completely anonymous, will solely be used for scientific purposes and will not be provided to any other (third) parties.
By clicking on the ‘Next >>’ button below, the survey will begin. The progress bar on the bottom of the screen will indicate how far along in the survey you are. It is a short survey and therefore will not take up any more than about 5 minutes of your time.
Beware that you cannot go back to previously filled in answers during the survey. Thank you in advance,
1. How old are you? ……… years old
2. Select your gender: 0 female
0 male
3. What is your highest level of education? 0 Primary school 0 VMBO 0 HAVO 0 VWO 0 MBO 0 HBO 0 WO
4. Are you currently a student? 0 Yes
0 No
5. Are you familiar with Instagram? 0 Yes
6. Do you have an Instagram account? 0 Yes
0 No
7. Do you use Instagram? 0 Yes
0 No
8. How often to you use Instagram?
Once a month
Once a week
Once a day
Multiple times a day
9. How many people do you follow on Instagram (estimate)?
0 – 25
25 – 50
50 – 100
100 – 500
500+
10. Do you follow brands on Instagram? 0 Yes
11. Do you follow bloggers on Instagram? 0 Yes
0 No
(Qualtrics randomizer selects one of four possible conditions)
12. You will now view an Instagram post from fashion blogger Lizzy van der Ligt. She has been a professional blogger for over 4,5 years and has a Bachelor degree in allround styling from the leading fashion academy in the Netherlands, Academie Artemis, in Amsterdam.
High source credibility + disclosure High source credibility + no disclosure
OR OR
12. You will now view an Instagram post from fashion blogger Milou Knierim who has a blog called Amsterdam Style Hunter. She is a Bachelor Law student at the Vrije Universiteit in Amsterdam and has just started her fashion blog a few months ago.
Low source credibility + disclosure Low source credibility + no disclosure
OR
13. Do you find the blogger who posted the Instagram picture: Trustworthy 0 0 0 0 0 0 0 Not trustworthy Good 0 0 0 0 0 0 0 Bad
An expert 0 0 0 0 0 0 0 Not an expert Experienced 0 0 0 0 0 0 0 Not experienced Trained 0 0 0 0 0 0 0 Untrained
14. Indicate the extent to which you agree/disagree with the following statement: The Instagram post is a sponsored advertisement.
Strongly agree 0 0 0 0 0 0 0 Strongly disagree
15. Why do you think the Instagram post is / is not a sponsored advertisement?
……….. ………...
16. Were you already familiar with the brand (SEGOLDA) in the posts? 0 Yes
0 No
Appendix B
Experiment questionnaire
Thank you for showing interest in participating in this study. Please read the description below carefully.
The following questionnaire was created as part of the Master's thesis conducted by a student at the University of Amsterdam. The aim of this study is to research the effectiveness of Instagram posts.
In a minute, you will read a text about a fashion blogger and see an Instagram post by this blogger, followed by a number of questions with regards to the blogger and the Instagram post. Please read the text carefully and take your time to look at the Instagram post before you answer all the questions.
The progress bar on the bottom of the screen will indicate how far along in the questionnaire you are. This questionnaire will take approximately 5-10 minutes to complete. Beware that you cannot go back to previously filled in answers during the questionnaire.
Please read the following statement carefully and accept the research conditions:
I hereby declare that I have been informed in a clear manner about the nature and method of the research.
I agree, fully and voluntarily, to participate in this research study. With this, I retain the right to withdraw my consent, without having to give a reason for doing so. I am aware that I may halt my participation in the study at any time.
If my research results are used in scientific publications or are made public in another way, this will be done such a way that my anonymity is completely safeguarded. My personal data will not be passed on to third parties without my express permission.
If I wish to receive more information about the research, either now or in the future, I can contact kim.vanstokrom@student.uva.nl. Should I have any complaints about this research, I can contact the designated member of the Ethics Committee representing the ASCoR, at the following address: ASCoR secretariat, Ethics Committee, University of Amsterdam, Postbus 15793, 1001 NG Amsterdam, 020-5253680; ascor-secr-fmg@uva.nl.
Click on the button below to accept the conditions and ‘Next >>’ to participate in the study. 0 I understand the tekst presented above and I agree to participate in this research study
1. How old are you? ……… years old
2. Select your gender: 0 female
0 male
3. What is your highest level of education? 0 Primary school 0 VMBO 0 HAVO 0 VWO 0 MBO 0 HBO 0 WO
4. Are you currently a student? 0 Yes
0 No
5. Are you familiar with Instagram? 0 Yes
6. Do you have an Instagram account? 0 Yes
0 No
7. Do you use Instagram? 0 Yes
0 No
8. How often to you use Instagram?
Once a month
Once a week
Once a day
Multiple times a day
9. How many people do you follow on Instagram (estimate)?
0 – 25
25 – 50
50 – 100
100 – 500
500+
10. Do you follow brands on Instagram? 0 Yes
11. Do you follow bloggers on Instagram? 0 Yes
0 No
(Qualtrics randomizer selects one of four possible conditions) 12. Read the following text carefully.
You will now view an Instagram post from fashion blogger Lizzy van der Ligt. She has been a professional blogger for over 5 years and has a Bachelor degree in allround styling from the leading fashion academy in the Netherlands, Academie Artemis, in Amsterdam. Therefore, Lizzy is an expert in the field of both fashion as well as blogging. She has made a career out of her blog and is very successful.
High source credibility + disclosure High source credibility + no disclosure
OR
12. Read the following text carefully.
You will now view an Instagram post from a very new fashion blogger Milou Knierim who has a blog called Amsterdam Style Hunter. She is a Bachelor Law student at the Vrije Universiteit in Amsterdam and has just started her fashion blog a few months ago. She is not considered an expert in fashion and/or blogging since she has just started blogging and because she studies something completely different (than fashion) at her university. Her blog is just a hobby.
Low source credibility + disclosure Low source credibility + no disclosure
13. Describe your overall feelings about the brand (SEGOLDA) described in the Instagram post you just viewed.
Appealing 0 0 0 0 0 0 0 Unappealing Good 0 0 0 0 0 0 0 Bad
Pleasant 0 0 0 0 0 0 0 Unpleasant Favourable 0 0 0 0 0 0 0 Unfavourable Likable 0 0 0 0 0 0 0 Unlikable
14. To what extent was the Instagram post you just viewed a sponsored advertisement in your opinion?
Very much so 0 0 0 0 0 0 0 Not at all
15. Why do you think the Instagram post is or is not a sponsored advertisement?
……….. ………...
16. Do you find the blogger who posted the Instagram picture: Trustworthy 0 0 0 0 0 0 0 Not trustworthy Good 0 0 0 0 0 0 0 Bad
An expert 0 0 0 0 0 0 0 Not an expert Experienced 0 0 0 0 0 0 0 Not experienced Trained 0 0 0 0 0 0 0 Untrained
17. Were you already familiar with the brand (SEGOLDA) in the posts? 0 Yes
0 No
18. If you have any further comments about this questionnaire, please feel free to fill them in below.
……….. ………...
