Hotel guests can be gently persuaded to reduce the number of towels they use each day, psychology researchers at the University of Luxembourg have found. With fewer towels to wash, this reduces the waste of water, energy and detergent（清洁剂）. This is good news for the environment and it cuts costs, so enabling hotels to reduce prices. Two hotels in Swiss and Austrian ski resorts helped with an experiment in early 2013. Three different signs were placed separately in different bathrooms, all of which gently reminded guests of the environmental impact of towel use. However, one of the signs added that: "75% of guests in this hotel reuse their towels" with another sign talking of: "75% of guests in this room" reusing. 132 guests participated in this field experiment. Signs were in German and English, so would have been understood by guests in these Alpine resorts.

"We found that guests cut their towel use significantly when told of the behavior of previous guests in their room," said the lead researcher Dr Gerhard Reese. In the "room" scenario, guests used, on average, one towel per person per day. This compared with 1.6 towels per person per day for those told of behavior in the hotel as a whole. This amounted to a 40% saving in the number of towels needing to be washed.

Subtle social pressure

These results are consistent with a handful of similar studies conducted in the USA. "Humans are social beings," explained Dr Reese. "People want to be accepted into groups and so we act in ways that make us belong. Instinctively, we feel close to those who have used a hotel room before us, believing that they are similar to ourselves. Thus we are more likely to follow their behavior."

This research points to the possibility of finding other ways to persuade people to do the right thing using such subtle pressure.