The selection of celebrity endorsers is not an easy task; many scholars have tried to create models in order to help for the right selecting of celebrity endorsers. Hovland et al (1953) conceptually contributed one of the earliest models, which is Source Credibility Model. Afterwords, the Source Attractiveness Model (McGuire, 1985), the Product Match-Up Hypothesis (Forkan, 1980; Kamins, 1989, 1990), and the Meaning Transfer Model (McCracken, 1989) was presented through empirically researchers in turn.
The Source Credibility Model and Source Attractiveness Model are categorized under the generic name of Source Models since these two models basically show and reflect research of the Social Influence Theory/Source Effect Theory, which argues that various characteristics of a perceived communication source may have a beneficial effect on message receptivity (Kelman, 1961; Meenaghan, 1995).
The source credibility model is based on research in social psychology (Hovland and Weiss, 1951-1952; Hovland, Jani, and Kelley, 1953). The Hovland version of model present that a message depends for its effectiveness on the ‘expertness’ and ‘trustworthiness’ of the source (Hovland et al., 1953, p.20; Dholakia and Sternthal, 1977; Sternthal, Dholakia, and Leavitt, 1978), which means that information from a credible source (e.g.celebrity) can influence beliefs, opinions, attitudes, and/or behavior via a process called internalization, which occurs when receivers accept a source influence in terms of their personal attitude and value structures (Erdogan, 1999).
Expertness is defined as the extent to which a communicator is perceived to be a source of valid assertions and refers to the knowledge, experience or skills possessed by an endorser. Hovland et al (1953) and Ohanian (1991) believed that it does not really matter whether an endorser is an expert, but all that matters is how the target audience perceives the endorser. However, Aaker and Myers (1987) advocated a source/ celebrity that is more expert to be more persuasive and to generate more intentions to buy the brand (Ohanian, 1991). Hence, expert sources influence perceptions of the product’s quality (Erdogan, 1999).Meanwhile; Speck et al (1988) found that expert celebrities produced higher recall of product information than non-expert celebrities, even though the difference was not statistically significant. Moreover, celebrities’ professional accomplishments and expertise may serve as a logical connection with the products, and consequently make the endorsement more believable to consumers (Till and Brusler, 2000).
Trustworthiness refers to the honesty, integrity and believability of an endorser depending on target audience perceptions (Erdogan, 1999). Advertisers capitalize on the value of trustworthiness by selecting endorsers, who are widely regarded as honest, believable, and dependable (Shimp, 1997). Smith (1973) argues that consumers view untrustworthy celebrity endorsers as questionable message sources regardless of their qualities. Friedman, et al (1978) addressed that trustworthiness is the major determinant of source credibility and then tried to discover that likability was the most important attribute of trust. Thus, they recommended advertisers to select personalities who are well liked when a trustworthy celebrity is desired to endorse brands. However, Ohanian (1991) found that trustworthiness of a celebrity was not significant related to customers’ intentions to buy an endorsed ethnic status could affect endorser trustworthiness and brand attitudes, because people trust endorsers who are similar to them. Their findings implied that when targeting particular ethnic groups such as Africans and Asians, ethnic background should be carefully evaluated.
Measuring source credibility in selecting celebrity
It is quite reasonable to make sense that a source’s credibility is totally subjective, but research shows that in spite of individual preferences, a high degree of agreement exists among individuals (Berscheid et al, 1971). Patzer (1983) developed the Truth-of-Consensus method to assess a source’s credibility and attractiveness. The method is based on the foundation that individual’s judgments of attractiveness and credibility are naturally subjective, but these judgments are shaped through Gestalt principles of person perception rather than single characteristics. Notably, on the basis of extensive literature review and statistical tests, Ohanian (1990) constructed a tri- component celebrity endorser credibility scale, (see figure) which assumes that credibility and effectiveness of celebrity endorsers is associated with given characteristic dimensions, even though McCracken (1989) argued that the celebrity world consists of much more just attractive and credible individuals.
Table 2: Source Credibility Scale