Sentence:  All this experimentation is yielding insights into which <WSD>nudges</WSD> give the biggest shove. One question is whether nudges can be designed to harness existing social norms. In Copenhagen Pelle Guldborg Hansen, founder of the Danish Nudging Network, a non-profit organisation, tested two potential “social nudges” in partnership with the local government, both using symbols to try to influence choices. 
Meaning of the word marked with <WSD> tags:  The use of positive reinforcement and indirect suggestions as ways to influence.