When it comes to the public's understanding of the measles and vaccinations, what matters the most: Reports in the media? Statements from the Centers for Disease Control? Anonymous comments made online? 

Ioannis Kareklas, an assistant professor of marketing at Washington State University, has been looking into the question for a forthcoming paper in the Journal of Advertising.

Kareklas and his fellow researchers found that people were just as influenced by online comments from strangers as they were by PSAs from the Centers for Disease Control and Prevention on vaccines.

But the online comments didn't always hold equal weight. Kareklas explains that when online commenters were identified as either a doctor specializing in vaccines, a health care lobbyist, or an undergrad English major, the doctor's comments were more influential.

To hear the full interview with Ioannis Kareklas, click the link above.