No Prisoner’s Dilemma on the Western Front

Robert Axelrod’s story of how cooperation developed between British and German soldiers in the trench warfare of World War I is so elegant few people have questioned it.  Yet in a single sentence, Andrew Gelman says the emperor has no clothes and looky, looky, he’s right!

The crux of Axelrod’s story is that the soldiers were trapped in a prisoner’s dilemma: individual incentives were to shoot the enemy while the socially optimal outcome was cooperation.  Axelrod then introduces his famous ideas of tit for tat etc. etc. to explain how cooperation could evolve even under these most hostile of conditions.

But Gelman asks why should we think that shooting the enemy was in a soldier’s best interest?  Indeed,

…it seems more reasonable to
suppose that, as a soldier in the trenches, you would do better to avoid firing: shooting
your weapon exposes yourself as a possible target, and the enemy soldiers might
very well shoot back at where your shot came from.

I believe that on this point Gelman is totally correct [insert dope slap here].  But, as he continues, "If you have no
short-term motivation to fire, then cooperation is completely natural and
requires no special explanation."

Axelrod’s story and the large literature following it sometimes suggest that cooperation is always the thing to be explained.  Cooperation is what happens when the natural order is overcome.  Gelman reminds us that sometimes cooperation is the norm, it’s conflict that needs to be explained.  In this case, we need to explain why the soldiers fought. 

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