Ian Ayres notes that people conform, and — as Robert Cialdini emphasizes in Yes! — they like to conform to what they think other people are doing:
One of my favorite examples of the powerful urge to conform with the majority comes from an experiment he ran at Arizona’s Petrified Forest National Park. Conformity theory suggests the park service was sending exactly the wrong message when it posted signs saying:
Here’s how his paper describes the experiment:
We gained permission from Petrified Forest National Park officials to place secretly marked pieces of petrified wood along visitor pathways.
Over five consecutive weekends, Cialdini and coauthors varied the signs seen at the entrance to each path. Some weekends, visitors saw a sign that, like the original park-service sign, emphasized the wrong norm:
Many past visitors have removed petrified wood from the park, changing the natural state of the Petrified Forest.
This wording was accompanied by pictures of three visitors taking wood.
Other weekends, visitors saw:
Please don’t remove the petrified wood from the park, in order to preserve the natural state of the Petrified Forest.
This wording was accompanied by a picture of a lone visitor stealing a piece of wood, with a red circle-and-bar symbol superimposed over his hand.
Sure enough the “many past visitors” framing lead to more than four times the amount of pilfering of petrified wood (7.92 percent vs. 1.67 percent). But what’s truly amazing is that putting up no sign at all did a better job than putting up a sign suggesting that “everybody does it”:
In a finding that should petrify the National Park’s management, compared with a no-sign control condition in which 2.92 percent of the pieces were stolen, the social-proof message resulted in more theft (7.92 percent). In essence, it almost tripled theft. Thus, theirs was not a crime prevention strategy; it was a crime promotion strategy. (Yes!, p. 22)