Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We examine motivations for prosocial behavior using new data on volunteer firefighters that contain a dictator game based measure of altruism, surveyed measures of other behavioral factors, and call records that provide an objective measure of time spent volunteering. Controlling for a variety of other explanations, we find that the decision to volunteer is positively correlated with altruism as well as with concern for social reputation or "image." Moreover, by utilizing variation in the presence and level of small stipends paid to the firefighters, we find that the positive effect of monetary incentives declines with image concerns, supporting a prediction that extrinsic incentives can crowd out image motivation for prosocial behavior.