Prisoner’s Dilemma

Writing my last post on public transport etiquette prompted me to recall William Poundstone’s excellent book an game theory, ‘Prisoner’s Dilemma’.  Poundstone, in a very accessible manner, discusses the ideas behing game theory (a branch of mathematics developed by John Von Neuman), illustrating it terrifyingly with examples from the Cold War.

Deciding whether to get on the first bus, the crowded one that is already late, thus delaying it further, or waiting for the second, that is nearly empty and running ahead of time, is a dilemma. Do the former, and you’ll get to work a little quicker than you would if you did the latter. Do the second, and your journey takes a bit longer, but it is to the benefit of everyone else on the first bus, who aren’t delayed further by your boarding. The choice is yours. Our mathematician friends in Mexico are obviously going to try a publicity campaign for people to do the latter.

Public transport is perhaps a fairly trivial example – the stakes aren’t all that high. But you can imagine games where they are. The Cuban Missile Crisis could be considered as such a ‘game’ – a hideous one – no one wants a nuclear war (or maybe some people did / do?), but, if there is going to be one, isn’t it better to get your strike in first?  So, do you bomb your enemy off the map, or do you leave him alone, in the hope he will leave you alone?  I’m not suggesting the crisis was as simple as that – but you get the idea. Poundstone develops this discussion wonderfully.

N.B. Prisoner’s Dilemma, the title of Poundstone’s book, is another game – possibly I’ll discuss it later. If you’d like to know what it is, and ‘play’ against your friends, the rules are well-laid out on Wikipedia.

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