ORIGINAL ARTICLE How to persuade adolescents to use nutrition labels: effects of health consciousness, argument quality, and source credibility

This study tested the utility of the Elaboration Likelihood Model (ELM) in creating effective public service announcements (PSAs) of nutrition label use. Students (N = 169) from a secondary school in Hong Kong participated in a 2 × 2 × 3 (health consciousness: high vs. low × argument: informational vs. testimonial × source: expert vs. celebrity vs. ordinary person) factorial design experiment. Hypotheses were partially supported. Main effect was located for health consciousness. Adolescents with high health consciousness were more persuaded by the PSAs. There was an interaction effect between health consciousness and source. A dietitian as the source was most persuasive to people with high health consciousness, while low health conscious people were most influenced by a celebrity. The information processing route was biased by the match of argument and source. Informative argument made by an ordinary person was more likely to motivate adolescents to use nutrition label, while testimonial argument made by a celebrity was the most effective. The findings are discussed in light of ELM hypotheses. Recommendations are also offered for public health communication campaigns.