Communicator credibility and persuasian.

Prior research has usually found a positive relationship between a communicator's perceived credibility and his persuasiveness. An experiment was designed to test the hypothesis that the perceived vested interest of a speaker, the position the speaker advocated, and the social similarity between audience and speaker would influence attributions of credibility and affect the speaker's persuasiveness. Three variables were manipulated in a 2 by 2 by 2 factorial design. Ss read a speech that either favored (pro) or opposed (con) student voting rights; the speech was attributed to a speaker who was either similar (student) or dissimilar (townie) to the stndent audience and who either had a vested interest (running for elective office) or had no vested interest (merely giving his opinion) :in the position he advocated. As predicted, the similarity of the speaker to the audience, the vested interest of the speaker, and the position advocated in the speech strongly influenced attributions of credibility. However, in contrast to much previous research, persuasion was found to be relatively independent of the variation in the speaker's perceived credibility. It was suggested that the failure of attributions of credibility to relate to persuasion may have been due to the high degree of ego involvement for the Ss in the topic of student voting rights.