Have you ever noticed the "reuse your towels" cards in your hotel room? They typically show a beautiful vista with copy describing how reusing your towel will save energy, water, and, by extension, the environment. Are you convinced? Do you reuse your towels? Most people don't.

The hotel industry seemed to think that "some do" was good enough, though. Perhaps hotel executives thought they'd hit a compliance ceiling? So they continue (today!) to print the same cards with the same pictures and the same largely unpersuasive message.
Researchers Goldstein, Cialdini, and Griskevicius, however, felt that it was the hook ("Do this to save the earth.") not the sentiment ("save the earth") that was weak. They hypothesized that knowing that other people had done it would evoke greater compliance than just saving the earth.2
To test their hypothesis, Goldstein and team created two sets of request cards that contrasted the original conservationist message with a new social proof motivator message. The gist of the messages (although not the actual messages) were:
- Original conservationist message:
Reuse your towels. It will save the earth.
- Social proof message: Reuse your towels. Everybody's doing it.
Then they worked with hotel staff to distribute the cards throughout the rooms. And then waited to see who reused their towels and who didn't.
The result was impressive. Hotel guests who saw the "Everybody's doing it" message reused their towels 26% more than those who saw the "Save the earth" message. That represents a 26% increase over the accepted industry standard.
The researchers wondered if a shared social proof appeal could be even more persuasive through similarity. So they ran the study again. This time they included a third treatment variation, which essentially conveyed, "People in exactly your situation – who stayed in the same hotel room – have reused their towels." Their hunch was that knowing that people who had stayed in the room had participated in the desired behavior would add even more social pressure to comply.
Again they were correct. Individuals exposed to the same-room-social-proof motivator message were 33% more likely to reuse their towels than individuals in the conservationist message rooms.
It seems that the closer to home (away-from-home) the social comparison is, the more effective it is. |