“Please help us save the environment.”
Several hotel bathrooms carry a sticker with that headline. It tries to convince guests to reuse towels during their stay, telling them how many liters of water they would save in the process. It then informs guests to leave towels on the stand if they wished to reuse it or to leave them on the floor if they wanted them replaced.
The hotel’s notice is clever because it pits one norm against the other to drive behaviour change. Hotels normally provide their guests with fresh towels every day. Further, guests normally leave towels on the stand and not on the floor. By using one norm (leaving towels on stands) the hotel nudges their guests to change another (to fresh towels every day).
Behaviour change is hard and well designed nudges often lend a helping hand. One effective way to design a nudge is to utilize one norm to counter another.