Recently reviewed an interesting experiment conducted by Robery Cialdini of Arizona State University. The team were looking at ways at encouraging hotel guests to recycle their towels during their trip. 

Guests were given one of three reasons why they should chose to recyle on a card placed in their room:

1. For the sake of the environment.

2. For the sake of future generations.

3. Because the majority of guests did so.

The later, a form of peer pressure turned out to be the most successful strategy – 30% more effective than the other options.