Giving Back

Influencing the Norm

What persuasion science and the theory of social proof can teach us about what motivates people to do good - including your attendees.

We are bombarded with messages about conserving resources and helping the environment. One such message is presented in hotels across the country – that by using our towels more than once during our stay, we are helping to reduce the property’s water and detergent usage and conserve energy. But while a high percentage of hotels have a towel-reuse program in place (up to 83 percent, some studies show), guest participation is seriously lacking.

Robert Cialdini – president of Influence at Work, emeritus professor of psychology and marketing at Arizona State University, and bestselling author of Influence: The Psychology of Persuasion – has a theory about what influences people to take action to protect the environment. He says that people are more likely to do something not when they are presented with how large the problem is, with helping an organization be more green, or with conserving resources to help save future generations – but when they realize that other people who are like them are doing so.

To test this hypothesis with regard to towel reuse, Cialdini and his students conducted a study at an upscale hotel in the Phoenix area. No demographic information was collected about the guests for confidentiality reasons, but the study focused on single-occupancy rooms to ensure that only one guest was making the choice to reuse towels or not. Cialdini’s team created cards encouraging the reuse of towels with four different messages, and divided them among 260 rooms:

  • “Help Us Save the Environment,” with a message about respect for nature
  • “Help Save Resources for Future Generations,” with a message about the importance of saving energy for the future
  • “Partner With Us to Help Save the Environment,” with a message encouraging guests to cooperate with the hotel in preserving the environment
  • “Join Your Fellow Citizens in Helping to Save the Environment,” with a message indicating that the majority of guests who stayed in that particular room reused their towels. Cialdini found that the final message – called a descriptive social norm – increased towel reuse by 28.4 percent compared to the other cards.

The theory is called “social proof” – the idea that people make decisions based on what other people like them are doing – and it’s been found to be extremely effective at influencing decisions. The best way to help ensure that your attendees support your initiatives, for example, might be to tell them how many of their colleagues are doing so, not how great the problem is. “Meeting planners don’t want to say, ‘Because so many people in the past have been failing to engage in environmental practices at our meetings, we’ve decided to give people the option of doing the right thing,’” Cialdini said. “That just legitimizes the undesirable behavior.

“If you’ve got the data to say, ‘When we surveyed our membership, the great majority were in favor of undertaking green initiatives within our conferences’ – that tells people, oh, the people around me who are like me want me to do this thing.”

Understanding Persuasion

Why aren’t more organizations opting to use social proof in their messages and campaigns? It’s not entirely clear, but Robert Cialdini bets that it’s because people don’t recognize how powerful the influence of everyone around them can be, nor do they understand how persuasion science works. “People in organizations think they understand how [influence] works, because they live in a world where people are being persuaded all the time,” Cialdini said. “They would never say, ‘I live in a world of laws, therefore I’m going to decide what to do on our legal contracts.’ They’re going to get expert help from attorneys. They never do that with persuasion, because they think they know how it works. Well, they don’t, it turns out.”

More Resources
For more information about Robert Cialdini’s work and books, visit

Katie Kervin

Katie Kervin was formerly assistant editor of Convene.