Abstract
This paper presents evidence from a field experiment, which aims to identify the two sources of workers' pro-social motivation that have been considered in the literature: warm glow altruism and pure altruism. We employ an experimental design that first measures the level of effort exerted by student workers on a data entry task in an environment that elicits purely selfish behavior and we compare it to effort exerted in an environment that also induces warm glow altruism. We then compare the latter to effort exerted in an environment where both types of altruistic preferences are elicited. We find evidence that women increase effort due to warm glow altruism while we do not find any additional impact due to pure altruism. On the other hand, men in our sample are not responsive to any of the treatments. (C) 2010 Elsevier B.V. All rights reserved.