Comparative advertising effectiveness: the role of involvement and source credibility.

Comparative advertising is advocated as an effective method of communicating benefits of new brands (Droge and Darmon 1987; Murphy and Amundsen 1981). Although practitioners have shown increased interest in using comparative advertising (Phillips 1983; Shimp and Dyer 1978). Empirical evidence concerning its impact is inconsistent and remains controversial (Ash and Wee 1983; Belch 1981; Demirdjain 1983; Gorn and Weinberg 1984). This inconsistency suggests the need to identify conditions where comparative advertising is likely to be more persuasive than non-comparative advertising (Shimp and Dyer 1978) for new and/or unfamiliar brands.

Lack of credibility is a major explanation for the inconsistent persuasive impact of comparative advertisements (Belch 1981; Boddewyn and Marton 1978; Levine 1976; Swinyard 1981). Attribution theory suggests that a message lacking in credibility will be discounted and will not be very persuasive (Kelly 1967, 1972). Therefore, to understand the role of credibility in comparative advertising, the following issue must be resolved: Will the use of other external stimuli, such as sources of higher credibility, enhance the persuasive impact of comparative advertising?

Researchers have also suggested that an evaluation of a comparative advertisement may require a higher hevel of involvement than may be present within many consumers (Wilson and Muderrisoglu 1980). Involvement has been defined as personal relevance (Petty and Cacioppo 1986; Salma and Tashchian 1985). Higher involvement might be necessary to motivate a consumer to make the cognitive effort required to fully process and evaluate the comparison of two brands. While higher involvement might be required for a comparative advertisement to be more persuasive, researchers are unclear whether comparative advertisements actually activate higher involvement. If higher involvement is required but is not always activated by comparative advertisements, then the use of other message stimuli to increase involvement should be examined. Therefore, to understand the role of activated and required involvement in comparative advertisement two issues must be resolved. First, does a comparative advertisement activate a higher level of involvement than a non-comparative advertisement? Second, when other message stimuli increase involvement, is a comparative advertisement more persuasive than a non-comparative advertisement?

The research reported in this paper provides empirical evidence which helps to fill three gaps in the literature. First, previously reported research has provided virtually no empirical evidence concerning differences between the effects of comparative advertisements and non-comparative advertisements on involvement. Second, earlier research provides no empirical evidence concerning differences between the effects of comparative advertisements and non-comparative advertisements when sources of varying credibility are included in the advertisements. Third, previously reported comparative-advertising research has not examined the differences between the effects of comparative and non-comparative advertising in instances when higher involvement is activated and higher credibility sources are included in the advertisements.

This paper reports the results of an experiment that was conducted to examine the questions discussed previously. Attribution theory provided the framework for the hypotheses tested in the experiment. The empirical evidence derived provides insight into the conditions under which comparative advertisements are likely to be more persuasive than non-comparative advertisements. Specifically, the role of required and activated involvement and source credibility are examined. Recommendations for future research are discussed in the final section of the paper.

Background

Involvement. Involvement has been identified as a variable significantly affecting the processing of information (Petty and Cacioppo 1979), and has been recognized as a good indicator of motivation to process the message (Celsi and Olson 1988; Petty and Cacioppo 1979; Zaichkowsky 1985). Researchers have suggested that involvement could be an important variable which mediates the effect of comparative advertising (Ash and Wee 1983).

There are at least two forms of involvement, issue involvement and response involvement (Leippe and Elkin 1987; Zimbardo 1960). Response involvement occurs when the subject is motivated to develop an attitude that can pass public scrutiny. Issue involvement occurs when the subject is motivated to develop an attitude that is consistent with the subject's values and goals (Zimbardo 1960). Construction-motivated involvement is a form of issue involvement, and occurs when individuals do not have an existing attitude, but find it necessary to construct a new attitude in a manner that is consistent with their values and goals (Leippe and Elkin 1987). The work of Leippe and Elin (1987) could be applied to comparative advertising. Their work suggests that construction-motivated involvement is activated when the recipient of an advertisement does not have a prior purchase intention, but is motivated to construct a purchase intention toward a new brand (i.e., when exposed to an advertisement for a new brand) in a manner which is consistent with the recipient's goals and values. Since the remainder of this paper examines differences between the effects of comparative and non-comparative advertising for a new brand, the balance of the paper …