STANFORD, Calif., Oct. 20 (UPI) -- A novice is more persuasive when expressing opinions with certainty but an expert is more persuasive when expressing uncertainty, U.S. researchers say.
Uma R. Karmarkar and Zakary L. Tormala of Stanford University presented study participants with a restaurant review from either a novice or an expert, and looked at how that source's expressed certainty or uncertainty about the review influenced the effects of the message.
"We predicted that mismatches between the source's level of expertise and the level of expressed certainty, or confidence, would lead people to be more persuaded by a good and compelling review," the study authors said in a statement."In other words, a novice would be more persuasive when he expressed certainty about his opinions, whereas an expert would be more persuasive when he expressed uncertainty."
The study, published in the the Journal of Consumer Research, said participants found the restaurant review more surprising and unexpected when a novice reviewer expressed certainty, or when an expert reviewer expressed uncertainty.
"Investigating further, we found that when the level of certainty expressed was incongruent with the source's expertise, it increased involvement with the restaurant review," the researchers said.
