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When Three Charms but Four Alarms

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Following the financial crisis in spring 2009, four banks were eager to announce their earnings.

The first three banks to make announcements, which were better than expected, immediately saw their stocks rise. When a fourth bank announced their earnings, the stocks of all four banks plummeted.

In a paper forthcoming in the Journal of Marketing, “When Three Charms but Four Alarms: Identifying the Optimal Number of Claims in Persuasion Settings,” Georgetown McDonough Associate Professor Kurt Carlson and his co-author (Suzanne Shu) report that people, firms, and products do better by presenting three positive claims than presenting four or more. In the study, Carlson discusses how an individual’s impression of something fits a pattern referred to as the “charm of three,” in which three positive claims creates a more positive impression than two claims or four or more. This phenomenon provides invaluable insight to marketers for understanding consumer perceptions, inferences and persuasion techniques as well as prescriptive advice to improve messaging.

“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,” said Carlson. “But there is danger to that as consumers’ awareness of persuasive intent will convert into skepticism, causing the consumer to discount all claims.”

Whether it’s a corporation selling a product, politician running for election, or firm promoting new services, there is a tipping point of positive claims for target audiences. While this pattern illustrates that three dimensions are sufficient to draw a conclusion, this effect occurs only when observers know the message is an attempt to persuade and where the observer has the ability to draw the skepticism inference.

The Role of Persuasion Knowledge
In settings where consumers know that the message source has a persuasion motive, the optimal number of positive claims is three. When the fourth claim is made, consumers’ persuasion knowledge makes them skeptical of all claims. Consumers feel that four or more positive claims communicates that the persuader is trying too hard to create a positive impression. However, in environments where audiences believe the message source has no persuasion motive, the ‘charm of three’ does not apply.

The Cognitively Depleted Consumer 
The ‘charm of three’ requires that consumers have enough cognitive resources to draw an inference about the validity of the claims. When consumers are cognitively depleted (due to their engagement in a cognitively taxing secondary task) the ‘charm of three’ does not (i.e., adding claims beyond three improves impressions).

Advice to Marketers
Whether selling consumer goods, discussing interpersonal communications or promoting service providers, marketers can use the ‘charm of three’ to minimize skepticism and maximize positive impressions. When selling consumer goods, marketers should list only three positive claims on packaging. Marketers also can create more effective messaging in distracting environments by listing more than three positive claims on channels such as billboards on the side of highways or signage in busy retail spaces. When considering omnichannel marketing, marketers should send claims through channels that are perceived as having different sources to avoid potential skepticism.