Study shows that three, but not four or more, claims convince consumers

Politicians do well when they make three positive claims, but four or more arouse skepticism, according to a new study co-authored by a professor at the Georgetown University McDonough School of Business.

The study, published in the January 2014 issue of the Journal of Marketing, explores the "charm of three," in which three positive claims were found to create a more positive impression than two claims or four or more.

"Firms tend to believe their product is the best, which leads to a tendency among practicing marketers to present as many compelling claims as possible," says Kurt Carlson, associate professor at Georgetown who co-authored the study with Suzanne Shu of UCLA's Anderson School of Management. "But there is danger to that, as consumers' awareness of persuasive intent will convert into skepticism, causing the consumer to discount all claims."

The Power of Three

Whether it's a corporation selling a product, a politician running for election, or a firm promoting new services, there is a tipping point of positive claims for target audiences, he says.

Carlson says the study provides invaluable insight into consumer perceptions, inferences, and persuasion techniques, as well as prescriptive advice to improve messaging.

"We had previously examined how observing three events in a row was all it took for people to believe they were seeing a trend," Carlson says. "We surmised a similar pattern might exist in discourse involving persuasive claims. And it turns out we were right."

Previous research shows that people are predisposed to think of three items as a complete set. A 2007 study by Carlson and Shu found that "people reached their maximal willingness to infer that a sequence of events was a streak after witnessing a third event, be it the third time a coin landed on heads, the third basketball shot made, or the third day a stock closed up."

Try, But Not Too Hard

Consumers say that four or more positive claims communicates that the persuader is trying too hard to create a positive impression, the professor explains.

The "charm of three," does not apply, however, in environments in which audiences believe the message source has no persuasion motive.

Consumers must have enough cognitive resources to draw an inference about the validity of the claims, Carlson says.

"We expect marketers will use this information to design clearer and more compelling messages," he says of the study.

"We also hope consumers will be aware of their tendency to see more claims skeptically and that they might endeavor to be skeptical of messages consisting of fewer than three claims."