ABSTRACT
According to Aristotle in the Rhetoric, a speaker's credibility is based on the receiver's perception of the speaker's intelligence, character, and goodwill (Cooper, 1932). Aristotle argued a speaker's credibility is the most powerful rhetorical strategy a speaker has when persuading an audience. In the last century, researchers have identified the following characteristics as defining credibility: caring, competence,
composure, dynamism, emotional stability, expertness, extroversion, sociability, and trustworthiness (Berlo, Lemert, & Mertz, 1969; Falcione, 1974 Hovland, Janis, & Kelley, 1953; McCroskey, 1966). Findings involving the study of credibility include that (a) organized speakers are viewed as more credible (McCroskey & Mehrley, 1969), (b) low credible sources can gain credibility by saying competent things (Wheeless, 1973), (c) speakers that handle questions effectively are considered more credible (Ragsdale & Mikels, 1975), and (d) credible speakers have a greater impact on their audience (Infante, 1980). One area of interest for communication researchers interested in studying source credibility is teacher credibility.
