Bargaining outside the Lab - A newspaper experiment of a three person-ultimatum game

In November 2001, 5,558 readers of the German weekly Die Zeit participated in a three-person ultimatum experiment involving a proposer X, a responder Y, and a dummy Z (Guth and van Damme, 1998). A proposal is a vector (x,y,z) with x + y + z = DM 1,200, and x in {0, 200, 400, 600, 800, 1000}, and y, z in {100, 200, 300, 400, 500, 600}. Newspaper readers could participate via Internet, mail, or fax and had to decide in the role of X on the proposal and to indicate acceptance or rejection of any of the 18 different proposals in the role of Y. Response behavior is not always monotonic in the responder's share, suggesting that a substantial share of participants is intrinsically interested in a fair allocation. Participants using the Internet are more opportunistic than those using mail or fax, whereas older participants and women care more about fairness. Students behave similar to nonstudents of the same age group suggesting at least age group-specific external validity of experimental results relying on student participants.