Image Concerns in Pledges to Give Blood: Evidence from a Field Experiment

Abstract

We use a field experiment to study how social image concerns affect pledges to engage in a charitable activity. We work with two different blood banks and a municipal government in Germany to offer sign-ups for human whole blood donations. Motivated by a simple signaling framework, we randomly vary the type of organization to donate to and the visibility of the pledge. Our setting also provides natural variation in the group of people that form the “audience” for social image concerns. We find evidence for strong social image concerns when subjects are asked in public whether they would like to pledge a donation with a well-known charity. Almost all subjects renege on their pledge, with no detectable differences between treatments. We discuss avenues for further research and end on a cautionary note for organizations looking to harness pledges as nudges to do good.

Keywords: prosocial behavior, social image, commitment, incentives, field experiment

JEL Classification: C91, D64, H41, I18