  Social distancing has been one of the core public policy measures used to
mitigate the economic and health impacts of the COVID-19 pandemic. Such
widespread adoption of social distancing measures is wholly unprecedented, and
governments have implemented a variety of policies to encourage compliance.
These typically rely on financial penalties (fines) and/or informational
messages (nudges). There is, however, a lack of evidence on the impact of these
policies. We examine the effectiveness of fines and nudges in promoting social
distancing in a web-based interactive experiment. The study involves a
nearrepresentative sample of 400 participants from the US population, and it
was conducted in May 2020 at the height of the pandemic. Fines significantly
promote distancing, but nudges only have a marginal impact. Political ideology
also has a causal impact -- progressives are more likely to practice
distancing, and are marginally more responsive to fines. Further, individuals
do more social distancing when they know they may be a superspreader. Our
results highlight the crucial role of web-based interactive experiments in
informing governments on the causal impact of policies at a time when lab
and/or field-based experimental research is not feasible.
