Prisoner's Dilemma

02What People Think

“If cooperation leaves both of us better off, choosing it should be straightforward.”

03What’s Underneath

Imagine two adult siblings caught eating a cake intended for a party. Their parent gives each the same private offer: if neither blames the other, each washes dishes for one day; if only one blames the other, the accuser does no washing and the other washes for seven days; if both accuse, each washes for three days.

For either sibling, accusing reduces their own punishment regardless of what the other does. Yet mutual accusation produces three days each, worse for both than the one day each they would receive by cooperating. That ordering of incentives makes the situation a prisoner’s dilemma. A story about mistrust alone is not enough.

The model separates an individually attractive move from a better joint outcome. Repeated encounters, communication, enforceable agreements or concern for the other person can change the situation. Those additions matter because the original problem comes from the specified choices and consequences, not from an assumption that people always behave selfishly.

04The Game

Does each person gain by defecting whatever the other chooses, while both prefer mutual cooperation to mutual defection? If either condition is missing, the conflict may be a different game.