Persuasion about Health Risks: Evidence, Credibility, Scientific Flourishes, and Risk Perceptions

Abstract

We explored the effects of evidence, credibility, style, and risk perceptions on attitudes toward the recommendations of persuasive health messages. The health messages concerned antibacterial soap, meningitis vaccination, and an over-the-counter diet drug. Respondents (N = 916) provided their perceptions of the messages' evidence, the source's intrinsic credibility, and severity of and susceptibility to risk. We found that the effects of credibility on attitudes were spurious, and that the apparent effects were entirely due to the messages' evidence quality. Severity and susceptibility influenced attitudes even in the presence of evidence effects. Evidence influenced the levels of perceived severity and susceptibility. The inclusion of scientific jargon and statistical information had no discernible effect on either attitudes or credibility. The results indicate that evidence quality should be a fundamental consideration in the design of health messages.

Key Words:

• persuasion
• evidence
• credibility
• risk
• health