Quick test. Which shampoo sounds better to you?
“Makes hair cleaner, stronger and shinier.”
Or “Makes hair cleaner, stronger, healthier, softer, shinier and fuller.”
If you picked the first one, congratulations, you’re normal!
Researchers at UCLA and Georgetown tested exactly this. They showed people ads with anywhere from one to six positive claims about a shampoo, a cereal, even a politician. Impressions got better with each claim, right up to the magic number: three. At four claims, people got sceptical and started doubting all of them, including the good ones.
We slip past the 3rd benefit all the time, thinking that we’re building a better case. We want the proposal to stand out - so we list 5 incredible benefits - making it quite literally incredible.
I hope you found this blog: interesting, compelling and applicable and cool.
Source: Shu, S. B., & Carlson, K. A. (2014). When Three Charms but Four Alarms: Identifying the Optimal Number of Claims in Persuasion Settings. Journal of Marketing, 78(1), 127–139.