eldavojohn writes: "It's a well known situation and one often studied in everything from behavioral sciences to artificial intelligence. It involves the idea that cooperation is promoted by two or more individuals working together to achieve a return greater than working for their own interests. Scientists are now leaning toward the iterated snow drift game (ISD) replacing the iterated prisoner's dilemma (IPD) to accurately model what humans experience in real life. Essentially it removes the defective partner risk that is inherent in the IPD situation. If you are fingered by your friend while in separate interrogation rooms while you claim that both you and your friend are innocent, the outcome is much worse. In the ISD, your idle partner does not negate points from your efforts to work together — it just doesn't add anything either."