Experimental evidence of self-image concerns as motivation for giving

We conduct an experiment in which subjects make a series of decisions of allocating an endowment of £10 between themselves and a passive recipient that is either a charity or the experimenter. When making these decisions 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 around one third of subjects choose to opt out. The fact that a subject decides to revise a decision to give and chooses instead to exit and 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 indicates that giving is also motivated by self-image concerns.