Three is a Magic Number

Published: May 9, 2014

“You may have a host of compelling reasons to choose your product or service that you’d like to let people know about, but mentioning them all may actually lead consumers to discount your proposition entirely.”

Three is a magic number for the communications profession. To me, three has always just felt… right. I try to keep to three key points when I give presentations. I normally make three arguments in the blogs and essays I write. And yes, there have even been times when I’ve sat staring at my screen trying to think of a third, largely unnecessary, adjective that’ll really make a sentence pop. (And I just gave three examples, if you don’t count this one.)

A recent study sheds some light on why I’m not alone in my triadic obsession. US behavioural scientists Kurt A. Carlson and Suzanne B. Shu wanted to know how many positive claims should be used in marketing messages. They specifically looked at scenarios where people know they are trying to be persuaded by a product, service or argument – like reading new packaging for breakfast cereal, listening to a politician give a speech or even talking with a friend about rekindling a failed relationship with an ex-boyfriend. They then varied the number of positive claims used in the scenarios, from one to six.

What they found is that when up to three reasons are given people are likely to believe them. So when your friend tells you she is getting back with her old flame because he’s “intelligent, kind and funny” you assume he’s a catch. But when your friend says she’s together with her high school sweetheart again because he’s “intelligent, kind, funny and cute” you start wondering whether she’s kidding herself about him.

Similarly, when a cereal box’s packaging tells you that the brand is now “healthier, better tasting, crunchier, and with higher quality ingredients” you sniff a sales motive and are sceptical. But if the packaging uses just three of these claims, you are more likely to conclude that the cereal inside really is healthier, better tasting and crunchier. The conclusion is: if you use any more than three positive claims, people dismiss your message as too try-hard. Carlson and Shu called this effect the ‘charm of three’.

The lesson for marketing and communications professionals (as well as reconnected lovers) is: don’t overload your messages with positive claims. You may have a host of compelling reasons to choose your product or service that you’d like to let people know about, but mentioning them all may actually lead consumers to discount your proposition entirely. Stick to just three if you want to persuade.

Madeleine Crowther
Junior Consultant

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