Prisoner’s Dilemma
The prisoner’s dilemma models a situation where two partners in crime are interrogated separately and must independently choose to co-operate (stay silent) or defect (betray the other). Mutual co-operation gives each a light sentence, but if one defects while the other co-operates, the defector walks free and the co-operator gets the maximum penalty; if both defect, they both get medium sentences. Because each person’s best individual move is to defect—regardless of what the other does—the game captures how rational self-interest can lead to an outcome that’s worse for everyone than mutual trust would have produced.
