Theories of Metaphor and Persuasion - Communicator Credibility

The enhancement of communicator credibility view proposes that communicators who use metaphors are judged more credible than those who use literal language. In turn, this enhanced source judgment leads to greater persuasion by marking the attitude towards the message advocacy more positive. This higher credibility judgment may occur for two related reasons. First, as Aristotle (1952), in his Poetics, argued, "But the greatest thing by far is to be a master of metaphor. It is the one thing that cannot be learned from others, and it is also a sign of genius (p.225). The assumption of this view is that metaphors are exceptional language and are like "ornaments" on the literal language that are used only by poets and writers, not by ordinary folks in everyday discourse. Thus, people who use metaphors are perceived as highly creative and are judged positively. The second reason is derived from metaphor's ability to point out previously unknown similarities between entities to a person. This newfound appreciation of commonalities is a source of interest and pleasure to the comprehender, who consequently is grateful to the message source, leading to the enhanced judgment of communicator credibility. In contemporary terms, the key idea of the communicator credibility view is that the source judgment may act as a persiasopm heuristic (Chaiken, Liberman, & Eagly, 1989). 

 

The communicator's credibility explanation was clearly not supported by the results of the meta-analysis, which showed that, on the whole, people do not judge metaphor-using communicators more favorably than they do those who use literal language. Another line of research on the effects of rebuttal analogy on receiver perceptions of communicators and message arguments corroborates this finding (Whaley, 1997, 1998; Whaley, Nocotera, & Samter, 1998). A rebuttal analogy serves two communicative functions: as a method of counterarguementation and as a method of social attack. Communicators who use such analogies are perceived as less polite, less ethical, and less competent, and their arguments are seen as less effective than those of sources who are nonanalogy messages. Thus, the view that use of metaphor prompts a positive source heuristic to be engaged, leading to greater persuasion, is not the right explanation. 

 

The assumption that metaphor is "exceptional language" is also not defensible. Metaphors are not mere ornaments on the literal language used only by poets and writers; rather, they are common in everyday language. For example, Pollio, Barlow, Fine, and Pollio (1977), after examining various psychotherapeutic interviews, essays, and the Kennedy-Nixon presidential debates, estimated that 1.80 novel metaphors and 4.08 dead metaphors were used per minute of discourse. Another study looking at metaphors in news and public affairs programs found that one novel metaphor was used for every 25 words (Graesser, Mio, & Millis, 1989). Thus, the use of metaphor does not seem to require any special genius. As such, there is little reason to expect its use to enhance the credibility, at least as related to the expertise and character, of a communicator.