Pledges as a Social Influence Device: Experimental Evidence.

Summary This paper reports the results from a two-person "pledge and give" experiment. Each person’s endowment is private information available only to him. In the first stage, each agent informs the other about the amount he intends to give, or makes a pledge. In the second stage, each agent makes a contribution to the joint donation. A simple theoretical model shows that in this game the equilibrium pledge function is linear in the endowment of each agent. Furthermore, if agents have a strong taste for conformity, the optimal gift is positively related to one’s own endowment and to the pledge of his partner. Data from the lab experiment show that, indeed, subjects pledge approximately 60% of their endowment. Also, pledges have an important social influence role: an agent will increase his donation by 20 cents on average if his partner pledges one more euro.