Are Normative Appeals Moral Taxes? Evidence from a Field Experiment on Water Conservation

We investigate how normative appeals for water conservation drive behavioral change using a large-scale field experiment. Using a new social comparison that reduces the correlation between pre-treatment consumption and the difference from the peer group, we isolate the normative component of the message. The strength of the message, which we define as a household's performance relative to a peer group, is a primary driver of social comparisons' efficacy, consistent with social compar- isons imposing a moral cost on excess consumption. Relative to a nudge highlighting financial savings, social comparisons generate less persistent water savings and are more dependent on multiple mailers.