How to convince people to wash their hands during flu season

Suppose there were signs in a restaurant bathroom telling customers that they must wash their hands. Would customers obey them? It really depends on the tone of the sign and whether the message praises or scolds, says a forthcoming study in the Journal of Marketing Research. According to the study, to persuade customers to behave in a certain way, businesses should praise with an assertive tone and scold with a non-assertive tone.