Extrinsic credibility refers to the credibility a source is thought to have prior to the time he or she delivers the message. For example, if Ronald Reagan or Gloria Steinem gives a speech on your campus, his or her reputation will undoubtedly influence your evaluation of that speech. Similarly, if the top student in your class gives a speech, your previous impression of him or her affects your attitude toward the message.
There has been ample research on the influence of extrinsic credibility. The typical study involves the delivery of the same speech (sometimes tape-recorded for greater consistency) to several audiences but with the speaker introduced differently to each. For example, a taped speech (supposedly for a radio program) favoring lenient treatment of juvenile delinquents was presented to three separate groups of high school students, but the speaker was identified to one group as a juvenile court judge, to the second as a neutral member of the studio audience, and to the third as an audience member who had a criminal record and had been a juvenile delinquent himself. As might be expected, the speech that was supposedly delivered by the judge, a high-credibility source, was considered much fairer than the speech delivered by the ex-convict. The judge's speech also resulted in more attitude change than the ex-convict's (Kelman and Hovland, 1953).
A number of studies confirm that speakers with high credibility tend to have more influence on an audience's attitudes than do those with low credibility. One summary of the literature qualifies this statement with the observation that "the perceived-competence aspect adds to persuasive impact more than the trustworthiness aspect does. By competence we mean the perceived expertness, status, intelligence, etc., of the attributed source; by trustworthiness, we refer to his perceived disinterestedness, objectivity, and lack of persuasive intent" (McGuire, in Lindzey and Aronson, 1969 p. l87). But the credibility of the speaker does not seem to have a significant effect on the level of the audience's comprehension (Petrie, 1963). Credibility appears to be a more important consideration when we are persuading an audience than when we are informing them.
Extrinsic credibility may have another, more subtle effect on persuasion. Suppose that Cesar Chavez comes to your campus and that, in the middle of a discussion on how he organized the migrant farm workers' strikes in California, he goes into a long digression about religion or sex or even African art. On these topics his views may be no more authoritative than those of the person in the street. How much of his extrinsic credibility will be generalized to areas in which his expertise has not been demonstrated? Consider this question the next time one of your professors expresses strong opinions about a subject far removed from his or her field of specialization.
Date: 2015-02-16; view: 2057