Glossary
Social proof
What is social proof?
Social proof is using other people's choices as a cue for what to do. A popular action may look like a sensible choice. Popularity alone does not make it right for you.
Research example
Experiment 1: the norm message
Goldstein, Cialdini, and Griskevicius tested signs at a midpriced hotel in the southwestern United States. In experiment 1, the environmental sign asked guests to conserve resources by reusing towels. The social-norm sign additionally said that almost 75 percent of guests participated. Reuse was 44.1 percent with the norm sign versus 35.1 percent with the environmental sign: 9 percentage points, or about 26 percent higher relative to 35.1 percent.
Experiment 2: the reference group
Experiment 2 changed the reference group. A sign stating that 75 percent of previous guests in that particular room reused towels produced 49.3 percent reuse, compared with 42.8 percent across the other three norm-message conditions combined. That is 6.5 percentage points, or about 15 percent higher in relative terms.
What the researchers measured
Researchers counted whether at least one towel was reused on the first eligible day among guests staying two nights or longer. The advertised participation percentage referred to reuse during a stay, a different measure. These are results for particular signs and conditions, not a universal expected gain.
Using the idea
Specify whose behavior the message describes, make sure the claim is accurate, and measure the outcome. Do not invent a crowd to make a choice look popular.
The hotel findings concern those messages and that behavior. Their effects can differ across hotels, websites, and products.