Dr. Robert Cialdini is a psychology professor at Arizona State University who has conducted some interesting research studies with the help of his students. In the “hotel towel test”, he changed the language on signs in hotel rooms urging guests to reuse their towels. Compared to no sign, adding a standard message about “have concern for the environment” increased reuse 30%. But when the wording was revised to “three-quarters of the guests staying in this hotel reuse their towels” reuse increased to 44%. And when it was revised to “three-quarters of the guests staying in this room reuse their towels” reuse increased to nearly 50%.
In an interview with the American Psychological Association, Cialdini attributed these results to social proof: “If this is what people around you have decided is a good choice, it’s a great shortcut for you to determine what’s a good choice.” He cites a study by a Beijing restaurant in which a restaurant put on the menu, “these are our most popular items” and the items immediately became 17-20% more popular.
I thought about these results while working on a project in a new field for me, making requests for donations from college alumni. For the typical school well under half the alumni make gifts, so it’s fair to assume the ones who do give were happy with their experience or at least felt it was worthwhile. Thus the formula is to generate a mental picture of those halcyon college years for the reader, then tell them they can make the same thing possible for someone through their gift. You and your classmates were fortunate, therefore you should allow a new or current student to be fortunate.
Cialdini has another study in which the results backfired from what was desired, while upholding the principle of social proof. He distributed bits of petrified wood in the Petrified Forest Natural Park and tested signs admonishing visitors not to remove them. In situations where there was no sign at all, 2.92% of the pieces disappeared.
When a sign was added with a picture of several visitors taking wood and the caption “many past visitors have removed the petrified wood from the park, changing the natural state of the Petrified Forest”, theft actually increased to 7.92%. As copywriters we know this flabby third-party syntax is unlikely to persuade anybody, but what it does is introduce the concept of stealing wood to somebody who had not previously thought about it. And the social proof is that “many” visitors do this, so you should too.
A third sign showed a single visitor with a “no” symbol over his hand and the caption “please don’t remove the petrified wood from the park, in order to preserve the natural state of the Petrified Forest”. This reduced theft modestly, to 1.67% vs 2.92% for the control with no sign at all. It’s a direct request and clearly shows what not to do, but it’s not really social proof but a one-to-one message. What if the sign had said, “97 out of 100 visitors enjoy the park without disturbing its beauty. Thank you for preserving the natural state of the Petrified Forest”?
Cialdini summed up in an interview on NPR: “When we are uncertain about whether to be altruistic or pro-social or environmentally conscious, we look around us for the answer. We don’t look inside ourselves. We are all swept by the power of the crowd.”