In the late
1970's, political scientist
Robert Axelrod held a computer tournament designed to investigate the prisoner's dilemma situation. Contestants in the tournament submitted computer programs that would compete in an
iterated prisoner's dilemma game of approximately two hundred rounds. Each contestant's program played five iterated games against each of the other programs submitted, and after all games had been played the scores were tallied.
The winner of the contest was tit for tat: Clam up on the first round. On the next rounds, always do what the other prisoner did on the previous round. How's that for trust and cooperation.
A later tentative of Perl Journal promoting a contest on a three-way Prisoner's Dilemma was met with a somewhat of a failure: The winner program was aided by 'sucker' programs, that simply confessed all the time while it clammed up.
Book: Axelrod, The Evolution of Cooperation.
Link: http://itknowledge.com/tpj/contest-tpd.html