A problem in game theory first discussed by A. Tucker. Suppose each of two prisoners 
and 
, who are not allowed to communicate with each other, is offered
to be set free if he implicates the other. If neither implicates the other, both
will receive the usual sentence. However, if the prisoners implicate each other,
then both are presumed guilty and granted harsh sentences.
A dilemma arises in deciding the best course of action in the absence of knowledge of the other prisoner's decision. Each prisoner's best
strategy would appear to be to turn the other in (since if 
makes the worst-case assumption that 
will turn him in, then 
will walk free and 
will be stuck in jail if he remains silent). However, if the
prisoners turn each other in, they obtain the worst possible outcome for both.
Mosteller (1987) describes a different problem he terms "the prisoner's dilemma." In this problem, three prisoners 
, 
, and 
with apparently equally good records have applied for parole,
and the parole board has decided to release two, but not all three. A warder knows
which two are to be released, and one of the prisoners (
) asks the warder for the name of the one prisoner other than
himself who is to be released. While his chances of being released before asking
are 2/3, he thinks his chances after asking and being told "
will be released" are reduced to 1/2, since now either
and 
or 
and 
are to be released. However, he is mistaken since his chances remain 2/3.
The Season 1 episode "Dirty Bomb" (2005) of the television crime drama NUMB3RS mentions the Prisoner's dilemma.
