No one ever shows up at brunch and says, "Oh my gosh, I was so sober last night!"
Risky behavior draws attention. As a result, people tend to assume that everyone else is doing it more than they really are.
But, over the last two decades, research on college campuses has shown that giving students the real facts about their peers reduces unsafe drinking. This approach is called positive social norms. It works because of a basic truth of human nature: People want to do what others are doing.