We study an ultimatum experiment in which the responder does not know the offer when accepting or rejecting. Unconditional veto power leads to acceptances, although proposers are significantly greedier than in standard ultimatum games, and this is anticipated by responders.

We study an ultimatum experiment in which the responder does not know the offer when accepting or rejecting. Unconditional veto power leads to acceptances, although proposers are significantly greedier than in standard ultimatum games, and this is anticipated by responders.

Retributive responses do play a role in human behavior. Whether they are primarily triggered by supposed intentions or by observed consequences of actions is an important question. It can be addressed by experimental studies of retributive responses in situations in which the individual actor...

Fairness is a strong concern as shown by dictator and ultimatum experiments. Efficiency, measured by the sum of individual payoffs, is a potentially competing concern in games such as the prisoners' dilemma. In our experiment participants can increase efficiency by gift giving. In the one-sided...