Nudging the electorate : what works and why?

Policymakers are increasingly interested these days in how they can achieve desired outcomes using 'nudges' - low-cost and non-obtrusive interventions which rely on psychological mechanisms, rather than high-powered economic incentives, to influence people's behaviour. This paper applies the concept of nudging to voter registration. The authors are interested not only in which types of nudge are successful in inducing citizens to register to vote, but also the reasons why some nudges might work while others might not. To address these questions, the researchers teamed up with Oxford City Council and ran a field experiment, ahead of the 2015 UK General Election, whereby postcards were sent to 7,679 unregistered students living in the city. All postcards encouraged students to register to vote, but the precise messages they featured varied. Results showed that, relative to a baseline message, a message emphasising the possibility of incurring a small fine for failing to register increased the likelihood of the postcards' recipients registering. However, messages offering a small possibility of financial reward for registering, along with those which attempted to use purely non-monetary persuasion strategies, were not effective in raising registration. In a separate experiment, the authors also showed that the differences in these interventions' successfulness could be partly explained by their effects on social norms: emphasising the possibility of being fined for failing to register strengthened the perceived social norm that one ought to register, while offering money for registering weakened it.