After reading flagamuffin's recent post about prisoners, it makes a lot of sense that they would be more willing to work cooperatively than students. It just seems like cooperation has become engrained in them for survival. I mean people sacrificed food for months. Points/money is nothing compared to that. Another factor is assumptions of selfishness/selflessness. Humans are typically pretty selfish in their ways but you can't be selfish in prison. With gang ties, race ties, etc. prisoners are, more often than not, working cooperatively or following orders rather than acting on their own will. Because of this, prisoners could be more likely to assume that the other prisoner is of the same mindset and be more willing to chose A. Students assume the other is being selfish (just like they are).