The Prisoner's Dessert

[billroper]

So I was having dinner with Katie and agreed to split a dessert with her.

While we were waiting for the dessert to arrive, Katie started making fake gobbling motions with her hand and mouth, indicating to me that she intended to eat it as fast as possible so that she would get a larger share and I would not.

"This is a problem in game theory," I told her. "Have you ever heard of the Prisoner's Dilemma?"

No, no, she had not.

And I proceeded to explain how the problem of sharing the dessert was, in fact, the same as the classic case of the Prisoner's Dilemma. If each of us ate slowly and savored our dessert, then we would both arrive at a good outcome. If one of us defected and started gobbling down the dessert, then they would be slightly better off, because they would get much more of the dessert, but the other one would be much worse off, because they would not get their fair share of the dessert. This would mean that he (that would be me) would have to defect as well and start gobbling down the dessert, and now each of us would enjoy it less, while still ending up with the same amount of dessert.

The dessert was consumed slowly, evenly, and properly savored. :)

It is good when game theory has real life applications...

Comments

[madfilkentist]

There's an important difference, of course. In Prisoner's Dilemma, the prisoners can't communicate, and neither one knows the other's decision till it's too late. With table manners and most other real-life situations, you have information on what the other person is doing and can change your strategy accordingly.

[tigertoy]

What makes the prisoner's dilemma actually interesting is when you extend the single game to understanding of how past history affects current choices. In this case, if Katie gobbles down the dessert and doesn't let you have any, next time there won't *be* dessert...