Source credibility

Source credibility is "a term commonly used to imply a communicator's positive characteristics that affect the receiver's acceptance of a message." Academic studies of this topic began in the 20th century and were given a special emphasis during World War II, when the US government sought to use propaganda to influence public opinion in support of the war effort. Psychologist Carl Hovland and his colleagues worked at the War Department upon this during the 1940s and then continued experimental studies at Yale University. They built upon the work of researchers in the first half of the 20th century who had developed a Source-Message-Channel-Receiver model of communication and, with Muzafer Sherif, developed this as part of their theories of persuasion and social judgement.

Source credibility theory is an established theory that explains how communication's persuasiveness is affected by the perceived credibility of the source of the communication. The credibility of all communication, regardless of format, has been found to be heavily influenced by the perceived credibility of the source of that communication.

The idea of credibility was first derived from Aristotle who argued that the speaker's reliability must be built and established in speech and that what the speaker did or said before such a speech was not of importance. Aristotle divided the aspects of persuasion into three categories: ethos (credibility), pathos (emotion) and logos (logic). As credibility refers to people believing who they trust, emotion and logic indicate a person's emotional connection and means of reasoning to convince one of a particular argument and/or speech. The area of source credibility is studied for practical applications in communication, marketing, law, and political science.

There are several dimensions of credibility that affect how an audience will perceive the speaker: competence, extraversion, composure, character, and sociability. These dimensions can be related to French & Raven's five bases of power (see below). These characteristics are fluid and affect each other as well as the speaker's transactional credibility. One dimension may strengthen the speaker's credibility if he/she struggles in another.

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