Effect of source attribution on judgments of warning credibility and compliance likelihood (pp. 451-454)

Communication models frequently include the source of a message as an important detenninant of persuasion. However, research on the contribution of source characteristics to warning effectiveness is virtually non-existent. The present research investigated three types of sources: (1) specific regulatory governmental agencies (e.g., U.S. FOOD AND DRUG ADMINISTRATION), (2) specific scientific professional groups (e.g., AMERICAN MEDICAL ASSOCIATION), and (3) general statements in which an explicit source is not mentioned (e.g., IMPORTANT HEALTH WARNING). Participants rated 11 sources of the alcohol, cigarette, and iron supplement warnings on credibility and compliance likelihood. The results show that exemplars from the two types of specific sources made the warnings more credible and increased the compliance likelihood ratings compared to a signal word (WARNING) by itself. Having a signal word was better than no signal word. Implications for warning design are discussed.