Comments on anti-smoking public service announcements (PSAs) in online forums like YouTube degrade the persuasiveness of the videos - even if the comments are positive. PSAs lose their effectiveness when the public being protected is allowed to discuss.

Comments are controversial, and even science media is not immune. The problem is not spam, organizations can get rid of that by requiring a login. Contradictory comments are also a concern and so some popular websites that prefer to talk at the audience have banned comments by the public entirely.

They may be onto something, according to the results of a new paper - all comments were a detriment to the message. Humanities scholars had a group of nearly 600 adult regular smokers complete an online survey where they were told they were testing a new website where people can share health related video clips and PSAs. Everyone was shown and asked to respond to an equal number of anti-smoking PSAs. Each PSA had a carefully balanced mix of comments that were:

  • Positive and civil
  • Positive and uncivil
  • Negative and civil
  • Negative and uncivil
  • Mixed positive and negative comments
  • No comments, just PSAs

The results showed the PSAs with no commentary were rated the most effective overall. Any form of commentary – positive, negative and mixed -- made the PSA less persuasive.

"The most surprising finding from the study is that positive comments failed to improve PSA evaluation over the no-comment exposure to ads," the team writes.

They speculate that the pure existence of comments reduces the effects of the PSA in part because comments distracted the audience from the PSA's message. Those who watched the PSAs without any commentary had better recall of the PSA's content than those who read comments.

"The detrimental effect of comments […] seems to suggest anti-smoking PSAs would be better off without comments, especially if the PSAs are strong or if the target audience is somewhat ready to quit smoking," they write.

The power of audience participation via social media is clearly a double-edged sword. They note that a concerted effort to understand the influence of online commentary and social media is necessary to understand the way emerging media affect the public for good and for ill.

Published in the Journal of Computer Mediated-Communication.