The prisoner’s tie-breaker

That annoying prisoner & his dilemma crop up in far too many places these days. Perhaps there is a solution before which all will one day bow down & worship its discoverer; more likely it will join Achilles & the tortoise & those lying Cretans in the pantheon of the insoluble.

The real lifer probably has a tie-breaker to fall back on. What would Mum want me to do? What will my criminal friend’s nasty associates do to my family if I snitch?

Or a rule of thumb to be relied upon: Never trust the word of a policeman; when you get cornered, keep schtum.

Or an ancient principle: Do not do to others what you would not do to yourself.

Of course the person who set the poser may not understand the context in which this particular prisoner makes his decision – maybe his life outside is so awful, or the local prisons so cushy, that incarceration would be the preferred option (not that this changes the dilemma, just switches it all around).

In the real world people tend to learn – often over a long period time – how best to solve such a problem if it is one that faces many people day after day. Take driving for example.

I marvel at the cast of mind which keeps people working away at it.

And I wonder if psychologists have ever have consulted experimental subjects to gather empirical data about whether real people analyse the problem in a truly rational way, whether children respond differently than adults.

But how curious that the supposed tension between stories & statistics, between imagination & hard rationality is somehow central to making these knotty theoretical problems so attractive & annoyingly frustrating to such a wide range of would-be solvers. Few would get excited by a dilemma posed in the notation of probability & mathematical logic.