Experimentalists have tried to understand what could increase cooperation in games such as a prisoners' dilemma game. Charness, Frechette and Qin allow for side payements. Dal Bo and Dal Bo show that moral messages have a significant but temporary effect. Goette, Huffman and Meier, in a very interesting paper, show that if people are assigned to some groups, cooperation will be higher between two members of the same group than two members of different groups. You also have papers using trust games, typically of the form:
one agent, the “trustor” (A), can sendsomeor none of anendowmentprovided by the experimenter to another agent, the “trustee” (B), who receives triple the amount sent.Bcan then returnsomeornoneofwhathe or she received to A.Ben Ner, Putterman and Ren show that two-way communication improves trust(and trustworthiness) substantially. Charness and Dwufenberg find that the content of the communication is important: bare promises are as good as no communication at all. And that goes on and on.
All this is all good, but here is a more efficient way to prove your willingness to cooperate, provided by Filipino politicians. The background story is that the former president, Gloria Arroyo, is reportedly sick and cannot get treatment for her ailment in the Philippines. She wants to leave, but the current government is afraid she will not come back because of some potential corruption cases against her. Her husband's lawyer found the way to make her return credible:
Earlier in the week, Ferdinand Topacio, the lawyer for Mrs. Arroyo’s husband, said in a television interview that he was so confident that his clients would return if allowed to leave that he would have one of his testicles removed if they did not.
After the arrest warrant was issued on Friday, Edwin Lacierda, a presidential spokesman, said: “The order in the Pasay court has allowed Attorney Topacio to save his family jewels.”.