Assuming both prisoners are
rational: Suppose if one
prisoner confesses and the other stays silent, the confessor will be sentenced to 0 months in
prison, and the other will get 9 months in prison. If they both
confess, they both serve 6 months. If they both stay silent, they both serve one month.
If one suspect is going to
confess, the other would prefer to confess and stay in jail for 6 months rather than stay
silent and be in jail for 9 months. If one suspect is going to stay silent, then the other would prefer to confess, and be released
immediately rather than be silent and stay in jail for one month.
For some, this goes against
common sense, as the solution which has the most greater good is when both stay silent, as the total
jail time would be minimized, while the
situation that
occurs when both confess has the most total jail time.
This dilemma helps illustrate the practical applications of
game theory to problems like the
arms race or
oligopolistic competition.