The prisoner’s dilemma is a concept used to help explain situations in which individual actors may pursue their own self-interest even in situations where they would all be better off if they cooperated and acted for the good of the group. In this short video posted at Scientific American, Michael Moyer explains the prisoner’s dilemma puzzle and how it helps explain situations such as the global nuclear arms race:

See also: Game Theory and the Prisoner’s Dilemma.