Experimental evidence of self-image concerns as motivation for giving

In this paper we present evidence of self-image concerns in charitable giving using a laboratory experiment. Subjects make a series of three decisions of allocating an endowment of £10 between themselves and a passive recipient that is either a charity or the experimenters. When making these decision subjects are informed that one of them will be chosen randomly at the end to determine payoffs. After all decisions have been made and it has been revealed which decision will determine payoffs we offer subjects an opportunity to opt out from their initial decision and receive £10 instead. We find that almost a quarter of subjects choose to opt out, while around one third opt out from a positive donation. The fact that a subject decides to revise a decision to give and chooses instead to keep the whole amount – an option that was available when she made the first decision and was not exercised – indicates that giving in the first instance was not motivated solely by altruism toward the recipient. We argue that opting out can be explained through a combination of a reduced benefit of self-signaling due to satiation, and an increase in the costs of giving at the opt out stage, as they are realized with certainty.