Communicator Effectiveness in Producing Public Conformity and Private Attitude Change.

One of the most widely held generalizabons m social psychology IS that the efiEectiveness of a persuasive communication IS mcreased if its source is "credible " The early research by Hovland and Weiss (1951) and by Kelman and Hovland (1953) which gave substance to this conclusion has recently been extended to demonsbate the efficacy of credible communicators even when the amount of change advocated is extreme (Aronson, Tumer, & Carlsmith, 1963) Credibility has been defined traditionally m terms of communicator atbibutes which are perceived by the audience as relevant to the topic bemg communicated Two of its major components which have been experimentally manipulated are the communicator's ability and his motives for personal gam, or what Hovland, Jams, and Kelley (1953) term "expertness" and "trustworthmess," respectively However, positive and negative source baits which bear no objective relevance to the topic of the commumcabon can also be effective m modifying attitudes toward its conclusions The potent effect of such irrelevant communicator characteristics has long been utilized m pracbcal mfluence situabons outside the laboratory by lawyers aware of the miportance of