When are nudges most effective? A study by Pelle Guldborg Hansen, founder of the Danish Nudging Network, a non-profit organisation in Copenhagen, suggests that nudges may work only if they are in line with social norms. They tested two potential “social nudges” in partnership with the local government, both using symbols to try to influence choices:
– In one trial, green arrows pointing to stairs were put next to railway-station escalators, in the hope of encouraging people to take the healthier option. This had almost no effect.
– The other experiment had a series of green footprints leading to rubbish bins. These signs reduced littering by 46% during a controlled experiment in which wrapped sweets were handed out.
“There are no social norms about taking the stairs but there are about littering,” said Mr Hansen. Hence, perhaps existing social norms must be studied before designing a nudge!