The Persuasive Effectiveness of Famous and Non Famous Endorsers in Advertising

This research aims to compare the persuasive effectiveness and attitudes change induced in the case of famous and non famous endorser in advertisement. An experimentation was conducted by 290 tunisian women. Our empirical results showed that the non celebrity spokesperson was more credible and generated more favourable attitudes towards advertising, brand and purchase intent than celebrity spokesperson.


Introduction
To use an endorsement by celebrities is not a new phenomenon (Mehulkumar 2005).During, more than 50 years the advertising sector had used celebrities, Marilyn Monroe and Marlène Dietrich are famous examples (Iddiols 2002).This endorsement strategy owes its popularity to the development of radio advertising in the 30s, and the TV advertising in the 50s, so the cinema widened the extent of this strategy (McDonough 1995).In the late 70's, this strategy continues to develop in a remarkable way.Today, the endorsement by the celebrities became a full element of the Marketing communications strategies (Erdogan 1999).

Numerous researches
have proved empirically the effectiveness and the positive influence of the endorsements by the celebrities in advertising, particularly on endorser's credibility, message reminder, announcements approval and purchase's intention (Menon 2001, Pornpitakpan 2003, Pringle and Binet 2005, Roy 2006).
Of the fact their potential advantages in term of attention and reminder to message (Ohanian 1991, O'Mahony andMeenaghan 1997) celebrities endorsement can present a high risk and "no win situation" (celebrities's surrounding scandals, as those of Michael Jackson, Kate Moss and Britney Spears).Some advertiser favour non famous endorsers.Tom and al (1992) noticed that created endorsers were more effective in creating a link to the product than celebrity endorsers.This requires a more detailed study of endorsement's strategy.
The objective of our research is to study: "Which strategy is most adapted through a televised advertising, in the case of a famous and non famous endorser?" We will tend to answer two principal interrogations: -What are the specific characteristics of celebrity and non celebrity which influence endorser's effectiveness in term of credibility, expertise and attractiveness?
IBIMA Business Review 2 -What is the persuasive process by which an endorser (celebrity / non celebrity) affectattitude toward advertising, attitude toward brand and intentions to purchase in TV advertising

Literature review
According to McCracken (1989) definition "a celebrity endorser is a person who enjoys the public recognition and who uses this recognition in the name of goods while appearing with this one in advertising".
In the literature, two general models are often used to study celebrities endorsement effectiveness in advertising.At the beginning of the 50's, Hovland and his associates were turned to source's credibility model and to source's attractiveness model (McGuire 1968).

The source credibility model
A source is a person or an organization disseminating a message.The source's credibility is "the degree to which a viewer perceives the source to possess knowledge or an appropriate experience and do not provide biased information".Thus, two fundamental dimensions of source's credibility are: expertise and trustworthiness (Hovland and Weiss 1951).
Expertise is defined as « the extent to which a communicator is perceived to be a source of valid assertions" (Hovland, Janis and Kelly 1953).The communicator has the ability to make these reports (Hovland and Weiss 1951).
At the beginning of the eighty year in a context of sale, the results showed that the expert salesman induced a number of consumers significantly higher to buy the product, that induced by the inexpert salesman (Woodside and Devenport 1974).Trustworthiness is defined as «the degree of confidence in communicator' intend to communicate the assertions that he considers the most valid» (Woodside and Devenport 1974).
In certain circumstances the high source credibility and expertise were demonstrated to carry out a greater effectiveness (attitudes change and behavioral intention) that a low source credibility (Crano 1970, Kelman and Hovland 1953, Ross 1989).Other studies proved that there is no relationship between the expertise or the credibility level and the communication effectiveness (Bergin 1962, McGarry andHendrich 1974).
This literature review leads us to put the first two hypotheses: H1: Perceived endorser credibility has a positive significant effect on: • H1.1.the attitude towards the advertising, • H1.2 the attitude towards the brand, and H1.3 the intention to buy.
H2: Endorser expertise has a positive significant effect on: • H2.1.the attitude towards the advertising, • H2.2. the attitude towards the brand, H2.3. the intention to buy.
By using a perceptual judgment and operating the source expertise dimension, Crano (1970) showed that the subjects exposed to an expert source show more advertising appreciation than those exposed to low expertise treatment.
While a certain support was shown for the positive relationship between the source credibility and persuasion, other studies indicates that the high source credibility has not a greater persuasion as consequence (McGarry andHendrich 1974, Rhine andLaurence 1970).The studies on credibility which concentrated on the expertise dimension, also failed to indicate the positive relationship between expertise and persuasion (Johnson and Steiner 1968).

The source attractiveness model
The source attractiveness model is a component of the "source valence" (McGuire 1968).This model showed that the communicator's message effectiveness depend on source "familiarity", "sympathy" and "similarity" with the receivers.
Similarity is the "degree to which a source is perceived as similar to the audience in terms of attitudes, opinion, activities, interests or lifestyle» (O'Mahony and Meenaghan 1997).
Many young male athletes are regarded as attractive sources with the same teenagers's genre.Familiarity is " the extent to which the audience members feel that they know endorser".Sympathy refers to the "presence or absence of the feelings which the message receiver would have towards the source information" (O'Mahony and Meenaghan 1997).
The physical attractiveness, the lively personality and the charisma play in the source agreement aspect.Baker and Churchill (1977) noted that the use of attractive characters has a positive influence on the emotional reactions of advertising, contrary to the cognitive and conative reactions which prove to be negative.However, Petroshius and Crocker (1989) and O'Mahony and Meenaghan (1997) stipulated that attractive characters used in advertising lead to a more favourable attitude towards the advertising and to high purchasing intentions.The hypothesis 3 is then the following one: H3: Perceived endorser attractiveness has a positive significant effect on: • H3.1.the attitude towards advertising, • H3.2. the intention to buy.Kamins (1990) affirmed that an attractive celebrity is likely to be a particularly effective source of public image, because of the duel advantage: its celebrity statute and its attractiveness.In this same register, Joseph (1982) declares that the physically attractive celebrities exert a positive effect on the evaluations and product's opinions.On the other hand, two other studies ( Caballero and Solomon (1984), Cabballero, Lumpki and Madden 1989) did not make it possible to detect an effect for the human model attractiveness and that human people with low/ moderate/ and high attractiveness do not affect the purchasing intention.
The two models have a major importance in the explanation of attributed characteristics to celebrities communicators, but certain the following authors McCracken (1989), Walker and al (1992) come to demonstrate the limits of these two models.

Importance of source's characteristics on persuasion: the role of expertise and similarity
Because of their considerable importance, communicator's characteristics (famous or not famous) "can increase or decrease the message potential to carry out attitude's or belief change" (Wilson and Sherell 1993).As we quoted already higher, for the credibility's characteristic, many research affirmed the principal effect of a credible source, and that « more the source is credible, more the message is persuasive" (Hovland andWeiss 1951, Kelman andHovland 1953).
In their recent research, Goldsmith, Lafferty and Newell (2000) noted that "endorser credibility has an impact on the attitude towards advertising".
Of their share, O'Mahony and Meenaghan (1997) proved that "credibility towards communicator had the greatest impact on the purchase intention".In fact, endorsers which were considered to be very credible generated a high intention to buy the product.Ohanian (1991) also examined the impact of attractiveness, expertise and trustworthiness towards celebrities and respondents intention to buy the product.It found that attractiveness and trustworthiness towards celebrity were not related to purchase, without worrying if IBIMA Business Review 4 the purchase was for a personal use or a gift.However, expertise dimension was significantly linked with purchase.
A main interest was proven for the similarity characteristic with the endorser's message.Research contradictory results were also reported for similarity and its impact on persuasion.For example, Brock (1965) showed that similar sources achieve a higher behavioural change than the non similar sources.
As for Stafford (1998), he postulated that the intense similarity can, in fact, increase perceived confidence and credibility of endorser.
The similarity expresses a variety of characteristics including the age, the gender, the social class, the educational level, the profession (Feick and Higgie 1992).Alpert and Anderson (1973) examined the agreement degree between airline's companies and awarded declarations to various sources.A source moderate similarity with respondents carries out a high agreement degree, indicating that non optimal similarity could exist and generate a very effective communication.Leavitt and Karen (1975), also, reported a high agreement level in the presence of a source considered little similar, than that extremely similar.

The Meaning transfer model
According to McCracken (1989), these models do not take into account adequate distinctions between celebrities because those who are relatively similar in their credibility and attractiveness can produce various effects.According to McCracken, the source attractiveness and credibility model do not explain in detail "match-up" between celebrity and specific product or product category.He affirms that the combination of other factors such as cultural significances is important.Every celebrity represents a class, a statute, a personality, a lifestyle and a cultural category of gender and age, which are different for each endorser.

According
to McCracken (1989), practitioner and researchers should concentrate on "the cultural significance" that each celebrity has.Walker, Langemeyer and Langemeyer (1992) stressed that if celebrity endorser can indeed transmit its image to the products; there are limits to the final impact.For example, "the significance transferred by the mean of a celebrity is not necessarily translated into purchase intention" (p41).
In other words, although a celebrity can modify the perception toward the brand, that does not always lead to high level of sales.Furthermore, this meaning transfer may only occur with brands which have indefinite images.These critics interested the researchers to develop other ideal models such as the match-up hypothesis to answer as well as possible at appropriate fit between endorser and product.

Effectiveness of celebrity endorser compared to a non celebrity endorser
A recent evaluation indicates that almost 20% of all the advertisements in the whole world employ celebrities as spokespersons.Almost all the advertisers believe that "the messages transmitted by celebrities provide a higher degree of call, attention that those delivered by the non famous ones" (Cooper, 1984).Atkin and Block (1983) found that a famous communicator in advertising for an alcohol brand generate more favourable affectives responses than non famous communicator.However, advertising's credibility was higher under the condition of non famous communicator.
Of its share, Erdogan (1999) has concludes in the light of academic results that "famous endorsers are more effective than the non famous ones to influence the attitudes towards: advertising, endorsed brand, and purchase intentions.However, advertisers should use well celebrities who are congruent with brands and target public".We can put hypothesis 4 as follows: 5 IBIMA Business Review H4: Celebrity endorser has a more significant positif effect than a non celebrity endorser on : • H4.1 the attitude towards the advertising, • H4.2 the attitude towards the brand, H4. 3 purchase to buy.
However, Mehta (1994) postulated "that there was no significant difference for the concepts of attitude towards advertising, brand, and purchase intention for endorsed brands by celebrities and those endorsed by non celebrities".As for Mehta (1994), "once confronted to non famous endorsers, the consumers were significantly concentrated more on the brand and its characteristics, while with the famous endorser, the subject were significantly more concentrated on the celebrity in publicity" 1.6 Conceptual model

Research Methodology
We realized a quasi -experimentation which was led by 290 tunisian women having profile of present or potential consumer of the published products in TV advertising.This female target is old between 18 and 35 years.
Eight televised advertising for real brand had showed female spokespersons (famous / non famous) for 60 women.Two advertising were selected for our experimentation, which had the most raised scores and were appreciated better by respondents.The first television advertising showed a celebrity "Claudia Schiffer" endorsing an anti-wrinkle cream of «l'Oréal" brand.The second advertising exhibited a non celebrity "young girl" endorsing an anti-solar cream of "Olay" brand.As asserts it, Rossiter (1982) "televised advertising mobilize 100% of individual's attention, on the other hand printed advertisements attract only 46% of attention".To test reactions and attitudes which can be generated by real televised publicities, we had chosen the most seen spots by tunisian viewers from Arabic channels: "LBC and MBC" (according to SigMag on 2006)1 .
The choice of real and familiar endorsed brands is justified to eliminate the artefact risk of the tested advertisements.This goes against certain researchers such as Muehling and Lacziniak (1988) who privileged advertisements with fictitious brand names to not bias study's results.

Choice of product's category
Our choice of product's category is explained by the fact that products of care and beauty included products to solve imperfections and defects of consumer's appearance (Brower and Landreth 2001).We can quote the care -body products, face or hair.This category occupied the second position after product food as regards investment in Tunisia (SigMag, May 2006).This confirms our published product's choice in the two commercials advertising: an anti-wrinkle cream and an anti-solar cream.

Choice of female sample
To respect the similarity between the endorser gender (celebrity/ non celebrity) and female respondents, we wished to not vary the celebrity sex and to choose televised advertisements with a female spokesperson promoting a product for a female use.What only confirms the choice of a women population.

Choice of age bracket
As we do not have a sounding base, the sampling method by convenience is adopted.
Our choice of this method is explained by the fact that it is simple and practical to use, also we tried to exceed some limits met in the previous researches which consisted in targeting students considering their availability.We want to touch all the possible categories (students, liberal profession, employee, executive, worker, housewives), where an age bracket between 18 and 35 years is selected to represent all these categories as well as possible.

Choice of sample's number
To guarantee good population representativeness, the sample size is determined in the following way given (Roussel and al 2002).N= n × 10 with N= sample size n = number of items By applying this formula, our sample is composed of 290 women.

Experimental procedure
The experimentation is carried out by a laptop and a high speaker.The visited places are varied: a sporting room, a hairdresser for woman, an aesthetician, primary school teachers, teachers in university.This variety of places allows us to meet groups of the women with different ages and professional socio-categories.
Respondents were exposed at two experimental conditions: each respondant is exposed to the first televised advertising presented by a celebrity, once she finishes to fill the first questionnaire, she will be exposed to the second televised advetising presented by a non celebrity.Each questionnaire is auto-managed and lasts approximately 15 minutes.

Validity of chosen scales
The measurement scale of each concept used in our model was taken from literature.Some of them were subject of French adaptations, whereas others were translated from English by "Back to back translation" technique by two bilingual people.We present the operationalization of constructs as following : Independent variables -To measure the celebrity's credibility, we used the credibility scale developed by Ohanian (1990).The source credibility scale is characterized by three dimensions: expertise (Coefficient Alpha = 0,893), attractiveness (coefficient alpha = 0.832) and reliability (coefficient alpha = 0.832).Each of source credibility dimensions is composed of 5 items measured on a bipolar scale on 7 points.We evaluated 15 items on a semantic differential scale on 7 points.

Dependent variables
-To measure attitude toward advertising, we use scale of Baker and Churchill (1977).This semantic differential scale is composed of 11 items measured on 7 point.It is a three-dimensional scale in the literature and characterised by affective, cognitive and conative attitudes.A principal component analysis with varimax rotation was conducted.Three items that represent cognitive attitude were eliminated from the scale because they represented poorly the studied phenomenon.Their elimination has also contributed to increase alpha's coefficient of attitude's scale (alpha = 0.877) which is very satisfactory.For affective attitude (Coefficient Alpha = 0,868) and conative attitude (Coefficient Alpha = 0,938).
-To measure attitudes toward the brand in advertising, we use the scale of Till and Busler (2000).This scale is composed of 3 items and allows a Cronbach alpha with good value equal to 0.904, which is very satisfactory.

Conclusion
Our research showed the persuasive power of non famous endorser's credibility as a major asset to reinforce advertising effectiveness.The advertisers should exploit it in their messages, to guarantee a favourable attitude toward advertising and the promoted brand of the target public.
We agreed that famous endorser strategy is used in international scale, considering its effectiveness and its repercussions of sale which it generates.
Hence, our research demonstrated that non celebrity endorsement is more appreciated than celebrity endorsement and induced more positive attitudes.What questions the frequent and increasing use of famous endorsers.Until this level, we can affirm that "match-up " between endorser and receiver is a determining factor for advertising's persuasive effectiveness.

Research limits
Our research presents some limits which touch conditions exposure and familiarity with the brand presented in the selected TV advertisements: -Although the two TV advertising were chosen and presented under favourable conditions, an absence of natural exposure took place: considering the lack of insertion of a televised program in our experimentation.This lack can increase the attention degree at answering, which can be considered to be higher in the event of natural exposure.
-Familiarity with brands presented in the two advertising (the first brand of " l'Oréal "presented by Claudia Schiffer and the second brand of "Olay" presented by a non famous endorser), can present cognitive bias in term of attitude toward the promoted brand.
-An external validity problem, considering our sample is chosen by convenience.But, according to Thiétart and all. (2003) the internal validity is priority.
Research perspectives 1-Examine in the case of celebrity and non celebrity, attitude towards an unknown brand for other product categories and see the impact of affective, cognitive and conative attitudes it can generate.2-Study the possible role of famous and non famous spokesperson presence with other advertising strategies such as the emblem and allegory for identifying the persuasive impact which it can generate.3-Enclose other variables such as age, gender, involvement toward the product.

Fig 1 .
Fig 1. Conceptual model and research hypotheses

Table 1 .
Distribution of respondents

Table 2 :
Effect of credibility on attitude toward advertising

Table 3 :
Effect of credibility on the attitude to brand

Table 4 :
Effect of credibility on the intention to buy

Table 5 :
Effect of expertise on the attitude toward the advertising

Table 6 :
Effect of expertise on the attitude towards brand

Table 7 :
Effect of expertise on intention to purchase

Table 8 :
Effect of attractiveness on attitude toward the advertising

Table 9 :
Effect of attractiveness on intension to purchase

Table 10 :
Effect of the presence of celebrity endorser compared to a non celebrity endorser on